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Sample records for seawater

  1. Nature/culture/seawater.

    PubMed

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory. PMID:21560270

  2. Nature/culture/seawater.

    PubMed

    Helmreich, Stefan

    2011-01-01

    Seawater has occupied an ambiguous place in anthropological categories of "nature" and "culture." Seawater as nature appears as potentiality of form and uncontainable flux; it moves faster than culture - with culture frequently figured through land-based metaphors - even as culture seeks to channel water's (nature's) flow. Seawater as culture manifests as a medium of pleasure, sustenance, travel, disaster. I argue that, although seawater's qualities in early anthropology were portrayed impressionistically, today technical, scientific descriptions of water's form prevail. For example, processes of globalization - which may also be called "oceanization" - are often described as "currents," "flows," and "circulations." Examining sea-set ethnography, maritime anthropologies, and contemporary social theory, I propose that seawater has operated as a “theory machine” for generating insights about human cultural organization. I develop this argument with ethnography from the Sargasso Sea and in the Sea Islands. I conclude with a critique of appeals to water's form in social theory.

  3. SRB seawater corrosion project

    NASA Technical Reports Server (NTRS)

    Bozack, M. J.

    1991-01-01

    The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

  4. Uranium from seawater

    SciTech Connect

    Gregg, D.; Folkendt, M.

    1982-09-21

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10/sup 5/, which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10/sup 3/ in seawater instead of the reported values of 10/sup 5/. However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10/sup 5/ in fresh water. However, the system was not tested in seawater.

  5. Seawater Chemistry Package

    2005-11-23

    SeaChem Seawater Chemistry package provides routines to calculate pH, carbonate chemistry, density, and other quantities for seawater, based on the latest community standards. The chemistry is adapted from fortran routines provided by the OCMIP3/NOCES project, details of which are available at http://www.ipsl.jussieu.fr/OCMIP/. The SeaChem package can generate Fortran subroutines as well as Python wrappers for those routines. Thus the same code can be used by Python or Fortran analysis packages and Fortran ocean models alike.

  6. Glyphosate persistence in seawater.

    PubMed

    Mercurio, Philip; Flores, Florita; Mueller, Jochen F; Carter, Steve; Negri, Andrew P

    2014-08-30

    Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard "simulation" flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25 °C in low-light was 47 days, extending to 267 days in the dark at 25 °C and 315 days in the dark at 31 °C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.

  7. Recovery of uranium from seawater

    SciTech Connect

    Sugasaka, K.; Katoh, S.; Takai, N.; Takahashi, H.; Umezawa, Y.

    1981-01-01

    Seawater contains various elements in solution. Deuterium, lithium, and uranium are the important ingredients for energy application at present and in the future. This paper deals with the recovery of uranium from seawater, with emphasis on the development of an adsorbent with high selectivity and rate of adsorption for uranium. Polyacrylamidoxime chelating resins were synthesized from various co-polymers of acrylonitrile and cross-linking agents. The resulting resins with the chelating amidoxime group showed selective adsorption for uranium in seawater. The amount of uranium adsorbed from seawater at room temperature reached 3.2 mg/g resin after 180 days. Polyacrylamidoxime fiber, which was prepared from polyacrylonitrile fiber and hydroxylamine, showed a high rate of adsorption for uranium. The polyacrylamidoxime fiber conditioned with 1 M HC1 and 1 M NaOH adsorbed 4 mg U/g fiber from seawater in ten days. 9 figures, 6 tables.

  8. Seawater transport during coral biomineralization

    NASA Astrophysics Data System (ADS)

    Gagnon, Alexander C.; Adkins, Jess F.; Erez, Jonathan

    2012-05-01

    Cation transport during skeletal growth is a key process controlling metal/calcium (Me/Ca) paleoproxy behavior in coral. To characterize this transport, cultured corals were transferred into seawater enriched in the rare earth element Tb3 + as well as stable isotopes of calcium, strontium, and barium. Subsequent NanoSIMS ion images of each coral skeleton were used to follow uptake dynamics. These images show a continuous region corresponding to new growth that is homogeneously enriched in each tracer. Isotope ratio profiles across the new growth boundary transition rapidly from natural abundance ratios to a ratio matching the enriched culture solution. The location of this transition is the same for each element, within analytical resolution. The synchronous incorporation of all these cations, including the dissimilar ion terbium, which has no known biological function in coral, suggests that: (1) there is cation exchange between seawater and the calcifying fluid, and (2) these elements are influenced by similar transport mechanisms consistent with direct and rapid seawater transport to the site of calcification. Measured using isotope ratio profiles, seawater transport rates differ from place to place on the growing coral skeleton, with calcifying fluid turnover times from 30 min to 5.7 h. Despite these differences, all the elements measured in this study show the same transport dynamics at each location. Using an analytical geochemical model of biomineralization that includes direct seawater transport we constrain the role of active calcium pumping during calcification and we show that the balance between seawater transport and precipitation can explain observed Me/Ca variability in deep-sea coral.

  9. Neodymium isotopic variations in seawater

    NASA Technical Reports Server (NTRS)

    Piepgras, D. J.; Wasserburg, G. J.

    1980-01-01

    Direct measurement of the isotopic composition of Nd in the Atlantic agree with the Nd content in ferromanganese sediments and differ from the observed amounts in the Pacific samples. These data indicate the existence of distinctive differences in the isotopic composition of Nd in the waters of major oceans; the average values determined from seawater and ferromanganese sediments are considerably lower than in sources with oceanic mantle affinities showing that the REE in the oceans is dominated by continental sources. The Nd isotopic variations in seawater are applied to relate the residence time of Nd and mixing rates between the oceans.

  10. Gases in Seawater

    NASA Astrophysics Data System (ADS)

    Nightingale, P. D.; Liss, P. S.

    2003-12-01

    production and consumption, photochemistry, air-sea exchange, and vertical mixing. We will not discuss the effect of vertical mixing on gases in seawater and instead refer the reader to Chapter 6.08. Nor will we consider the deeper oceans as this region is discussed in chapters on benthic fluxes and early diagenesis (Chapter 6.11), the biological pump (Chapter 6.04), and the oceanic calcium carbonate cycle (Chapter 6.19) all in this volume. We will discuss the cycling of gases in surface oceans, including the thermocline, and in particular concentrate on the exchange of various volatile compounds across the air-sea interface.As we will show, while much is known about the cycling of gases such as CO2 and DMS in the water column, frustratingly little is known about many of the chemical species for which the ocean is believed to be a significant source to the atmosphere. We suspect the passage of time will reveal that the cycling of volatile compounds containing selenium and iodine may well prove as complex as that of DMS. Early studies of DMS assumed that it was produced from a precursor compound, dimethylsulfoniopropionate (DMSP), known to be present in some species of phytoplankton, and that the main sink in the water column was exchange across the air-sea interface. We now know that DMSP and DMS are both rapidly cycled in water column by a complex interaction between phytoplankton, microzooplankton, bacteria, and viruses (see Figure 1). Some detailed process experiments have revealed that only ˜10% of the total DMS produced (and less than 1.3% of the DMSP produced) is transferred to the atmosphere, with the bulk of the DMS and DMSP, either being recycled in the water column or photo-oxidized (Archer et al., 2002b).

  11. Faraday's Law and Seawater Motion

    ERIC Educational Resources Information Center

    De Luca, R.

    2010-01-01

    Using Faraday's law, one can illustrate how an electromotive force generator, directly utilizing seawater motion, works. The conceptual device proposed is rather simple in its components and can be built in any high school or college laboratory. The description of the way in which the device generates an electromotive force can be instructive not…

  12. Isotopic composition of Silurian seawater

    SciTech Connect

    Knauth, L.P.; Kealy, S.; Larimer, S.

    1985-01-01

    Direct isotopic analyses of 21 samples of the Silurian hydrosphere preserved as fluid inclusions in Silurian halite deposits in the Michigan Basin Salina Group yield delta/sup 18/O, deltaD ranging from 0.2 to +5.9 and -26 to -73, respectively. delta/sup 18/O has the same range as observed for modern halite facies evaporite waters and is a few per thousand higher than 100 analyses of fluid inclusions in Permian halite. deltaD is about 20 to 30 per thousand lower than modern and Permian examples. The trajectory of evaporating seawater on a deltaD-delta/sup 18/O diagram initially has a positive slope of 3-6, but hooks strongly downward to negative values, the shape of the hook depending upon humidity. Halite begins to precipitate at delta values similar to those observed for the most /sup 18/O rich fluid inclusions. Subsequent evaporation yields progressively more negative delta values as observed for the fluid inclusions. The fluid inclusion data can be readily explained in terms of evaporating seawater and are consistent with the degree of evaporation deduced from measured bromide profiles. These data are strongly inconsistent with arguments that Silurian seawater was 5.5 per thousand depleted in /sup 18/O. delta/sup 18/O for evaporite waters is systematically related to that of seawater, and does not show a -5.5 per thousand shift in the Silurian, even allowing for variables which affect the isotope evaporation trajectory. The lower deltaD may indicate a component of gypsum dehydration waters or may suggest a D-depleted Silurian hydrosphere.

  13. Mn solubility tested in seawater

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    It has been known for the past 2 or 3 years that the concentration of manganese in the upper several hundred meters of ocean water is unlike that of other trace metals such as copper, zinc, cadmium, and nickel. Trace metals are needed as a sort of ‘vitamin supplement’ by marine plants and animals; the surface supply is biologically scavenged and regenerated at depth. Thus ocean concentrations of trace metals increase with depth.Manganese, by contrast, appears to be concentrated in the photic zone and becomes relatively depleted in the depth interval 50-100 m from the surface. W. Landing and K. Bruland (Ear. Planet. Sci. Lett. 49, 45-56, 1980) described their observations of vertical distributions of manganese in a study of samples from the north Pacific. Recently, W. Sunda, S. A. Huntsman, and A. Harvey, in a study supported by the National Oceanic and Atmospheric Administration have found similar behavior of manganese in samples of coastal seawater and offshore seawater collected off North Carolina (Nature, 20, January 1983). They suggest on the basis of experiments conducted with these samples that the marine biological community itself serves to condition the surface seawater and, with the assistance of photoreduction, cause manganese to dissolve in the otherwise oxygenated zones.

  14. Freshwater to seawater transitions in migratory fishes

    USGS Publications Warehouse

    Zydlewski, Joseph; Michael P. Wilkie,

    2012-01-01

    The transition from freshwater to seawater is integral to the life history of many fishes. Diverse migratory fishes express anadromous, catadromous, and amphidromous life histories, while others make incomplete transits between freshwater and seawater. The physiological mechanisms of osmoregulation are widely conserved among phylogenetically diverse species. Diadromous fishes moving between freshwater and seawater develop osmoregulatory mechanisms for different environmental salinities. Freshwater to seawater transition involves hormonally mediated changes in gill ionocytes and the transport proteins associated with hypoosmoregulation, increased seawater ingestion and water absorption in the intestine, and reduced urinary water losses. Fishes attain salinity tolerance through early development, gradual acclimation, or environmentally or developmentally cued adaptations. This chapter describes adaptations in diverse taxa and the effects of salinity on growth. Identifying common strategies in diadromous fishes moving between freshwater and seawater will reveal the ecological and physiological basis for maintaining homeostasis in different salinities, and inform efforts to conserve and manage migratory euryhaline fishes.

  15. Early Triassic seawater sulfate drawdown

    NASA Astrophysics Data System (ADS)

    Song, Huyue; Tong, Jinnan; Algeo, Thomas J.; Song, Haijun; Qiu, Haiou; Zhu, Yuanyuan; Tian, Li; Bates, Steven; Lyons, Timothy W.; Luo, Genming; Kump, Lee R.

    2014-03-01

    The marine sulfur cycle is intimately linked to global carbon fluxes, atmospheric composition, and climate, yet relatively little is known about how it responded to the end-Permian biocrisis, the largest mass extinction of the Phanerozoic. Here, we analyze carbonate-associated-sulfate (CAS) from three Permo-Triassic sections in South China in order to document the behavior of the C-S cycle and its relationship to marine environmental changes during the mass extinction and its aftermath. We find that δ34SCAS varied from +9‰ to +44‰ at rates up to 100‰ Myr-1 during the Griesbachian-Smithian substages of the Early Triassic. We model the marine sulfur cycle to demonstrate that such rapid variation required drawdown of seawater sulfate concentrations to ⩽4 mM and a reduction in its residence time to ⩽200 kyr. This shorter residence time resulted in positive covariation with δ13Ccarb due to strong coupling of the organic carbon and pyrite burial fluxes. Carbon and sulfur isotopic shifts were associated with contemporaneous changes in climate, marine productivity, and microbial sulfate reduction rates, with negative shifts in δ13Ccarb and δ34SCAS linked to warming, decreased productivity, and reduced sulfate reduction. Sustained cooling during the Spathian re-invigorated oceanic overturning circulation, reduced marine anoxia, and limited pyrite burial. As seawater sulfate built to higher concentrations during the Spathian, the coupling of the marine C and S cycles came to an end and a general amelioration of marine environmental conditions set the stage for a recovery of invertebrate faunas. Variation in seawater sulfate during the Early Triassic was probably controlled by climate change, possibly linked to major eruptive phases of the Siberian Traps.

  16. Rapid determination of actinides in seawater samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-03-09

    A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti+3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used tomore » separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1–2 weeks and provide chemical yields of ~30–60 %. This new sample preparation method can be performed in 4–8 h with tracer yields of ~85–95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort.« less

  17. Chemical effect on ozone deposition over seawater

    EPA Science Inventory

    Surface layer resistance plays an important role in determining ozone deposition velocity over seawater. Recent studies suggest that surface layer resistance over sea-water is influenced by wind-speed and chemical interaction at the air-water interface. Here, we investigate the e...

  18. Automated nutrient analyses in seawater

    SciTech Connect

    Whitledge, T.E.; Malloy, S.C.; Patton, C.J.; Wirick, C.D.

    1981-02-01

    This manual was assembled for use as a guide for analyzing the nutrient content of seawater samples collected in the marine coastal zone of the Northeast United States and the Bering Sea. Some modifications (changes in dilution or sample pump tube sizes) may be necessary to achieve optimum measurements in very pronounced oligotrophic, eutrophic or brackish areas. Information is presented under the following section headings: theory and mechanics of automated analysis; continuous flow system description; operation of autoanalyzer system; cookbook of current nutrient methods; automated analyzer and data analysis software; computer interfacing and hardware modifications; and trouble shooting. The three appendixes are entitled: references and additional reading; manifold components and chemicals; and software listings. (JGB)

  19. Tidal Boundary Conditions in SEAWAT

    USGS Publications Warehouse

    Mulligan, Ann E.; Langevin, Christian; Post, Vincent E.A.

    2011-01-01

    SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.

  20. Tidal boundary conditions in SEAWAT.

    PubMed

    Mulligan, Ann E; Langevin, Christian; Post, Vincent E A

    2011-01-01

    SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.

  1. The Geologic History of Seawater

    NASA Astrophysics Data System (ADS)

    Holland, H. D.

    2003-12-01

    Aristotle proposed that the saltness of the sea was due to the effect of sunlight on water. Robert Boyle took strong exception to this view and - in the manner of the Royal Society - laid out a program of research in the opening paragraph of his Observations and Experiments about the Saltness of the Sea (1674) (Figure 1): (20K)Figure 1. Title page of Robert Boyle's Tracts consisting of Observations about the Saltness of the Sea and other essays (1674). The Cause of the Saltness of the Sea appears by Aristotle's Writings to have busied the Curiosity of Naturalists before his time; since which, his Authority, perhaps much more than his Reasons, did for divers Ages make the Schools and the generality of Naturalists of his Opinion, till towards the end of the last Century, and the beginning of ours, some Learned Men took the boldness to question the common Opinion; since when the Controversie has been kept on foot, and, for ought I know, will be so, as long as ‘tis argued on both sides but by Dialectical Arguments, which may be probable on both sides, but are not convincing on either. Wherefore I shall here briefly deliver some particulars about the Saltness of the Sea, obtained by my own trials, where I was able; and where I was not, by the best Relations I could procure, especially from Navigators.Boyle measured and compiled a considerable set of data for variations in the saltness of surface seawater. He also designed an improved piece of equipment for sampling seawater at depth, but the depths at which it was used were modest: 30 m with his own instrument, 80 m with another, similar sampler. However, the younger John Winthrop (1606-1676), an early member of the Royal Society, an important Governor of Connecticut, and a benefactor of Harvard College, was asked to collect seawater from the bottom of the Atlantic Ocean during his crossing from England to New England in the spring of 1663. The minutes of the Royal Society's meeting on July 20, 1663, give the

  2. Technical note: Examining ozone deposition over seawater

    NASA Astrophysics Data System (ADS)

    Sarwar, Golam; Kang, Daiwen; Foley, Kristen; Schwede, Donna; Gantt, Brett; Mathur, Rohit

    2016-09-01

    Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic carbon, and bromide in seawater on ozone deposition. We perform a series of simulations using the hemispheric Community Multiscale Air Quality model for summer months in the Northern Hemisphere. Our results suggest that each chemical interaction enhances the ozone deposition velocity and decreases the atmospheric ozone mixing ratio over seawater. Iodide enhances the median deposition velocity over seawater by 0.023 cm s-1, dissolved organic carbon by 0.021 cm s-1, dimethylsulfide by 0.002 cm s-1, and bromide by ∼0.0006 cm s-1. Consequently, iodide decreases the median atmospheric ozone mixing ratio over seawater by 0.7 ppb, dissolved organic carbon by 0.8 ppb, dimethylsulfide by 0.1 ppb, and bromide by 0.02 ppb. In a separate model simulation, we account for the effect of dissolved salts in seawater on the Henry's law constant for ozone and find that it reduces the median deposition velocity by 0.007 cm s-1 and increases surface ozone mixing ratio by 0.2 ppb. The combined effect of these processes increases the median ozone deposition velocity over seawater by 0.040 cm s-1, lowers the atmospheric ozone mixing ratio by 5%, and slightly improves model performance relative to observations.

  3. Cenozoic seawater Sr/Ca evolution

    NASA Astrophysics Data System (ADS)

    Sosdian, Sindia M.; Lear, Caroline H.; Tao, Kai; Grossman, Ethan L.; O'Dea, Aaron; Rosenthal, Yair

    2012-10-01

    Records of seawater chemistry help constrain temporal variations in geochemical processes that impact the global carbon cycle and climate through Earth's history. Here we reconstruct Cenozoic seawater Sr/Ca (Sr/Casw) using fossil Conus and turritellid gastropod Sr/Ca. Combined with an oxygen isotope paleotemperature record from the same samples, the gastropod record suggests that Sr/Caswwas slightly higher in the Eocene (˜11.4 ± 3 mmol/mol) than today (˜8.54 mmol/mol) and remained relatively stable from the mid- to late Cenozoic. We compare our gastropod Cenozoic Sr/Casw record with a published turritellid gastropod Sr/Casw record and other published biogenic (benthic foraminifera, fossil fish teeth) and inorganic precipitate (calcite veins) Sr/Caswrecords. Once the uncertainties with our gastropod-derived Sr/Casw are taken into account the Sr/Casw record agrees reasonably well with biogenic Sr/Caswrecords. Assuming a seawater [Ca] history derived from marine evaporite inclusions, all biogenic-based Sr/Casw reconstructions imply decreasing seawater [Sr] through the Cenozoic, whereas the calcite vein Sr/Casw reconstruction implies increasing [Sr] through the Cenozoic. We apply a simple geochemical model to examine the implications of divergence among these seawater [Sr] reconstructions and suggest that the interpretation and uncertainties associated with the gastropod and calcite vein proxies need to be revisited. Used in conjunction with records of carbonate depositional fluxes, our favored seawater Sr/Ca scenarios point to a significant increase in the proportion of aragonite versus calcite deposition in shelf sediments from the Middle Miocene, coincident with the proliferation of coral reefs. We propose that this occurred at least 10 million years after the seawater Mg/Ca threshold was passed, and was instead aided by declining levels of atmospheric carbon dioxide.

  4. Chinese Primary Standard Seawater: Stability checks and comparisons with IAPSO Standard Seawater

    NASA Astrophysics Data System (ADS)

    Li, Yanan; Luo, Yan; Kang, Ying; Yu, Tao; Wang, Aijun; Zhang, Chuan

    2016-07-01

    The authors give a brief introduction to the Chinese Primary Standard Seawater, with a description of its preparation procedures. IAPSO Standard Seawater (IAPSO SSW), was taken as a stable reference in the stability check of Chinese Primary Standard Seawater (CP SSW), and linear regression model as well as hypothesis testing were introduced into the analysis of check results; a demonstration check of CP SSW (batch number P8) achieved a positive conclusion. In comparisons of several batches of these two kinds of standard seawater on Practical Salinity, identical seawater samples from a homogeneous source were measured repeatedly. To evaluate the comparison results, performance criteria referred to as En numbers were adopted, the maximum of which was 0.42, indicating that no significant differences lay between these two kinds of SSWs when used to determine Practical Salinity. Measures taken to assure the reliability of measurement results are presented.

  5. RAPID DETERMINATION OF RADIOSTRONTIUM IN SEAWATER SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-01-16

    A new method for the determination of radiostrontium in seawater samples has been developed at the Savannah River National Laboratory (SRNL) that allows rapid preconcentration and separation of strontium and yttrium isotopes in seawater samples for measurement. The new SRNL method employs a novel and effective pre-concentration step that utilizes a blend of calcium phosphate with iron hydroxide to collect both strontium and yttrium rapidly from the seawater matrix with enhanced chemical yields. The pre-concentration steps, in combination with rapid Sr Resin and DGA Resin cartridge separation options using vacuum box technology, allow seawater samples up to 10 liters to be analyzed. The total {sup 89}Sr + {sup 90}Sr activity may be determined by gas flow proportional counting and recounted after ingrowth of {sup 90}Y to differentiate {sup 89}Sr from {sup 90}Sr. Gas flow proportional counting provides a lower method detection limit than liquid scintillation or Cerenkov counting and allows simultaneous counting of samples. Simultaneous counting allows for longer count times and lower method detection limits without handling very large aliquots of seawater. Seawater samples up to 6 liters may be analyzed using Sr Resin for {sup 89}Sr and {sup 90}Sr with a Minimum Detectable Activity (MDA) of 1-10 mBq/L, depending on count times. Seawater samples up to 10 liters may be analyzed for {sup 90}Sr using a DGA Resin method via collection and purification of {sup 90}Y only. If {sup 89}Sr and other fission products are present, then {sup 91}Y (beta energy 1.55 MeV, 58.5 day half-life) is also likely to be present. {sup 91}Y interferes with attempts to collect {sup 90}Y directly from the seawater sample without initial purification of Sr isotopes first and {sup 90}Y ingrowth. The DGA Resin option can be used to determine {sup 90}Sr, and if {sup 91}Y is also present, an ingrowth option with using DGA Resin again to collect {sup 90}Y can be performed. An MDA for {sup 90}Sr of <1 m

  6. Seawater Chemistry and the Advent of Biocalcification

    SciTech Connect

    Brennan, S. T.; Lowenstein, T K.; Horita, Juske

    2004-01-01

    Major ion compositions of primary fluid inclusions from terminal Proterozoic (ca. 544 Ma) and Early Cambrian (ca. 515 Ma) marine halites indicate that seawater Ca{sup 2+} concentrations increased approximately threefold during the Early Cambrian. The timing of this shift in seawater chemistry broadly coincides with the 'Cambrian explosion,' a brief drop in marine {sup 87}Sr/{sup 86}Sr values, and an increase in tectonic activity, suggesting a link between the advent of biocalcification, hydrothermal mid-ocean-ridge brine production, and the composition of seawater. The Early Cambrian surge in oceanic [Ca{sup 2+}] was likely the first such increase following the rise of metazoans and may have spurred evolutionary changes in marine biota.

  7. Environmental impact of seawater desalination plants.

    PubMed

    Al-Mutaz, I S

    1991-01-01

    Enormous amounts of seawater are desalted everyday worldwide. The total world production of fresh water from the sea is about 2621 mgd (9.92 million m(3) day(-1) 1985 figures). Desalting processes are normally associated with the rejection of high concentration waste brine from the plant itself or from the pretreatment units as well as during the cleaning period. In thermal processes, mainly multistage flash (MSF) thermal pollution occurs. These pollutants increase the seawater temperature, salinity, water current and turbidity. They also harm the marine environment, causing fish to migrate while enhancing the presence of algae, nematods and tiny molluscus. Sometimes micro-elements and toxic materials appear in the discharged brine.This paper will discuss the impact of the effluents from the desalination plants on the seawater environment with particular reference to the Saudi desalination plants, since they account for about 50% of the world desalination capacity.

  8. Seawater chemistry and the advent of biocalcification

    USGS Publications Warehouse

    Brennan, S.T.; Lowenstein, T.K.; Horita, J.

    2004-01-01

    Major ion compositions of primary fluid inclusions from terminal Proterozoic (ca. 544 Ma) and Early Cambrian (ca. 515 Ma) marine halites indicate that seawater Ca2+ concentrations increased approximately threefold during the Early Cambrian. The timing of this shift in seawater chemistry broadly coincides with the "Cambrian explosion," a brief drop in marine 87Sr/86Sr values, and an increase in tectonic activity, suggesting a link between the advent of biocalcification, hydrothermal mid-ocean-ridge brine production, and the composition of seawater. The Early Cambrian surge in oceanic [Ca2+] was likely the first such increase following the rise of metazoans and may have spurred evolutionary changes in marine biota. ?? 2004 Geological Society of America.

  9. Environmental impact of seawater desalination plants.

    PubMed

    Al-Mutaz, I S

    1991-01-01

    Enormous amounts of seawater are desalted everyday worldwide. The total world production of fresh water from the sea is about 2621 mgd (9.92 million m(3) day(-1) 1985 figures). Desalting processes are normally associated with the rejection of high concentration waste brine from the plant itself or from the pretreatment units as well as during the cleaning period. In thermal processes, mainly multistage flash (MSF) thermal pollution occurs. These pollutants increase the seawater temperature, salinity, water current and turbidity. They also harm the marine environment, causing fish to migrate while enhancing the presence of algae, nematods and tiny molluscus. Sometimes micro-elements and toxic materials appear in the discharged brine.This paper will discuss the impact of the effluents from the desalination plants on the seawater environment with particular reference to the Saudi desalination plants, since they account for about 50% of the world desalination capacity. PMID:24241776

  10. Seawater bicarbonate removal during hydrothermal circulation

    NASA Astrophysics Data System (ADS)

    Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

    2013-12-01

    High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

  11. Nucleation from seawater emissions during mesocosm experiments

    NASA Astrophysics Data System (ADS)

    Rose, Clémence; Culot, Anais; Pey, Jorge; Schwier, Allison; Mas, Sébastien; Charriere, Bruno; Sempéré, Richard; Marchand, Nicolas; D'Anna, Barbara; Sellegri, Karine

    2015-04-01

    Nucleation and new particle formation in the marine atmosphere is usually associated to the presence of macroalgea emerged at low tides in coastal areas, while these processes were very rarely detected away from coastlines. In the present study, we evidence the formation of new particles from the 1 nm size above the seawater surface in the absence of any macroalgea population. Within the SAM project (Sources of marine Aerosol in the Mediterranean),seawater mesocosms experiments were deployed in May 2013 at the STARESO in western Corsica, with the goal of investigating the relationship between marine aerosol emissions and the seawater biogeochemical properties. Three mesocosms imprisoned 3,3 m3 of seawater each and their emerged part was flushed with aerosol-filtered natural air. One of these mesocosms was left unchanged as control and the two others were enriched by addition of nitrates and phosphates respecting Redfield ratio (N:P = 16) in order to create different levels of phytoplanctonic activities. We followed both water and air characteristics of three mesocosms during a period of three weeks by using online water and atmospheric probes as well as seawater daily samples for chemical and biological analysis. Secondary new particle formation was followed on-line in the emerged parts of the mesocosms, using a SMPS for the size distribution above 6 nm and a Particle Size Magnifyer (PSM) for the number of cluster particles between 1 and 6 nm. We will present how the cluster formation rates and early growth rates relate to the gaz-phase emissions from the seawater and to its biogeochemical properties. Aknowledgemnts: The authors want to acknowledge the financial support of the ANR "Source of marine Aerosol in the Mediterranean" (SAM), and the support of MISTRAL CHARMEX and MERMEX programs.

  12. Floating plant can get uranium from seawater

    SciTech Connect

    Not Available

    1984-02-01

    A floating plant has been designed to extract uranium from seawater using solid adsorbents. Ore is removed from the adsorbent material by means of a solvent and concentrated in ion exchangers. Seawater is supplied to the adsorbent inside by wave energy and is based on the principle that waves will rush up a sloping plane that is partly submerged and fill a reservoir to a level higher than the still water level in the sea. The company projects that an offshore plant for recovering 600 tons of uranium/yr would comprise 22 floating concrete units, each measuring 430 x 75 meters.

  13. Impacts of seawater rise on seawater intrusion in the Nile Delta Aquifer, Egypt.

    PubMed

    Sefelnasr, Ahmed; Sherif, Mohsen

    2014-01-01

    Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents

  14. Impacts of seawater rise on seawater intrusion in the Nile Delta Aquifer, Egypt.

    PubMed

    Sefelnasr, Ahmed; Sherif, Mohsen

    2014-01-01

    Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents

  15. New aspects of uranium recovery from seawater

    SciTech Connect

    Hetkamp, D.; Wagener, K.

    1982-10-01

    The properties of various adsorbents for uranium extraction from seawater are measured under standardized experimental conditions. It turns out that fractionated humic acids have exceptionally fast loading kinetics. This property leads to a substantial reduction of capital investments in conventional adsorbent bed techniques as well as in a procedure designed to avoid large adsorbent bed constructions by using carrier bodies in the open sea.

  16. Technical note: Examining ozone deposition over seawater

    EPA Science Inventory

    Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic c...

  17. Thermoresponsive magnetic nanoparticles for seawater desalination.

    PubMed

    Zhao, Qipeng; Chen, Ningping; Zhao, Dieling; Lu, Xianmao

    2013-11-13

    Thermoresponsive magnetic nanoparticles (MNPs) as a class of smart materials that respond to a change in temperature may by used as a draw solute to extract water from brackish or seawater by forward osmosis (FO). A distinct advantage is the efficient regeneration of the draw solute and the recovery of water via heat-facilitated magnetic separation. However, the osmotic pressure attained by this type of draw solution is too low to counteract that of seawater. In this work, we have designed a FO draw solution based on multifunctional Fe3O4 nanoparticles grafted with copolymer poly(sodium styrene-4-sulfonate)-co-poly(N-isopropylacrylamide) (PSSS-PNIPAM). The resulting regenerable draw solution shows high osmotic pressure for seawater desalination. This is enabled by three essential functional components integrated within the nanostructure: (i) a Fe3O4 core that allows magnetic separation of the nanoparticles from the solvent, (ii) a thermoresponsive polymer, PNIPAM, that enables reversible clustering of the particles for further improved magnetic capturing at a temperature above its low critical solution temperature (LCST), and (iii) a polyelectrolyte, PSSS, that provides an osmotic pressure that is well above that of seawater.

  18. Thermoresponsive magnetic nanoparticles for seawater desalination.

    PubMed

    Zhao, Qipeng; Chen, Ningping; Zhao, Dieling; Lu, Xianmao

    2013-11-13

    Thermoresponsive magnetic nanoparticles (MNPs) as a class of smart materials that respond to a change in temperature may by used as a draw solute to extract water from brackish or seawater by forward osmosis (FO). A distinct advantage is the efficient regeneration of the draw solute and the recovery of water via heat-facilitated magnetic separation. However, the osmotic pressure attained by this type of draw solution is too low to counteract that of seawater. In this work, we have designed a FO draw solution based on multifunctional Fe3O4 nanoparticles grafted with copolymer poly(sodium styrene-4-sulfonate)-co-poly(N-isopropylacrylamide) (PSSS-PNIPAM). The resulting regenerable draw solution shows high osmotic pressure for seawater desalination. This is enabled by three essential functional components integrated within the nanostructure: (i) a Fe3O4 core that allows magnetic separation of the nanoparticles from the solvent, (ii) a thermoresponsive polymer, PNIPAM, that enables reversible clustering of the particles for further improved magnetic capturing at a temperature above its low critical solution temperature (LCST), and (iii) a polyelectrolyte, PSSS, that provides an osmotic pressure that is well above that of seawater. PMID:24134565

  19. The sound speed anomaly of Baltic Seawater

    NASA Astrophysics Data System (ADS)

    von Rohden, C.; Weinreben, S.; Fehres, F.

    2015-11-01

    The effect of the anomalous chemical composition of Baltic seawater on the speed of sound relative to seawater with quasi-standard composition was quantified at atmospheric pressure and temperatures of 1 to 46 °C. Three modern oceanographic time-of-flight sensors were applied in a laboratory setup for measuring the speed-of-sound difference δ w in a pure water diluted sample of North Atlantic seawater and a sample of Baltic seawater of the same conductivity, i.e. the same Practical Salinity (SP=7.766). The average δ w amounts to 0.069 ± 0.014 m s-1, significantly larger than the resolution and reproducibility of the sensors and independent of temperature. This magnitude for the anomaly effect was verified with offshore measurements conducted at different sites in the Baltic Sea using one of the sensors. The results from both measurements show values up to one order of magnitude smaller than existing predictions based on chemical models.

  20. The sound speed anomaly of Baltic seawater

    NASA Astrophysics Data System (ADS)

    von Rohden, C.; Weinreben, S.; Fehres, F.

    2016-02-01

    The effect of the anomalous chemical composition of Baltic seawater on the speed of sound relative to seawater with quasi-standard composition was quantified at atmospheric pressure and temperatures of 1 to 46 °C. Three modern oceanographic time-of-flight sensors were applied in a laboratory setup for measuring the speed-of-sound difference δw in a pure water diluted sample of North Atlantic seawater and a sample of Baltic seawater of the same conductivity, i.e., the same practical salinity (SP = 7.766). The average δw amounts to 0.069 ± 0.014 m s-1, which is significantly larger than the resolution and reproducibility of the sensors and independent of temperature. This magnitude for the anomaly effect was verified with offshore measurements conducted at different sites in the Baltic Sea using one of the sensors. The results from both measurements show values up to 1 order of magnitude smaller than existing predictions based on chemical models.

  1. The rate of sulfite oxidation in seawater

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-Zhong; Millero, Frank J.

    1991-03-01

    The rate of oxidation of sulfite, S( IV), in seawater was measured as a function of pH (4.0- 8.5), temperature ( 15-45°C), and salinity (0-35). The observed rate constant, k, in seawater at a pH = 8.2 was found to be second order with respect to S( IV) and half order with respect to oxygen: -d[S(IV)]/dt = k[S(IV)] 2[O 2] 0.5. The resulting values of k ( M-1.5 min -1) have been fitted to a function of ionic strength, I, and temperature, T(K): logk = 19.54 - 5069.47/ T + 14.74 I0.5 - 2.93 I - 2877.0 I0.5/ T, and the standard error is 0.05 in log k. The energy of activation was found to be a function of salinity and has a value of 140 ± 6 kJ mol -1atS = 35. The rates measured in 0.57 M NaCl were found to be higher than the rates in seawater. Measurements made in the major sea salts indicate that Ca 2+, Mg 2+, and SO 42- added to NaCl cause the decrease. Measurements made in artificial seawater (Na +, Mg 2+, Ca 2+, Cl -, and SO 42-) were found to be in good agreement with the measurements in real seawater. The rate increased from pH 4 to a maximum at pH 6.5 and decreased at higher pH. The effect of pH on the rates was attributed to the rate-determining step involving the combination of HSO 3- and SO 32-. This yields k = k″ αHSO3- αSO32- where α i is the molar fraction of species i. Values of k″ equal to 6.66 ± 0.06 and 6.17 ± 0.17 were found for NaCl and seawater, respectively. The larger range of k″ in seawater is due to it being a function of pH. The addition of Mn 2+ was found to increase the rate apparently due to the formation of MnSO 3. Additions of Fe 3+ and Fe 2+ have a catalytic effect only before they hydrolyze to colloidal iron.

  2. Changes in Escherichia coli cells starved in seawater or grown in seawater-wastewater mixtures.

    PubMed Central

    Munro, P M; Gauthier, M J; Laumond, F M

    1987-01-01

    Some metabolic modifications of Escherichia coli cells during starvation in seawater were studied in laboratory microcosms. The apparent die-off of this bacterium under such conditions, as observed by comparing the enumeration of CFU in conventional freshwater media and direct epifluorescence counts, was partially prevented when cells were previously grown in salted organic medium or on seawater-wastewater agar. beta-Galactosidase activity of starved cells disappeared gradually with time, even though some other enzymatic activities, such as that of alkaline phosphatase, increased. Moreover, some modifications of sensitivity to antibiotics, heavy metals, and bacteriophages in seawater- and wastewater-grown cells suggested that the cells undergo structural changes under natural marine conditions. These results provide additional experimental data indicating the possible active adaptation of E. coli cells to seawater. PMID:3116927

  3. Secular decline of seawater calcium increases seawater buffering and pH

    NASA Astrophysics Data System (ADS)

    Hain, M.; Sigman, D. M.; Higgins, J. A.; Haug, G. H.

    2015-12-01

    Reconstructed changes in seawater calcium and magnesium concentration ([Ca2+], [Mg2+]) predictably affect the ocean's acid/base and carbon chemistry. Yet inaccurate formulations of chemical equilibrium "constants" are currently in use to account for these changes. Here we develop an efficient implementation of the MIAMI Ionic Interaction Model (Millero and Pierrot, 1998) to predict all chemical equilibrium constants required for carbon chemistry calculations under variable [Ca2+] and [Mg2+] (Hain et al., 2015). We investigate the impact of [Ca2+] and [Mg2+] on the relationships among the ocean's pH, CO2, dissolved inorganic carbon (DIC), saturation state of CaCO3 (Ω), and buffer capacity. Increasing [Ca2+] and/or [Mg2+] enhances "ion pairing," which increases seawater buffering by increasing the concentration ratio of total to "free" (uncomplexed) carbonate ion. An increase in [Ca2+], however, also causes a decline in carbonate ion to maintain a given Ω, thereby overwhelming the ion pairing effect and decreasing seawater buffering. Given the reconstructions of Eocene [Ca2+] and [Mg2+] ([Ca2+]~20mM; [Mg2+]~30 mM), Eocene seawater would have required essentially the same DIC as today to simultaneously explain a similar-to-modern Ω and the estimated Eocene atmospheric CO2 of ~1000 ppm. During the Cretaceous, at ~4 times modern [Ca2+], ocean buffering would have been at a minimum. Overall, during times of high seawater [Ca2+], CaCO3 saturation, pH, and atmospheric CO2 were more susceptible to perturbations of the global carbon cycle. For example, given both Eocene and Cretaceous seawater [Ca2+] and [Mg2+], a doubling of atmospheric CO2 would require less carbon addition to the ocean/atmosphere system than under modern seawater composition. Moreover, increase in seawater buffering since the Cretaceous may have been a driver of evolution by raising energetic demands of biologically controlled calcification and CO2 concentration mechanisms that aid photosynthesis.

  4. Sulfur isotopic composition of cenozoic seawater sulfate

    PubMed

    Paytan; Kastner; Campbell; Thiemens

    1998-11-20

    A continuous seawater sulfate sulfur isotope curve for the Cenozoic with a resolution of approximately 1 million years was generated using marine barite. The sulfur isotopic composition decreased from 19 to 17 per mil between 65 and 55 million years ago, increased abruptly from 17 to 22 per mil between 55 and 45 million years ago, remained nearly constant from 35 to approximately 2 million years ago, and has decreased by 0.8 per mil during the past 2 million years. A comparison between seawater sulfate and marine carbonate carbon isotope records reveals no clear systematic coupling between the sulfur and carbon cycles over one to several millions of years, indicating that changes in the burial rate of pyrite sulfur and organic carbon did not singularly control the atmospheric oxygen content over short time intervals in the Cenozoic. This finding has implications for the modeling of controls on atmospheric oxygen concentration.

  5. Toxicological Investigation of Radioactive Uranium in Seawater

    PubMed Central

    Bae, Jeong Mi; Kim, Jin

    2012-01-01

    Trace uranium detection measurement was performed using DNA immobilized on a graphite pencil electrode (DGE). The developed probe was connected to the portable handheld voltammetric systems used for seawater analysis. The sensitive voltammogram was obtained within only 30 s accumulation time, and the anodic stripping working range was attained at 100~800 μg/l U and 10~50 μg/l. The statistic relative standard deviation of 30.0 mg/l with the 15th stripping was 0.2115. Here, toxicological and analytical application was performed in the seawater survey in a contaminated power plant controlling water. The results were found to be applicable for real-time toxicological assay for trace control. PMID:24278591

  6. Gradient zone erosion in seawater solar ponds

    SciTech Connect

    Shi, J.; Hart, R.A.; Kleis, S.J.; Bannerot, R.B.

    1995-11-01

    An experimental program has been conducted to examine the feasibility of using seawater solar ponds in mariculture operations along the Texas gulf coast to protect fish crops from the potentially lethal, cold temperatures experienced in outdoor ponds. Seawater solar ponds in the form of floating thermal refuge areas are proposed as a method for reducing the loss of heat from small sections of a pond. Gradient zone erosion under various ambient and operating conditions is examined. Comparisons with previous laboratory studies show a much lower entrainment rate in the natural environment. A simple (linear) correlation of entrainment rate with wind speed was found, for conditions which are typical of those encountered in mariculture pond operations.

  7. Seawater sulfur isotope fluctuations in the Cretaceous.

    PubMed

    Paytan, Adina; Kastner, Miriam; Campbell, Douglas; Thiemens, Mark H

    2004-06-11

    The exogenic sulfur cycle is tightly coupled with the carbon and oxygen cycles, and therefore a central component of Earth's biogeochemistry. Here we present a high-resolution record of the sulfur isotopic composition of seawater sulfate for the Cretaceous. The general enrichment of isotopically light sulfur that prevailed during the Cretaceous may have been due to increased volcanic and hydrothermal activity. Two excursions toward isotopically lighter sulfur represent periods of lower rates of pyrite burial, implying a shift in the location of organic carbon burial to terrestrial or open-ocean settings. The concurrent changes in seawater sulfur and inorganic carbon isotopic compositions imply short-term variability in atmospheric oxygen partial pressure.

  8. Effect of Greenhouse Gases Dissolved in Seawater.

    PubMed

    Matsunaga, Shigeki

    2015-12-30

    A molecular dynamics simulation has been performed on the greenhouse gases carbon dioxide and methane dissolved in a sodium chloride aqueous solution, as a simple model of seawater. A carbon dioxide molecule is also treated as a hydrogen carbonate ion. The structure, coordination number, diffusion coefficient, shear viscosity, specific heat, and thermal conductivity of the solutions have been discussed. The anomalous behaviors of these properties, especially the negative pressure dependence of thermal conductivity, have been observed in the higher-pressure region.

  9. Projected world market for seawater desalination equipment

    SciTech Connect

    Not Available

    1984-10-01

    A forecast is presented of the market for seawater desalination plants. The conclusions presented herein are based on a number of sources of information, of which the most important are: responses to questionnaires mailed to 300 cognizant water agencies in 61 countries; the published market growth trend over the period 1971 to 1983; and an analysis of the geography, rainfall, population, industrial growth, and energy availability in the respective countries. Analysis suggests the possibility that financing, although currently a major stumbling block to the purchase of desalting plants, may be effected by an exchange program in which the purchaser of plants will offer some exportable product(s) in exchange. The forecast suggests the likelihood that the seawater desalination market is becoming saturated. A plateau is expected to develop in new plant sales of additional capacity in the immediate future, followed by a downturn by the end of the century. This report, however, emphasizes the importance of the replacement market, which will involve substantial sales to replace worn-out and obsolescent equipment. The combined new-plus-replacement annual sales can be expected to reach 1.25 million m/sup 3//d (330 Mgd) by the year 2000. Seawater reverse osmosis (SWRO) is expected to represent 270,000 m/sup 3//d (70 Mgd) by the end of the century because of technological improvements in membrane systems and components.

  10. Constructing a Neoproterozoic Seawater Strontium Isotope Curve

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Shields-Zhou, G. A.; Manning, C. J.; Thirlwall, M.; Thurow, J. W.; Zhu, M.; Ling, H.

    2014-12-01

    The strontium isotopic composition of seawater has varied throughout Earth history in response to the balance between Sr isotopic exchange with ocean crust and input of riverine Sr derived from continental weathering. Because of this, seawater 87Sr/86Sr highs are interpreted to reflect erosion events, related to mountain building, while 87Sr/86Sr lows are considered to result from low weathering rates or increased seafloor spreading. Seawater 87Sr/86Sr also responds to changes in the isotopic composition of material undergoing weathering. The largest ever increase in seawater 87Sr/86Sr took place sometime from approximately 900 Ma to 500 Ma, and was associated with a permanent step shift in baseline 87Sr/86Sr composition. The unprecedented size of this increase, its timing and causation remains unconstrained. This study attempts firstly to reconstruct global seawater 87Sr/86Sr trends through this increase, using well-preserved carbonate rock samples from the North China craton, calibrated against additional 87Sr/86Sr and δ13C data from Neoproterozoic samples collected from other sections around the world. Sample preparation techniques for bulk carbonate Sr isotope stratigraphy are being honed during the course of this study. Other stable isotope systems (δ13C and δ18O) and trace elements, including REE have been investigated on the same samples to identify pristine samples for Sr isotope analysis and help in interpretation. The newly obtained data from this study (mainly Huaibei group of Huaibei area), using the excellently preserved early marine calcite cements and some bulk rock samples, confirm that the carbonate strata across the Jiao-Liao-Xu-Huai stratigraphic realm of the North China Craton exhibit the moderately positive δ13C values and low 87Sr/86Sr values that are characteristic of the early Neoproterozoic (Tonian).The results help to recreate the global curve by linking negative excursions in the Shijia (Xuzhou) (Xiao et al., 2014, Precambr. Res., 246

  11. The major-ion composition of Silurian seawater

    USGS Publications Warehouse

    Brennan, S.T.; Lowenstein, T.K.

    2002-01-01

    One-hundred fluid inclusions in Silurian marine halite were analyzed in order to determine the major-ion composition of Silurian seawater. The samples analyzed were from three formations in the Late Silurian Michigan Basin, the A-1, A-2, and B Evaporites of the Salina Group, and one formation in the Early Silurian Canning Basin (Australia), the Mallowa Salt of the Carribuddy Group. The results indicate that the major-ion composition of Silurian seawater was not the same as present-day seawater. The Silurian ocean had lower concentrations of Mg2+, Na+, and SO2-4, and much higher concentrations of Ca2+ relative to the ocean's present-day composition. Furthermore, Silurian seawater had Ca2+ in excess of SO2-4. Evaporation of Silurian seawater of the composition determined in this study produces KC1-type potash minerals that lack the MgSO4-type late stage salts formed during the evaporation of present-day seawater. The relatively low Na+ concentrations in Silurian seawater support the hypothesis that oscillations in the major-ion composition of the oceans are primarily controlled by changes in the flux of mid-ocean ridge brine and riverine inputs and not global or basin-scale, seawater-driven dolomitization. The Mg2+/Ca2+ ratio of Silurian seawater was ~1.4, and the K+/Ca2+ ratio was ~0.3, both of which differ from the present-day counterparts of 5 and 1, respectively. Seawaters with Mg2+/Ca2+ 2 (e.g., modern seawater) facilitate the precipitation of aragonite and high-magnesian calcite. Therefore, the early Paleozoic calcite seas were likely due to the low Mg2+/Ca2+ ratio of seawater, not the pCO2 of the Silurian atmosphere. Copyright ?? 2002 Elsevier Science Ltd.

  12. Ion exchange properties of Japanese natural zeolites in seawater.

    PubMed

    Wajima, Takaaki

    2013-01-01

    Ion exchange properties of five different Japanese natural zeolites in seawater were examined. Sodium ions could be reduced by all zeolites, although anions, Cl(-) and SO(4)(2-), in seawater showed barely changes. Natural zeolite desalination treatment mainly depends on the ion exchange between Na(+), K(+) and Mg(2+) in seawater and Ca(2+) in natural zeolite. This study found that mordenite is superior to clinoptilolite for use in Na(+) reduction. Mordenite with high cation exchange capacity containing Ca(2+) resulted in the highest Na(+) reduction from seawater.

  13. Physicochemical properties of protein-modified silver nanoparticles in seawater

    NASA Astrophysics Data System (ADS)

    Zhong, Hangyue

    2013-10-01

    This study investigated the physicochemical properties of silver nanoparticles stabilized with casein protein in seawater. UV?vis spectrometry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied to measure the stability of silver nanoparticles in seawater samples. The obtained results show an increased aggregation tendency of silver nanoparticles in seawater, which could be attributed its relatively high cation concentration that could neutralize the negatively charges adsorbed on the surface of silver nanoparticles and reduce the electrostatic repulsion forces between nanoparticles. Similarly, due to the surface charge screening process, the zeta potential of silver nanoparticles in seawater decreased. This observation further supported the aggregation behavior of silver nanoparticles. This study also investigated the dissolution of silver nanoparticles in seawater. Result shows that the silver nanoparticle dissolution in DI water is lower than in seawater, which is attributed to the high Cl? concentration present in seawater. As Cl? can react with silver and form soluble AgCl complex, dissolution of silver nanoparticles was enhanced. Finally, this study demonstrated that silver nanoparticles are destabilized in seawater condition. These results may be helpful in understanding the environmental risk of discharged silver nanoparticles in seawater conditions.

  14. Hydrothermal transport of heavy metals by seawater: The role of seawater/basalt ratio

    USGS Publications Warehouse

    Seyfried, W.; Bischoff, J.L.

    1977-01-01

    Seawater reacted with basaltic glass at 260??C and 500 bars under water-dominated conditions (50 : 1 water/rock ratio) efficiently leached and maintained heavy metals in solution. Cu, Zn, and Ba are transferred in significant proportions to the aqueous phase, while Fe and Mn attain concentrations of 45 and 20 ppm respectively as the basalt is completely made over to magnesian smectite. High metal solubility is a function of acidity maintained by large excess of dissolved Mg and equilibria with the alteration phase. Metal concentrations and relative proportions are consistent within limits required for metal-rich fluid which produced East Pacific Rise metalliferous sediments. Experiments mixing metal-bearing altered seawater and normal seawater were carried out as a qualitative indicator of sea-floor precipitation processes. Bulk composition of the precipitates are strongly influenced by mixing ratio. Precipitates range from silica-magnesium rich under low dilution by seawater to essentially pure ferric hydroxide under conditions of high dilution. ?? 1977.

  15. On the GIBBS thermodynamic potential of seawater

    NASA Astrophysics Data System (ADS)

    Feistel, Rainer; Hagen, Eberhard

    Free Enthalpy, the GIBBS thermodynamic potential G(S,t,p) of seawater, has been recomputed including the sound speed equation of DEL GROSSO (1974), temperatures of maximum density (TMD) of CALDWELL (1978), freezing point depression measurements of DOHERTY and KESTER (1974), rederived limiting laws and ice properties, and an extended set of dilution heat data of BROMLEY (1968) and MILLERO, HANSEN and HOFF (1973). As a new reference state, the standard ocean state has been chosen. The resulting average deviations are 0.0006 kg m -3 for pure water density at 1 atm, 0.002 kg m -3 for seawater density at 1 atm, 0.02 m/s for sound speed, 0.01 J kgK -1 for heat capacity at 1 atm, 0.4 kJ kg -1 for dilution heats, 0.002°C for freezing points, and 0.04°C for TMDs. Resulting pressure-dependent freezing points are in good agreement with experiments and UNESCO (1978) formulas. Enthalpy as thermodynamic potential has been explicitly determined for easy computation of potential temperature, potential density, and sound speed. All functions are expressed in the new International Temperature Scale ITS-90.

  16. Corrosion of barrier materials in seawater environments

    SciTech Connect

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ` Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys.

  17. Controls of Trace Metals in Seawater

    NASA Astrophysics Data System (ADS)

    Bruland, K. W.; Lohan, M. C.

    2003-12-01

    Since the early 1970s, marine chemists have gained a first-order understanding of the concentrations, distributions, and chemical behaviors of trace metals in seawater. Important factors initiating this quantum leap in knowledge were major advances in modern analytical chemistry and instrumentation, along with the development and adoption of clean techniques. An instrumental development in the mid-1970s that spurred the early research on trace metals was the availability of the sensitive graphite furnace as the sample introduction system to an atomic absorption spectrometer. More recently, the appearance of inductively coupled plasma (ICP) mass spectrometers has provided an even more sensitive and powerful instrumental capability to the arsenal of marine chemists. In addition to these instruments back in shore-based laboratories, there has been the development of sensitive shipboard methods such as stripping voltammetry and flow injection analysis (FIA) systems with either chemiluminescence or catalytically enhanced spectrophotometric detection. Along with the development of these highly sensitive analytical techniques came a recognition and appreciation of the importance of handling contamination issues by using clean techniques during all phases of sampling and analysis. This is necessary due to low concentrations of trace metals in seawater relative to the ubiquitousness of metals on a ship or in a laboratory (e.g., dust, steel hydrowire, rust, paint with copper and zinc antifouling agents, brass fittings, galvanized material, sacrificial zinc anodes, etc.). As a result, seawater concentrations of most trace metals have now been accurately determined in at least some parts of the oceans, and their oceanic distributions have been found to be consistent with oceanographic processes.The concentrations and distributions of trace metals in seawater are controlled by a combination of processes. These processes include external sources of trace metals delivered by

  18. Influence of seawater intrusion on microbial communities in groundwater.

    PubMed

    Unno, Tatsuya; Kim, Jungman; Kim, Yumi; Nguyen, Son G; Guevarra, Robin B; Kim, Gee Pyo; Lee, Ji-Hoon; Sadowsky, Michael J

    2015-11-01

    Groundwater is the sole source of potable water on Jeju Island in the Republic of (South) Korea. Groundwater is also used for irrigation and industrial purposes, and it is severely impacted by seawater intrusion in coastal areas. Consequently, monitoring the intrusion of seawater into groundwater on Jeju is very important for health and environmental reasons. A number of studies have used hydrological models to predict the deterioration of groundwater quality caused by seawater intrusion. However, there is conflicting evidence of intrusion due to complicated environmental influences on groundwater quality. Here we investigated the use of next generation sequencing (NGS)-based microbial community analysis as a way to monitor groundwater quality and detect seawater intrusion. Pristine groundwater, groundwater from three coastal areas, and seawater were compared. Analysis of the distribution of bacterial species clearly indicated that the high and low salinity groundwater differed significantly with respect to microbial composition. While members of the family Parvularculaceae were only identified in high salinity water samples, a greater percentage of the phylum Actinobacteria was predominantly observed in pristine groundwater. In addition, we identified 48 shared operational taxonomic units (OTUs) with seawater, among which the high salinity groundwater sample shared a greater number of bacterial species with seawater (6.7%). In contrast, other groundwater samples shared less than 0.5%. Our results suggest that NGS-based microbial community analysis of groundwater may be a useful tool for monitoring groundwater quality and detect seawater intrusion. This technology may also provide additional insights in understanding hydrological dynamics.

  19. Henry's law constants for dimethylsulfide in freshwater and seawater

    NASA Technical Reports Server (NTRS)

    Dacey, J. W. H.; Wakeham, S. G.; Howes, B. L.

    1984-01-01

    Distilled water and several waters of varying salinity were subjected, over a 0-32 C temperature range, to measurements for Henry's law constants for dimethylsulfide. Values for distilled water and seawater of the solubility parameters A and C are obtained which support the concept that the concentration of dimethylsulfide in the atmosphere is far from equilibrium with seawater.

  20. Analysis of seawater flow through optical fiber

    NASA Astrophysics Data System (ADS)

    Fernández López, Sheila; Carrera Ramírez, Jesús; Rodriguez Sinobar, Leonor; Benitez, Javier; Rossi, Riccardo; Laresse de Tetto, Antonia

    2015-04-01

    The relation between sea and coastal aquifer is very important to the human populations living in coastal areas. The interrelation involves the submarine ground water discharge of relatively fresh water to the sea and the intrusion of sea water into the aquifer, which impairs the quality of ground water. The main process in seawater intrusion is managed by fluid-density effects which control the displacement of saline water. The underlain salinity acts as the restoring force, while hydrodynamic dispersion and convection lead to a mixing and vertical displacement of the brine. Because of this, a good definition of this saltwater-freshwater interface is needed what is intimately joined to the study of the movements (velocity fields) of fresh and salt water. As it is well known, the flow of salt water studied in seawater intrusion in stationary state, is nearly null or very low. However, in the rest of cases, this flux can be very important, so it is necessary its study to a better comprehension of this process. One possible manner of carry out this analysis is through the data from optical fiber. So, to research the distribution and velocity of the fresh and saltwater in the aquifer, a fiber optic system (OF) has been installed in Argentona (Baix Maresme, Catalonia). The main objective is to obtain the distributed temperature measurements (OF-DTS) and made progress in the interpretation of the dynamic processes of water. For some applications, the optical fiber acts as a passive temperature sensor but in our case, the technique Heated Active Fiber Optic will be used. This is based on the thermal response of the ground as a heat emission source is introduced. The thermal properties of the soil, dependent variables of soil water content, will make a specific temperature distribution around the cable. From the analyzed data we will deduce the velocity field, the real objective of our problem. To simulate this phenomenon and the coupled transport and flow problem

  1. Mortality of fecal bacteria in seawater

    SciTech Connect

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G. )

    1991-03-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which ({sup 3}H)thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate.

  2. Optimal conditions for bioremediation of oily seawater.

    PubMed

    Zahed, Mohammad Ali; Aziz, Hamidi Abdul; Isa, Mohamed Hasnain; Mohajeri, Leila; Mohajeri, Soraya

    2010-12-01

    To determine the influence of nutrients on the rate of biodegradation, a five-level, three-factor central composite design (CCD) was employed for bioremediation of seawater artificially contaminated with crude oil. Removal of total petroleum hydrocarbons (TPH) was the dependent variable. Samples were extracted and analyzed according to US-EPA protocols. A significant (R(2)=0.9645, P<0.0001) quadratic polynomial mathematical model was generated. Removal from samples not subjected to optimization and removal by natural attenuation were 53.3% and 22.6%, respectively. Numerical optimization was carried out based on desirability functions for maximum TPH removal. For an initial crude oil concentration of 1g/L supplemented with 190.21 mg/L nitrogen and 12.71 mg/L phosphorus, the Design-Expert software predicted 60.9% hydrocarbon removal; 58.6% removal was observed in a 28-day experiment. PMID:20705460

  3. Energy Implications of Seawater Desalination (Invited)

    NASA Astrophysics Data System (ADS)

    Cooley, H.; Heberger, M. G.

    2013-12-01

    Freshwater has traditionally come from rivers, lakes, streams, and groundwater aquifers. As demand increases and climate change alters the location and timing of water supply, these traditional sources are becoming unavailable, more difficult, or increasingly expensive to develop. As a result, many communities are switching to alternative sources of water. Interest in pursuing seawater desalination is high in many coastal communities. In California, for example, 17 plants are proposed for development along the California coast and two in Mexico. Water managers are pursing desalination because is a local supply that can help diversify the water supply portfolio. Additionally, it is a reliable supply, which can be especially valuable during a drought. But removing the salt from seawater is an energy-intensive process that consumes more energy per gallon than most other water supply and treatment options. These energy requirements are key factors that will impact the extent and success of desalination in California. Energy requirements for seawater desalination average about 4.0 kWh per cubic meter (m3) of water produced. By comparison, the least energy-intensive options of local sources of groundwater and surface water require 0 - 0.90 kWh per m3; wastewater reuse, depending on treatment levels, may require from 0.26 - 2.2 kWh per m3. Beyond the electricity required for the desalination facility itself, producing any new source of water, including through desalination, increases the amount of energy required to deliver and use the water produced as well as collect, treat, and dispose of the wastewater generated. Energy is the largest single variable cost for a desalination plant, varying from one-third to more than one-half the cost of produced water. Building a desalination plant may reduce a water utility's exposure to water reliability risks at the added expense of an increase in exposure to energy price risk. In dependent on hydropower, electricity prices tend to

  4. Effect of seawater temperature on uranium recovery from seawater using amidoxime adsorbents

    SciTech Connect

    Sekiguchi, Koji; Saito, Kyoichi; Konishi, Satoshi; Furusaki, Shintaro . Dept. of Chemical Engineering); Sugo, Takanobu . Takasaki Radiation Chemistry Research Establishment); Nobukawa, Hisashi . Dept. of Naval Architecture and Ocean Engineering)

    1994-03-01

    Porous amidoxime hollow fibers, which were prepared by radiation-induced graft polymerization of acrylonitrile onto porous polyethylene hollow fibers and subsequent amidoximation, were used as packing materials of the adsorption bed for uranium recovery from seawater. Seawater was forced to flow through the bed charged with the amidoxime hollow fibers either by pumping or by ocean current. Uranium concentration decay through the bed could be well correlated with residence time based on the adsorption rate expressed in terms of the overall mass-transfer coefficient. The resultant activation energy of 20 kcal/mol for uranium adsorption was indicative of the chelate formation of the amidoxime group with uranyl species as a rate-determining step.

  5. Post-mesozoic rapid increase of seawater Mg/Ca due to enhanced mantle-seawater interaction.

    PubMed

    Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. PMID:24067442

  6. Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

    PubMed Central

    Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. PMID:24067442

  7. Post-mesozoic rapid increase of seawater Mg/Ca due to enhanced mantle-seawater interaction.

    PubMed

    Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

    2013-09-25

    The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater.

  8. Herbicide Persistence in Seawater Simulation Experiments.

    PubMed

    Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P

    2015-01-01

    Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

  9. Energy balance for uranium recovery from seawater

    SciTech Connect

    Schneider, E.; Lindner, H.

    2013-07-01

    The energy return on investment (EROI) of an energy resource is the ratio of the energy it ultimately produces to the energy used to recover it. EROI is a key viability measure for a new recovery technology, particularly in its early stages of development when financial cost assessment would be premature or highly uncertain. This paper estimates the EROI of uranium recovery from seawater via a braid adsorbent technology. In this paper, the energy cost of obtaining uranium from seawater is assessed by breaking the production chain into three processes: adsorbent production, adsorbent deployment and mooring, and uranium elution and purification. Both direct and embodied energy inputs are considered. Direct energy is the energy used by the processes themselves, while embodied energy is used to fabricate their material, equipment or chemical inputs. If the uranium is used in a once-through fuel cycle, the braid adsorbent technology EROI ranges from 12 to 27, depending on still-uncertain performance and system design parameters. It is highly sensitive to the adsorbent capacity in grams of U captured per kg of adsorbent as well as to potential economies in chemical use. This compares to an EROI of ca. 300 for contemporary terrestrial mining. It is important to note that these figures only consider the mineral extraction step in the fuel cycle. At a reference performance level of 2.76 g U recovered per kg adsorbent immersed, the largest energy consumers are the chemicals used in adsorbent production (63%), anchor chain mooring system fabrication and operations (17%), and unit processes in the adsorbent production step (12%). (authors)

  10. Herbicide Persistence in Seawater Simulation Experiments.

    PubMed

    Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P

    2015-01-01

    Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

  11. Uranium from Seawater Program Review; Fuel Resources Uranium from Seawater Program DOE Office of Nuclear Energy

    SciTech Connect

    2013-07-01

    For nuclear energy to remain sustainable in the United States, economically viable sources of uranium beyond terrestrial ores must be developed. The goal of this program is to develop advanced adsorbents that can extract uranium from seawater at twice the capacity of the best adsorbent developed by researchers at the Japan Atomic Energy Agency (JAEA), 1.5 mg U/g adsorbent. A multidisciplinary team from Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory, and the University of Texas at Austin was assembled to address this challenging problem. Polymeric adsorbents, based on the radiation grafting of acrylonitrile and methacrylic acid onto high surface-area polyethylene fibers followed by conversion of the nitriles to amidoximes, have been developed. These poly(acrylamidoxime-co-methacrylic acid) fibers showed uranium adsorption capacities for the extraction of uranium from seawater that exceed 3 mg U/g adsorbent in testing at the Pacific Northwest National Laboratory Marine Sciences Laboratory. The essence of this novel technology lies in the unique high surface-area trunk material that considerably increases the grafting yield of functional groups without compromising its mechanical properties. This technology received an R&D100 Award in 2012. In addition, high surface area nanomaterial adsorbents are under development with the goal of increasing uranium adsorption capacity by taking advantage of the high surface areas and tunable porosity of carbon-based nanomaterials. Simultaneously, de novo structure-based computational design methods are being used to design more selective and stable ligands and the most promising candidates are being synthesized, tested and evaluated for incorporation onto a support matrix. Fundamental thermodynamic and kinetic studies are being carried out to improve the adsorption efficiency, the selectivity of uranium over other metals, and the stability of the adsorbents. Understanding

  12. Seawater neutralization of alkaline bauxite residue and implications for revegetation.

    PubMed

    Menzies, N W; Fulton, I M; Morrell, W J

    2004-01-01

    Reaction of bauxite residue with seawater results in neutralization of alkalinity through precipitation of Mg-, Ca-, and Al-hydroxide and carbonate minerals. In batch studies, the initial pH neutralization reaction was rapid (<5 min), with further reaction continuing to reduce pH for several weeks. Reaction with seawater produced a residue pH of 8 to 8.5. Laboratory leaching column studies were undertaken to provide information on seawater neutralization of the coarse-textured fraction of the waste, residue sand (RS), under conditions comparable with those that might be applied in the field. An 0.80-m-deep column of RS was neutralized by the application of the equivalent of 2-m depth of seawater. In addition to lowering the pH and Na content of the residue, seawater neutralization resulted in the addition of substantial amounts of the plant nutrients Ca, Mg, and K to the profile. Similar results were also obtained from a field-scale assessment of neutralization. However, the accumulation of precipitate, consisting of hydrotalcite, aragonite, and pyroaurite, in the drainage system may preclude the use of in situ seawater neutralization as a routine rehabilitation practice. Following seawater neutralization, RS remains too saline to support plant growth and would require fresh water leaching before revegetation. PMID:15356249

  13. Cr isotopic composition of modern carbonates and seawater

    NASA Astrophysics Data System (ADS)

    Bonnand, P.; Parkinson, I. J.; James, R. H.; Fehr, M.; Connelly, D. P.

    2010-12-01

    Recent development in MC-ICP-MS instrumentation, coupled with double-spike techniques has led to the improvement of stable Cr isotopes measurements and allows the determination of Cr isotopes in low concentration samples such as carbonates and seawater. Cr is a redox sensitive element and its isotopes are fractionated during the reduction of Cr(VI) to Cr(III) [1]. Chromium isotopic variations in BIFs have been linked to the redox conditions of ancient oceans[2]. However, in order to understand Cr isotopic fractionation in the past it is important to constrain the Cr isotopic composition of modern seawater. Chromium concentrations in seawater are between 2 and 5nM, and therefore the measurement of stable Cr isotopes in seawater is an analytical challenge. We have developed a new technique to measure Cr isotopes in seawater based on the Cr co-precipitation with Fe[3], the chemical purification of Cr using an anion exchange chromatography and analyses using the double-spike technique with a ThermoFisher Neptune MC-ICP-MS. Using this method, seawater samples from the Argentinean Basin and from Southampton Water (UK) have been analysed, which have Cr concentrations of ~6nM of Cr. Chromium isotopic composition of our seawater samples is consistently heavier than continental crust and mantle values (δ53Cr -0.18‰)[4] with δ53Cr values of ~+0.5‰. We have also measured Cr isotopic compositions in ooids from the Bahamas Banks, which represent chemical precipitates from modern seawater. These also record consistently heavy δ53Cr values (0.6-0.8‰), which overlap the range of modern seawater. We conclude that heavy δ53Cr in seawater reflect either redox cycling of Cr in the oceans[3] or fractionation during the weathering of the continental crust. Moreover, Cr isotopes in modern carbonates are not significantly offset from seawater and therefore, these carbonates reflect the Cr composition of seawater. Thus, Cr isotopes in carbonates can be used to reconstruct the Cr

  14. Seawater piping systems designed with AISI 316 and RCP anodes

    SciTech Connect

    Valen, S.; Johnsen, R.; Gartland, P.O.; Drugli, J.M.

    1999-11-01

    Internal cathodic protection by resistor controlled anodes--Resistor controlled Cathodic Protection (RCP)--has been introduced as an alternative method for the prevention of localized corrosion of seawater transportation systems. More than 1000 RCP anodes have been installed in seawater piping systems made from highly alloyed stainless steel which previously had suffered from corrosion. The application of cheaper stainless steels like AISI 316 in combination with RCP anodes results in significant cost savings for the seawater system, and a few systems have been installed. This paper gives a short review of the theoretical background, and a presentation of the experience from some of the installations with these materials and RCP.

  15. HYDRAULIC CONDUCTIVITY OF SOME BENTONITES IN ARTIFICIAL SEAWATER

    NASA Astrophysics Data System (ADS)

    Komine, Hideo; Yasuhara, Kazuya; Murakami, Satoshi

    A high-level radioactive waste disposal facility might be built in a coastal area in Japan from the viewpoint of feasible transportation of waste. Therefore, it is important to investigate the effects of seawater on a bentonite-based buffer. This study investigated the influence of seawater on hydraulic conductivity of three common sodium-types of bentonite and one calcium-type bentonite by the laboratory experiments. From the results of laboratory experiment, this study discussed the influence of seawater on hydraulic conductivity of bentonites from the viewpoints of kinds of bentonite such as exchangeable-cation type and montmorillonite content and dry density of bentonite-based buffer.

  16. The Major-ion Composition of Permian Seawater

    SciTech Connect

    Lowenstein, T K.; Timofeeff, Michael N.; Kovalevych, Volodymyr M.; Horita, Juske

    2005-01-01

    The major-ion (Mg{sup 2+}, Ca{sup 2+}, Na{sup +}, K{sup +}, SO{sub 4}{sup 2-}, and Cl{sup -}) composition of Permian seawater was determined from chemical analyses of fluid inclusions in marine halites. New data from the Upper Permian San Andres Formation of Texas (274--272 Ma) and Salado Formation of New Mexico (251 Ma), analyzed by the environmental scanning electron microscopy (ESEM) X-ray energy-dispersive spectrometry (EDS) method, along with published chemical compositions of fluid inclusions in Permian marine halites from North America (two formations of different ages) and the Central and Eastern European basins (eight formations of four different ages) show that Permian seawater shares chemical characteristics with modern seawater, including SO{sub 4}{sup 2-} > Ca{sup 2+} at the point of gypsum precipitation, evolution into Mg{sup 2+}-Na{sup +}-K{sup +}-SO{sub 4}{sup 2-}-Cl{sup -} brines, and Mg{sup 2+}/K{sup +} ratios {approx} 5. Permian seawater, however, is slightly depleted in SO{sub 4}{sup 2-} and enriched in Ca{sup 2+}, although modeling results do not rule out Ca{sup 2+} concentrations close to those in present-day seawater. Na{sup +} and Mg{sup 2+} in Permian seawater are close to (slightly below) their concentrations in modern seawater. Permian and modern seawater are both classified as aragonite seas, with Mg{sup 2+}/Ca{sup 2+} ratios >2, conditions favorable for precipitation of aragonite and magnesian calcite as ooids and cements. The chemistry of Permian seawater was modeled using the chemical composition of brine inclusions for three periods: Lower Permian Asselian-Sakmarian (296--283 Ma), Lower Permian Artinskian-Kungurian (283--274 Ma), and Upper Permian Tatarian (258--251 Ma). Parallel changes in the chemistry of brine inclusions from equivalent age evaporites in North America, Central Europe, and Eastern Europe show that seawater underwent secular variations in chemistry over the 50 million years of the Permian. Modeled SO{sub 4}{sup 2

  17. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions.

  18. Seawater batteries for the Luna 27

    SciTech Connect

    1997-04-01

    On 20 January 1996, the first installation of seawater batteries (SWBs) on a live subsea well was successfully completed on the Luna 27 well in 591 ft of water in the Ionian Sea. The SWB pack is composed of six cells, each measuring 3.3 ft in diameter by 6.6 ft high, and is designed to provide all the electrical energy required by the autonomous control system for the well. The only operations required in the future will be periodic replacement of the anodes by use of a remotely operated vehicle (ROV) every 3 to 5 years. This application of the SWBs is a part of the continuing research by Agip SpA in the area of autonomous control that began with the subsea-wells autonomous-control system (SWACS) project. This project began in 1982 and culminated with the installation of a SWACS prototype in December 1987 on the Luna 27 gas well offshore Crotone and 2.5 miles form the Luna A platform. Notwithstanding the 5-year predicted life, the system was still operating in 1996 without any noticeable problems.

  19. Dokdonia pacifica sp. nov., isolated from seawater.

    PubMed

    Zhang, Zenghu; Gao, Xin; Wang, Long; Zhang, Xiao-Hua

    2015-07-01

    A Gram-stain-negative, aerobic, non-flagellated, non-gliding, oxidase- and catalase-positive, rod-shaped, yellow-pigmented bacterium, designated strain SW230(T), was isolated from a surface seawater sample collected from the South Pacific Gyre. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW230(T) shared highest similarity with members of the genus Dokdonia (95.0-94.5%), exhibiting 95.0% sequence similarity to Dokdonia genika NBRC 100811(T). Optimal growth occurred in the presence of 2-3% (w/v) NaCl, at pH 8.0 and at 28 °C. The DNA G+C content of strain SW230(T) was 36 mol%. The major fatty acids (>10% of the total) were iso-C15:1 G, iso-C15:0, iso-C17:0 3-OH, and C16:1 ω7c and/or C16:1ω6c. The major respiratory quinone was menaquinone-6. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. On the basis of data from the present polyphasic study, strain SW230(T) is considered to represent a novel species of the genus Dokdonia, for which the name Dokdonia pacifica sp. nov. is proposed. The type strain is SW230(T) ( = CGMCC 1.12184(T) = JCM 18216(T)). PMID:25862384

  20. Analyzing, solving offshore seawater injection problems

    SciTech Connect

    Al-Rubale, J.S.; Muhsin, A.A.; Shaker, H.A.; Washash, I.

    1988-01-01

    Changes in seawater treatment, necessary cleaning of injection lines, and modifying well completion practices have reduced injection well plugging on pressure maintenance projects operated by Abu Dhabi Marine Operating Co., (Adma-Opco) in Zakum and Umm Shaif fields, offshore Abu Dhabi, in the Arabian Gulf. Plugging was caused primarily by iron sulfide and corrosion products that were displaced down hole after being formed in the water distribution system. These materials, in turn, resulted from O/sub 2/ inadvertently entering the injection system where it combined with corrosive H/sub 2/S generated by sulfate-reducing bacteria. The problem was further compounded by debris peeling from the interior of well tubulars, a high solids content of brine used to complete injectors, and slime formation in injection pipe lines. Acidizing wells proved a quick method for partially restoring injectivity, but a continuing concerted effort is being made to achieve more permanent results by eliminating the O/sub 2/ and H/sub 2/S, which are at the root of the difficulty.

  1. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions. PMID:25051401

  2. A closed recirculated sea-water system

    USGS Publications Warehouse

    1967-01-01

    Study of a virus disease in the chinook salmon (Oncorhynchus tshawytscha) necessitated the use of a marine environment to study the long range effects of the disease and to complete the life cycle of its etiologic agent. A closed recirculated sea-water system was designed for use under experimental laboratory conditions so that controlled studies of the disease could be made. As others may wish to do marine environment studies in the laboratory, the design and operation of our system are presented. Other systems currently in use have been described by Chin (1959), DeWitt and Salo (1960), McCrimmon and Berst (1966), and the authors of collected papers edited by Clark and Clark (1964). Preparatory to the design and construction of the system in use in this laboratory, visits were made to marine systems in use at the University of Washington's College of Fisheries, Seattle, -washington, and Friday Harbor Laboratory, San Juan Island, Washington; the Washington State Department of Fisheries' Point whitney Shellfish Laboratory, Brinnon, Washington; Humboldt State College, Arcata, California; and the Steinhart Aquarium of the California Academy of Science, San Francisco, California.

  3. Dynamics of seawater bacterial communities in a shellfish hatchery.

    PubMed

    Powell, S M; Chapman, C C; Bermudes, M; Tamplin, M L

    2013-08-01

    Bacterial disease is a significant issue for larviculture of several species of shellfish, including oysters. One source of bacteria is the seawater used throughout the hatchery. In this study carried out at a commercial oyster hatchery in Tasmania, Australia, the diversity of the bacterial community and its relationship with larval production outcomes were studied over a 2-year period using terminal restriction fragment length polymorphism and tag-encoded pyrosequencing. The bacterial communities were very diverse, dominated by the Alphaproteobacteria, Gammaproteobacteria, Flavobacteria and Cyanobacteria. The communities were highly variable on scales of days, weeks and seasons. The difference between the intake seawater and treated clean seawater used in the hatchery was smaller than the observed temporal differences in the seawater throughout the year. No clear correlation was observed between production outcomes and the overall bacterial community structure. However, one group of Cyanobacterial sequences was more abundant when mass mortality events occurred than when healthy spat were produced although they were always present.

  4. Similarities in the chemical composition of carbonate groundwaters and seawater

    SciTech Connect

    Hodge, V.F.; Stetzenbach, K.J.; Johannesson, K.H.

    1998-09-01

    Fifty-four elements were quantified in spring waters emanating from carbonate rock in Ash Meadows, in southern Nevada, and in Death Valley, CA. The results show that the concentrations of many of the trace elements found in these groundwaters are remarkably close to those found in modern seawater. The concentrations of 26 of the elements in the spring waters and seawater are within a factor of 2; 14 more are within a factor of 10; 8 elements are enriched in the groundwater by more than a factor of 10; and 6 elements are depleted by more than a factor of 10. Similarities in the trace chemical composition of ancient seawater and modern seawater can be inferred from the fingerprint of trace elements found in these carbonate rock-source spring waters.

  5. Oscillations in Phanerozoic seawater chemistry: evidence from fluid inclusions.

    PubMed

    Lowenstein, T K; Timofeeff, M N; Brennan, S T; Hardie, L A; Demicco, R V

    2001-11-01

    Systematic changes in the chemistry of evaporated seawater contained in primary fluid inclusions in marine halites indicate that seawater chemistry has fluctuated during the Phanerozoic. The fluctuations are in phase with oscillations in seafloor spreading rates, volcanism, global sea level, and the primary mineralogies of marine limestones and evaporites. The data suggest that seawater had high Mg2+/Ca2+ ratios (>2.5) and relatively high Na+ concentrations during the Late Precambrian [544 to 543 million years ago (Ma)], Permian (258 to 251 Ma), and Tertiary through the present (40 to 0 Ma), when aragonite and MgSO4 salts were the dominant marine precipitates. Conversely, seawater had low Mg2+/Ca2+ ratios (<2.3) and relatively low Na+ concentrations during the Cambrian (540 to 520 Ma), Silurian (440 to 418 Ma), and Cretaceous (124 to 94 Ma), when calcite was the dominant nonskeletal carbonate and K-, Mg-, and Ca-bearing chloride salts, were the only potash evaporites.

  6. A STRATEGY FOR PROTECTING CIRCULATING SEAWATER SYSTEMS FROM OIL SPILLS

    EPA Science Inventory

    A strategy is described for establishing a simple, inexpensive monitoring program for determining approximate levels of petroleum hydrocarbons in ambient water collected near intake structures of circulating seawater systems. The ambient water is obtained from the depth of intake...

  7. Latent Toxicity of Endothall to Anadromous Salmonids During Seawater Challenge.

    PubMed

    Courter, Lauren A; Garrison, Thomas M; Courter, Ian I

    2016-05-01

    Limited evidence exists on the latent effects of toxicant exposure on the seawater adaptability of anadromous salmon and steelhead. It is unclear whether such an effect exists for the widely used and relatively non-toxic herbicide endothall. Coho salmon, Oncorhynchus kisutch (coho), Chinook salmon, O. tshawytscha (Chinook), and anadromous rainbow trout, O. mykiss (steelhead) were subjected to a 10-day seawater challenge following freshwater treatments [0-12 mg acid equivalent (a.e)./L at 96 h]. Mean survival resulted in 82 % (n = 225), 84 % (n = 133), 90 % (n = 73) and 59 % (n = 147) survival for 0, 3-5, 6-8, and 9-12 mg a.e./L, respectively. Our results indicate a lower toxicity threshold compared with previously reported acute toxicity results, but higher compared with previous seawater challenge studies. We demonstrate the utility of the seawater challenge assay to accurately define toxic effects of pesticides on salmonids with complex life-histories. PMID:27000379

  8. The future of seawater desalination: energy, technology, and the environment.

    PubMed

    Elimelech, Menachem; Phillip, William A

    2011-08-01

    In recent years, numerous large-scale seawater desalination plants have been built in water-stressed countries to augment available water resources, and construction of new desalination plants is expected to increase in the near future. Despite major advancements in desalination technologies, seawater desalination is still more energy intensive compared to conventional technologies for the treatment of fresh water. There are also concerns about the potential environmental impacts of large-scale seawater desalination plants. Here, we review the possible reductions in energy demand by state-of-the-art seawater desalination technologies, the potential role of advanced materials and innovative technologies in improving performance, and the sustainability of desalination as a technological solution to global water shortages.

  9. Corrosion performance of zinc coated steel in seawater environment

    NASA Astrophysics Data System (ADS)

    Liu, Shuan; Zhao, Xia; Zhao, Haichao; Sun, Huyuan; Chen, Jianmin

    2016-05-01

    Considering the continuous exploitation of marine resources, it is very important to study the anticorrosion performance and durability of zinc coated streel (ZCS) because its increasing use as reinforcements in seawater. Tafel polarization curves and linear polarization curves combined with electrochemical impedance spectroscopy (EIS) were employed to evaluate the corrosion performance of ZCS at Qingdao test station during long-term immersion in seawater. The results indicated that the corrosion rate of the ZCS increased obviously with immersion time in seawater. The corrosion products that formed on the zinc coated steel were loose and porous, and were mainly composed of Zn5(OH)8Cl2, Zn5(OH)6(CO3)2, and ZnO. Pitting corrosion occurred on the steel surface in neutral seawater, and the rate of ZCS corrosion decreased with increasing pH.

  10. Uptake of elements from seawater by ferromanganese crusts: Solid-phase associations and seawater speciation

    USGS Publications Warehouse

    Koschinsky, A.; Hein, J.R.

    2003-01-01

    Marine Fe-Mn oxyhydroxide crusts form by precipitation of dissolved components from seawater. Three hydrogenetic crust samples (one phosphatized) and two hydrothermal Mn-oxide samples were subjected to a sequential-leaching procedure in order to determine the host phases of 40 elements. Those host-phase associations are discussed with respect to element speciation in seawater. The partitioning of elements between the two major phases, Mn oxide and Fe oxyhydroxide, can in a first-order approximation be explained by a simple sorption model related to the inorganic speciation of the elements in seawater, as has been proposed in earlier models. Free and weakly complexed cations, such as alkali and alkaline earth metals, Mn, Co, Ni, Zn, T1(I), and partly Y, are sorbed preferentially on the negatively charged surface of the MnO2 in hydrogenetic crusts. The driving force is a strong coulombic interaction. All neutral or negatively charged chloro (Cd, Hg, T1), carbonate (Cu, Y, Pb, and U), and hydroxide (Be, Sc, Ti, Fe, Zr, Nb, In, Sn, Sb, Te, Hf, Ta, Bi, Th, and T1(III)) complexes and oxyanions (V, Cr, As, Se, Mo, and W) bind to the slightly positively charged surface of the amorphous FeOOH phase. While coulombic interaction can explain the sorption of the negatively charged species, the binding of neutral species is based on specific chemical interaction. Organic complexation of elements in deep-ocean water seems to be at most of minor importance. Surface oxidation can explain some strong metal associations, e.g. of Co and T1 with the MnO2 and Te with the FeOOH. Sorption reactions initially driven by coulombic forces are often followed by the formation of specific bonds between the adsorbate and the atoms of the oxide surface. Differences in the associations of some metals between the non-phosphatized and phosphatized hydrogenetic crusts and between the hydrogenetic and the hydrothermal samples reflect the different physico-chemical environments of formation and

  11. Seawater pretreatment for reverse osmosis: chemistry, contaminants, and coagulation.

    PubMed

    Edzwald, James K; Haarhoff, Johannes

    2011-11-01

    The paper addresses the effects of salinity and temperature on the chemistry of important parameters affecting coagulation pretreatment including the ion product of water, acid-base chemistry, dissolved metal speciation, and precipitation reactions for aluminum and iron coagulants. The ion product of seawater is greater than for freshwaters and affects chemical hydrolysis and metal-hydroxide solubility reactions. Inorganic carbon is the main cause of seawater alkalinity and buffer intensity but borate B(OH)(4)(1-) also contributes. Buffer intensity is an important parameter in assessing coagulation pH adjustment. Mineral particles are relatively unstable in seawater from electrical double layer compression, and when present these particles are easily coagulated. Algal-particle stability is affected by steric effects and algal motility. Dissolved natural organic matter from algae and humic substances causes fouling of RO membranes and pretreatment removal is essential. Aluminum coagulants are not recommended, and not used, because they are too soluble in seawater. Ferric coagulants are preferred and used. The equilibrium solubility of Fe with amorphous ferric hydroxide in seawater is low over a wide range of pH and temperature conditions. Ferric chloride dosing guidelines are presented for various raw seawater quality characteristics. The effect of pH on coagulant dose and the role of buffer intensity are addressed. A dual coagulation strategy is recommended for treating seawater with moderate to high concentrations of algae or seawater with humic matter. This involves a low and constant dose with high charge-density cationic polymers using Fe as the main coagulant where it is varied in response to raw water quality changes.

  12. Seawater pretreatment for reverse osmosis: chemistry, contaminants, and coagulation.

    PubMed

    Edzwald, James K; Haarhoff, Johannes

    2011-11-01

    The paper addresses the effects of salinity and temperature on the chemistry of important parameters affecting coagulation pretreatment including the ion product of water, acid-base chemistry, dissolved metal speciation, and precipitation reactions for aluminum and iron coagulants. The ion product of seawater is greater than for freshwaters and affects chemical hydrolysis and metal-hydroxide solubility reactions. Inorganic carbon is the main cause of seawater alkalinity and buffer intensity but borate B(OH)(4)(1-) also contributes. Buffer intensity is an important parameter in assessing coagulation pH adjustment. Mineral particles are relatively unstable in seawater from electrical double layer compression, and when present these particles are easily coagulated. Algal-particle stability is affected by steric effects and algal motility. Dissolved natural organic matter from algae and humic substances causes fouling of RO membranes and pretreatment removal is essential. Aluminum coagulants are not recommended, and not used, because they are too soluble in seawater. Ferric coagulants are preferred and used. The equilibrium solubility of Fe with amorphous ferric hydroxide in seawater is low over a wide range of pH and temperature conditions. Ferric chloride dosing guidelines are presented for various raw seawater quality characteristics. The effect of pH on coagulant dose and the role of buffer intensity are addressed. A dual coagulation strategy is recommended for treating seawater with moderate to high concentrations of algae or seawater with humic matter. This involves a low and constant dose with high charge-density cationic polymers using Fe as the main coagulant where it is varied in response to raw water quality changes. PMID:21907384

  13. A gradient maintenance technique for seawater solar ponds

    SciTech Connect

    Kleis, S.J.; Li, H.; Shi, J.

    1997-02-01

    Seawater solar ponds are being evaluated as a means of reducing heat losses from thermal refuge areas in outdoor mariculture ponds during cold weather. The thermal refuge areas are intended to provide a reliable means of protecting fish crops from lethal cold water temperatures in the winter months. A continuous filling technique is demonstrated for use in gradient zone maintenance of the seawater solar ponds. The technique allows indefinite operation of the refuge areas with a minimal amount of fresh water.

  14. Temperature Sensing in Seawater Based on Microfiber Knot Resonator

    PubMed Central

    Yang, Hongjuan; Wang, Shanshan; Wang, Xin; Liao, Yipeng; Wang, Jing

    2014-01-01

    Ocean internal-wave phenomena occur with the variation in seawater vertical temperature, and most internal-wave detections are dependent on the measurement of seawater vertical temperature. A seawater temperature sensor based on a microfiber knot resonator (MKR) is designed theoretically and demonstrated experimentally in this paper. Especially, the dependences of sensing sensitivity on fiber diameter and probing wavelength are studied. Calculated results show that sensing sensitivity increases with the increasing microfiber diameter with the range of 2.30–3.91 μm and increases with the increasing probing wavelength, which reach good agreement with results obtained by experiments. By choosing the appropriate parameters, the maximum sensitivity measured can reach to be 22.81 pm/°C. The seawater temperature sensor demonstrated here shows advantages of small size, high sensitivity, easy fabrication, and easy integration with fiber systems, which may offer a new optical method to detect temperature of seawater or ocean internal-wave phenomenon and offer valuable reference for assembling micro sensors used for other parameters related to seawater, such as salinity, refractive index, concentration of NO3− and so on. PMID:25299951

  15. [Regulation effects of tourmaline on seawater pH value].

    PubMed

    Xia, Meisheng; Zhang, Hongmei; Hu, Caihong; Xu, Zirong

    2005-10-01

    In this paper, chemical analysis, X-ray diffraction and atomic force microscopy were employed to examine the characteristics of tourmaline produced in east Inner Mongolia Autonomous Region, and batch experiments were conducted to study its regulation effects on seawater pH value. The factors affecting the regulation, such as the dosage of tourmaline and the salinity and initial pH value of seawater, were also studied. The results showed that tourmaline could regulate the seawater pH value from its initial 3 and 10 to 7.1 and 8.9, respectively, and the regulation effect was greater in the seawater with lower salinity, e.g., after 120 minutes treatment, the initial pH value (5.0) of the seawater with a salinity of 5, 10, 15, 20 and 35 was increased by 3.24, 3.16, 3.06, 2.99 and 2.85 unit, respectively. Tourmaline had little effect on seawater conductivity. This study would provide an experimental base for the application of tourmaline in aquaculture. PMID:16422525

  16. [Regulation effects of tourmaline on seawater pH value].

    PubMed

    Xia, Meisheng; Zhang, Hongmei; Hu, Caihong; Xu, Zirong

    2005-10-01

    In this paper, chemical analysis, X-ray diffraction and atomic force microscopy were employed to examine the characteristics of tourmaline produced in east Inner Mongolia Autonomous Region, and batch experiments were conducted to study its regulation effects on seawater pH value. The factors affecting the regulation, such as the dosage of tourmaline and the salinity and initial pH value of seawater, were also studied. The results showed that tourmaline could regulate the seawater pH value from its initial 3 and 10 to 7.1 and 8.9, respectively, and the regulation effect was greater in the seawater with lower salinity, e.g., after 120 minutes treatment, the initial pH value (5.0) of the seawater with a salinity of 5, 10, 15, 20 and 35 was increased by 3.24, 3.16, 3.06, 2.99 and 2.85 unit, respectively. Tourmaline had little effect on seawater conductivity. This study would provide an experimental base for the application of tourmaline in aquaculture.

  17. Loktanella tamlensis sp. nov., isolated from seawater.

    PubMed

    Lee, Soon Dong

    2012-03-01

    An aerobic, Gram-reaction-negative, chemo-organotrophic bacterium, designated strain SSW-35(T), was isolated from seawater in Jeju, Republic of Korea. Cells were motile, short rods; colonies were circular, smooth, convex, translucent and beige in colour. No diffusible pigment formed on any of the media tested. The bacterium grew at 4-30 °C and pH 7.1-10.1. Phylogenetic analysis based on 16S rRNA gene sequences showed that the organism was related to members of the genus Loktanella, its closest recognized relatives being Loktanella rosea Fg36(T) (98.1% sequence similarity) and Loktanella maricola DSW-18(T) (97.8%). Levels of 16S rRNA gene similarity between strain SSW-35(T) and other recognized species of the genus Loktanella were all <97%. Polar lipid analysis revealed the presence of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unknown lipid as major components, as well as small amounts of two unknown phospholipids. The predominant ubiquinone was Q-10. The major cellular fatty acid was C(18:1) (summed feature 7), and the 3-hydroxy fatty acids detected were C(12:1) 3-OH and C(10:0) 3-OH. The genomic DNA G+C content was 55.0 mol%. In DNA-DNA hybridization experiments, the relatedness values between strain SSW-35(T) and the type strains of the phylogenetically closest recognized species were all <11%. On the basis of the phenotypic and genotypic characteristics, phylogenetic analysis and DNA-DNA relatedness, a novel species, Loktanella tamlensis sp. nov., is proposed. The type strain is SSW-35(T) (=KCTC 12722(T)=JCM 14020(T)).

  18. Actibacterium ureilyticum sp. nov., isolated from seawater.

    PubMed

    Lin, Shih-Yao; Young, Chiu-Chung; Hameed, Asif; Liu, You-Cheng; Hsu, Yi-Han; Chung, Wei-Ching; Young, Li-Sen

    2016-08-01

    A polyphasic approach was used to characterize a novel marine bacterial strain, designated LS-811T, isolated from seawater of the South China Sea (Taiwan). Cells of strain LS-811Twere Gram-staining negative, aerobic and rod-shaped with polar flagella. The 16S rRNA gene sequence analysis of strain LS-811T showed highest sequence similarity to Actibacterium mucosum (96.5 %) and Actibacterium atlanticum (95.6 %), and lower sequence similarity (<96.0 %) to members of all other related genera. Strain LS-811Twas able to grow at 15-40 °C and pH 5.0-9.0. The quinone system was ubiquinone (Q-10), and the DNA G+C content was 60.1 mol%. The major fatty acids (>5 %) found in strain LS-811T were C18 : 0, C10 : 0 3-OH, C19 : 0 cyclo ω8c and C18 : 1ω7c/C18 : 1ω6c. The major polar lipid profile consisted of glycolipids, phosphatidylglycerol and one unidentified aminolipid. Based on the distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence analysis, strain LS-811T is considered to represent a novel species in the genus Actibacterium, for which the name Actibacterium ureilyticum sp. nov. is proposed. The type strain is LS-811T (=BCRC 80823T=JCM 30681T). PMID:27031530

  19. Shewanella dokdonensis sp. nov., isolated from seawater.

    PubMed

    Sung, Hye-Ri; Yoon, Jung-Hoon; Ghim, Sa-Youl

    2012-07-01

    A novel bacterial strain, designated UDC329(T), was isolated from a sample of seawater collected at Dong-do, on the coast of Dokdo Island, in the East Sea of the Republic of Korea. The Gram-staining-negative, motile, facultatively anaerobic, non-spore-forming rods of the strain developed into dark orange-yellow colonies. The strain grew optimally between 25 and 30 °C, with 1% (w/v) NaCl and at pH 7. It grew in the absence of NaCl, but not with NaCl at >7% (w/v). The predominant menaquinone was MK-7, the predominant ubiquinones were Q-7 and Q-8, and the major fatty acids were iso-C(15:0) (33.52%) and C(17:1)ω8c (11.73%). The genomic DNA G+C content of strain UDC329(T) was 50.2 mol%. In phylogenetic analyses based on 16S rRNA and gyrB gene sequences, strain UDC329(T) was grouped with members of the genus Shewanella and appeared most closely related to Shewanella fodinae JC15(T) (97.9% 16S rRNA gene sequence similarity), Shewanella indica KJW27(T) (95.0%), Shewanella algae ATCC 51192(T) (94.8%), Shewanella haliotis DW01(T) (94.5%) and Shewanella chilikensis JC5(T) (93.9%). The level of DNA-DNA relatedness between strain UDC329(T) and S. fodinae JC15(T) was, however, only 27.4%. On the basis of phenotypic, genotypic and DNA-DNA relatedness data, strain UDC329(T) represents a novel species in the genus Shewanella, for which the name Shewanella dokdonensis sp. nov. is proposed. The type strain is UDC329(T) (=KCTC 22898(T)=DSM 23626(T)).

  20. Marinicella pacifica sp. nov., isolated from seawater.

    PubMed

    Wang, Yanan; Liu, Yan; Zhang, Zenghu; Zheng, Yanfen; Zhang, Xiao-Hua

    2016-06-01

    A Gram-stain-negative, strictly aerobic, non-motile, non-gliding, oxidase-positive, catalase-positive, rod-shaped bacterium, designated strain sw153T, was isolated from surface seawater of the South Pacific Gyre (39° 19' S 139° 48' W) during Integrated Ocean Drilling Program Expedition 329. Growth occurred at 10-42 °C (optimum 28 °C), in the presence of 1-8 % (w/v) NaCl (optimum 2 %) and at pH 6.0-10.0 (optimum pH 7.5-8.5). The major fatty acids (>10 %) were iso-C15:0 and summed feature 3 (C16:1ω6c and/or C16:1ω7c). The major polar lipids comprised phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, an unidentified polar lipid and an unidentified phospholipid. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content of strain sw153T was 44.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences placed strain sw153T within the genus Marinicella, class Gammaproteobacteria. The most closely related species was Marinicella litoralis KMM 3900T (96.6 % 16S rRNA gene sequence similarity). Based on the polyphasic analyses in this study, strain sw153T is considered to represent a novel species of the genus Marinicella, for which the name Marinicella pacifica sp. nov. is proposed. The type strain is sw153T (=JCM 18208T=CGMCC 1.12181T).

  1. Marinicella pacifica sp. nov., isolated from seawater.

    PubMed

    Wang, Yanan; Liu, Yan; Zhang, Zenghu; Zheng, Yanfen; Zhang, Xiao-Hua

    2016-06-01

    A Gram-stain-negative, strictly aerobic, non-motile, non-gliding, oxidase-positive, catalase-positive, rod-shaped bacterium, designated strain sw153T, was isolated from surface seawater of the South Pacific Gyre (39° 19' S 139° 48' W) during Integrated Ocean Drilling Program Expedition 329. Growth occurred at 10-42 °C (optimum 28 °C), in the presence of 1-8 % (w/v) NaCl (optimum 2 %) and at pH 6.0-10.0 (optimum pH 7.5-8.5). The major fatty acids (>10 %) were iso-C15:0 and summed feature 3 (C16:1ω6c and/or C16:1ω7c). The major polar lipids comprised phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, an unidentified polar lipid and an unidentified phospholipid. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content of strain sw153T was 44.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences placed strain sw153T within the genus Marinicella, class Gammaproteobacteria. The most closely related species was Marinicella litoralis KMM 3900T (96.6 % 16S rRNA gene sequence similarity). Based on the polyphasic analyses in this study, strain sw153T is considered to represent a novel species of the genus Marinicella, for which the name Marinicella pacifica sp. nov. is proposed. The type strain is sw153T (=JCM 18208T=CGMCC 1.12181T). PMID:26978647

  2. Aquimarina megaterium sp. nov., isolated from seawater.

    PubMed

    Yu, Tong; Zhang, Zenghu; Fan, Xiaoyang; Shi, Xiaochong; Zhang, Xiao-Hua

    2014-01-01

    A novel Gram-stain-negative, rod-shaped, non-flagellated, strictly aerobic strain with gliding motility, designated XH134(T), was isolated from surface seawater of the South Pacific Gyre (45° 58' S 163° 11' W) during the Integrated Ocean Drilling Program Expedition 329. The major respiratory quinone of strain XH134(T) was MK-6. The dominant fatty acids of strain XH134(T) were iso-C15 : 0, iso-C15 : 1 G, C16 : 1ω6c and/or C16 : 1ω7c, iso-C17 : 0 3-OH, iso-C15 : 0 3-OH and 10-methyl C16 : 0 and/or iso-C17 : 1ω9c. The polar lipids of strain XH134(T) comprised phosphatidylethanolamine, one unknown aminolipid and three unknown polar lipids. The DNA G+C content of strain XH134(T) was 32.4 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that the novel strain was related most closely to Aquimarina macrocephali JAMB N27(T) with 96.9 % sequence similarity. A number of phenotypic characteristics distinguished strain XH134(T) from described members of the genus Aquimarina. On the basis of combined phenotypic and phylogenetic analyses, strain XH134(T) represents a novel species of the genus Aquimarina, for which the name Aquimarina megaterium sp. nov. is proposed. The type strain is XH134(T) ( = CGMCC 1.12186(T) = JCM 18215(T)). PMID:24030690

  3. Belliella marina sp. nov., isolated from seawater.

    PubMed

    Song, Lei; Liu, Hongcan; Wang, Jian; Huang, Ying; Dai, Xin; Han, Xiqiu; Zhou, Yuguang

    2015-12-01

    Gram-stain-negative, rod-shaped bacterium, strain SW112T, was isolated from a seawater sample collected from the Indian Ocean. The strain was strictly aerobic and catalase- and oxidase-positive. Strain SW112T grew at 4-42 °C (optimum 30 °C), at pH 5.5-9.5 (optimum pH 7.5) and in the presence of 0-9.0 % (w/v) NaCl (optimum 2.0-3.0 %). The predominant cellular fatty acids were iso-C15 : 0 (29.7 %), iso-C17 : 03-OH (14.3 %) and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 15.1 %). The major menaquinone was menaquinone-7 and the major polar lipid was phosphatidylethanolamine. The genomic DNA G+C content of strain SW112T was 39 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain SW112T was related to members of the genus Belliella, showing the highest similarity with Belliella aquatica TS-T86T and Belliella baltica DSM 15883T (96.5 % and 96.4 %sequence similarity, respectively). On the basis of phylogenetic inference and phenotypic characteristics, it is proposed that strain SW112T represents a novel species of the genus Belliella, for which the name Belliella marina sp. nov. is proposed. The type strain is SW112T(=CGMCC 1.15180T=KCTC 33694T). PMID:26346194

  4. Actibacterium ureilyticum sp. nov., isolated from seawater.

    PubMed

    Lin, Shih-Yao; Young, Chiu-Chung; Hameed, Asif; Liu, You-Cheng; Hsu, Yi-Han; Chung, Wei-Ching; Young, Li-Sen

    2016-08-01

    A polyphasic approach was used to characterize a novel marine bacterial strain, designated LS-811T, isolated from seawater of the South China Sea (Taiwan). Cells of strain LS-811Twere Gram-staining negative, aerobic and rod-shaped with polar flagella. The 16S rRNA gene sequence analysis of strain LS-811T showed highest sequence similarity to Actibacterium mucosum (96.5 %) and Actibacterium atlanticum (95.6 %), and lower sequence similarity (<96.0 %) to members of all other related genera. Strain LS-811Twas able to grow at 15-40 °C and pH 5.0-9.0. The quinone system was ubiquinone (Q-10), and the DNA G+C content was 60.1 mol%. The major fatty acids (>5 %) found in strain LS-811T were C18 : 0, C10 : 0 3-OH, C19 : 0 cyclo ω8c and C18 : 1ω7c/C18 : 1ω6c. The major polar lipid profile consisted of glycolipids, phosphatidylglycerol and one unidentified aminolipid. Based on the distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence analysis, strain LS-811T is considered to represent a novel species in the genus Actibacterium, for which the name Actibacterium ureilyticum sp. nov. is proposed. The type strain is LS-811T (=BCRC 80823T=JCM 30681T).

  5. Sporulation and survival of Toxoplasma gondii oocysts in seawater

    USGS Publications Warehouse

    Lindsay, D.S.; Collins, M.V.; Mitchell, S.M.; Cole, R.A.; Flick, G.J.; Wetch, C.N.; Lindquist, A.; Dubey, J.P.

    2003-01-01

    We have been collaborating since 1992 in studies on southern sea otters (Enhdyra lutris nereis) as part of a program to define factors, which may be responsible for limiting the growth of the southern sea otter population. We previously demonstrated Toxoplasma gondii in sea otters. We postulated that cat feces containing oocysts could be entering the marine environment through storm run-off or through municipal sewage since cat feces are often disposed down toilets by cat owners. The present study examined the sporulation of T. gondii oocysts in seawater and the survival of sporulated oocysts in seawater. Unsporulated oocysts were placed in 15 ppt artificial seawater, 32 ppt artificial seawater or 2% sulfuric acid (positive control) at 24 C in an incubator. Samples were examined daily for 3 days and development monitored by counting 100 oocysts from each sample. From 75 to 80% of the oocysts were sporulated by 3 days post-inoculation under all treatment conditions. Groups of 2 mice were fed 10,000 oocysts each from each of the 3 treatment groups. All inoculated mice developed toxoplasmosis indicating that oocysts were capable of sporulating in seawater. Survival of sporulated oocysts was examined by placing sporulated T. gondii oocysts in 15 ppt seawater at room temperature 22a??24 C (RT) or in a refrigerator kept at 4 C. Mice fed oocysts that had been stored at 4C or RT for 6 months became infected. These results indicate that T. gondii oocysts can sporulate and remain viable in seawater for several months.

  6. Estimates of ikaite export from sea ice to the underlying seawater in a sea ice-seawater mesocosm

    NASA Astrophysics Data System (ADS)

    Geilfus, Nicolas-Xavier; Galley, Ryan J.; Else, Brent G. T.; Campbell, Karley; Papakyriakou, Tim; Crabeck, Odile; Lemes, Marcos; Delille, Bruno; Rysgaard, Søren

    2016-09-01

    The precipitation of ikaite and its fate within sea ice is still poorly understood. We quantify temporal inorganic carbon dynamics in sea ice from initial formation to its melt in a sea ice-seawater mesocosm pool from 11 to 29 January 2013. Based on measurements of total alkalinity (TA) and total dissolved inorganic carbon (TCO2), the main processes affecting inorganic carbon dynamics within sea ice were ikaite precipitation and CO2 exchange with the atmosphere. In the underlying seawater, the dissolution of ikaite was the main process affecting inorganic carbon dynamics. Sea ice acted as an active layer, releasing CO2 to the atmosphere during the growth phase, taking up CO2 as it melted and exporting both ikaite and TCO2 into the underlying seawater during the whole experiment. Ikaite precipitation of up to 167 µmol kg-1 within sea ice was estimated, while its export and dissolution into the underlying seawater was responsible for a TA increase of 64-66 µmol kg-1 in the water column. The export of TCO2 from sea ice to the water column increased the underlying seawater TCO2 by 43.5 µmol kg-1, suggesting that almost all of the TCO2 that left the sea ice was exported to the underlying seawater. The export of ikaite from the ice to the underlying seawater was associated with brine rejection during sea ice growth, increased vertical connectivity in sea ice due to the upward percolation of seawater and meltwater flushing during sea ice melt. Based on the change in TA in the water column around the onset of sea ice melt, more than half of the total ikaite precipitated in the ice during sea ice growth was still contained in the ice when the sea ice began to melt. Ikaite crystal dissolution in the water column kept the seawater pCO2 undersaturated with respect to the atmosphere in spite of increased salinity, TA and TCO2 associated with sea ice growth. Results indicate that ikaite export from sea ice and its dissolution in the underlying seawater can potentially hamper

  7. Aquimarina pacifica sp. nov., isolated from seawater.

    PubMed

    Zhang, Zenghu; Yu, Tong; Xu, Tingting; Zhang, Xiao-Hua

    2014-06-01

    A Gram-stain-negative, rod-shaped, non-flagellated, strictly aerobic bacterium with gliding motility, designated strain SW150(T), was isolated from surface seawater of the South Pacific Gyre (39° 19' S 139° 48' W) during the Integrated Ocean Drilling Program Expedition 329. Optimal growth occurred in the presence of 2-4% (w/v) NaCl, at pH 7-8 and at 28-30 °C. The dominant fatty acids were iso-C(15 : 0), iso-C(17 : 0) 3-OH, iso-C(15 : 1) G, C(16 : 1)ω6c and/or C(16 : 1)ω7c and 10-methyl C(16 : 0) and/or iso-C(17 : 1)ω9c. The polar lipids of strain SW150(T) comprised phosphatidylethanolamine, three unknown polar lipids and one unknown aminolipid. The major respiratory quinone was MK-6. The DNA G+C content of strain SW150(T) was 33.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Aquimarina macrocephali JAMB N27(T) and Aquimarina muelleri KMM 6020(T) with 97.8 and 96.8% sequence similarities, respectively. The estimated DNA-DNA hybridization values were 21.00±2.33% between strain SW150(T) and A. macrocephali JAMB N27(T) and 20.60±2.32% between strain SW150(T) and Aquimarina megaterium XH134(T). On the basis of polyphasic analyses, strain SW150(T) represents a novel species of the genus Aquimarina, for which the name Aquimarina pacifica sp. nov. is proposed. The type strain is SW150(T) ( = JCM 18214(T) = CGMCC 1.12180(T)). PMID:24626966

  8. Abiotic Nitrous Oxide Production in Natural and Artificial Seawater

    NASA Astrophysics Data System (ADS)

    Ochoa, H.; Stanton, C. L.; Cavazos, A. R.; Ostrom, N. E.; Glass, J. B.

    2014-12-01

    The ocean contributes approximately one third of global sources of nitrous oxide (N2O) to the atmosphere. While nitrification is thought to be the dominant pathway for marine N2O production, mechanisms remain unresolved. Previous studies have carried the implicit assumption that marine N2O originates directly from enzymatic sources. However, abiotic production of N2O is possible via chemical reactions between nitrogenous intermediates and redox active trace metals in seawater. In this study, we investigated N2O production and isotopic composition in treatments with and without added hydroxylamine (NH2OH) and nitric oxide (NO), intermediates in microbial oxidation of ammonia to nitrite, and Fe(III). Addition of substrates to sterile artificial seawater was compared with filtered and unfiltered seawater from Sapelo Island, coastal Georgia, USA. N2O production was observed immediately after addition of Fe(III) in the presence of NH2OH at pH 8 in sterile artificial seawater. Highest N2O production was observed in the presence of Fe(III), NO, and NH2OH. The isotopomer site preference of abiotically produced N2O was consistent with previous studies (31 ± 2 ‰). Higher abiotic N2O production was observed in sterile artificial seawater (salinity: 35 ppt) than filtered Sapelo Island seawater (salinity: 25 ppt) whereas diluted sterile artificial seawater (18 ppt) showed lowest N2O production, suggesting that higher salinity promotes enhanced abiotic N2O production. Addition of Fe(III) to unfiltered Sapelo Island seawater stimulated N2O production. The presence of ammonia-oxidizing archaea (AOA), which lack known N2O producing enzymes, in Sapelo Island seawater was confirmed by successful amplification of the archaeal amoA gene, whereas ammonia-oxidizing bacteria (AOB), which contain N2O-producing enzymes were undetected. Given the few Fe-containing proteins present in AOA, it is likely that Fe(III) addition promoted N2O production via an abiotic vs. enzymatic N2O mechanism

  9. Development of analytical techniques of vanadium isotope in seawater

    NASA Astrophysics Data System (ADS)

    Huang, T.; Owens, J. D.; Sarafian, A.; Sen, I. S.; Huang, K. F.; Blusztajn, J.; Nielsen, S.

    2015-12-01

    Vanadium (V) is a transition metal with isotopes of 50V and 51V, and oxidation states of +2, +3, +4 and +5. The average concentration in seawater is 1.9 ppb, which results in a marine residence time of ~50 kyrs. Its various oxidation states make it a potential tool for investigating redox conditions in the ocean and sediments due to redox related changes in the valance state of vanadium. In turn, chemical equilibrium between different oxidation states of V will likely cause isotopic fractionation that can potentially be utilized to quantify past ocean redox states. In order to apply V isotopes as a paleo-redox tracer, it is required that we know the isotopic composition of seawater and the relation to marine sources and sinks of V. We developed a novel method for pre-concentrating V and measuring the isotope ratio in seawater samples. In our method, we used four ion exchange chromatography columns to separate vanadium from seawater matrix elements, in particular titanium and chromium, which both have an isobaric interference on 50V. The first column uses the NOBIAS resin, which effectively separates V and other transition metals from the majority of seawater matrix. Subsequent columns are identical to those utilized when separating V from silicate samples (Nielsen et al, Geostand. Geoanal. Res., 2011). The isotopic composition of the purified V is measured using a Thermo Scientific Neptune multiple collector inductively coupled plasma mass spectrometer (MC-ICP-MS) in medium resolution mode. This setup resolves all molecular interferences from masses 49, 50, 51, 52 and 53 including S-O species on mass 50. To test the new method, we spiked an open ocean seawater sample from the Bermuda Atlantic Time Series (BATS) station with 10-25 μg of Alfa Aesar vanadium solution, which has an isotopic composition of δ51V = 0 [where δ51V = 1000 × [(51V/50Vsample - 51V/50VAA)/51V/50VAA]. The average of six spiked samples is -0.03±0.19‰, which is within error of the true

  10. Biogeochemical effects of seawater restoration to diked salt marshes

    USGS Publications Warehouse

    Portnoy, J.W.; Giblin, A.E.

    1997-01-01

    We conducted greenhouse microcosm experiments to examine the biogeochemical effects of restoring seawater to historically diked Cape Cod salt marshes. Peat cores from both seasonally flooded and drained diked marshes were waterlogged with seawater, and porewater chemistry was subsequently monitored for 21 mo. The addition of seawater to highly organic, seasonally flooded peat caused the death of freshwater wetland plants, 6-8 cm of sediment subsidence, and increased N and P mineralization. Also, sulfides and alkalinity increased 10-fold, suggesting accelerated decomposition by sulfate reduction. Addition of seawater to the low-organic-content acidic peat from the drained marsh increased porewater pH, alkalinity, PO4-P, and Fe(II), which we attribute to the reestablishment of SO4 and Fe(III) mineral reduction. Increased cation exchange contributed to 6-fold increases in dissolved Fe(II) and Al and 60-fold increases in NH4-N within 6 mo of sail-nation. Seawater reintroductions to seasonally flooded diked marshes will cause porewater sulfides to increase, likely reducing the success of revegetation efforts. Sulfide toxicity is of less concern in resalinated drained peats because of the abundance of Fe(II) to precipitate sulfides, and of NH4-N to offset sulfide inhibition of N uptake. Restoration of either seasonally flooded or drained diked marshes could stimulate potentially large nutrient and Fe(II) releases, which could in turn increase primary production and lower oxygen in receiving waters. These findings suggest that tidal restoration be gradual and carefully monitored.

  11. Seawater calcium isotope ratios across the Eocene-Oligocene transition

    USGS Publications Warehouse

    Griffith, E.M.; Paytan, A.; Eisenhauer, A.; Bullen, T.D.; Thomas, E.

    2011-01-01

    During the Eocene-Oligocene transition (EOT, ca. 34 Ma), Earth's climate cooled significantly from a greenhouse to an icehouse climate, while the calcite (CaCO3) compensation depth (CCD) in the Pacific Ocean increased rapidly. Fluctuations in the CCD could result from various processes that create an imbalance between calcium (Ca) sources to, and sinks from, the ocean (e.g., weathering and CaCO3 deposition), with different effects on the isotopic composition of dissolved Ca in the oceans due to differences in the Ca isotopic composition of various inputs and outputs. We used Ca isotope ratios (??44/40Ca) of coeval pelagic marine barite and bulk carbonate to evaluate changes in the marine Ca cycle across the EOT. We show that the permanent deepening of the CCD was not accompanied by a pronounced change in seawater ??44/40Ca, whereas time intervals in the Neogene with smaller carbonate depositional changes are characterized by seawater ??44/40Ca shifts. This suggests that the response of seawater ??44/40Ca to changes in weathering fluxes and to imbalances in the oceanic alkalinity budget depends on the chemical composition of seawater. A minor and transient fluctuation in the Ca isotope ratio of bulk carbonate may reflect a change in isotopic fractionation associated with CaCO3 precipitation from seawater due to a combination of factors, including changes in temperature and/or in the assemblages of calcifying organisms. ?? 2011 Geological Society of America.

  12. Quasi-horizontal circulation cells in 3D seawater intrusion

    USGS Publications Warehouse

    Abarca, E.; Carrera, J.; Sanchez-Vila, X.; Voss, C.I.

    2007-01-01

    The seawater intrusion process is characterized by the difference in freshwater and seawater density that causes freshwater to float on seawater. Many confined aquifers have a large horizontal extension with respect to thickness. In these cases, while buoyancy acts in the vertical direction, flow is confined between the upper and bottom boundaries and the effect of gravity is controlled by variations of aquifer elevation. Therefore, the effective gravity is controlled by the slope and the shape of the aquifer boundaries. Variability in the topography of the aquifer boundaries is one case where 3D analysis is necessary. In this work, density-dependent flow processes caused by 3D aquifer geometry are studied numerically and specifically, considering a lateral slope of the aquifer boundaries. Sub-horizontal circulation cells are formed in the saltwater entering the aquifer. The penetration of the saltwater can be quantified by a dimensionless buoyancy number that measures the lateral slope of the aquifer relative to freshwater flux. The penetration of the seawater intrusion wedge is controlled more by this slope than by the aquifer thickness and dispersivity. Thus, the slope must be taken into account in order to accurately evaluate seawater intrusion. ?? 2007 Elsevier B.V. All rights reserved.

  13. XAS and TRLIF spectroscopy of uranium and neptunium in seawater.

    PubMed

    Maloubier, Melody; Solari, Pier Lorenzo; Moisy, Philippe; Monfort, Marguerite; Den Auwer, Christophe; Moulin, Christophe

    2015-03-28

    Seawater contains radionuclides at environmental levels; some are naturally present and others come from anthropogenic nuclear activity. In this report, the molecular speciation in seawater of uranium(VI) and neptunium(V) at a concentration of 5 × 10(-5) M has been investigated for the first time using a combination of two spectroscopic techniques: Time-resolved laser-induced fluorescence (TRLIF) for U and extended X-ray absorption fine structure (EXAFS) for U and Np at the LIII edge. In parallel, the theoretical speciation of uranium and neptunium in seawater at the same concentration is also discussed and compared to spectroscopic data. The uranium complex was identified as the neutral carbonato calcic complex UO2(CO3)3Ca2, which has been previously described in other natural systems. In the case of neptunium, the complex identified is mainly a carbonato complex whose exact stoichiometry is more difficult to assess. The knowledge of the actinide molecular speciation and reactivity in seawater is of fundamental interest in the particular case of uranium recovery and more generally regarding the actinide life cycle within the biosphere in the case of accidental release. This is the first report of actinide direct speciation in seawater medium that can complement inventory data.

  14. Effect of calcium carbonate saturation of seawater on coral calcification

    USGS Publications Warehouse

    Gattuso, J.-P.; Frankignoulle, M.; Bourge, I.; Romaine, S.; Buddemeier, R.W.

    1998-01-01

    The carbonate chemistry of seawater is usually not considered to be an important factor influencing calcium-carbonate-precipitation by corals because surface seawater is supersaturated with respect to aragonite. Recent reports, however, suggest that it could play a major role in the evolution and biogeography of recent corals. We investigated the calcification rates of five colonies of the zooxanthellate coral Stylophora pistillata in synthetic seawater using the alkalinity anomaly technique. Changes in aragonite saturation from 98% to 585% were obtained by manipulating the calcium concentration. The results show a nonlinear increase in calcification rate as a function of aragonite saturation level. Calcification increases nearly 3-fold when aragonite saturation increases from 98% to 390%, i.e., close to the typical present saturation state of tropical seawater. There is no further increase of calcification at saturation values above this threshold. Preliminary data suggest that another coral species, Acropora sp., displays a similar behaviour. These experimental results suggest: (l) that the rate of calcification does not change significantly within the range of saturation levels corresponding to the last glacial-interglacial cycle, and (2) that it may decrease significantly in the future as a result of the decrease in the saturation level due to anthropogenic release of CO2 into the atmosphere. Experimental studies that control environmental conditions and seawater composition provide unique opportunities to unravel the response of corals to global environmental changes.

  15. Flow through luminescence for heavy metal analysis in seawater

    NASA Astrophysics Data System (ADS)

    San Vicente De la Riva, Blanca; Costa Fernandez, Jose M.; Pereiro Garcia, Rosario; Sanz-Medel, Alfredo

    1999-12-01

    The toxicity of heavy metals is well documented today and legislation for their control in seawater continuously becomes more and more restrictive. In order to control and ensure the marine environment quality it is demanded an effort to develop new analytical tools, which allow the analysis of trace levels of heavy metals in seawater. The measurement of luminescence (phosphorescence and fluorescence) gives rise to high sensitive, selective and innovative approaches which could be used to develop new trace metal sensing methods. In this way, we have observed that the metal-chelates formed between different sulphonic-hydroxyquinolines with heavy metals, such as lead, or the metal-chelates between mercury and purines exhibit strong room temperature phosphorescence and fluorescence, respectively. Based on the formation of such quelates, two luminescence methods are investigated for sensing of lead and mercury in seawater. Optimum experimental conditions and the analytical performance characteristics of the methods are discussed. Relative standard deviations in the order of 4% are typical at 100 ng mL-1 of Pb(II) and Hg (II). The detection limits are 0.1 and 1.4 ng mL-1 for lead and mercury, respectively. Possible interferences present in seawater, including sea water cations and anions are evaluated in detail. Finally, the methods are applied to the determination de mercury and lead in seawater samples.

  16. Table Salt from Seawater (Solar Evaporation). What We Take from Our Environment. Science and Technology Education in Philippine Society.

    ERIC Educational Resources Information Center

    Philippines Univ., Quezon City. Science Education Center.

    This module discusses methods of obtaining table salt from seawater. Topic areas considered include: (1) obtaining salt by solar evaporation of seawater in holes; (2) obtaining salt by boiling seawater in pots; (3) how table salt is obtained from seawater in the Philippines; and (4) methods of making salt by solar evaporation of seawater in the…

  17. Extraction of uranium from seawater using magnetic adsorbents

    SciTech Connect

    Yamashita, H.; Fujita, K.; Nakajima, F.; Ozawa, Y.; Murata, T.

    1981-01-01

    A new process for the extraction of uranium from seawater was developed. In the process, uranium adsorption is effected using powdered magnetic adsorbents; the adsorbents are then separated from seawater using magnetic separation technology. This process is superior to a column method using a granulated hydrous titanium oxide adsorber bed in the following ways: (1) a higher rate of adsorption is realized because smaller particles are used in the uranium adsorption; and (2) blocking, which is inevitable in an adsorber bed, is eliminated. The composite hydrous titanium-iron oxide as a magnetic adsorbent having high uranium adsorption capacity and magnetization can be prepared by adding urea to a mixed solution of titanium sulfate and ferrous sulfate. Adsorption and desoprtion of uranium and the removal of the adsorbent using a small-scale uranium extraction plant (about 15 m/sup 3//d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures.

  18. Numerical modeling of seawater intrusion into endorheic hydrological systems

    NASA Astrophysics Data System (ADS)

    Kafri, U.; Shalev, E.; Lyakhovsky, V.; Wollman, S.; Yechieli, Y.

    2013-08-01

    Several groundwater endorheic base levels are known in different parts of the world. Some of them allow seawater encroachment into them. Two examples of such groundwater systems, at Lake Asal in the Afar Depression of East Africa and Lago Enriquillo in the Dominican Republic, have been modeled using FEFLOW. The simulated flow pattern reproduces the seawater encroachment all the way from the sea to the endorheic base level. When the water in that base level undergoes concentration to brine through evaporation, the dense brine starts to flow below the encroaching seawater body in the opposite direction toward the sea. These processes reach steady-state conditions in a relatively short time of several hundred years.

  19. Bacteria-driven production of alkyl nitrates in seawater

    NASA Astrophysics Data System (ADS)

    Kim, Michelle J.; Michaud, Jennifer M.; Williams, Renee; Sherwood, Byron Pedler; Pomeroy, Robert; Azam, Farooq; Burkart, Michael; Bertram, Timothy H.

    2015-01-01

    and ship-borne measurements have shown that the ocean is a large, diffuse source for short chain (C1-C3) gas phase alkyl nitrates (RONO2). Photochemical production of RONO2 has been demonstrated previously as a viable mechanism in surface waters; however, it cannot account for the observed depth profile of RONO2, suggesting an additional, dark RONO2 production mechanism. We present measurements of gas phase C1-C5 alkyl nitrates emitted from seawater in a controlled mesocosm experiment conducted under low-light conditions in a glass-walled wave channel. Ethyl and butyl nitrate emission rates from seawater are strongly correlated with the abundance of heterotrophic bacteria (R2 ≥ 0.89) and show no correlation to chlorophyll a concentration. Controlled flask experiments conducted using ambient and sterile seawater, inoculated with a heterotrophic bacterium, confirm that bacterial driven production of select RONO2 can proceed efficiently in the absence of light.

  20. Analytical calculation of muon intensities under deep sea-water

    NASA Technical Reports Server (NTRS)

    Inazawa, H.; Kobayakawa, K.

    1985-01-01

    The study of the energy loss of high energy muons through different materials, such as rock and sea-water can cast light on characteristics of lepton interactions. There are less ambiguities for the values of atomic number (Z) and mass number (A) in sea-water than in rock. Muon intensities should be measured as fundamental data and as background data for searching the fluxes of neutrino. The average range energy relation in sea-water is derived. The correction factors due to the range fluctuation is also computed. By applying these results, the intensities deep under sea are converted from a given muon energy spectra at sea-level. The spectra of conventional muons from eta, K decays have sec theta enhancement. The spectrum of prompt muons from charmed particles is almost isotropic. The effect of prompt muons is examined.

  1. Mining Critical Metals and Elements from Seawater: Opportunities and Challenges.

    PubMed

    Diallo, Mamadou S; Kotte, Madhusudhana Rao; Cho, Manki

    2015-08-18

    The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater.

  2. Mining Critical Metals and Elements from Seawater: Opportunities and Challenges.

    PubMed

    Diallo, Mamadou S; Kotte, Madhusudhana Rao; Cho, Manki

    2015-08-18

    The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater. PMID:25894365

  3. Reconstruction of secular variation in seawater sulfate concentrations

    NASA Astrophysics Data System (ADS)

    Algeo, T. J.; Luo, G. M.; Song, H. Y.; Lyons, T. W.; Canfield, D. E.

    2015-04-01

    Long-term secular variation in seawater sulfate concentrations ([SO42-]SW) is of interest owing to its relationship to the oxygenation history of Earth's surface environment. In this study, we develop two complementary approaches for quantification of sulfate concentrations in ancient seawater and test their application to late Neoproterozoic (635 Ma) to Recent marine units. The "rate method" is based on two measurable parameters of paleomarine systems: (1) the S-isotope fractionation associated with microbial sulfate reduction (MSR), as proxied by Δ34SCAS-PY, and (2) the maximum rate of change in seawater sulfate, as proxied by &partial; δ 34SCAS/∂ t(max). The "MSR-trend method" is based on the empirical relationship of Δ34SCAS-PY to aqueous sulfate concentrations in 81 modern depositional systems. For a given paleomarine system, the rate method yields an estimate of maximum possible [SO42-]SW (although results are dependent on assumptions regarding the pyrite burial flux, FPY), and the MSR-trend method yields an estimate of mean [SO42-]SW. An analysis of seawater sulfate concentrations since 635 Ma suggests that [SO42-]SW was low during the late Neoproterozoic (<5 mM), rose sharply across the Ediacaran-Cambrian boundary (~5-10 mM), and rose again during the Permian (~10-30 mM) to levels that have varied only slightly since 250 Ma. However, Phanerozoic seawater sulfate concentrations may have been drawn down to much lower levels (~1-4 mM) during short (<~2 Myr) intervals of the Cambrian, Early Triassic, Early Jurassic, and Cretaceous as a consequence of widespread ocean anoxia, intense MSR, and pyrite burial. The procedures developed in this study offer potential for future high-resolution quantitative analyses of paleo-seawater sulfate concentrations.

  4. Present status and problems on extraction of uranium from seawater

    SciTech Connect

    Not Available

    1980-07-01

    The Research Committee on Extraction of Uranium from Seawater worked on the technical survey of the present situation of the above technique and the exchange of information among the members, during 1977 to 1979. This is a report of its activity and present status of the research in this field. It includes the development of various adsorbents, extraction of uranium by flotation, various kinds of chemical analyses, some comparisons among different kinds of seawater contacting systems, the secondary concentrations and the cost of assessment.

  5. A new focus on groundwater-seawater interactions

    USGS Publications Warehouse

    Langevin, C.; Sanford, W.; Polemio, M.; Povinec, P.

    2007-01-01

    In summary, the papers in this volume present research by those working from the marine and the terrestrial sides of issues related to SGD and groundwater-seawater interactions. The first part of this paper provides an introduction and background information on the subject of SGD and groundwater-seawater interactions. The second part of this paper provides an overview of the 38 symposium papers and places them in context according to the methods used to quantify SGD. The papers presented in this volume describe important contributions to the literature and document a variety of investigative approaches applied over a range of conditions at locations across the globe.

  6. Analytical approximations to seawater optical phase functions of scattering

    NASA Astrophysics Data System (ADS)

    Haltrin, Vladimir I.

    2004-11-01

    This paper proposes a number of analytical approximations to the classic and recently measured seawater light scattering phase functions. The three types of analytical phase functions are derived: individual representations for 15 Petzold, 41 Mankovsky, and 91 Gulf of Mexico phase functions; collective fits to Petzold phase functions; and analytical representations that take into account dependencies between inherent optical properties of seawater. The proposed phase functions may be used for problems of radiative transfer, remote sensing, visibility and image propagation in natural waters of various turbidity.

  7. Seawater temperature trends at Usa Tide Gauge sites

    NASA Astrophysics Data System (ADS)

    Maul, George A.; Davis, Andria M.; Simmons, Jeffrey W.

    Seawater temperatures have been measured at United States tide gauges throughout most of the 20th century. All available records have been digitized, and the longest 14 have been analyzed by linear least-square regression. The largest positive trend is from Boston MA (+3.6±0.4°C per century), and the largest negative trend is at Charleston SC (-0.1±0.3°C per century). No consistent latitudinal or east-coast vs. west-coast patterns are discernable, but air temperature trends are typically greater than seawater changes.

  8. Molecular Architecture for Polyphosphazene Electrolytes for Seawater Batteries

    SciTech Connect

    Mason K. Harrup; Mason K. Harrup; Thomas A. Luther; Christopher J. Orme; Eric S. Peterson

    2005-08-01

    In this work, a series of polyphosphazenes were designed to function as water resistant, yet ionically conductive membranes for application to lithium/seawater batteries. In membranes of this nature, various molecular architectures are possible and representatives from each possible type were chosen. These polymers were synthesized and their performance as solid polymer electrolytes was evaluated in terms of both lithium ion conductivity and water permeability. The impact that this molecular architecture has on total performance of the membranes for seawater batteries is discussed. Further implications of this molecular architecture on the mechanisms of lithium ion transport through polyphosphazenes are also discussed.

  9. The major-ion composition of Carboniferous seawater

    NASA Astrophysics Data System (ADS)

    Holt, Nora M.; García-Veigas, Javier; Lowenstein, Tim K.; Giles, Peter S.; Williams-Stroud, Sherilyn

    2014-06-01

    The major-ion chemistry (Na+, Mg2+, Ca2+, K+, SO42-, and Cl-) of Carboniferous seawater was determined from chemical analyses of fluid inclusions in marine halites, using the cryo scanning electron microscopy (Cryo-SEM) X-ray energy-dispersive spectrometry (EDS) technique. Fluid inclusions in halite from the Mississippian Windsor and Mabou Groups, Shubenacadie Basin, Nova Scotia, Canada (Asbian and Pendleian Substages, 335.5-330 Ma), and from the Pennsylvanian Paradox Formation, Utah, USA, (Desmoinesian Stage 309-305 Ma) contain Na+-Mg2+-K+-Ca2+-Cl- brines, with no measurable SO42-, which shows that the Carboniferous ocean was a “CaCl2 sea”, relatively enriched in Ca2+ and low in SO42- with equivalents Ca2+ > SO42- + HCO3-. δ34S values from anhydrite in the Mississippian Shubenacadie Basin (13.2-14.0 ‰) and the Pennsylvanian Paradox Formation (11.2-12.6 ‰) support seawater sources. Br in halite from the Shubenacadie Basin (53-111 ppm) and the Paradox Basin (68-147 ppm) also indicate seawater parentages. Carboniferous seawater, modeled from fluid inclusions, contained ∼22 mmol Ca2+/kg H2O (Mississippian) and ∼24 mmol Ca2+/kg H2O (Pennsylvanian). Estimated sulfate concentrations are ∼14 mmol SO42-/kg H2O (Mississippian), and ∼12 mmol SO42-/kg H2O (Pennsylvanian). Calculated Mg2+/Ca2+ ratios are 2.5 (Mississippian) and 2.3 (Pennsylvanian), with an estimated range of 2.0-3.2. The fluid inclusion record of seawater chemistry shows a long period of CaCl2 seas in the Paleozoic, from the Early Cambrian through the Carboniferous, when seawater was enriched in Ca2+ and relatively depleted in SO42-. During this ∼200 Myr interval, Ca2+ decreased and SO42- increased, but did not cross the Ca2+-SO42- chemical divide to become a MgSO4 sea (when SO42- in seawater became greater than Ca2+) until the latest Pennsylvanian or earliest Permian (∼309-295 Ma). Seawater remained a MgSO4 sea during the Permian and Triassic, for ∼100 Myr. Fluid inclusions also record

  10. Estimation of endotoxin-like substances in deep seawater by using bioassay.

    PubMed

    Takagi, Kuniaki; Inamura, Tatsumi; Kawajiri, Masahiro; Noya, Kazuo; Hagiwara, Yoshitugu; Suketa, Yasunobu

    2002-01-01

    Deep seawater has recently been under trial as a fundamental material for mineral water, food, face lotion and an efficacious reagent for the cure of atopic dermatitis in Japan. However, little is known about the biologically effective substances, including toxic compounds in deep seawater. In this study, we investigated the effects of deep seawater on the function of murine macrophages in vitro, and examined the endotoxin-like substances in seawater. Mitochondrial activity and NO production in macrophage cells cultured with stimulants were enhanced in a depth dependent manner by pretreatment with deep seawater. In addition, fractions from deep seawater, enriched by hydrophobic column chromatography, activated the macrophage cells much more than the corresponding fractions from surface seawater. Furthermore, the effects of the fractions on macrophage cells remained significant, even with the addition of polymyxin B. which is a specific inhibitor of endotoxins. These results indicate that endotoxins and unknown substances, which affect macrophage functions, exist in a depth dependent manner in seawater.

  11. Tandem electrochemical desalination-potentiometric nitrate sensing for seawater analysis.

    PubMed

    Cuartero, Maria; Crespo, Gastón A; Bakker, Eric

    2015-08-18

    We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec(-1), limit of detection of 5 × 10(-7) M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater. PMID:26201537

  12. Constraining the oxygen isotope composition of early Cretaceous seawater

    NASA Astrophysics Data System (ADS)

    Price, Gregory; VanDeVelde, Justin; Passey, Ben; Grimes, Stephen

    2015-04-01

    The oxygen isotopic composition of well-preserved marine fossils fundamentally underpins our understanding of the evolution of the Earth's climate. However, a lack of constraint on the delta18O of seawater provides a major challenge. In this study new analyses of sub-Arctic and Boreal Cretaceous (Berriasian-late Valanginian, ca. 145-134 Ma) fossil molluscs (belemnites) have been undertaken using carbonate clumped isotopes, an approach based on the "clumping" of 13C and 18O in the carbonate mineral lattice into bonds with each other. From our analyses we infer Early Cretaceous marine temperatures ranging from 10 °C to 20 °C. We identify a cooler late Valanginian interval with temperatures consistent with regions a few degrees above freezing. Our combined temperature and delta18O belemnite data imply seawater delta18O values that have a remarkably modern profile in that they are similar to modern high-latitude seawater and much more positive than values typically assumed for Cretaceous seawater. These high oxygen isotope ratios suggest a hydrological cycle similar to the modern rather than a substantial increase towards a more vigorous hydrological cycle. Our results argue for generally warm but dynamic polar climates during Cretaceous greenhouse intervals that were punctuated by periods of ice growth.

  13. Combining mariculture and seawater-based solar ponds

    SciTech Connect

    Lowrey, P.; Ford, R.; Collando, F.; Morgan, J.; Frusti, E. . Dept. of Mechanical Engineering)

    1990-05-01

    Solar ponds have been thoroughly studied as a means to produce electricity or heat, but there may be comparable potential to use solar ponds to produce optimized environments for the cultivation of some aquaculture crops. For this, conventional brine-based solar ponds could be used. This strategy would probably be most suitable at desert sites where concentrated brine was abundant, pond liners might not be needed, and the crop produced could be shipped to market. Generally, a heat exchanger would be required to transfer heat from the solar pond into the culture ponds. Culture ponds could therefore use either fresh or marine water. In contrast, this paper explores seawater-based solar ponds. These are solar ponds which use seawater in the bottom storage zone and fresh water in the upper convective zone. Because the required temperature elevations for mariculture are only about 10{degrees}C, seawater-based solar ponds are conceivable. Seawater-based ponds should be very inexpensive because, by the shore, salt costs would be negligible and a liner might be unnecessary.

  14. Physiological indices of seawater readiness in postspawning steelhead kelts

    USGS Publications Warehouse

    Buelow, Jessica; Moffitt, Christine M.

    2015-01-01

    Management goals to improve the recovery of steelhead (Oncorhynchus mykiss) stocks at risk of extinction include increasing the proportion of postspawning fish that survive and spawn again. To be successful, postspawning steelhead (kelts) migrating downstream to the ocean must prepare physiologically and physically for a seawater transition. We sampled blood, gill filaments, and evaluated the external condition of migrating kelts from an ESA-listed population in the Snake/Columbia River system over two consecutive years to evaluate their physiological readiness for transition to seawater. We chose attributes often considered as measures of preparation for seawater in juveniles, including gill Na+,K+ ATPase activity, plasma electrolytes and hormones to consider factors related to external condition, size and sex. We found kelts in good external condition had plasma profiles similar to downstream-migrating smolts. In addition, we found more than 80% of kelts ranked in good external condition had smolt-like body silvering. We compared measures from migrating kelts with samples obtained from hatchery fish at the time of spawning to confirm that Na+, K+ ATPase activity in kelts was significantly elevated over spawning fish. We found significant differences in gill Na+, K+ ATPase activity in migrating kelts between the years of sampling, but little indication of influence of fish condition. We conclude that the postspawning steelhead sampled exhibited a suite of behaviours, condition and physiology characteristic of fish prepared for successful transition to a seawater environment.

  15. Extracting uranium from seawater: Promising AI series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-10

    A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged frommore » 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.« less

  16. Oscillations in Phanerozoic seawater chemistry: evidence from fluid inclusions.

    PubMed

    Lowenstein, T K; Timofeeff, M N; Brennan, S T; Hardie, L A; Demicco, R V

    2001-11-01

    Systematic changes in the chemistry of evaporated seawater contained in primary fluid inclusions in marine halites indicate that seawater chemistry has fluctuated during the Phanerozoic. The fluctuations are in phase with oscillations in seafloor spreading rates, volcanism, global sea level, and the primary mineralogies of marine limestones and evaporites. The data suggest that seawater had high Mg2+/Ca2+ ratios (>2.5) and relatively high Na+ concentrations during the Late Precambrian [544 to 543 million years ago (Ma)], Permian (258 to 251 Ma), and Tertiary through the present (40 to 0 Ma), when aragonite and MgSO4 salts were the dominant marine precipitates. Conversely, seawater had low Mg2+/Ca2+ ratios (<2.3) and relatively low Na+ concentrations during the Cambrian (540 to 520 Ma), Silurian (440 to 418 Ma), and Cretaceous (124 to 94 Ma), when calcite was the dominant nonskeletal carbonate and K-, Mg-, and Ca-bearing chloride salts, were the only potash evaporites. PMID:11691988

  17. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water.

  18. Time and the crystallization of apatite in seawater

    USGS Publications Warehouse

    Gulbrandsen, R.A.; Roberson, C.E.; Neil, S.T.

    1984-01-01

    Carbonate fluorapatite has been synthesized in seawater in an experiment of nearly 10-years duration. The addition of phosphate to seawater whose fluoride concentration had been increased to 7.6 mg/l brought about an initial amorphous phosphate precipitate. After 20 months, a crystalline magnesium phosphate phase developed within the amorphous phosphate. Crystallization of apatite, which occurred during the last 3 years of the experiment, was accompanied by dissolution of the crystalline magnesium phosphate phase. The MgO content of the apatite (1.9 percent) is high in comparison to Tertiary and older apatite but similar to some young apatite; the CO2 content (3.6 percent) is medium, and the fluorine content (2.2 percent) is low but again similar to some young apatite. The hydroxyl ion (OH-) likely fills the need for additional fluorine-position atoms. The mole ratio of Ca plus substituent elements to P plus substituent elements (1.50) is low in comparison to the expected ratio of 1.67. The substitution of the hydronium ion (H3O+) for Ca may account for this difference. The synthesis of apatite in seawater demonstrates that the factor of time overcomes the well known inhibiting effect of magnesium upon the crystallization of apatite. It also implies that given an adequate supply of phosphate, apatite can form in most ocean environments and likely plays a major pan in the control of the phosphate content of seawater. ?? 1984.

  19. Tandem electrochemical desalination-potentiometric nitrate sensing for seawater analysis.

    PubMed

    Cuartero, Maria; Crespo, Gastón A; Bakker, Eric

    2015-08-18

    We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec(-1), limit of detection of 5 × 10(-7) M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater.

  20. Freeze desalination of seawater using LNG cold energy.

    PubMed

    Chang, Jian; Zuo, Jian; Lu, Kang-Jia; Chung, Tai-Shung

    2016-10-01

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around -8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater. PMID:27371931

  1. Precipitation softening: a pretreatment process for seawater desalination.

    PubMed

    Ayoub, George M; Zayyat, Ramez M; Al-Hindi, Mahmoud

    2014-02-01

    Reduction of membrane fouling in reverse osmosis systems and elimination of scaling of heat transfer surfaces in thermal plants are a major challenge in the desalination of seawater. Precipitation softening has the potential of eliminating the major fouling and scaling species in seawater desalination plants, thus allowing thermal plants to operate at higher top brine temperatures and membrane plants to operate at a reduced risk of fouling, leading to lower desalinated water costs. This work evaluated the use of precipitation softening as a pretreatment step for seawater desalination. The effectiveness of the process in removing several scale-inducing materials such as calcium, magnesium, silica, and boron was investigated under variable conditions of temperature and pH. The treatment process was also applied to seawater spiked with other known fouling species such as iron and bacteria to determine the efficiency of removal. The results of this work show that precipitation softening at a pH of 11 leads to complete elimination of calcium, silica, and bacteria; to very high removal efficiencies of magnesium and iron (99.6 and 99.2 %, respectively); and to a reasonably good removal efficiency of boron (61 %). PMID:24151028

  2. Macroporous monoliths for trace metal extraction from seawater

    SciTech Connect

    Yue, Yanfeng; Mayes, Richard T.; Gill, Gary; Kuo, Li -Jung; Wood, Jordana; Binder, Andrew J.; Brown, Suree; Dai, Sheng

    2015-05-29

    The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 gL-1). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N -methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawater containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. Furthermore, the preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.

  3. Extracting uranium from seawater: Promising AI series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-10

    A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.

  4. COMBINED SEWER OVERFLOW CONTROL USING STORAGE IN SEAWATER

    EPA Science Inventory

    This paper describes the flow balance method facility (FBM) used to control a combined sewer overflow (CSO) and a statistically based efficiency evaluation for the system. he FBM uses containment within a receiving water body (in this case seawater) to store CSO followed by pumpb...

  5. Physical and biological characterization of a seawater ultraviolet radiation sterilizer

    NASA Astrophysics Data System (ADS)

    Torrentera, Laura; Uribe, Roberto M.; Rodríguez, Romana R.; Carrillo, Ricardo E.

    1994-03-01

    The physical and biological characterization of a seawater ultraviolet (UV) sterilizer is described. The physical characterization was performed using radiochromic dye films by evaluating the uniformity of the radiant exposure along each lamp, the effect of the radiation from one lamp on the array of adjacent lamps, and by measuring the UV radiation absorption of seawater with respect to distilled water. The biological characterization was performed by measuring the amount of reduction of bacteria in stored seawater after different filtration and UV treatments. Among the filtration methods tested, differential filtration (5, 3 and 0.45 μm filters connected in series) caused the highest bacterial reduction factor of 60%. UV radiant exposures of 212, 424, 636 and 848 J m -2 yielded bacteria reduction factors of 99.86, 99.969, 99.997 and 100%, respectively, for populations of Vibrio and Pseudomonas bacteria present in stored seawater. It is concluded that the system is useful for water disinfection when 1, 2 or 3 lamps are on; when 4 lamps are used the treated water becomes sterile.

  6. Macroporous monoliths for trace metal extraction from seawater

    SciTech Connect

    Yue, Yanfeng; Mayes, Richard; Gill, Gary A.; Kuo, Li -Jung; Wood, Jordana R.; Binder, Andrew; Brown, Suree; Dai, Sheng

    2015-05-29

    The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 μgL⁻¹). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N’-methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawater containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. The preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.

  7. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water. PMID:26099832

  8. Freeze desalination of seawater using LNG cold energy.

    PubMed

    Chang, Jian; Zuo, Jian; Lu, Kang-Jia; Chung, Tai-Shung

    2016-10-01

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around -8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  9. Precipitation softening: a pretreatment process for seawater desalination.

    PubMed

    Ayoub, George M; Zayyat, Ramez M; Al-Hindi, Mahmoud

    2014-02-01

    Reduction of membrane fouling in reverse osmosis systems and elimination of scaling of heat transfer surfaces in thermal plants are a major challenge in the desalination of seawater. Precipitation softening has the potential of eliminating the major fouling and scaling species in seawater desalination plants, thus allowing thermal plants to operate at higher top brine temperatures and membrane plants to operate at a reduced risk of fouling, leading to lower desalinated water costs. This work evaluated the use of precipitation softening as a pretreatment step for seawater desalination. The effectiveness of the process in removing several scale-inducing materials such as calcium, magnesium, silica, and boron was investigated under variable conditions of temperature and pH. The treatment process was also applied to seawater spiked with other known fouling species such as iron and bacteria to determine the efficiency of removal. The results of this work show that precipitation softening at a pH of 11 leads to complete elimination of calcium, silica, and bacteria; to very high removal efficiencies of magnesium and iron (99.6 and 99.2 %, respectively); and to a reasonably good removal efficiency of boron (61 %).

  10. Evaluating Foraminifera as an Archive for Seawater Chromium Isotopic Composition

    NASA Astrophysics Data System (ADS)

    Wang, X.; Planavsky, N.; Hull, P. M.; Tripati, A.; Reinhard, C.; Zou, H.; Elder, L. E.; Henehan, M. J.

    2015-12-01

    In recent years there has been growing interest in using chromium isotopes (δ53Cr) as a proxy to investigate the redox evolution of Earth's ocean-atmosphere system throughout geological history. Potential archives for seawater δ53Cr that have been identified to date include iron formations and organic-rich siliciclastic sediments. However, these types of sediments are not common and they are discontinuous over geologic time. As a result, alternative types of archives are needed. Here we evaluate the utility of foraminifera tests as a recorder of seawater δ53Cr. Core-tops used were from different ocean basins. Mono-specific samples of Globigerinoides sacculifer, Orbulina universa, Pulleniatina obliquiloculata, Globoratalia crassula-crassaformis, Globoratalia truncatulinoides, and Globigerinella siphonifera were isolated to investigate inter-species isotope fractionation. Chromium concentrations were measured by isotope dilution method to be 0.1-0.3 μg/g. The δ53Cr values of these species range from 0.2‰ to 2.4‰, with an analytical uncertainty of 0.3‰ (95% confidence). Despite the high analytical uncertainty due to the extremely low levels of Cr present, there is still large detectable variation in foraminiferal δ53Cr values, which overlap presently available seawater values (Bonnand et al., 2013; Scheiderich et al., 2015). Possible explanations for such variations in foraminiferal δ53Cr values include heterogeneity of seawater δ53Cr in the modern oceans, and/or photobiochemical redox cycling of Cr in the surface oceans. Therefore, care should be taken when using foraminifera to reconstruct past seawater δ53Cr values. ReferencesBonnand, P., James, R., Parkinson, I., Connelly, D., Fairchild, I., 2013. The chromium isotopic composition of seawater and marine carbonates. Earth and Planetary Science Letters, 382: 10-20. Scheiderich, K., Amini, M., Holmden, C., Francois, R., 2015. Global variability of chromium isotopes in seawater demonstrated by Pacific

  11. Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

    SciTech Connect

    Asmerom, Y.; Jacobsen, S.B.; Knoll, A.H.; Butterfield, N.J. ); Swett, K. )

    1991-10-01

    The authors report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Samples with low {sup 87}Rb/{sup 86}Sr ratios (<0.01) were selected for Sr isotopic analysis. {delta}{sup 18}O, Mn, Ca, Mg, and Sr data were used to recognize altered samples. The altered samples are characterized by high Mn/Sr ({ge}2) and variable {delta}{sup 18}O; most are dolomites. The data indicate that between ca. 790-850 Ma the {sup 87}Sr/{sup 86}Sr ratio of seawater varied between 0.70676 and 0.70561. The samples show smooth and systematic variation, with the lowest {sup 87}Sr/{sup 86}Sr value of 0.70561 at ca. 830 Ma. The low {sup 87}Sr/{sup 86}Sr ratio of carbonates from the lower parts of the section is similar to a value reported for one sample from the Adrar of Mauritania ({approx}900 Ma), West African Craton. Isotopic ratios from the upper part of the Shaler section are identical to values from the lower part of the Neoproterozoic Akademikerbreen Group, Spitsbergen. Although a paucity of absolute age determinations hinders attempts at the precise correlation of Neoproterozoic successions, it is possible to draw a broad outline of the Sr isotopic composition of seawater for this period. Data from this study and the literature are used to construct a curve of the {sup 87}Sr/{sup 86}Sr ratio of Neoproterozoic seawater. The Sr isotope composition of seawater reflects primarily the balance between continental Sr input through river input and mantle input via hydrothermal circulation of seawater through mid-ocean ridges. Coupling of Nd and Sr isotopic systems allows the authors to model changes in seafloor spreading rates (or hydrothermal flux) and continental erosion. The Sr hydrothermal flux and the erosion rate (relative to present-day value) are modeled for the period 500-900 Ma.

  12. Adsorption and desorption of phosphate on limestone in experiments simulating seawater intrusion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The absorption and desorption of phosphorus on a large block of limestone was investigated using deionized water (DIW) and seawater. The limestone had a high affinity to adsorb phosphorus in DIW. Phosphate adsorption was significantly less in seawater, and more phosphorus was desorbed in the seawate...

  13. The composition of Standard Seawater and the definition of the Reference-Composition Salinity Scale

    NASA Astrophysics Data System (ADS)

    Millero, Frank J.; Feistel, Rainer; Wright, Daniel G.; McDougall, Trevor J.

    2008-01-01

    Fundamental determinations of the physical properties of seawater have previously been made for Atlantic surface waters, referred to as "Standard Seawater". In this paper a Reference Composition consisting of the major components of Atlantic surface seawater is determined using these earlier analytical measurements. The stoichiometry of sea salt introduced here is thus based on the most accurate prior determination of the composition, adjusted to achieve charge balance and making use of the 2005 atomic weights. Reference Seawater is defined as any seawater that has the Reference Composition and a new Reference-Composition Salinity SR is defined to provide the best available estimate of the Absolute Salinity of both Reference Seawater and the Standard Seawater that was used in the measurements of the physical properties. From a practical point of view, the value of SR can be related to the Practical Salinity S by S=(35.16504/35)gkg×S. Reference Seawater that has been "normalized" to a Practical Salinity of 35 has a Reference-Composition Salinity of exactly SR=35.16504 g kg -1. The new independent salinity variable SR is intended to be used as the concentration variable for future thermodynamic functions of seawater, as an SI-based extension of Practical Salinity, as a reference for natural seawater composition anomalies, as the currently best estimate for Absolute Salinity of IAPSO Standard Seawater, and as a theoretical model for the electrolyte mixture "seawater".

  14. River-derived humic substances as iron chelators in seawater

    PubMed Central

    Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.

    2015-01-01

    The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5

  15. Experimental calibration of Mg isotope fractionation between aragonite and seawater

    NASA Astrophysics Data System (ADS)

    Wang, Zhengrong; Hu, Ping; Gaetani, Glenn; Liu, Chao; Saenger, Casey; Cohen, Anne; Hart, Stanley

    2013-02-01

    The detectable magnesium (Mg) isotope fractionation between biogenic aragonite (including aragonitic corals, bivalves, scaphopod, and sclerosponges) and seawater can potentially be applied to reconstruct sea surface temperature (SST) in the past. To calibrate this thermometer, eight sets of inorganic precipitation experiments ('free-drift') in seawater (Mg/Ca = 5 or 10) have been carried out at 25-55 °C over a range of degassing rate. A cleaning procedure was adopted to remove Mg contamination by sea salt, surface absorbed Mg and silicate dust as nucleation centers. The Mg isotope fractionation between cleaned aragonite and seawater-like aqueous solution varies insignificantly with Mg/Ca ratios and Mg isotope compositions of the initial solution, and the CO2-degassing rate (0-75 cc/min), but decreases noticeably with increasing temperatures having a temperature sensitivity of ˜0.008-0.01‰/°C in the following form: Δ≈1000lnα=1.67(±0.36)-0.82(±0.11)×{1000}/{T} where αaragonite-seawater is the fractionation factor, and T is the absolute temperature in Kelvin. It is consistent with equilibrium fractionation between Mg2+ aquo-complex and magnesite predicted by one theoretical calculation. Qualitative comparison among Mg-bearing carbonates based on Mg-O bond strengths show the relative sequence of 26Mg enrichment is aragonite > dolomite > magnesite > calcite. Thus, the surprising agreement indicates either the calculation overestimated Mg fractionation between magnesite and fluid, or both theoretical calculation and our calibration represent Mg isotope fractionation between MgCO30-H2O cluster and Mg2+ aquo complexes. Comparison of our calibration with the Mg isotope fractionation between biogenic aragonite and seawater suggests Mg and oxygen isotope fractionations of some biogenic aragonites (e.g., Porites sp. corals) agree with our calibration within analytical uncertainty, whereas others deviate significantly, indicating biological and/or kinetic isotope

  16. Scleractinian Fossil Corals as Archives of Seawater δ26Mg

    NASA Astrophysics Data System (ADS)

    Gothmann, A. O.; Higgins, J. A.; Adkins, J. F.; Stolarski, J.; Bender, M. L.

    2014-12-01

    The recovery of environmental signatures from coral skeletons is often made difficult by 'vital effects', which cause skeletal chemistry to deviate from the expected composition of aragonite in equilibrium with seawater. Recent studies show that Mg isotopes in scleractinian corals are subject to vital effects, which appear as a departure of the δ26Mg coral temperature dependence from that of inorganic aragonite [1]. However, different from the case for Mg/Ca or δ44Ca in coral, the magnitude of the observed Mg-isotope vital effect is small (on the order of 0.1 ‰ or less). In addition, measurements of different species of modern coral show similar fractionations, suggesting that coral δ26Mg is not species dependent [2]. Together, these observations indicate that corals should faithfully record the seawater Mg-isotope composition, and that vital effects will not bias reconstructions. We measured Mg isotopes in a set of extremely well-preserved fossil scleractinian corals, ranging in age from Jurassic through Recent, to reconstruct past seawater δ26Mg. Well-preserved fossil corals of similar age show a range in δ26Mg of ~0.2 ‰, pointing to the presence of vital effects. However, our results show little variability in the δ26Mg of fossil corals across different geologic ages, suggesting that seawater δ26Mg has remained relatively constant throughout the Cenozoic and Mesozoic. This pattern has implications for our understanding of the mechanisms driving secular variations in seawater Mg/Ca. In particular, our data imply that dolomitization rates have not changed enough during the Mesozoic and Cenozoic to account for secular variations in seawater Mg/Ca. Our coral δ26Mg record agrees with a Cenozoic record from bulk foraminifera, further supporting the faithfulness of the coral archive. However, both of these records disagree with a third Cenozoic Mg-isotope record, derived from species-specific planktic forams [3]. [1] Saenger, C. et al. (2014) Chem. Geol

  17. Development of Novel Sorbents for Uranium Extraction from Seawater

    SciTech Connect

    Lin, Wenbin; Taylor-Pashow, Kathryn

    2014-01-08

    As the uranium resource in terrestrial ores is limited, it is difficult to ensure a long-term sustainable nuclear energy technology. The oceans contain approximately 4.5 billion tons of uranium, which is one thousand times the amount of uranium in terrestrial ores. Development of technologies to recover the uranium from seawater would greatly improve the uranium resource availability, sustaining the fuel supply for nuclear energy. Several methods have been previously evaluated including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons such as cost effectiveness, long term stability, and selectivity. Recent research has focused on the amidoxime functional group as a promising candidate for uranium sorption. Polymer beads and fibers have been functionalized with amidoxime functional groups, and uranium adsorption capacities as high as 1.5 g U/kg adsorbent have recently been reported with these types of materials. As uranium concentration in seawater is only ~3 ppb, great improvements to uranium collection systems must be made in order to make uranium extraction from seawater economically feasible. This proposed research intends to develop transformative technologies for economic uranium extraction from seawater. The Lin group will design advanced porous supports by taking advantage of recent breakthroughs in nanoscience and nanotechnology and incorporate high densities of well-designed chelators into such nanoporous supports to allow selective and efficient binding of uranyl ions from seawater. Several classes of nanoporous materials, including mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), meta-organic frameworks (MOFs), and covalent-organic frameworks (COFs), will be synthesized. Selective uranium-binding liagnds such as amidoxime will be incorporated into the nanoporous materials to afford a new generation of sorbent materials that will be

  18. Impediment to symbiosis establishment between giant clams and Symbiodinium algae due to sterilization of seawater.

    PubMed

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment ("symbiosis rate") is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds.

  19. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    PubMed Central

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  20. Modification of Optical Properties of Seawater Exposed to Oil Contaminants Based on Excitation-Emission Spectra

    NASA Astrophysics Data System (ADS)

    Baszanowska, E.; Otremba, Z.

    2015-10-01

    The optical behaviour of seawater exposed to a residual amount of oil pollution is presented and a comparison of the fluorescence spectra of oil dissolved in both n-hexane and seawater is discussed based on excitation-emission spectra. Crude oil extracted from the southern part of the Baltic Sea was used to characterise petroleum properties after contact with seawater. The wavelength-independent fluorescence maximum for natural seawater and seawater artificially polluted with oil were determined. Moreover, the specific excitation-emission peaks for natural seawater and polluted water were analysed to identify the natural organic matter composition. It was found that fluorescence spectra identification is a promising method to detect even an extremely low concentration of petroleum residues directly in the seawater. In addition, alien substances disturbing the fluorescence signatures of natural organic substances in a marine environment is also discussed.

  1. Microbial Specificity of Metallic Surfaces Exposed to Ambient Seawater

    PubMed Central

    Zaidi, B. R.; Bard, R. F.; Tosteson, T. R.

    1984-01-01

    High-molecular-weight materials associated with the extracellular matrix and film found on titanium and aluminum surfaces after exposure to flowing coastal seawater were isolated. This material was purified by hydroxylapatite chromatography and subsequently employed to produce antibodies in the toad, Bufo marinus. The antibodies were immobilized on a solid support and employed to isolate adhesion-enhancing, high-molecular-weight materials from the laboratory culture media of bacterial strains recovered from the respective metallic surfaces during the course of their exposure to seawater. The adhesion-enhancing materials produced by the surface-associated bacterial strains were immunologically related to the extracellular biofouling matrix material found on the surfaces from which these bacteria were isolated. The surface selectivity of these bacterial strains appeared to be based on the specificity of the interaction between adhesion-enhancing macromolecules produced by these bacteria and the surfaces in question. PMID:16346622

  2. Performance of OTEC Heat Exchanger Materials in Tropical Seawaters

    NASA Astrophysics Data System (ADS)

    Larsen-Basse, Jorn

    1985-03-01

    The corrosion of several aluminum alloys in flowing Hawaiian surface seawater and water from 600 m depth for exposure periods up to three years has been studied. The alloys tested in cold water were Alclad (7072) 3003 and 3004; and bare 3004 and 5052). All show some pitting. Pit growth is slow, and pits do not penetrate the cladding. In the warm water, only uniform corrosion has been found. All alloys corrode at the same, low rate of˜3 μm/year after an initial short period of more rapid corrosion. This behavior is closely linked to the formation of a protective inorganic scale film on the surface. It consists of precipitated scale minerals from the seawater and aluminum corrosion products. The results indicate that OTEC evaporator heat exchangers constructed of aluminum alloys should have acceptable service lives.

  3. The Separation and Isotopic Analysis Seawater Cu and Zn

    NASA Astrophysics Data System (ADS)

    Bermin, J.; Vance, D.; Archer, C.; Statham, P. J.

    2004-12-01

    Many transition metals are key micronutrients and their concentration profiles in the oceans often show nutrient-like patterns, with strong surface depletions and deep enrichments1. In addition, their biological usage has been shown to induce isotopic fractionations2 so that the precise and accurate analysis of their isotope systems in seawater has potential applications in tracing metal micronutrient usage in the past ocean. The analytical challenges involved in realising this goal are, however, considerable, given the low concentrations of transition metals in seawater and the requirement to extract small amounts from large samples at low blank and with no artificial isotopic fractionation. Here we present a method for the separation an analysis of Cu and Zn isotopes that is applicable to 0.1-5 L samples of seawater. Trace metals were concentrated from seawater using a Chelex-100 ion-exchange column3 and further purified and separated from each other using a small anion column4,5. All isotopic analyses were performed on a ThermoFinnigan Neptune instrument at the University of Bristol. The main requirements for precise and accurate isotopic analyses are a low contribution from analytical blank and the robust correction for analytical mass discrimination. Our blanks allow the analysis of seawater samples of 50-250 mL for Cu, samples of about 100 mL for Zn in the deep oceans and for Zn-depleted open ocean surface water samples of around 5L. The correction for mass discrimination is most readily considered as two components - that occurring during the chemical separation procedure in response to non-100% yields and that occurring in the mass spectrometer. Correction of all mass discrimination throughout the procedure is most robustly done for Zn and Fe using a double-spike that is added prior to any chemical treatment. This approach has been tested using standard-doped seawater samples that had previously been stripped of their metal contents using the Chelex column

  4. Determination of photosynthetic parameters in two seawater-tolerant vegetables

    NASA Astrophysics Data System (ADS)

    Qiu, Nianwei; Zhou, Feng; Liu, Qian; Zhao, Wenqian

    2016-03-01

    It is difficult to determine the photosynthetic parameters of non-flat leaves/green stems using photosynthetic instruments, due to the unusual morphology of both organs, especially for Suaeda salsa and Salicornia bigelovii as two seawater-tolerant vegetables. To solve the problem, we developed a simple, practical, and effective method to measure and calculate the photosynthetic parameters (such as P N, g s, E) based on unit fresh mass, instead of leaf area. The light/CO2/temperature response curves of the plants can also be measured by this method. This new method is more effective, stable, and reliable than conventional methods for plants with non-flat leaves. In addition, the relative notes on measurements and calculation of photosynthetic parameters were discussed in this paper. This method solves technical difficulties in photosynthetic parameter determination of the two seawater-tolerant vegetables and similar plants.

  5. Isolation and characterization of microalgae for biodiesel production from seawater.

    PubMed

    Zhao, Liu; Qi, Yun; Chen, Guanyi

    2015-05-01

    As green marine microalgae isolated from local seawater in Tianjin, China, Nannochloropsis gaditana Q6 was tolerant to the variation of salinity with the highest biomass and lipid concentration in natural seawater medium. Although this strain could grow mixotrophically with glycerol, the narrow gap between mixotrophic and autotrophic cultivation suggested that autotrophic cultivation was the optimal trophic type for N. gaditana Q6 growth. In addition, strain Q6 was more sensitive to the variance of NH4HCO3 concentration than NaH2PO4 concentration. Consequently, the lipid production could be maximized by the two-stage cultivation strategy, with an initial high NH4HCO3 concentration for biomass production followed by low NH4HCO3 concentration for lipid accumulation. PMID:25453432

  6. Microbial specificity of metallic surfaces exposed to ambient seawater

    SciTech Connect

    Zaidi, B.R.; Bard, R.F.; Tosteson, T.R.

    1984-09-01

    High-molecular-weight materials associated with the extracellular matrix and film found on titanium and aluminum surfaces after exposure to flowing coastal seawater were isolated. This material was purified by hydroxylapatite chromatography and subsequently employed to produce antibodies in the toad, Bufo marinus. The antibodies were immobilized on a solid support and employed to isolate adhesion-enhancing, high-molecular-weight materials from the laboratory culture media of bacterial strains recovered from the respective metallic surfaces during the course of their exposure to seawater. The adhesion-enhancing materials produced by the surface-associated bacterial strains were immunologically related to the extracellular biofouling matrix material found on the surfaces from which these bacteria were isolated. The surface selectivity of these bacterial strains appeared to be based on the specificity of the interaction between adhesion-enhancing macromolecules produced by these bacteria and the surfaces in question. 30 references, 6 tables.

  7. Recovery of uranium from seawater by immobilized tannin

    SciTech Connect

    Sakaguchi, T.; Nakajima, A.

    1987-06-01

    Tannin compounds having multiple adjacent hydroxy groups have an extremely high affinity for uranium. To prevent the leaching of tannins into water and to improve the adsorbing characteristics of these compounds, the authors tried to immobilize tannins. The immobilized tannin has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. The immobilized tannin can recover uranium from natural seawater with high efficiency. About 2530 ..mu..g uranium is adsorbed per gram of this adsorbent within 22 h. Depending on the concentration in seawater, an enrichment of up to 766,000-fold within the adsorbent is possible. Almost all uranium adsorbed is easily desorbed with a very dilute acid. Thus, the immobilized tannin can be used repeatedly in the adsorption-desorption process.

  8. Seawater as salt and water source for solar ponds

    SciTech Connect

    Folchitto, S. )

    1991-01-01

    This paper presents a method for preliminary design of a 1 km{sup 2} solar pond that will be supplied with salt and water from the sea. The evaporating basins, needed to concentrate the seawater are also included in the project. Starting from the experience that Agip Petroli gained in running the 25,000 m{sup 2} Solar Pond, built inside a salt-work in Margherita di Savoia, in southern Italy, two projects were worked out: the first one of 25,000 m{sup 2} and the second one of 1 km{sup 2} of surface. Making comparison between harvested energy cost of the solar pond, and the energy cost of alternative and traditional energy sources, the coastal Solar Pond of 1 km{sup 2} that utilizes seawater as salt and water source, is competitive.

  9. Desalting seawater and brackish waters: 1981 cost update

    SciTech Connect

    Reed, S.A.

    1982-08-01

    This is the fourth in a series of desalting cost update reports. Cost data are reported for desalting seawater by various distillation systems and by reverse osmosis. Costs of desalting four brackish waters, representative of those found in the United States by both reverse osmosis and electrodialysis are also given. Cost data are presented parametrically as a function of energy cost and plant size. The cost of desalting seawater by distillation has increased by 40% during the past two years, while desalting by reverse osmosis has increased by about 36% during the same period. Brackish water desalting by reverse osmosis has only increased by about 12%, and brackish water desalting by electrodialysis is up by 40%. Again, the continued increase in energy costs has had a major impact on all desalination systems.

  10. Last Glacial Maximum and deglacial abyssal seawater oxygen isotopic ratios

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2016-06-01

    An earlier analysis of pore-water salinity (chlorinity) in two deep-sea cores, using terminal constraint methods of control theory, concluded that although a salinity amplification in the abyss was possible during the LGM, it was not required by the data. Here the same methodology is applied to δ18Ow in the upper 100 m of four deep-sea cores. An ice volume amplification to the isotopic ratio is, again, consistent with the data but not required by it. In particular, results are very sensitive, with conventional diffusion values, to the assumed initial conditions at -100 ky and a long list of noise (uncertainty) assumptions. If the calcite values of δ18O are fully reliable, then published enriched values of the ratio in seawater are necessary to preclude sub-freezing temperatures, but the seawater δ18O in pore fluids does not independently require the conclusion.

  11. Gradient-zone erosion in seawater solar ponds

    SciTech Connect

    Shi, J.; Hart, R.A.; Kleis, S.J.; Bannerot, R.B.

    1997-02-01

    An experimental program has been conducted to examine the feasibility of using seawater solar ponds in mariculture operations along the Texas gulf coast to protect fish crops from the potentially lethal, cold temperatures experienced in outdoor ponds. Seawater solar ponds in the form of floating thermal refuge areas are proposed as a method for reducing the loss of heat from small sections of a pond. Gradient zone erosion under various ambient and operating conditions is examined. Comparisons with previous laboratory studies show a much lower entrainment rate in the natural environment. For conditions which are typical of those encountered in mariculture pond operation, the entrainment rate was found to depend only weakly on the Richardson number. For these conditions, a simple (linear) correlation of entrainment rate with wind speed was developed.

  12. Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

    SciTech Connect

    Lee, B.G.; Fisher, N.S. )

    1993-12-01

    The influence of microbial activity on Co and Mn oxidation in decomposing diatom cultures was determined with radiotracer techniques. Adding a consortium of microorganisms collected from coastal seawater (0.2-3-[mu]m size fraction) to the cultures increased particulate Co formation rates at 18[degrees]C by an order of magnitude (to 3.8% d[sup [minus]1]) and particulate Mn formation rates 3-fold (to 7.9% d[sup [minus

  13. Development and extension of seawater desalination by reverse osmosis

    NASA Astrophysics Data System (ADS)

    Gao, Congjie

    2003-03-01

    Seawater desalination has been people's fond dream since ancient times, the dream is now becoming a reality. This paper presents a brief development history of reverse osmosis. Much attention was paid to innovative development in membranes, modules, equipments and applied technology, including asymmetric and composite membranes, spiral-wound element and hollow fiber module, energy recovery equipments and different technological processes. The extension of reverse osmosis, such as desalination, pre-concentration, integrated processes and nanofiltration, is also briefly mentioned.

  14. Characteristics of trace elements in freshwater and seawater cultured pearls.

    PubMed

    Zhang, En; Huang, Fu-Quan; Wang, Zi-Tong; Li, Qian

    2014-09-01

    Trace elements in pearls have characteristic disciplines and functions. The previous work had paid attention to different characteristics of trace elements in freshwater and seawater cultured pearls, but only limited species of trace elements have been detected by former testing techniques and analysis methods, and the test results have not been further analyzed. With the advantages of detection in good capability and high speed, inductively coupled plasma mass spectrometer (ICP-MS) can concurrently test various trace and ultra-trace elements. In the present paper, trace elements of cultured pearls in freshwater and seawater were measured by ICP-MS, and analyzed compared by a method of data processing. The results show that: (1) The kinds of higher content of trace elements (Sr, Zn, Ni, Ba, Mn, Cr, Cu, Pb, Ti, Co, Ce, Zr, La, Rb) in cultured pearls are approximately the same, but the total amount of trace elements in freshwater cultured pearls is significantly less than that of seawater cultured pearls. (2) The content of trace elements (Sr, Mn, Ba, Ni, Cr, Pb) in freshwater cultured pearls is more regular, and has a relatively fixed sequence from high to low, namely Sr > Mn > Ba > Ni > Cr > Pb. The content of trace elements in seawater cultured pearls is quite different. Sr is enriched in all samples. There is no a stable order of contents for the other trace elements. (3) There is a significant correlation among some trace elements in cultured pearls. The conclusion is instructive to indicate cultured environment, cultured technology, identification, comprehensive development and utilization of cultured pearls.

  15. Extracting uranium from seawater: Promising AF series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.

  16. Extracting uranium from seawater: Promising AF series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8more » ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.« less

  17. Boron isotope fractionation during brucite deposition from artificial seawater

    NASA Astrophysics Data System (ADS)

    Xiao, J.; Xiao, Y. K.; Liu, C. Q.; Jin, Z. D.

    2011-07-01

    Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite and the influence of it on Mg/Ca-SST proxy and δ11B-pH proxy. The results show that both the concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (Kd) between deposited brucite and final seawater are controlled by the pH of the solution. The incorporation capacity of boron into brucite is almost the same as that into corals, but much stronger than that into oxides and clay minerals. The isotopic compositions of boron in deposited brucite (δ11Bd) are higher than those in the associated artificial seawater (δ11Bisw) with fractionation factors ranging between 1.0177 and 1.0569, resulting from the preferential incorporation of B(OH)3 into brucite. Both boron adsorptions onto brucite and the precipitation reaction of H3BO3 with brucite exist during deposition of brucite from artificial seawater. The simultaneous occurrence of both processes determines the boron concentration and isotopic fractionation of brucite. The isotopic fractionation behaviors and mechanisms of boron incorporated into brucite are different from those into corals. The existence of brucite in corals can affect the δ11B and Mg/Ca in corals and influences the Mg/Ca-SST proxy and δ11B-pH proxy negatively. The relationship between δ11B and Mg/Ca in corals can be used to judge the existence of brucite in corals, which should provide a reliable method for better use of δ11B and Mg/Ca in corals to reconstruct paleo-marine environment.

  18. The mercury isotope composition of Arctic coastal seawater

    NASA Astrophysics Data System (ADS)

    Štrok, Marko; Baya, Pascale Anabelle; Hintelmann, Holger

    2015-11-01

    For the first time, Hg isotope composition of seawater in the Canadian Arctic Archipelago is reported. Hg was pre-concentrated from large volumes of seawater sampling using anion exchange resins onboard the research vessel immediately after collection. Elution of Hg was performed in laboratory followed by isotope composition determination by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). For comparison, seawater from two stations was shipped to the laboratory and processed within it. Results showed negative mass-dependent fractionation in the range from -2.85 to -1.10‰ for δ202Hg, as well as slightly positive mass-independent fractionation of odd Hg isotopes. Positive mass-independent fractionation of 200Hg was also observed. Samples that were pre-concentrated in the laboratory showed different Hg isotope signatures and this is most probably due to the abiotic reduction of Hg in the dark by organic matter during storage and shipment after sampling. This emphasizes the need for immediate onboard pre-concentration.

  19. Prospects for the recovery of uranium from seawater

    SciTech Connect

    Best, F.R.; Driscoll, M.

    1986-04-01

    A computer program entitled URPE (Uranium Recovery Performance and Economics) has been developed to simulate the engineering performance and provide an economic analysis of a plant recovering uranium from seawater. The conceptual system design used as the focal point for the more general analysis consists of a floating oil-rig type of platform single-point moored in an open ocean current, using either high-volume-low-head axial pumps or the velocity head of the ambient ocean current to force seawater through a mass transfer medium (hydrous titanium oxide (HTO) coated onto particle beds or stacked tubes). Uranium is recovered from the seawater by an adsorption process, and later eluted from the adsober by an ammonium carbonate solution. A multiproduct cogenerating plant on board the platform burns coal to raise steam for electricity generation, desalination, and process heat requirements. Scrubbed stack gas from the plant is processed to recover carbon dioxide for chemical make-up needs. The equilibrium isotherm and the diffusion constant for the uranyl-HTO system, which are needed for bed performance calculations, have been calculated based on the data reported in the literature. In addition, a technique for calculating the rate constant of a fixed-bed adsoorbing system has been developed for use with Thomas' solution for predicting fixed-bed performance.

  20. Strontium isotopic variations of Neoproterozoic seawater - Implications for crustal evolution

    NASA Technical Reports Server (NTRS)

    Asmerom, Yemane; Jacobsen, Stein B.; Knoll, Andrew H.; Butterfield, Nicholas J.; Swett, Keene

    1991-01-01

    High-precision Sr isotopic data were obtained on carbonate samples from the Neoproterozoic Shaler Group, Victoria Island (Canada). Results indicate that, between ca. 790 and 850 Ma, the Sr-87/Sr-86 ratio of seawater varied betweeen 0.70676 and 0.70561, with the minimum value at about 830 Ma. A curve of the Sr-87/Sr-86 seawater ratio vs. age showed that the new data substantially improve the existing isotopic record of Sr in seawater for the period 790-850 Ma. The Sr isotopic system data were coupled with data for the Nd isotopic system to model changes in the seafloor spreading rates (hydrothermal flux) and the continental erosion for the period 500-900 Ma. Results indicate that hydrothermal flux reached a maximum value at ca. 830 Ma, while a maximum in erosion rate occurred at ca. 570 Ma. These peaks are considered to be related to the developments in the Pan-African and related orogenic events.

  1. Adsorption combined with ultrafiltration to remove organic matter from seawater.

    PubMed

    Tansakul, Chatkaew; Laborie, Stéphanie; Cabassud, Corinne

    2011-12-01

    Organic fouling and biofouling are the major severe types of fouling of reverse osmosis (RO) membranes in seawater (SW) desalination. Low pressure membrane filtration such as ultrafiltration (UF) has been developed as a pre-treatment before reverse osmosis. However, UF alone may not be an effective enough pre-treatment because of the existence of low-molecular weight dissolved organic matter in seawater. Therefore, the objective of the present work is to study a hybrid process, powdered activated carbon (PAC) adsorption/UF, with real seawater and to evaluate its performance in terms of organic matter removal and membrane fouling. The effect of different PAC types and concentrations is evaluated. Stream-activated wood-based PAC addition increased marine organic matter removal by up to 70% in some conditions. Moreover, coupling PAC adsorption with UF decreased UF membrane fouling and the fouling occurring during short-term UF was totally reversible. It can be concluded that the hybrid PAC adsorption/UF process performed in crossflow filtration mode is a relevant pre-treatment process before RO desalination, allowing organic matter removal of 75% and showing no flux decline for short-term experiments. PMID:21996607

  2. Constitutive modeling of calcium carbonate supersaturated seawater mixtures

    NASA Astrophysics Data System (ADS)

    Reis, Martina; Sousa, Maria De Fátima; Bertran, Celso; Bassi, Adalberto

    2014-11-01

    Calcium carbonate supersaturated seawater mixtures have attracted attention of many researchers since the deposition of CaCO3(s) from such solutions can lead to scaling problems in oil fields. However, despite their evident practical importance in petroleum engineering, the hydro and thermodynamic behaviors of these mixtures have not been well-understood yet. In this work, a constitutive model based on the foundations of the constitutive theory of continuum mechanics, and the Müller-Liu entropy principle is proposed. The calcium carbonate supersaturated seawater mixture is regarded as a reactive viscous fluid with heat and electrical conductions. The obtained results indicate that the thermodynamic behavior of CaCO3 supersaturated seawater mixtures is closely related to the individual dynamics of each constituent of the mixture, particularly to the linear momentum, and mass exchanges. Furthermore, the results show that, unlike classical continuum mixtures, the extra entropy flux is not null, and higher-order gradients of deformation contribute to the residual entropy production of the class of mixtures under study. The results of this work may be relevant for the prevention of the mineral scale formation in oil fields. The first author acknowledges the São Paulo Research Foundation (Grant 2013/ 20872-2) for its funding.

  3. Identification of Corrosion Products Due to Seawater and Fresh Water

    NASA Astrophysics Data System (ADS)

    Gismelseed, A.; Elzain, M.; Yousif, A.; Al Rawas, A.; Al-Omari, I. A.; Widatallah, H.; Rais, A.

    2004-12-01

    Mössbauer and X-ray diffraction (XRD) measurements were performed on corrosion products extracted from the inner surface of two different metal tubes used in a desalination plant in Oman. One of the tubes corroded due to the seawater while the second was corroded due to fresh water. The corrosion products thus resulted due to seawater were scrapped off in to two layers, the easily removable rust from the top is termed outer surface corrosion product and the strongly adhered rust as internal corrosion product. The Mössbauer spectra together with the XRD pattern of the outer surface showed the presence of magnetite (Fe3O4), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and hematite (Fe2O3). The inner surface however showed the presence of akaganite, goethite, and magnetite. On the other hand, the corrosion products due to the fresh water showed only the presence of goethite and magnetite. The mechanism of the corrosion process will be discussed based on the significant differences between the formation of the iron components of the corrosion products due to seawater and the fresh water.

  4. Misleading reconstruction of seawater intrusion via integral depth sampling

    NASA Astrophysics Data System (ADS)

    Colombani, N.; Volta, G.; Osti, A.; Mastrocicco, M.

    2016-05-01

    Saltwater intrusion in coastal aquifers is an urgent issue for the actual and future groundwater supply and a detailed characterization of groundwater quality with depth is a fundamental prerequisite to correctly distinguish salinization processes. In this study, interpolated Cl- maps of the Po River delta coastal aquifer (Italy), gained with Integrated Depth Sampling (IDS) and Multi-Level Sampling (MLS) techniques, are compared. The data set used to build up the IDS and MLS interpolated Cl- maps come from numerous monitoring campaigns on surface and ground waters, covering the time frame from 2010 to 2014. The IDS interpolated Cl- map recalls the phenomenon of actual seawater intrusion, with Cl- concentration never exceeding that of seawater and the absence of hypersaline groundwater all over the study area. On the contrary, in the MLS interpolated Cl- maps the lower portion of the unconfined aquifer presents hypersaline groundwater making it necessary to consider salinization processes other than actual seawater intrusion, like upward flux from a saline aquitard. Results demonstrate the obligation of using MLS in reconstructing a reliable representation of the distribution of salinity, especially in areas where the density contrast between fresh and saline groundwater is large. Implications of the reported field case are not limited to the local situation but have a wider significance, since the IDS technique is often employed in saltwater intrusion monitoring even in recent works, with detrimental effect on the sustainable water resource management of coastal aquifers.

  5. Turbidity study of solar ponds utilizing seawater as salt source

    SciTech Connect

    Li, Nan; Sun, Wence; Shi, Yufeng; Yin, Fang; Zhang, Caihong

    2010-02-15

    A series of experiments were conducted to study the turbidity reduction in solar ponds utilizing seawater as salt source. The experiment on the turbidity reduction efficiency with chemicals indicates that alum (KAl(SO{sub 4}){sub 2}.12H{sub 2}O) has a better turbidity control property because of its strongly flocculating and also well depressing the growing of algae and bacteria in the seawater. In comparison with bittern and seawater, our experiment shows that the residual brine after desalination can keep limpidity for a long time even without any chemical in it. Experiments were also conducted on the diffusion of turbidity and salinity, which show that the turbidity did not diffuse upwards in the solution. In the experiment on subsidence of soil in the bittern and saline with the same salinity, it was found that soil subsided quite quickly in the pure saline water, but very slowly in the bittern. In this paper we also proposed an economical method to protect the solar pond from the damage of rain. Finally, thermal performance of a solar pond was simulated in the conditions of different turbidities using a thermal diffusion model. (author)

  6. Does chlorination of seawater reverse osmosis membranes control biofouling?

    PubMed

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  7. Preliminary design studies on a nuclear seawater desalination system

    SciTech Connect

    Wibisono, A. F.; Jung, Y. H.; Choi, J.; Kim, H. S.; Lee, J. I.; Jeong, Y. H.; No, H. C.

    2012-07-01

    Seawater desalination is one of the most promising technologies to provide fresh water especially in the arid region. The most used technology in seawater desalination are thermal desalination (MSF and MED) and membrane desalination (RO). Some developments have been done in the area of coupling the desalination plant with a nuclear reactor to reduce the cost of energy required in thermal desalination. The coupling a nuclear reactor to a desalination plant can be done either by using the co-generation or by using dedicated heat from a nuclear system. The comparison of the co-generation nuclear reactor with desalination plant, dedicated nuclear heat system, and fossil fueled system will be discussed in this paper using economical assessment with IAEA DEEP software. A newly designed nuclear system dedicated for the seawater desalination will also be suggested by KAIST (Korea Advanced Inst. of Science and Technology) research team and described in detail within this paper. The suggested reactor system is using gas cooled type reactor and in this preliminary study the scope of design will be limited to comparison of two cases in different operating temperature ranges. (authors)

  8. Adsorption combined with ultrafiltration to remove organic matter from seawater.

    PubMed

    Tansakul, Chatkaew; Laborie, Stéphanie; Cabassud, Corinne

    2011-12-01

    Organic fouling and biofouling are the major severe types of fouling of reverse osmosis (RO) membranes in seawater (SW) desalination. Low pressure membrane filtration such as ultrafiltration (UF) has been developed as a pre-treatment before reverse osmosis. However, UF alone may not be an effective enough pre-treatment because of the existence of low-molecular weight dissolved organic matter in seawater. Therefore, the objective of the present work is to study a hybrid process, powdered activated carbon (PAC) adsorption/UF, with real seawater and to evaluate its performance in terms of organic matter removal and membrane fouling. The effect of different PAC types and concentrations is evaluated. Stream-activated wood-based PAC addition increased marine organic matter removal by up to 70% in some conditions. Moreover, coupling PAC adsorption with UF decreased UF membrane fouling and the fouling occurring during short-term UF was totally reversible. It can be concluded that the hybrid PAC adsorption/UF process performed in crossflow filtration mode is a relevant pre-treatment process before RO desalination, allowing organic matter removal of 75% and showing no flux decline for short-term experiments.

  9. Uranium from seawater research. Final progress report, FY 1982

    SciTech Connect

    Borzekowski, J.; Driscoll, M.J.; Best, F.R.

    1982-09-01

    During the FY 1982 campaign 14 new ion exchange resin formulations, prepared by the Rohm and Haas Company, were tested by MIT at the Woods Hole Oceanographic Institution. The best of these chelating resins was again of the acrylic amidoxime type; it picked up approximately 100 ppM uranium in seven days' exposure to seawater, which represents a factor of better than two improvement over the seven-day results for the best FY 1981 candidate (which saturated at roughly 100 ppM U after 30 days' exposure). Saturation was not reached and, within experimental accuracy, uranium accumulated at a constant rate over the seven-day period; it is speculated that a useful capacity of over 300 ppM U would be achieved. All resins of the styrenic amidoxime type were found to be an order of magnitude lower in their effective capacity for uranium in seawater than the best of the acrylic forms. Particle size effects, which were found to be less than expected from theoretical computations of both fluid and solid side mass transfer resistance, can not account for this difference. Scanning electron microscope examination by R and H scientists of ion exchange resin beads from beds subjected to seawater flow for 30 days in MIT's WHOI columns showed that the internal pores of the macro-reticular-type resins become filled with debris (of undetermined nature and effect) during exposure.

  10. Medication inhibits tolerance to seawater in coho salmon smolts

    USGS Publications Warehouse

    Bouck, Gerald R.; Johnson, David A.

    1979-01-01

    Applications of 10 therapeutic and two anesthetic agents to healthy smolts of coho salmon (Oncorhynchus kisutch) by conventional methods were followed by two different posttreatment circumstances. In condition I, fish were treated and then transferred directly to 28‰ seawater for 10 days; in condition II, fish were treated and held in fresh water for 4 days before their medium was gradually changed over a 4-hour period to 28‰ seawater. In condition I, no mortality occurred among fish treated with 2,4-D, trichlorofon, simazine, quinaldine, or light to moderate doses of MS-222. About 10% mortality occurred among fish treated with formalin and nifurpirinol. High mortality in seawater followed treatments with copper sulfate, hyamine 1622, potassium permanganate, malachite green (one protocol), and heavy doses of MS-222. In condition II, mortality was reduced but still high for copper sulfate and potassium permanganate, much lower for malachite green and hyamine 1622, and zero for the other agents. The results indicate that additional recovery time in fresh water is necessary between some treatments and exposure to salt water.

  11. Does chlorination of seawater reverse osmosis membranes control biofouling?

    PubMed

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations. PMID:25917390

  12. Macroporous monoliths for trace metal extraction from seawater

    DOE PAGES

    Yue, Yanfeng; Mayes, Richard T.; Gill, Gary; Kuo, Li -Jung; Wood, Jordana; Binder, Andrew J.; Brown, Suree; Dai, Sheng

    2015-05-29

    The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 gL-1). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N -methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawatermore » containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. Furthermore, the preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.« less

  13. In vitro survival of human pathogenic fungi in seawater.

    PubMed

    Anderson, J H

    1979-03-01

    The survival of propagules from 4 pathogenic fungi, Trichophyton mentagrophytes, Trichosporon cutaneum, Candida albicans, and Microsporum gypseum was studied in seawater subjected to different temperature (20--35 degrees C) and salinity (6--50%) levels in diurnal rhythm of 12 h cycles. Survival was measured by viability of propagules over a period of 52 weeks. All fungi, except T. cutaneum at 35 degrees C survived the experimental conditions for 52 weeks. Temperature was the most influential factor. When temperature increased, M. gypseum responded with enhanced viability whereas survival for C. albicans and T. cutaneum was inhibited. At 35 degrees C, T. cutaneum was not viable after 6--7 weeks even though it survived the initial 5 weeks with less loss of viability than the other test organisms. No correlation was seen between salinity level and loss of viability. Diurnal light had an inhibitory effect on T. cutaneum and C. albicans survival under in vitro conditions approximating those of seawater in Hawaii. M. gypseum had the highest level of survival over 52 weeks under usual in situ conditions simulated in vitro, followed by T. mentagrophytes, T. cutaneum, and C. albicans. Survival for 52 weeks even when salinity and temperature levels exceed those of the natural habitat indicates that seawater which washes sand beaches can be an environmental niche for potentially pathogenic fungi. PMID:375437

  14. Assessment of regional management strategies for controlling seawater intrusion

    USGS Publications Warehouse

    Reichard, E.G.; Johnson, T.A.

    2005-01-01

    Simulation-optimization methods, applied with adequate sensitivity tests, can provide useful quantitative guidance for controlling seawater intrusion. This is demonstrated in an application to the West Coast Basin of coastal Los Angeles that considers two management options for improving hydraulic control of seawater intrusion: increased injection into barrier wells and in lieu delivery of surface water to replace current pumpage. For the base-case optimization analysis, assuming constant groundwater demand, in lieu delivery was determined to be most cost effective. Reduced-cost information from the optimization provided guidance for prioritizing locations for in lieu delivery. Model sensitivity to a suite of hydrologic, economic, and policy factors was tested. Raising the imposed average water-level constraint at the hydraulic-control locations resulted in nonlinear increases in cost. Systematic varying of the relative costs of injection and in lieu water yielded a trade-off curve between relative costs and injection/in lieu amounts. Changing the assumed future scenario to one of increasing pumpage in the adjacent Central Basin caused a small increase in the computed costs of seawater intrusion control. Changing the assumed boundary condition representing interaction with an adjacent basin did not affect the optimization results. Reducing the assumed hydraulic conductivity of the main productive aquifer resulted in a large increase in the model-computed cost. Journal of Water Resources Planning and Management ?? ASCE.

  15. Mercury isotope signatures of seawater discharged from a coal-fired power plant equipped with a seawater flue gas desulfurization system.

    PubMed

    Lin, Haiying; Peng, Jingji; Yuan, Dongxing; Lu, Bingyan; Lin, Kunning; Huang, Shuyuan

    2016-07-01

    Seawater flue gas desulfurization (SFGD) systems are commonly used to remove acidic SO2 from the flue gas with alkaline seawater in many coastal coal-fired power plants in China. However, large amount of mercury (Hg) originated from coal is also transferred into seawater during the desulfurization (De-SO2) process. This research investigated Hg isotopes in seawater discharged from a coastal plant equipped with a SFGD system for the first time. Suspended particles of inorganic minerals, carbon residuals and sulfides are enriched in heavy Hg isotopes during the De-SO2 process. δ(202)Hg of particulate mercury (PHg) gradually decreased from -0.30‰ to -1.53‰ in study sea area as the distance from the point of discharge increased. The results revealed that physical mixing of contaminated De-SO2 seawater and uncontaminated fresh seawater caused a change in isotopic composition of PHg isotopes in the discharging area; and suggested that both De-SO2 seawater and local background contributed to PHg. The impacted sea area predicted with isotopic tracing technique was much larger than that resulted from a simple comparison of pollutant concentration. It was the first attempt to apply mercury isotopic composition signatures with two-component mixing model to trace the mercury pollution and its influence in seawater. The results could be beneficial to the coal-fired plants with SFGD systems to assess and control Hg pollution in sea area. PMID:27155100

  16. An experimental investigation of barite formation in seawater

    USGS Publications Warehouse

    Ganeshram, R.S.; Francois, R.; Commeau, J.; Brown-Leger, S. L.

    2003-01-01

    We report results from time-series decay and sequential leaching experiments of laboratory cultured and coastal plankton to elucidate the mechanisms controlling barite formation in seawater. Batch-cultured diatoms ( Stephanopyxis palmerina ) and coccolithophorids (Emiliania huxleyi) were let to decay in the dark for 8-10 weeks, suspended in aerated seawater. The development of barite crystals was monitored by Scanning Electron Microscopy (SEM). A similar experiment was conducted with plankton collected during the spring-bloom in Vineyard Sound (MA). In addition to SEM, suspended particles were sequentially leached for Ba (distilled water rinse; 10% (v/v) HNO3 rinse at room temperature; 30% (v/v) HCl at 80??C overnight; 50% (v/v) HNO3 at 80??C overnight) immediately after collection, and after 10-week decay in seawater, in seawater poisoned with HgCl2, and in seawater spiked with 135Ba. Both experiments showed an increase in the number of barite crystals during decay. The spring-bloom plankton had initially a large pool of labile Ba, soluble in distilled water and cold dilute HNO3 that was lost from the plankton after 10-week decay in both axenic and nonaxenic conditions. In contrast, Ba in the decayed plankton samples was predominantly in forms extracted by hot HCl and hot HNO3 acids, which were attributed to presence of barite Ba and refractory organic Ba respectively. The increase in barite crystal counts under a Scanning Electron Microscope (SEM), the increase in HCl extractable Ba relative to organic carbon, and the loss of a large fraction of Ba during plankton decay suggest that living plankton consists of a relatively large pool of labile Ba, which is rapidly released during plankton decomposition and acts as the main source of Ba for barite formation in supersaturated microenvironments. Since mass balance indicates that only a small proportion (2 to 4%) of the labile-Ba pool is converted to barite, the availability of microenvironments that could locally

  17. Planktic foraminifera shell chemistry response to seawater chemistry: Pliocene-Pleistocene seawater Mg/Ca, temperature and sea level change

    NASA Astrophysics Data System (ADS)

    Evans, David; Brierley, Chris; Raymo, Maureen E.; Erez, Jonathan; Müller, Wolfgang

    2016-03-01

    Foraminifera Mg/Ca paleothermometry forms the basis of a substantial portion of ocean temperature reconstruction over the last 5 Ma. Furthermore, coupled Mg/Ca-oxygen isotope (δ18O) measurements of benthic foraminifera can constrain eustatic sea level (ESL) independent of paleo-shoreline derived approaches. However, this technique suffers from uncertainty regarding the secular variation of the Mg/Ca seawater ratio (Mg/Casw) on timescales of millions of years. Here we present coupled seawater-test Mg/Ca-temperature laboratory calibrations of Globigerinoides ruber in order to test the widely held assumptions that (1) seawater-test Mg/Ca co-vary linearly, and (2) the Mg/Ca-temperature sensitivity remains constant with changing Mg/Casw. We find a nonlinear Mg/Catest-Mg/Casw relationship and a lowering of the Mg/Ca-temperature sensitivity at lower than modern Mg/Casw from 9.0% °C-1 at Mg/Casw = 5.2 mol mol-1 to 7.5 ± 0.9% °C-1 at 3.4 mol mol-1. Using our calibrations to more accurately calculate the offset between Mg/Ca and biomarker-derived paleotemperatures for four sites, we derive a Pliocene Mg/Casw ratio of ∼4.3 mol mol-1. This Mg/Casw implies Pliocene ocean temperature 0.9-1.9 °C higher than previously reported and, by extension, ESL ∼30 m lower compared to when one assumes that Pliocene Mg/Casw is the same as at present. Correcting existing benthic foraminifera datasets for Mg/Casw indicates that deep water source composition must have changed through time, therefore seawater oxygen isotope reconstructions relative to present day cannot be used to directly reconstruct Pliocene ESL.

  18. Seawater fluid inclusions preserved within Cambrian-Ordovician marine cements indicate Cambrian-Ordovician seawater precipitated low-magnesium calcite

    SciTech Connect

    Johnson, W.J.; Goldstein, R.H. . Dept. of Geology)

    1992-01-01

    The San Saba Member of the Wilberns Formation (Llano Uplift, Texas) contains a series of Late Cambrian-Early Ordovician hardgrounds. Bladed low-Mg calcite cements are truncated at hardground surfaces and overlain by shallow marine limestones, indicating a syndepositional shallow marine origin. Primary one-phase fluid inclusions within bladed cements have marine salinities, suggesting that these low-Mg calcite cements formed as a precipitate from Late Cambrian and Early Ordovician seawater and have not undergone recrystallization. Stable isotope analysis of the bladed cement yields delta O-18 values that cluster between [minus]5.6--[minus]6.0 ([per thousand] PDB) which is comparable to those previously reported for Early Ordovician marine calcite. The delta C-13 values are more positive than those reported for this time interval (0.6--1.3 [per thousand] PDB). Trace element analysis indicates that strontium content ranges from 200 to 2,200 ppm. Iron ranges from below detection by electron microprobe to 800 ppm. Mg is generally below detection, however, cements in one hardground display Mg contents that increase progressively toward pore centers. Trace element data lack covariance that would suggest recrystallization. In addition, closed system recrystallization cannot be supported here due to a lack of microdolomite inclusions. Stable isotope, trace element, and fluid inclusion data are consistent with submarine cementation at or below the sediment-water interface. These cements have not undergone significant recrystallization and preserve a primary low Mg calcite mineralogy. These data suggest that early Paleozoic seawater differed chemically from modern seawater. Moreover, preservation of ancient seawater, within fluid inclusions, may provide a direct means of determining those differences.

  19. Seawater pH at the advent of metazoan calcification

    NASA Astrophysics Data System (ADS)

    Ries, Justin; Gonzalez-Roubaud, Cécile; Douville, Eric; Montagna, Paolo

    2016-04-01

    The boron isotopic composition (δ11B) of bulk limestones provides a potentially powerful tool for reconstructing seawater pH deep into the geologic past (Kasemann et al., 2005; Paris et al., 2010; Ohnemueller et al., 2014). Here, we present δ11B of 35 calcitic limestones derived from a ca. 9 m.y. interval of the terminal Proterozoic Nama Group of southern Namibia. These units immediately precede the so-called Cambrian Radiation - the greatest diversification of metazoans in Earth history marked by the near-simultaneous advent of calcification across most animal phyla. The Nama Group represents one of the best preserved (average [Sr] = 1805 ppm; Mn/Sr < 2; δ18O > -10‰) and most continuous terminal Proterozoic limestone sequences known in the world. The carbonate units investigated here were deposited between ca. 552 and 543 Ma in a semi-divided foreland basin of the Kalahari Craton (Grotzinger and Miller, 2008). Depositional environments were shore-associated and ranged from upper shoreline/tidal flats to below-wave-base lower shoreface, and comprise calcisiltites, calcarenites, heterolithic interbeds, grainstones, and microbialites (Saylor et al., 1998; Grotzinger and Miller, 2008). The δ11B of the 35 sampled Nama Group carbonates were obtained via MC-ICP-MS. Samples were screened for contamination of the δ11B signal by clays (using [Al] as a proxy for clay content) (Paris et al., 2010) and by open-system meteoric diagenesis (δ11B-δ18O correlation). The δ11B values of the limestones ranged from 0.5 to 10.8‰ (avg. = 5.3‰), which is consistent with the previously observed increasing trend in carbonate δ11B (Paris et al., 2010) from the -6.2 to 2.7‰ values reported for Neoproterozoic cap carbonate dolostones (Kasemann et al., 2005) to the ca. 25‰ value reported for most modern marine carbonates. B/Ca ratios for the sampled limestones ranged from 3.4 to 24.0 ppm (avg. = 11.0). Assuming a seawater temperature of 25° C, a salinity of 35, a depth of 10

  20. Concentration of enteric virus indicator from seawater using granular activated carbon.

    PubMed

    Cormier, Jiemin; Gutierrez, Miguel; Goodridge, Lawrence; Janes, Marlene

    2014-02-01

    Fecal contamination of shellfish growing seawater with enteric viruses is often associated with human outbreaks of gastroenteritis. Male specific bacteriophage MS2 is correlated with those of enteric viruses in a wide range of water environments and has been used widely as a surrogate for pathogenic waterborne viruses. Since viruses in contaminated water are usually at low levels, the development of methods to concentrate viruses from water is crucial for detection purposes. In the present study, granular activated carbon was evaluated for concentration of MS2 from artificial seawater, and different parameters of the seawater were also compared. Recovery of MS2 from warm seawater (37°C) was found to be significantly greater than from cold seawater (4 and 20°C), and even greater than from fresh water (4, 20 and 37°C); the difference between seawater and fresh water became less profound when the temperatures of both were below 37°C. Although not of statistical significance, recovery of MS2 from low salinity seawater (10 and 20 parts per thousand, ppt) was greater than from high salinity seawater (30 and 40ppt). One gram of granular activated carbon was able to extract 6-log plaque forming units (PFU) of MS2 from 500ml seawater at 37°C. This study demonstrated that granular activated carbon can concentrate an enteric virus indicator from shellfish growing seawater effectively.

  1. Strontium isotopic variations of Neoproterozoic seawater: implications for crustal evolution.

    PubMed

    Asmerom, Y; Jacobsen, S B; Knoll, A H; Butterfield, N J; Swett, K

    1991-01-01

    We report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Lithostratigraphic correlations with the relatively well-dated Mackenzie Mountains Supergroup constrain Shaler deposition to approximately 770-880 Ma, a range corroborated by 723 +/- 3 Ma lavas that disconformably overlie Shaler carbonates and by Late Riphean microfossils within the section. Samples with low 87Rb/86Sr ratios (<0.01) were selected for Sr isotopic analysis. Delta 18O, Mn, Ca, Mg, and Sr data were used to recognize altered samples. The altered samples are characterized by high Mn/Sr (> or = 2) and variable delta 18O; most are dolomites. The data indicate that between ca. 790-850 Ma the 87Sr/86Sr ratio of seawater varied between 0.70676 and 0.70561. The samples show smooth and systematic variation, with the lowest 87Sr/86Sr value of 0.70561 at ca. 830 Ma. The low 87Sr/86Sr ratio of carbonates from the lower parts of our section is similar to a value reported for one sample from the Adrar of Mauritania (approximately 900 Ma), West African Craton. Isotopic ratios from the upper part of the Shaler section are identical to values from the lower part of the Neoproterozoic Akademikerbreen Group, Spitsbergen. Although a paucity of absolute age determinations hinders attempts at the precise correlation of Neoproterozoic successions, it is possible to draw a broad outline of the Sr isotopic composition of seawater for this period. Indeed, the Sr isotope data themselves provide a stratigraphic tool of considerable potential. Data from this study and the literature are used to construct a curve of the 87Sr/86Sr ratio of Neoproterozoic seawater. The new data reported in this study substantially improve the isotopic record of Sr in seawater for the period 790-850 Ma. The Sr isotope composition of seawater reflects primarily the balance between continental Sr input through river input and mantle input via hydrothermal

  2. Strontium isotopic variations of Neoproterozoic seawater: implications for crustal evolution.

    PubMed

    Asmerom, Y; Jacobsen, S B; Knoll, A H; Butterfield, N J; Swett, K

    1991-01-01

    We report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Lithostratigraphic correlations with the relatively well-dated Mackenzie Mountains Supergroup constrain Shaler deposition to approximately 770-880 Ma, a range corroborated by 723 +/- 3 Ma lavas that disconformably overlie Shaler carbonates and by Late Riphean microfossils within the section. Samples with low 87Rb/86Sr ratios (<0.01) were selected for Sr isotopic analysis. Delta 18O, Mn, Ca, Mg, and Sr data were used to recognize altered samples. The altered samples are characterized by high Mn/Sr (> or = 2) and variable delta 18O; most are dolomites. The data indicate that between ca. 790-850 Ma the 87Sr/86Sr ratio of seawater varied between 0.70676 and 0.70561. The samples show smooth and systematic variation, with the lowest 87Sr/86Sr value of 0.70561 at ca. 830 Ma. The low 87Sr/86Sr ratio of carbonates from the lower parts of our section is similar to a value reported for one sample from the Adrar of Mauritania (approximately 900 Ma), West African Craton. Isotopic ratios from the upper part of the Shaler section are identical to values from the lower part of the Neoproterozoic Akademikerbreen Group, Spitsbergen. Although a paucity of absolute age determinations hinders attempts at the precise correlation of Neoproterozoic successions, it is possible to draw a broad outline of the Sr isotopic composition of seawater for this period. Indeed, the Sr isotope data themselves provide a stratigraphic tool of considerable potential. Data from this study and the literature are used to construct a curve of the 87Sr/86Sr ratio of Neoproterozoic seawater. The new data reported in this study substantially improve the isotopic record of Sr in seawater for the period 790-850 Ma. The Sr isotope composition of seawater reflects primarily the balance between continental Sr input through river input and mantle input via hydrothermal

  3. Biochemical alterations induced in Hediste diversicolor under seawater acidification conditions.

    PubMed

    Freitas, Rosa; Pires, Adília; Moreira, Anthony; Wrona, Frederick J; Figueira, Etelvina; Soares, Amadeu M V M

    2016-06-01

    Seawater pH is among the environmental factors controlling the performance of marine organisms, especially in calcifying marine invertebrates. However, changes in non-calcifying organisms (including polychaetes) may also occur due to pH decrease. Polychaetes are often the most abundant group of organisms in estuarine systems, representing an important ecological and economic resource. Thus, the present study aimed to evaluate the impacts of seawater acidification in the polychaete Hediste diversicolor, a species commonly used as bioindicator. For this, organisms were exposed to different pH levels (7.9, 7.6 and 7.3) during 28 days and several biochemical markers were measured. The results obtained demonstrated that pH decrease negatively affected osmotic regulation and polychaetes metabolism, with individuals under low pH (7.6 and 7.3) presenting higher carbonic anhydrase activity, lower energy reserves (protein and glycogen content) and higher metabolic rate (measured as Electron transport system activity). The increase on CA activity was associated to organisms osmoregulation capacity while the increase on ETS and decrease on energy reserves was associated to the polychaetes capacity to develop defense mechanisms (e.g. antioxidant defenses). In fact, despite having observed higher lipid peroxidation at pH 7.6, in polychaetes at the lowest tested pH (7.3) LPO levels were similar to values recorded in individuals under control pH (7.9). Such findings may result from higher antioxidant enzyme activity at the lowest tested pH, which prevented organisms from higher oxidative stress levels. Overall, our study demonstrated how polychaetes may respond to near-future ocean acidification conditions, exhibiting the capacity to develop biochemical strategies which will prevent organisms from lethal injuries. Such defense strategies will contribute for polychaetes populations maintenance and survival under predicted seawater acidification scenarios. PMID:27088614

  4. Enteric neuroplasticity in seawater-adapted European eel (Anguilla anguilla).

    PubMed

    Sorteni, C; Clavenzani, P; De Giorgio, R; Portnoy, O; Sirri, R; Mordenti, O; Di Biase, A; Parmeggiani, A; Menconi, V; Chiocchetti, R

    2014-02-01

    European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/D-IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions.

  5. Innovative Elution Processes for Recovering Uranium from Seawater

    SciTech Connect

    Wai, Chien; Tian, Guoxin; Janke, Christopher

    2014-05-29

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  6. A seawater desalination scheme for global hydrological models

    NASA Astrophysics Data System (ADS)

    Hanasaki, Naota; Yoshikawa, Sayaka; Kakinuma, Kaoru; Kanae, Shinjiro

    2016-10-01

    Seawater desalination is a practical technology for providing fresh water to coastal arid regions. Indeed, the use of desalination is rapidly increasing due to growing water demand in these areas and decreases in production costs due to technological advances. In this study, we developed a model to estimate the areas where seawater desalination is likely to be used as a major water source and the likely volume of production. The model was designed to be incorporated into global hydrological models (GHMs) that explicitly include human water usage. The model requires spatially detailed information on climate, income levels, and industrial and municipal water use, which represent standard input/output data in GHMs. The model was applied to a specific historical year (2005) and showed fairly good reproduction of the present geographical distribution and national production of desalinated water in the world. The model was applied globally to two periods in the future (2011-2040 and 2041-2070) under three distinct socioeconomic conditions, i.e., SSP (shared socioeconomic pathway) 1, SSP2, and SSP3. The results indicate that the usage of seawater desalination will have expanded considerably in geographical extent, and that production will have increased by 1.4-2.1-fold in 2011-2040 compared to the present (from 2.8 × 109 m3 yr-1 in 2005 to 4.0-6.0 × 109 m3 yr-1), and 6.7-17.3-fold in 2041-2070 (from 18.7 to 48.6 × 109 m3 yr-1). The estimated global costs for production for each period are USD 1.1-10.6 × 109 (0.002-0.019 % of the total global GDP), USD 1.6-22.8 × 109 (0.001-0.020 %), and USD 7.5-183.9 × 109 (0.002-0.100 %), respectively. The large spreads in these projections are primarily attributable to variations within the socioeconomic scenarios.

  7. Enteric neuroplasticity in seawater-adapted European eel (Anguilla anguilla).

    PubMed

    Sorteni, C; Clavenzani, P; De Giorgio, R; Portnoy, O; Sirri, R; Mordenti, O; Di Biase, A; Parmeggiani, A; Menconi, V; Chiocchetti, R

    2014-02-01

    European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/D-IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions. PMID:24433383

  8. A comparison of computer methods for seawater alkalinity titrations

    NASA Astrophysics Data System (ADS)

    Barron, J. L.; Dyrssen, D.; Jones, E. P.; Wedborg, M.

    1983-04-01

    Potentiometric hydrochloric acid titration of seawater provides a powerful technique for determining components of the carbonate system. Recently, questions have been raised regarding older computer procedures for extracting the carbonate system parameters from the titration curve. We compare four evaluation methods, an early Gran method, the GEOSECS Gran method, a new modified Gran method, and a curve-fitting method. We conclude that the new modified Gran method and the curve-fitting can result in a precision of better than 0.1% but because of possible problems associated with representing all relevant chemical reactions during titration, an alkalinity standard must be established before accuracies of 0.1% can be achieved.

  9. Uranyl peroxide enhanced nuclear fuel corrosion in seawater

    PubMed Central

    Armstrong, Christopher R.; Nyman, May; Shvareva, Tatiana; Sigmon, Ginger E.; Burns, Peter C.; Navrotsky, Alexandra

    2012-01-01

    The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances. PMID:22308442

  10. Documentation of the seawater intrusion (SWI2) package for MODFLOW

    USGS Publications Warehouse

    Bakker, Mark; Schaars, Frans; Hughes, Joseph D.; Langevin, Christian D.; Dausman, Alyssa M.

    2013-01-01

    The SWI2 Package is the latest release of the Seawater Intrusion (SWI) Package for MODFLOW. The SWI2 Package allows three-dimensional vertically integrated variable-density groundwater flow and seawater intrusion in coastal multiaquifer systems to be simulated using MODFLOW-2005. Vertically integrated variable-density groundwater flow is based on the Dupuit approximation in which an aquifer is vertically discretized into zones of differing densities, separated from each other by defined surfaces representing interfaces or density isosurfaces. The numerical approach used in the SWI2 Package does not account for diffusion and dispersion and should not be used where these processes are important. The resulting differential equations are equivalent in form to the groundwater flow equation for uniform-density flow. The approach implemented in the SWI2 Package allows density effects to be incorporated into MODFLOW-2005 through the addition of pseudo-source terms to the groundwater flow equation without the need to solve a separate advective-dispersive transport equation. Vertical and horizontal movement of defined density surfaces is calculated separately using a combination of fluxes calculated through solution of the groundwater flow equation and a simple tip and toe tracking algorithm. Use of the SWI2 Package in MODFLOW-2005 only requires the addition of a single additional input file and modification of boundary heads to freshwater heads referenced to the top of the aquifer. Fluid density within model layers can be represented using zones of constant density (stratified flow) or continuously varying density (piecewise linear in the vertical direction) in the SWI2 Package. The main advantage of using the SWI2 Package instead of variable-density groundwater flow and dispersive solute transport codes, such as SEAWAT and SUTRA, is that fewer model cells are required for simulations using the SWI2 Package because every aquifer can be represented by a single layer of cells

  11. Hydrochemical and isotopic characteristics of estuarial seawater and river water of Bailanghe in Laizhou Bay, China

    NASA Astrophysics Data System (ADS)

    Yang, Qiaofeng; Xu, Suning; Wang, Ruijiu; Li, Wenpeng; Wang, Zhiyi; Mei, Junjun; Ding, Zhilei; Yang, Peijie; Yu, Liangju; Lv, Tieying; Bai, Gang; Kang, Wei

    2016-04-01

    In the study of seawater intrusion, seawater is usually taken as an end-member that mixes with other source(s). However, compared to standard seawater, the coastal seawater particularly that near the estuary, can be strongly influenced by the rivers into the sea and by coastal human activities. Their composition can be thus continuously changed and redistributed with space and time. Therefore, before investigating seawater intrusion in a certain area, it is essentially important to determine the features of the estuarine seawater (e.g. the mixture percentage between standard seawater and river water). In this study, we aimed to gain a clear situation of the seawater intrusion in Laizhou Bay, Southern Bohai, China. The issue aforementioned was investigated by comparing the stable isotopic and hydrochemical composition of the marine and river water collected in this area. Samples investigated include 5 surface water samples collected at the downstream of the Bailanghe and 7 seawater samples near the estuary of Laizhou Bay. Inert tracers (δD, δ18O, Cl, Br) and reaction tracers (Na, Mg, SO4, HCO3, Ca, NO3) are particularly analyzed. The major results are as follows: 1) All the river water samples fall below the Global Meteoric Water Line in the δD - δ18O diagram, reflecting evaporation of the upstream reservoir water. The seawater samples fall on the mixing line of standard seawater and the river water in the stable isotopic diagram. 2) The Cl-δ18O diagram indicates widespread dissolution of evaporate into the river, while high concentration of Ca and HCO3-, as well as the SO42- - Cl relation of the river water samples reflect the dissolution of CO2 , carbonate and sulfate in the atmosphere and on the ground. 3) The Br/Cl ratios of seawater samples are closed to the marine ratios. This together with the plots of major ions vs. Cl suggest that the seawater samples are originated from the mixture of standard seawater and river water. Therefore, when referring to the

  12. Hydrochemical and isotopic characteristics of estuarial seawater and river water of Bailanghe in Laizhou Bay, China

    NASA Astrophysics Data System (ADS)

    Yang, Qiaofeng; Xu, Suning; Wang, Ruijiu; Li, Wenpeng; Wang, Zhiyi; Mei, Junjun; Ding, Zhilei; Yang, Peijie; Yu, Liangju; Lv, Tieying; Bai, Gang; Kang, Wei

    2016-04-01

    In the study of seawater intrusion, seawater is usually taken as an end-member that mixes with other source(s). However, compared to standard seawater, the coastal seawater particularly that near the estuary, can be strongly influenced by the rivers into the sea and by coastal human activities. Their composition can be thus continuously changed and redistributed with space and time. Therefore, before investigating seawater intrusion in a certain area, it is essentially important to determine the features of the estuarine seawater (e.g. the mixture percentage between standard seawater and river water). In this study, we aimed to gain a clear situation of the seawater intrusion in Laizhou Bay, Southern Bohai, China. The issue aforementioned was investigated by comparing the stable isotopic and hydrochemical composition of the marine and river water collected in this area. Samples investigated include 5 surface water samples collected at the downstream of the Bailanghe and 7 seawater samples near the estuary of Laizhou Bay. Inert tracers (δD, δ18O, Cl, Br) and reaction tracers (Na, Mg, SO4, HCO3, Ca, NO3) are particularly analyzed. The major results are as follows: 1) All the river water samples fall below the Global Meteoric Water Line in the δD - δ18O diagram, reflecting evaporation of the upstream reservoir water. The seawater samples fall on the mixing line of standard seawater and the river water in the stable isotopic diagram. 2) The Cl-δ18O diagram indicates widespread dissolution of evaporate into the river, while high concentration of Ca and HCO3‑, as well as the SO42‑ - Cl relation of the river water samples reflect the dissolution of CO2 , carbonate and sulfate in the atmosphere and on the ground. 3) The Br/Cl ratios of seawater samples are closed to the marine ratios. This together with the plots of major ions vs. Cl suggest that the seawater samples are originated from the mixture of standard seawater and river water. Therefore, when referring to

  13. Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C

    USGS Publications Warehouse

    Shanks, Wayne C.; Bischoff, James L.; Rosenbauer, Robert J.

    1981-01-01

    Systematics of sulfur isotopes in the 250 and 350°C experiments indicate that isotopic equilibrium is reached, and can be modeled as a Rayleigh distillation process. Isotopic composition of hydrothermally produced H2S in natural systems is strongly dependent upon the seawater/basalt ratio in the geothermal system, which controls the relative sulfide contributions from the two important sulfur sources, seawater sulfate and sulfide phases in basalt. Anhydrite precipitation during geothermal heating severely limits sulfate ingress into high temperature interaction zones. Quantitative sulfate reduction can thus be accomplished without producing strongly oxidized rocks and resultant sulfide sulfur isotope values represent a mixture of seawater and basaltic sulfur.

  14. The evolution of Phanerozoic seawater - Isotope paleothermometry finds consensus on Early Paleozoic warmth and constant seawater δ18O

    NASA Astrophysics Data System (ADS)

    Grossman, E. L.; Henkes, G. A.; Passey, B. H.; Shenton, B.; Yancey, T. E.; Perez-Huerta, A.

    2015-12-01

    Evolution of metazoan life is closely linked to the Phanerozoic evolution of ocean temperatures and chemistry. Oxygen isotopic evidence for early Phanerozoic paleotemperatures has been equivocal, with decreasing δ18O values with age being interpreted as warmer early oceans, decreasing seawater δ18O with age, or increasing diagenetic alteration in older samples. Here we compare an updated compilation of oxygen isotope data for carbonate and phosphate fossils and microfossils (Grossman, 2012, Geol. Time Scale, Elsevier, 195-220) with a compilation of new and existing clumped isotope data. Importantly, these data are curated based on sample preservation with special consideration given to screening techniques, and tectonic and burial history. Burial history is critical in the preservation of carbonate clumped isotope temperatures in particular, which can undergo reordering in the solid state. We use a model derived for reordering kinetics (Henkes et al., 2014, Geochim. Cosmochim. Acta 139:362-382) to screen clumped isotope data for the effects of solid-state burial alteration. With minor but significant exceptions (Late Cretaceous, Early Triassic), average δ18O values (4 m.y. window, 2 m.y. steps) for post-Devonian brachiopods, belemnites, and foraminifera, representing tropical-subtropical surface ocean conditions, yield average isotopic temperatures below 30°C (assuming a seawater δ18O value [ -1‰ VSMOW] of an "ice-free" world). In contrast, Ordovician to Devonian data show sustained temperatures of 35-40°C. Likewise, isotopic paleotemperatures from conodont apatite, known to be resistant to isotopic exchange, follow the same pattern. Clumped isotope data derived from Paleozoic brachiopod shells that experienced minimal burial (< 100 °C) and <1% reordering according to the taxon-specific clumped isotope reordering model yield typical temperatures of 25-30°C for the Carboniferous, and 35-40°C for the Ordovician-Silurian. Inserting clumped temperatures and

  15. Kinetics of adsorption of uranium from seawater by humic acids

    SciTech Connect

    Heitkamp, D. ); Wagener, K. )

    1990-04-01

    The kinetics of the adsorption of uranium from seawater by humic acids fixed onto a polymer matrix was measured in a fluidized bed as a function of the grain size of the adsorbent and the flow velocity of the seawater. The adsorption rate was found to be governed by the diffusion of the uranium ions through the hydrodynamic surface layer of the adsorbent which is always formed in laminar flows of liquids. The measured rate constants are interpreted in terms of effective diffusion coefficients of 3.6 {times} 10{sup {minus}5} cm{sup 2}/s for uranyl ions and 1.8 {times} 10{sup {minus}5} cm{sup 2}/s for tricarbonatouranate ions in the surface layer. As a consequence of this kinetic behavior, the geometry of the adsorbent as well as the velocity of the water flow are relevant parameters for the amount of adsorbent needed for a projected extraction rate. This conclusion applies to all adsorption processes where diffusion through the hydrodynamic layer is the rate-determining kinetic step.

  16. Characterisation of iron binding ligands in seawater by reverse titration.

    PubMed

    Hawkes, Jeffrey A; Gledhill, Martha; Connelly, Douglas P; Achterberg, Eric P

    2013-03-01

    Here we demonstrate the use of reverse titration - competitive ligand exchange-adsorptive cathodic stripping voltammetry (RT-CLE-ACSV) for the analysis of iron (Fe) binding ligands in seawater. In contrast to the forward titration, which examines excess ligands in solution, RT-CLE-ACSV examines the existing Fe-ligand complexes by increasing the concentration of added (electroactive) ligand (1-nitroso-2-naphthol) and analysis of the proportion of Fe bound to the added ligand. The data manipulation allows the accurate characterisation of ligands at equal or lower concentrations than Fe in seawater, and disregards electrochemically inert dissolved Fe such as some colloidal phases. The method is thus superior to the forward titration in environments with high Fe and low ligand concentrations or high concentrations of inert Fe. We validated the technique using the siderophore ligand ferrioxamine B, and observed a stability constant [Formula: see text] of 0.74-4.37×10(21) mol(-1), in agreement with previous results. We also successfully analysed samples from coastal waters and a deep ocean hydrothermal plume. Samples from these environments could not be analysed with confidence using the forward titration, highlighting the effectiveness of the RT-CLE-ACSV technique in waters with high concentrations of inert Fe.

  17. Effects of recharge wells and flow barriers on seawater intrusion.

    PubMed

    Luyun, Roger; Momii, Kazuro; Nakagawa, Kei

    2011-01-01

    The installation of recharge wells and subsurface flow barriers are among several strategies proposed to control seawater intrusion on coastal groundwater systems. In this study, we performed laboratory-scale experiments and numerical simulations to determine the effects of the location and application of recharge wells, and of the location and penetration depth of flow barriers, on controlling seawater intrusion in unconfined coastal aquifers. We also compared the experimental results with existing analytical solutions. Our results showed that more effective saltwater repulsion is achieved when the recharge water is injected at the toe of the saltwater wedge. Point injection yields about the same repulsion compared with line injection from a screened well for the same recharge rate. Results for flow barriers showed that more effective saltwater repulsion is achieved with deeper barrier penetration and with barriers located closer to the coast. When the flow barrier is installed inland from the original toe position however, saltwater intrusion increases with deeper barrier penetration. Saltwater repulsion due to flow barrier installation was found to be linearly related to horizontal barrier location and a polynomial function of the barrier penetration depth.

  18. Oxygen-isotope fractionation between marine biogenic silica and seawater

    SciTech Connect

    Matheney, R.K.; Knauth, L.P. )

    1989-12-01

    A stepwise fluorination technique has been used to selectively react away the water component of hydrous silica in order to better investigate the oxygen-isotope fractionation between biogenic opal and seawater, and to determine whether all taxa produce opal which is suitable for oxygen isotope paleothermometry. {delta}{sup 18}O of the tetrahedrally coordinated silicate oxygen of siliceous sponge spicules grown at a wide variety of temperatures varies independently of temperature. {delta}{sup 18}O from an Eocene radiolarian ooze sample is much more enriched than would be expected from any reasonable isotopic temperature curve, given the probable growing temperature of the sample. {delta}{sup 18}O of diatom samples seems to vary systematically with temperature and to conform approximately to the isotopic temperature curve for diatom frustules obtained by Labeyrie and coworkers using an entirely different analytical technique. Sponges appear to precipitate silica in isotopic disequilibrium with seawater oxygen, and old radiolarian silica may exchange readily with could oceanic bottom water. Neither will apparently be useful for paleoclimate reconstructions. Diatoms maybe useful in deducing ancient surface-water temperatures, but the systematic variation of {alpha} with temperature for diatoms may not be related to the quartz-H{sub 2}O equilibrium isotope fractionation.

  19. Seawater Sr isotopes at the Cretaceous/Tertiary boundary

    NASA Astrophysics Data System (ADS)

    Martin, E. E.; Macdougall, J. D.

    1991-06-01

    Seawater 87Sr/ 86Sr values increase abruptly by 28 × 10 -6 across the Cretaceous/Tertiary boundary (KTB). This small, but rapid shift is superimposed on the larger scale structure of the seawater Sr isotope curve. The time scale of radiogenic Sr addition appears to be too rapid to reconcile with sources associated with volcanism, and we show that the amount of Sr required to produce even this small increase is too large to be derived from: (1) a KT bolide of the size constrained by the Ir anomaly, (2) continental crust ejecta from the impact of such a bolide, (3) soot from global wildfires initiated by an impact, or (4) any combination of these sources. The probable source of the radiogenic Sr is enhanced continental weathering, but the high rate of increase appears to rule out processes such as sea level regression, glaciation or tectonism. A plausible mechanism for rapid addition of radiogenic Sr to the oceans is enhanced weathering associated with globally distributed acid rain (pH ˜ 1) which is a proposed by-product of a bolide impact [51, EPSL Vol. 83].

  20. Extracellular proteases are released by ciliates in defined seawater microcosms.

    PubMed

    Thao, Ngo Vy; Nozawa, Akino; Obayashi, Yumiko; Kitamura, Shin-Ichi; Yokokawa, Taichi; Suzuki, Satoru

    2015-08-01

    The biodegradation of proteins in seawater requires various proteases which are commonly thought to be mainly derived from heterotrophic bacteria. We, however, found that protists showed a high protease activity and continuously produced trypsin-type enzymes. The free-living marine heterotrophic ciliate Paranophrys marina together with an associated bacterium was isolated and used for microcosm incubation with different concentrations of killed bacteria as food for 10 days. The results showed that the co-existence of the ciliate with its associated bacterium produced a significant protease activity in both cell-associated and cell-free fractions while that in the associated bacterium only microcosm was negligible. The protease profiles are different between cell-associated and cell-free fractions, and a trypsin-type enzyme hydrolyzing Boc-Val-Leu-Lys-MCA was detected throughout the period in the presence of ciliates. This suggests that ciliates release proteases into the surrounding environment which could play a role in protein digestion outside cells. It has been previously suggested that bacteria are the major transformers in seawater. We here present additional data which indicates that protists, or at least ciliates with their specific enzymes, are a potential player in organic matter degradation in water columns.

  1. Flow development and analysis of MHD generators and seawater thrusters

    SciTech Connect

    Doss, E.D. ); Roy, G.D. )

    1992-03-01

    In this paper, the flow characteristics inside magnetohydrodynamic (MHD) plasma generators and seawater thrusters are analyzed and are compared using a three-dimensional computer model that solves the governing partial differential equations for fluid flow and electrical fields. Calculations have been performed for a Faraday plasma generator and for a continuous electrode seawater thruster. The results of the calculations show that the effects caused by the interaction of the MHD forces with the fluid flow are strongly manifested in the case of the MHD generator as compared to the flow development in the MHD thruster. The existence of velocity overshoots over the sidewalls confirm previously published results for MHD generators with strong MHD interaction. For MHD thrusters, the velocity profile is found to be slightly flatter over the sidewall as compared to that over the electrode wall. As a result, distinct enhancement of the skin friction exists over the sidewalls of MHD generators in comparison to that of MHD thrusters. Plots of velocity profiles and skin friction distributions are presented to illustrate and compare the flow development in MHD generators and thrusters.

  2. Extracellular proteases are released by ciliates in defined seawater microcosms.

    PubMed

    Thao, Ngo Vy; Nozawa, Akino; Obayashi, Yumiko; Kitamura, Shin-Ichi; Yokokawa, Taichi; Suzuki, Satoru

    2015-08-01

    The biodegradation of proteins in seawater requires various proteases which are commonly thought to be mainly derived from heterotrophic bacteria. We, however, found that protists showed a high protease activity and continuously produced trypsin-type enzymes. The free-living marine heterotrophic ciliate Paranophrys marina together with an associated bacterium was isolated and used for microcosm incubation with different concentrations of killed bacteria as food for 10 days. The results showed that the co-existence of the ciliate with its associated bacterium produced a significant protease activity in both cell-associated and cell-free fractions while that in the associated bacterium only microcosm was negligible. The protease profiles are different between cell-associated and cell-free fractions, and a trypsin-type enzyme hydrolyzing Boc-Val-Leu-Lys-MCA was detected throughout the period in the presence of ciliates. This suggests that ciliates release proteases into the surrounding environment which could play a role in protein digestion outside cells. It has been previously suggested that bacteria are the major transformers in seawater. We here present additional data which indicates that protists, or at least ciliates with their specific enzymes, are a potential player in organic matter degradation in water columns. PMID:26115436

  3. Seawater Pervaporation through Zeolitic Imidazolate Framework Membranes: Atomistic Simulation Study.

    PubMed

    Gupta, Krishna M; Qiao, Zhiwei; Zhang, Kang; Jiang, Jianwen

    2016-06-01

    An atomistic simulation study is reported for seawater pervaporation through five zeolitic imidazolate framework (ZIF) membranes including ZIF-8, -93, -95, -97, and -100. Salt rejection in the five ZIFs is predicted to be 100%. With the largest aperture, ZIF-100 possesses the highest water permeability of 5 × 10(-4) kg m/(m(2) h bar), which is substantially higher compared to commercial reverse osmosis membranes, as well as zeolite and graphene oxide pervaporation membranes. In ZIF-8, -93, -95, and -97 with similar aperture size, water flux is governed by framework hydrophobicity/hydrophilicity; in hydrophobic ZIF-8 and -95, water flux is higher than in hydrophilic ZIF-93 and -97. Furthermore, water molecules in ZIF-93 move slowly and remain in the membrane for a long time but undergo to-and-fro motion in ZIF-100. The lifetime of hydrogen bonds in ZIF-93 is found to be longer than in ZIF-100. This simulation study quantitatively elucidates the dynamic and structural properties of water in ZIF membranes, identifies the key governing factors (aperture size and framework hydrophobicity/hydrophilicity), and suggests that ZIF-100 is an intriguing membrane for seawater pervaporation. PMID:27195441

  4. Improved solvents for seawater desalination (the Puraq process)

    SciTech Connect

    Not Available

    1991-01-01

    The Puraq process for desalinating seawater is based on solven extraction of fresh water from seawater using specially tailored liquid polymers with molecular weights of 3000 or less. This polymeric solvent insures that the solubility of solvent in the coexistent aqueous phases within the process will be essentially zero. Although it was indicated earlier that the upper limit of polymer content in recycle solvent stream could not exceed 92%, this restrictive upper limit could be exceeded by broadening the field of possible polymer compositions used in choosing a particular sample. This would further decrease the projected cost of product water from $2.03 to $1.08 per thousand gallons. Presence in the polymer of water-soluble components prevented the separation of water droplets when determining the cloud point with small amounts of water in the sample. A number of measurements of true'' phase points indicated that for most samples, the difference in temperatures of phase separation between compositions of 80 and 98% was 15 C or less.

  5. Biodegradability of chlorophenols and mixtures of chlorophenols in seawater

    SciTech Connect

    Lindgaard-Jorgensen, P.

    1989-04-01

    Laboratory studies using chemical concentrations comparable to those found in nature have provided considerable knowledge of microbial transformations in nature. Although the number of studies performed is increasing rapidly, the effects of low substrate levels on growth, enzyme induction, enzyme activity, and the use of mixtures of substrates have not yet been clarified. Likewise, studies at low concentrations in seawater are lacking. This paper describes a study of the rates of degradation of chlorophenols 4-chlor-2-methylphenol, 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol at concentrations ranging from 2 to 18 micrograms/liter. The compounds were tested separately, in a mixture, and in waste water containing other organics. The obtained rates of 2,4-DCP in seawater were comparable to those found in fresh water. Also, the rates were in general agreement with a kinetic model proposed for degradation of chlorophenols. The rates of degradation of chlorophenols in the mixture were comparable to those found when tested separately. In the waste, very low rates were observed. It is suggested that this might be explained by a toxic effect, caused by other substances in the waste water, on the microorganisms considered to be active in degrading the chlorophenols at low concentrations.

  6. Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation

    NASA Astrophysics Data System (ADS)

    Ziervogel, K.; Steen, A. D.; Arnosti, C.

    2009-12-01

    Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregate-free seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawater relative to whole seawater are likely due to shifts in enzyme production by the aggregate-associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin- and xylan-hydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme lifetime

  7. Changes in the spectrum and rates of extracellular enzyme activities in seawater following aggregate formation

    NASA Astrophysics Data System (ADS)

    Ziervogel, K.; Steen, A. D.; Arnosti, C.

    2010-03-01

    Marine snow aggregates are heavily colonized by heterotrophic microorganisms that express high levels of hydrolytic activities, making aggregates hotspots for carbon remineralization in the ocean. To assess how aggregate formation influences the ability of seawater microbial communities to access organic carbon, we compared hydrolysis rates of six polysaccharides in coastal seawater after aggregates had been formed (via incubation on a roller table) with hydrolysis rates in seawater from the same site that had not incubated on a roller table (referred to as whole seawater). Hydrolysis rates in the aggregates themselves were up to three orders of magnitude higher on a volume basis than in whole seawater. The enhancement of enzyme activity in aggregates relative to whole seawater differed by substrate, suggesting that the enhancement was under cellular control, rather than due to factors such as lysis or grazing. A comparison of hydrolysis rates in whole seawater with those in aggregate-free seawater, i.e. the fraction of water from the roller bottles that did not contain aggregates, demonstrated a nuanced microbial response to aggregate formation. Activities of laminarinase and xylanase enzymes in aggregate-free seawater were higher than in whole seawater, while activities of chondroitin, fucoidan, and arabinogalactan hydrolyzing enzymes were lower than in whole seawater. These data suggest that aggregate formation enhanced production of laminarinase and xylanase enzymes, and the enhancement also affected the surrounding seawater. Decreased activities of chondroitin, fucoidan, and arabinoglactan-hydrolyzing enzymes in aggregate-free seawaters relative to whole seawater are likely due to shifts in enzyme production by the aggregate-associated community, coupled with the effects of enzyme degradation. Enhanced activities of laminarin- and xylan-hydrolyzing enzymes in aggregate-free seawater were due at least in part to cell-free enzymes. Measurements of enzyme

  8. EFFECT OF CHELATING AGENTS ON THE GROWTH OF ESCHERICHIA COLI IN SEAWATER.

    PubMed

    JONES, G E

    1964-03-01

    Jones, Galen E. (Scripps Institution of Oceanography, University of California, La Jolla). Effect of chelating agents on the growth of Escherichia coli in seawater. J. Bacteriol. 87:483-499. 1964.-Escherichia coli did not grow at 37 C, or grew only after a prolonged lag phase in filter-sterilized basal seawater medium (synthetic or natural seawater supplemented with glucose, NH(4)Cl, and K(2)HPO(4)). When this basal medium was enriched with 0.01% or less organic matter, such as casein hydrolysate, peptone, or yeast extract, growth always occurred after a short lag phase. Adding 10(-5)m cysteine or autoclaving the seawater gave a similar effect. A variety of organic chelating agents (histidine, glycine, methionine, glycylglycine, 8-hydroxyquinoline, thioglycolic acid, o-phenanthroline, disodium ethylenediaminetetraacetic acid, etc.) reversed the toxicity of filter-sterilized basal seawater medium in concentrations predictable from stability constants. Even metal-complexing agents such as Na(2)S(2)O(3), Na(2)S, and NaCN in appropriate concentrations reversed toxicity. The quality of the distilled water and the treatment of glassware had a significant effect on the growth of E. coli in basal seawater medium. It was concluded that iodate is probably not the toxic substance for E. coli in seawater, since relatively high concentrations were stimulatory. The inhibition resulting from the individual salts of synthetic seawater was proportional to their concentration; NaCl was most inhibitory. This toxicity is believed to be derived from trace impurities in the reagent-grade chemicals used to prepare synthetic seawater. Evidence was also found for the toxicity of heavy metals in natural seawater. Heavy metals in seawater appear to inhibit growth but not respiration. PMID:14127563

  9. High value pigment production from Arthrospira (Spirulina) platensis cultured in seawater.

    PubMed

    Leema, J T Mary; Kirubagaran, R; Vinithkumar, N V; Dheenan, P S; Karthikayulu, S

    2010-12-01

    The prospects of utilizing pretreated seawater for the culture of Arthrospira (Spirulina) platensis was evaluated under laboratory conditions with three seawater media and a control: (1) Zarrouk media (freshwater-control) (2) seawater media SW 1 (3) seawater media SW2 and (4) seawater media SW 3. The relative performance of these media were investigated with respect to their biomass production, pigment production (phycocyanin, lutein and betacarotene), and biochemical composition. A. platensis grown in media SW 2 had a biomass production (2.99+/-0.145 g L(-1)) comparable to that of control media (3.114+/-0.085 g L(-1)); highest specific growth rate (0.255 d(-1)) and lowest doubling time (2.720 days). Phycocyanin content of the cells grown in seawater media SW 3(81.85%) was closer to that of control. Similarly the purity ratio of phycocyanin produced from cells grown in seawater media SW 3 and control were closer to 4, while the phycocyanin obtained from cells grown in other two media exhibited lower purity ratios due to accumulation of lower molecular weight carbohydrates. The phycocyanin/Chl-a ratio and the betacarotene/Chl-a ratio of the cells grown in seawater media were higher than control. The lutein content of A. platensis cells grown in seawater media SW 2 was higher than that of control. The cells grown in seawater media had a slightly modified biochemical composition than the control with a higher carbohydrate and lower protein content. All the three seawater based media with fewer chemicals than the control (Zarrouk media) supported the growth of A. platensis as good as the control. PMID:20655201

  10. Quantification of glycine betaine, choline and trimethylamine N-oxide in seawater particulates: Minimisation of seawater associated ion suppression.

    PubMed

    Beale, Rachael; Airs, Ruth

    2016-09-28

    A liquid chromatography/mass spectrometry (LC/MS, electrospray ionisation) method has been developed for the quantification of nitrogenous osmolytes (N-osmolytes) in the particulate fraction of natural water samples. Full method validation demonstrates the validity of the method for measuring glycine betaine (GBT), choline and trimethylamine N-oxide (TMAO) in particulates from seawater. Limits of detection were calculated as 3.5, 1.2 and 5.9 pg injected onto column (equivalent to 1.5, 0.6 and 3.9 nmol per litre) for GBT, choline and TMAO respectively. Precision of the method was typically 3% for both GBT and choline and 6% for TMAO. Collection of the particulate fraction of natural samples was achieved via in-line filtration. Resulting chromatography and method sensitivity was assessed and compared for the use of both glass fibre and polycarbonate filters during sample collection. Ion suppression was shown to be a significant cause of reduced instrument response to N-osmolytes and was associated with the presence of seawater in the sample matrix. PMID:27619093

  11. Seawater mesocosm experiments in the Arctic uncover differential transfer of marine bacteria to aerosols.

    PubMed

    Fahlgren, Camilla; Gómez-Consarnau, Laura; Zábori, Julia; Lindh, Markus V; Krejci, Radovan; Mårtensson, E Monica; Nilsson, Douglas; Pinhassi, Jarone

    2015-06-01

    Biogenic aerosols critically control atmospheric processes. However, although bacteria constitute major portions of living matter in seawater, bacterial aerosolization from oceanic surface layers remains poorly understood. We analysed bacterial diversity in seawater and experimentally generated aerosols from three Kongsfjorden sites, Svalbard. Construction of 16S rRNA gene clone libraries from paired seawater and aerosol samples resulted in 1294 sequences clustering into 149 bacterial and 34 phytoplankton operational taxonomic units (OTUs). Bacterial communities in aerosols differed greatly from corresponding seawater communities in three out of four experiments. Dominant populations of both seawater and aerosols were Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria. Across the entire dataset, most OTUs from seawater could also be found in aerosols; in each experiment, however, several OTUs were either selectively enriched in aerosols or little aerosolized. Notably, a SAR11 clade OTU was consistently abundant in the seawater, but was recorded in significantly lower proportions in aerosols. A strikingly high proportion of colony-forming bacteria were pigmented in aerosols compared with seawater, suggesting that selection during aerosolization contributes to explaining elevated proportions of pigmented bacteria frequently observed in atmospheric samples. Our findings imply that atmospheric processes could be considerably influenced by spatiotemporal variations in the aerosolization efficiency of different marine bacteria. PMID:25682947

  12. Mercury content of shrimp (Penaeus vannamei) reared in a wastewater-seawater aquacultural system

    SciTech Connect

    Landau, M.; Pierce, R.

    1986-10-01

    Penaeus vannamei were reared in two ponds, one receiving 10% wastewater in seawater and no feed, and the other receiving only seawater and a prepared commercial feed. The pond receiving the wastewater had significantly more mercury in the sediment, yet shrimp in this pond did not accumulate significant amounts of the mercury in their edible tissue.

  13. Hydrogeochemical, multiple isotopic approaches to investigate seawater mixing of groundwater in volcanic Jeju Island, Korea

    NASA Astrophysics Data System (ADS)

    Koh, E. H.; Kaown, D.; Lee, S. H.; Lee, K. K.

    2014-12-01

    Groundwater is a sole resource for water supply in Jeju Island which is composed of various formations of porous volcanic rocks. Therefore, preservation of the groundwater resource is an essential issue. Due to its geological features of the island, seawater has been intruded landward, mainly in the eastern region, which restricts groundwater use in the area. In the western region, severe nitrate contaminations of groundwater have been occurred by heavily performed agricultural activities, and moreover deterioration of groundwater quality by seawater intrusion has been observed in recent years. In this study, to delineate the mixing process related to seawater intrusion into groundwater from Gosan (western region) and Pyoseon (eastern region) of Jeju Island, hydrogeochemical and multiple isotopic approaches were applied. Also, fractionation ratios of each factors (fresh groundwater, nitrate contaminated groundwater, and seawater) which affect the groundwater quality from the study areas were estimated by using the MIX_PROGRAM. The effect of seawater was observed at the groundwater wells located inland up to 1.5 km from the coast and showed to be enlarged landward during a dry season. The fractionation ratios of seawater had the minor range (0.1~1.2%) for the Pyoseon area and 0.4~3.7% of seawater was mixed with fresh groundwater in the Gosan area. Differences in hydrogeological properties between Gosan and Pyoseon areas made dissimilar occurrences of seawater mixing into groundwater in the island.

  14. Adsorption/desorption of phosphorus on limestone from the Biscayne Aquifer under freshwater and seawater conditions.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Areas of seawater intrusion are known geochemically active regions particularly in limestone aquifers, where carbonate mineral dissolution and ion exchange reactions are important. Both of these processes can lead to a release of phosphorus from the aquifer matrix to the groundwater as seawater int...

  15. Detection of crude oil emulsions in the Bering Sea by the analysis of seawater color

    NASA Astrophysics Data System (ADS)

    Salyuk, Pavel A.; Stepochkin, Igor E.; Sokolova, Ekaterina B.; Kachur, Vasiliy A.; Prokuda, Natalya A.

    2015-11-01

    The paper presents the analysis of uncertainties between observed remote sensed reflectance spectra of seawater, with crude oil emulsions and oil dissolved fractions, and modeled remote sensed reflectance spectra of seawater without oil calculated from the fluorometric measurements of chlorophyll-a and dissolved organic matter concentrations carried out in the layer under oil pollution.

  16. Crustal evolution reflected in seawater Sr and Nd isotope records

    NASA Astrophysics Data System (ADS)

    Peucker-Ehrenbrink, B.

    2013-12-01

    Radiogenic isotope ratios record time-integrated parent-daughter ratios, and are thus sensitive to chemical composition and time. The oceans recieve the integrated runoff from the continental surface and preserve these signals in marine sedimentary records. Radiogenic isotope records of seawater and marine sediments have been reconstructed over the past five decades for many of the radiogenic isotope systems. For some systems (Sr) excellent records do exist that integrate seawater signals for the entire ocean. In contrast, globally averaged records of radiogenic isotopes with short marine residence times (Nd, Pb) are much more difficult to establish. Here, I attempt to link long-term (Phanerozoic) records of marine radiogenic isotope systems to records of the evolution of the continental surface that interacts with the hydrologic cycle. For the present we can show that the dissolved and particulate loads from the continents integrate different portions of the continental surface (Peucker-Ehrenbrink et al., 2010, G-cubed 11, doi: 10.1029/2009GC002869). For instance, the areas generating the dissolved load are characterized by significantly older bedrock (~400 Myr) than those generating the particulate load (~320 Myr). The fact that both are younger than the mean bedrock age of the non-glaciated, exorheic portion of the continental surface (~450 Myr) reflects the disproportionate role active margins, high-standing ocean island, and weathering and erosion of young sedimentary strata play in exporting dissolved matter and sedimnent to the oceans. Using present-day systematics as a guide, I argue that the first-order trough-like shape of the Phanerozoic marine Sr isotope record reflects the rejuvenation of the continental surface involved in exporting Sr to the ocean from the early Phanerozoic to the mid Jurassic that is followed by an 'aging' that continues into the Quaternary. This long-term evolution of the continental surface is mirrored by a similar - though more

  17. Temporal Patterns in Seawater Quality from Dredging in Tropical Environments

    PubMed Central

    Jones, Ross; Fisher, Rebecca; Stark, Clair; Ridd, Peter

    2015-01-01

    Maintenance and capital dredging represents a potential risk to tropical environments, especially in turbidity-sensitive environments such as coral reefs. There is little detailed, published observational time-series data that quantifies how dredging affects seawater quality conditions temporally and spatially. This information is needed to test realistic exposure scenarios to better understand the seawater-quality implications of dredging and ultimately to better predict and manage impacts of future projects. Using data from three recent major capital dredging programs in North Western Australia, the extent and duration of natural (baseline) and dredging-related turbidity events are described over periods ranging from hours to weeks. Very close to dredging i.e. <500 m distance, a characteristic features of these particular case studies was high temporal variability. Over several hours suspended sediment concentrations (SSCs) can range from 100–500 mg L-1. Less turbid conditions (10–80 mg L-1) can persist over several days but over longer periods (weeks to months) averages were <10 mg L-1. During turbidity events all benthic light was sometimes extinguished, even in the shallow reefal environment, however a much more common feature was very low light ‘caliginous’ or daytime twilight periods. Compared to pre-dredging conditions, dredging increased the intensity, duration and frequency of the turbidity events by 10-, 5- and 3-fold respectively (at sites <500 m from dredging). However, when averaged across the entire dredging period of 80–180 weeks, turbidity values only increased by 2–3 fold above pre-dredging levels. Similarly, the upper percentile values (e.g., P99, P95) of seawater quality parameters can be highly elevated over short periods, but converge to values only marginally above baseline states over longer periods. Dredging in these studies altered the overall probability density distribution, increasing the frequency of extreme values. As such

  18. Glyoxal and Methylglyoxal in Atlantic Seawater and marine Aerosol Particles

    NASA Astrophysics Data System (ADS)

    van Pinxteren, Manuela; Herrmann, Hartmut

    2014-05-01

    The two α-dicarbonyls glyoxal (CHOCHO; GLY) and methylglyoxal (CH3COCHO; MGLY) have attracted increasing attention over the past years because of their potential role in secondary organic aerosol formation. Recently Sinreich et al. (2010) suggested the open ocean as an important (so far unknown) source for GLY in the atmosphere. To date, there are few available field data of these compounds in the marine area. In this study we present measurements of GLY and MGLY in seawater and marine aerosol particles sampled during a transatlantic Polarstern cruise in spring 2011. In seawater we especially investigated the sea surface microlayer (sampled with the glass plate technique) as it is the direct interface between ocean and atmosphere. Analytical measurements were based on derivatisation with o-(2,3,4,5,6-Pentafluorobenzyl)-hydroxylamine reagent, solvent extraction and GC-MS (SIM) analysis. The results show that GLY and MGLY are present in the sea surface microlayer of the ocean and corresponding bulkwater with average concentrations of 228 ng L-1 (GLY) and 196 ng L-1 (MGLY). Significant enrichment (factor of 4) of GLY and MGLY in the sea surface microlayer was found implying photochemical production of the two carbonyls though a clear connection to global radiation was not observed. On aerosol particles, both carbonyls were detected (average concentration 0.2 ng m-3) and are strongly connected to each other, suggesting similar formation mechanisms. Both carbonyls show a very good correlation with particulate oxalate, supporting the idea of a secondary formation of oxalic acid via GLY and MGLY. A slight correlation of the two carbonyls in the sea surface microlayer and in the aerosol particles was found at co-located sampling areas. In summary, the results of GLY and MGLY in marine aerosol particles and in the oceanic water give first insights towards interaction processes of these alpha dicarbonyls between ocean and atmosphere (van Pinxteren and Herrmann (2013

  19. Mercury and cadmium uptake from seawater and from food by the Norway lobster Nephrops norvegicus

    SciTech Connect

    Canli, M.; Furness, R.W.

    1995-05-01

    Norway lobsters, nephrops norvegicus, were fed on a mercury- and cadmium-rich diet for up to 50 d or were exposed to sublethal concentrations of organic mercury, inorganic mercury, or cadmium in seawater for 30 d. Cadmium taken up from seawater accumulated mainly in the hepatopancreas and gill, while it accumulated mainly in the hepatopancreas after feeding. Both organic and inorganic mercury taken up from seawater accumulated mainly in the gill, while highest concentrations were found in the hepatopancreas after the feeding experiment. Accumulation of organic mercury was higher than that of inorganic mercury. Although all treatments resulted in the accumulation of mercury and cadmium from seawater and food, tissue distribution of metals differed significantly among treatments. Distributions of organic and inorganic mercury also varied among tissues after uptake from seawater, with organic mercury being more evenly distributed among tissues than inorganic mercury, the latter being found predominantly in the gill.

  20. Geochemistry of Precambrian carbonates. V - Late Paleoproterozoic seawater

    NASA Technical Reports Server (NTRS)

    Veizer, Jan; Plumb, K. A.; Clayton, R. N.; Hinton, R. W.; Grotzinger, J. P.

    1992-01-01

    A study of mineralogy, chemistry, and isotopic composition of the Coronation Supergroup (about 1.9 Ga, NWT), Canada, and the McArthur Group (about 1.65 NT), Australia, is reported in order to obtain better constrained data for the first- and second-order variations in the isotopic composition of late Paleoproterozoic (1.9 +/- 0.2 Ga) seawater. Petrologically, both carbonate sequences are mostly dolostones. The McArthur population contains more abundant textural features that attest to the former presence of sulfates and halite, and the facies investigated represent ancient equivalents of modern evaporitic sabkhas and lacustrine playa lakes. It is suggested that dolomitization was an early diagenetic event and that the O-18 depletion of the Archean to late Paleoproterozoic carbonates is not an artifact of postdepositional alteration.

  1. A new method for stable lead isotope extraction from seawater.

    PubMed

    Zurbrick, Cheryl M; Gallon, Céline; Flegal, A Russell

    2013-10-24

    A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650M(®) resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for (206)Pb/(207)Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to (206)Pb, (207)Pb, and (208)Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values.

  2. Corrosion fatigue of high strength fastener materials in seawater

    NASA Technical Reports Server (NTRS)

    Tipton, D. G.

    1983-01-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  3. Corrosion fatigue of high strength fastener materials in seawater

    NASA Astrophysics Data System (ADS)

    Tipton, D. G.

    1983-12-01

    Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

  4. Wireless sensor node for surface seawater density measurements.

    PubMed

    Baronti, Federico; Fantechi, Gabriele; Roncella, Roberto; Saletti, Roberto

    2012-01-01

    An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

  5. Thermodynamic studies of the carbonate system in seawater

    NASA Astrophysics Data System (ADS)

    Lee, Kitack; Millero, Frank J.

    1995-11-01

    Laboratory measurements of the components of the carbonate system (pH, fCO 2, TCO 2 and TA) were made on Gulf Stream seawater and Certified Reference Material (CRM) as a function of salinity (33-37), temperature (0-40°C) and the ratio TA/ TCO2 (1.02 to 1.25). The pH (±0.002) was determined by spectrophotometry; the fCO 2 (±2 μatm) with an infrared detector; the TCO 2 (±2μol kg -1) by coulometry; and the TA (±2μmol kg -1) by potentiometric titrations. The results were used to examine the internal consistency of the thermodynamics of the carbonate system by calculation of various parameters (e.g., TA) from two input parameters (e.g., pH- TC0 2). The measurements on CRMs at 25°C were found to be consistent with the thermodynamic constants of Goyet and Poisson (1989) and Roy et al. (1993) to °0.005 in pH, °3 μmol kg -1 in TCO 2 and ±3 μmol kg -1 in TA. The measurements on Gulf Stream seawater from 0 to 40°C were also found to be consistent in pH to ±0.006, in TCO 2 to ±4μmol kg -1 and in TA to ±4μmol kg -1 when these constants were used. The pH and fCO 2 were measured on seawater with a know TA and TCO 2 from 5 to 35°C. The results give slopes of (d In fCO 2 dt) × 10 2 = 4.26 ± 0.03 and (dpH/d t) × 10 2 = 1.65 ± 0.01, in agreement with the values calculated from the thermodynamic constants of Roy et al. (1993) and Goyet and Poisson (1989) over the same temperature range. The measured fugacities were internally consistent to ±7 μatm with the values calculated with these same constants and with pH- TA or pH- TCO 2 as input parameters. All of these laboratory measurements indicate that the carbonic acid dissociation constants of Roy et al. (1993) and Goyet and Poisson (1989) give the best description of the thermodynamics of the CO 2 system in seawater over temperature from 0 to 40°C, salinity from 33 to 37 and the ratio TA/ TCO2 from 1.02 to 1.25. By using the p K1 determined from the equations of Roy et al. (1993), we have used our

  6. Cadmium Isotope Fractionation in Seawater - A Signature of Nutrient Utilization

    NASA Astrophysics Data System (ADS)

    Wichtlhuber, S.; Rehkaemper, M.; Halliday, A. N.

    2005-12-01

    Cadmium displays a nutrient-like distribution akin to phosphorous in the oceans. This has been attributed to the assimilation of Cd by phytoplankton in surface waters and re-mineralization at depth. If biological uptake is associated with kinetic isotopic fractionation, as recently suggested by Lacan et al. (2005), then the Cd-depleted surface waters of the oceans (with Cd contents of < 0.08 nmol/kg) should be depleted in the "light" isotopes of Cd, relative to the bottom waters, which typically have Cd concentrations of 0.2 to 1 nmol/kg. Previous investigations were, however, unable to identify any significant Cd isotope effects in either seawater samples or sedimentary rocks (Wombacher et. al, 2003; Lacan et al., 2005). In this study, we have extended the search for Cd isotope variations in the oceans with analyses of two depth profiles and various additional seawater samples from the North Pacific, the Arctic, and the Southern Ocean. The Cd isotope measurements utilized a double spike technique in conjunction with multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS), to achieve a precision and accuracy of about ± 0.8 to 1.5 ɛ114/110Cd. This precision is about a factor of 3 to 4 better than that of previous studies, which did not utilize a double spike. The data collected for the samples display a clear co-variation of Cd isotope compositions with Cd concentrations. The most Cd-rich water samples (with ~1 nmol/kg Cd) display the "lightest" Cd isotope compositions with ɛ114/110Cd ~ +3, akin to results previously obtained for crustal and mantle rocks (Wombacher et. al, 2003). In contrast, samples from the upper water column of the North Pacific (with < 0.02 nmol/kg Cd) have the heaviest Cd isotope compositions with ɛ114/110Cd values of up to +35. To a first order, the Cd isotope and concentration data can be accounted for with a simple, single-stage Rayleigh fractionation model that applies a fractionation factor of about 1.0002 to 1

  7. Cl-36 in polar ice, rainwater and seawater

    NASA Technical Reports Server (NTRS)

    Finkel, R. C.; Nishiizumi, K.; Elmore, D.; Ferraro, R. D.; Gove, H. E.

    1980-01-01

    Concentrations of the cosmogenic radioisotope Cl-36 in Antarctic ice, rain, and an upper limit of the seawater value are determined using van de Graaff accelerator high energy mass spectrometry. Cl-36 concentrations in Antarctic ice range between 2.5 to 8.7 x 10 to the 6th atoms Cl-36/kg, while those concentrations in samples collected at the Alan Hills ice field locations where meteorites have been brought to the surface by glacial flow and ablation are found to vary by more than a factor of three. This variation is attributed either to the effects of atmospheric mixing and scavenging or to radioactive decay in old ice. The Cl-36 concentration found in a present sample of rainwater is much lower than that reported in samples collected in the early 1960's, suggesting the occurrence of a decrease in the concentration of atmospheric Cl-36 derived from nuclear weapons tests over this time period.

  8. Crevice and pitting corrosion behavior of stainless steels in seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Orozco-Cruz, R.

    1999-11-01

    Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e., S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behavior and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S3 1603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.

  9. Cathodic properties of different stainless steels in natural seawater

    SciTech Connect

    Johnsen, R.; Bardal, E.

    1985-05-01

    The cathodic properties of a number of stainless steels, which were exposed to natural seawater flowing at 0 to 2.5 m/s and polarized to potentials from -300 to -950 mV SCE, have been studied. The current density development at constant potential and the free corrosion potential during the exposure time were recorded continuously. At the end of the exposure period, after approximately 28 to 36 days of exposure, polarization curves were determined. After one to three weeks of exposure, depending on the water velocity, microbiological activity on the surface caused an increase in the current density requirement of the specimen. An explanation for the mechanism behind the current density increase caused by slime production from marine bacteria may be increased exchange current density, i/sub 0/. There was no measurable calcareous deposit on the stainless steel surfaces at the end of the exposure periods.

  10. Wireless Sensor Node for Surface Seawater Density Measurements

    PubMed Central

    Baronti, Federico; Fantechi, Gabriele; Roncella, Roberto; Saletti, Roberto

    2012-01-01

    An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes’ law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings. PMID:22736986

  11. Wireless sensor node for surface seawater density measurements.

    PubMed

    Baronti, Federico; Fantechi, Gabriele; Roncella, Roberto; Saletti, Roberto

    2012-01-01

    An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings. PMID:22736986

  12. Preliminary ecotoxicity assessment of new generation alternative fuels in seawater.

    PubMed

    Rosen, Gunther; Dolecal, Renee E; Colvin, Marienne A; George, Robert D

    2014-06-01

    The United States Navy (USN) is currently demonstrating the viability of environmentally sustainable alternative fuels to power its fleet comprised of aircraft and ships. As with any fuel used in a maritime setting, there is potential for introduction into the environment through transport, storage, and spills. However, while alternative fuels are often presumed to be eco-friendly relative to conventional petroleum-based fuels, their environmental fate and effects on marine environments are essentially unknown. Here, standard laboratory-based toxicity experiments were conducted for two alternative fuels, jet fuel derived from Camelina sativa (wild flax) seeds (HRJ5) and diesel fuel derived from algae (HRD76), and two conventional counterparts, jet fuel (JP5) and ship diesel (F76). Initial toxicity tests performed on water-accommodated fractions (WAF) from neat fuels partitioned into seawater, using four standard marine species in acute and chronic/sublethal tests, indicate that the alternative fuels are significantly less toxic to marine organisms.

  13. Preliminary ecotoxicity assessment of new generation alternative fuels in seawater.

    PubMed

    Rosen, Gunther; Dolecal, Renee E; Colvin, Marienne A; George, Robert D

    2014-06-01

    The United States Navy (USN) is currently demonstrating the viability of environmentally sustainable alternative fuels to power its fleet comprised of aircraft and ships. As with any fuel used in a maritime setting, there is potential for introduction into the environment through transport, storage, and spills. However, while alternative fuels are often presumed to be eco-friendly relative to conventional petroleum-based fuels, their environmental fate and effects on marine environments are essentially unknown. Here, standard laboratory-based toxicity experiments were conducted for two alternative fuels, jet fuel derived from Camelina sativa (wild flax) seeds (HRJ5) and diesel fuel derived from algae (HRD76), and two conventional counterparts, jet fuel (JP5) and ship diesel (F76). Initial toxicity tests performed on water-accommodated fractions (WAF) from neat fuels partitioned into seawater, using four standard marine species in acute and chronic/sublethal tests, indicate that the alternative fuels are significantly less toxic to marine organisms. PMID:24315182

  14. Responses to high seawater temperatures in zooxanthellate octocorals.

    PubMed

    Sammarco, Paul W; Strychar, Kevin B

    2013-01-01

    Increases in Sea Surface Temperatures (SSTs) as a result of global warming have caused reef-building scleractinian corals to bleach worldwide, a result of the loss of obligate endosymbiotic zooxanthellae. Since the 1980's, bleaching severity and frequency has increased, in some cases causing mass mortality of corals. Earlier experiments have demonstrated that zooxanthellae in scleractinian corals from three families from the Great Barrier Reef, Australia (Faviidae, Poritidae, and Acroporidae) are more sensitive to heat stress than their hosts, exhibiting differential symptoms of programmed cell death - apoptosis and necrosis. Most zooxanthellar phylotypes are dying during expulsion upon release from the host. The host corals appear to be adapted or exapted to the heat increases. We attempt to determine whether this adaptation/exaptation occurs in octocorals by examining the heat-sensitivities of zooxanthellae and their host octocoral alcyonacean soft corals - Sarcophyton ehrenbergi (Alcyoniidae), Sinularia lochmodes (Alcyoniidae), and Xenia elongata (Xeniidae), species from two different families. The soft coral holobionts were subjected to experimental seawater temperatures of 28, 30, 32, 34, and 36°C for 48 hrs. Host and zooxanthellar cells were examined for viability, apoptosis, and necrosis (in hospite and expelled) using transmission electron microscopy (TEM), fluorescent microscopy (FM), and flow cytometry (FC). As experimental temperatures increased, zooxanthellae generally exhibited apoptotic and necrotic symptoms at lower temperatures than host cells and were expelled. Responses varied species-specifically. Soft coral hosts were adapted/exapted to higher seawater temperatures than their zooxanthellae. As with the scleractinians, the zooxanthellae appear to be the limiting factor for survival of the holobiont in the groups tested, in this region. These limits have now been shown to operate in six species within five families and two orders of the Cnidaria

  15. Simplified seawater alkalinity analysis: Use of linear array spectrometers

    NASA Astrophysics Data System (ADS)

    Yao, Wensheng; Byrne, Robert H.

    1998-08-01

    Modified spectrophotometric procedures are presented for the determination of seawater total alkalinity using rapid scan linear array spectrometers. Continuous monitoring of solution pH allows titrations to be terminated at relatively high pH, whereby excess acid terms are very small. Excess acid concentrations are quantified using the sulfonephthalein indicators, bromocresol green and bromocresol purple. The outlined spectrophotometric procedures require no thermal equilibration of samples. Using bromocresol green, solution pH T ([H +] T in moles per kg of solution) is given as: pHT=4.2699+0.002578(35- S)+ log((R(25)-0.00131)/(2.3148-0.1299 R(25))) - log(1-0.001005S) and R(25)= R( t){1+0.00909(25- t)}, where 29⩽S⩽37, 13° C⩽t⩽32° C, and R( t) is the absorbance ratio ( A616/ A444) at temperature t and salinity S. Using bromocresol purple, the solution pH T is given as pH T=5.8182+0.00129(35- S)+log(( R(25)-0.00381)/(2.8729-0.05104 R(25))) and R(25)= R( t){1+0.01869(25- t)}, where 29⩽S⩽37, 13° C⩽t⩽32° C, and R( t)= A589/ A432. Alkalinity measurements using bromocresol purple had a precision on the order of 0.3 μmol kg -1 and were within 0.3-0.9 μmol kg -1 of the alkalinities of certified seawater reference materials.

  16. Responses to High Seawater Temperatures in Zooxanthellate Octocorals

    PubMed Central

    Sammarco, Paul W.; Strychar, Kevin B.

    2013-01-01

    Increases in Sea Surface Temperatures (SSTs) as a result of global warming have caused reef-building scleractinian corals to bleach worldwide, a result of the loss of obligate endosymbiotic zooxanthellae. Since the 1980’s, bleaching severity and frequency has increased, in some cases causing mass mortality of corals. Earlier experiments have demonstrated that zooxanthellae in scleractinian corals from three families from the Great Barrier Reef, Australia (Faviidae, Poritidae, and Acroporidae) are more sensitive to heat stress than their hosts, exhibiting differential symptoms of programmed cell death – apoptosis and necrosis. Most zooxanthellar phylotypes are dying during expulsion upon release from the host. The host corals appear to be adapted or exapted to the heat increases. We attempt to determine whether this adaptation/exaptation occurs in octocorals by examining the heat-sensitivities of zooxanthellae and their host octocoral alcyonacean soft corals – Sarcophyton ehrenbergi (Alcyoniidae), Sinularia lochmodes (Alcyoniidae), and Xenia elongata (Xeniidae), species from two different families. The soft coral holobionts were subjected to experimental seawater temperatures of 28, 30, 32, 34, and 36°C for 48 hrs. Host and zooxanthellar cells were examined for viability, apoptosis, and necrosis (in hospite and expelled) using transmission electron microscopy (TEM), fluorescent microscopy (FM), and flow cytometry (FC). As experimental temperatures increased, zooxanthellae generally exhibited apoptotic and necrotic symptoms at lower temperatures than host cells and were expelled. Responses varied species-specifically. Soft coral hosts were adapted/exapted to higher seawater temperatures than their zooxanthellae. As with the scleractinians, the zooxanthellae appear to be the limiting factor for survival of the holobiont in the groups tested, in this region. These limits have now been shown to operate in six species within five families and two orders of the

  17. Chloroform extraction of iodine in seawater: method development

    NASA Astrophysics Data System (ADS)

    Seidler, H. B.; Glimme, A.; Tumey, S.; Guilderson, T. P.

    2012-12-01

    While 129I poses little to no radiological health hazard, the isotopic ratio of 129I to stable iodine is very useful as a nearly conservative tracer for ocean mixing processes. The unfortunate disaster at the Fukushima Daiichi nuclear power plant released many radioactive materials into the environment, including 129I. The release allows the studying of oceanic processes through the tracking of 129I. However, with such a low iodine (~0.5 micromolar) and 129I concentrations (<10-11) accelerator mass spectrometry (AMS) is needed for accurate measurements. In order to prepare the samples of ocean water for analysis by AMS, the iodine needs to be separated from the various other salts in the seawater. Solvent extraction is the preferred method for preparation of seawater for AMS analysis of 129I. However, given the relatively low background 129I concentrations in the Pacific Ocean, we sought to optimize recovery of thismethod, which would minimize both the sample size and the carrier addition required for analysis. We started from a base method described in other research and worked towards maximum efficiency of the process while boosting the recovery of iodine. During development, we assessed each methodological change qualitatively using a color scale (I2 in CHCl3) and quantitatively using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The "optimized method" yielded a 20-40% increase in recovery of the iodine compared to the base method (80-85% recovery vs. 60%). Lastly, the "optimized method" was tested by AMS for fractionation of the extracted iodine.

  18. Effects of seawater ozonation on biofilm development in aquaculture tanks.

    PubMed

    Wietz, Matthias; Hall, Michael R; Høj, Lone

    2009-07-01

    Microbial biofilms developing in aquaculture tanks represent a reservoir for opportunistic bacterial pathogens, and procedures to control formation and bacterial composition of biofilms are important for the development of commercially viable aquaculture industries. This study investigated the effects of seawater ozonation on biofilm development on microscope glass slides placed in small-scale aquaculture tanks containing the live feed organism Artemia. Fluorescence in situ hybridization (FISH) demonstrated that ozonation accelerated the biofilm formation cycle, while it delayed the establishment of filamentous bacteria. Gammaproteobacteria and Alphaproteobacteria were the most abundant bacterial groups in the biofilm for both water types, but ozonation influenced their dynamics. With ozonation, the bacterial community structure was relatively stable and dominated by Gammaproteobacteria throughout the experiment (21-66% of total bacteria). Without ozonation, the community showed larger fluctuations, and Alphaproteobacteria emerged as dominant after 18 days (up to 54% of total bacteria). Ozonation of seawater also affected the dynamics of less abundant populations in the biofilm such as Betaproteobacteria, Planctomycetales and the Cytophaga/Flavobacterium branch of phylum Bacteroidetes. The abundance of Thiothrix, a bacterial genus capable of filamentous growth and fouling of larvae, increased with time for both water types, while no temporal trend could be detected for the genus Vibrio. Denaturing gradient gel electrophoresis (DGGE) demonstrated temporal changes in the dominant bacterial populations for both water types. Sequencing of DGGE bands confirmed the FISH data, and sequences were related to bacterial groups commonly found in biofilms of aquaculture systems. Several populations were closely related to organisms involved in sulfur cycling. Improved Artemia survival rates in tanks receiving ozonated water suggested a positive effect of ozonation on animal

  19. Effects of seawater acidification on a coral reef meiofauna community

    NASA Astrophysics Data System (ADS)

    Sarmento, V. C.; Souza, T. P.; Esteves, A. M.; Santos, P. J. P.

    2015-09-01

    Despite the increasing risk that ocean acidification will modify benthic communities, great uncertainty remains about how this impact will affect the lower trophic levels, such as members of the meiofauna. A mesocosm experiment was conducted to investigate the effects of water acidification on a phytal meiofauna community from a coral reef. Community samples collected from the coral reef subtidal zone (Recife de Fora Municipal Marine Park, Porto Seguro, Bahia, Brazil), using artificial substrate units, were exposed to a control pH (ambient seawater) and to three levels of seawater acidification (pH reductions of 0.3, 0.6, and 0.9 units below ambient) and collected after 15 and 30 d. After 30 d of exposure, major changes in the structure of the meiofauna community were observed in response to reduced pH. The major meiofauna groups showed divergent responses to acidification. Harpacticoida and Polychaeta densities did not show significant differences due to pH. Nematoda, Ostracoda, Turbellaria, and Tardigrada exhibited their highest densities in low-pH treatments (especially at the pH reduction of 0.6 units, pH 7.5), while harpacticoid nauplii were strongly negatively affected by low pH. This community-based mesocosm study supports previous suggestions that ocean acidification induces important changes in the structure of marine benthic communities. Considering the importance of meiofauna in the food web of coral reef ecosystems, the results presented here demonstrate that the trophic functioning of coral reefs is seriously threatened by ocean acidification.

  20. Enriched Seawater Delivery System to Support In Situ Ocean Acidification Experiments using Carbon Dioxide for pH Adjustment of Seawater

    NASA Astrophysics Data System (ADS)

    Kirkwood, W. J.; Peltzer, E. T.; Walz, P. M.; Shane, F.; Kecy, C.; Headley, K. L.; Herlien, B.; Maughan, T.; Scholfield, J.; Salamy, K. A.; O'Reilly, T.; Brewer, P. G.

    2011-12-01

    A series of Free Ocean CO2 Enrichment (FOCE) experiments are underway or are in planning to perform in situ ocean acidification research at a number of locations around the world. One of the most challenging locations is in Monterey Bay at the site of the Monterey Accelerated Research System, the United States test facility for cabled observatories. This site is located at 890 m deep and 4 0C within the local oxygen minimum zone and approximately 50 kilometers from shore. At this depth and temperature the behavior of liquid CO2 presents various challenges that had to be addressed in order to provide the low pH seawater needed for the FOCE apparatus to perform as desired. To solve this challenge a team of engineers and scientists at the Monterey Bay Aquarium Research Institute (MBARI) have developed a standalone device referred to as the Enriched Seawater Delivery System. Simple injections of seawater saturated at one atmosphere with CO2 demonstrated that the FOCE unit itself performs as designed. However, providing a consistent source of CO2 enriched pH altered seawater within the design criteria proved to be an imposing problem which when solved could have a broader impact in the oceanographic community. The decision was made to build a stand-alone device separate from the FOCE flume to perform in situ CO2 experiments in conditions where CO2 hydrate can form. Challenges to be over-come by this work included: (1) liquid CO2 is buoyant at the prescribed depth; (2) minimizing the formation of hydrates while manufacturing the CO2 enriched seawater. Because CO2 hydrate is denser than seawater, management of the phases and stability of liquid CO2 was necessary to prevent clogging within the delivery system. Our earliest field experiments demonstrated that containing and controlling the CO2 and the CO2-enriched seawater is difficult and makes the metering of the enriched fluid with on demand milliliter per second precision an extremely challenging problem. The Enriched

  1. Ultra-trace plutonium determination in small volume seawater by sector field inductively coupled plasma mass spectrometry with application to Fukushima seawater samples.

    PubMed

    Bu, Wenting; Zheng, Jian; Guo, Qiuju; Aono, Tatsuo; Tagami, Keiko; Uchida, Shigeo; Tazoe, Hirofumi; Yamada, Masatoshi

    2014-04-11

    Long-term monitoring of Pu isotopes in seawater is required for assessing Pu contamination in the marine environment from the Fukushima Dai-ichi Nuclear Power Plant accident. In this study, we established an accurate and precise analytical method based on anion-exchange chromatography and SF-ICP-MS. This method was able to determine Pu isotopes in seawater samples with small volumes (20-60L). The U decontamination factor was 3×10(7)-1×10(8), which provided sufficient removal of interfering U from the seawater samples. The estimated limits of detection for (239)Pu and (240)Pu were 0.11fgmL(-1) and 0.08fgmL(-1), respectively, which corresponded to 0.01mBqm(-3) for (239)Pu and 0.03mBqm(-3) for (240)Pu when a 20L volume of seawater was measured. We achieved good precision (2.9%) and accuracy (0.8%) for measurement of the (240)Pu/(239)Pu atom ratio in the standard Pu solution with a (239)Pu concentration of 11fgmL(-1) and (240)Pu concentration of 2.7fgmL(-1). Seawater reference materials were used for the method validation and both the (239+240)Pu activities and (240)Pu/(239)Pu atom ratios agreed well with the expected values. Surface and bottom seawater samples collected off Fukushima in the western North Pacific since March 2011 were analyzed. Our results suggested that there was no significant variation of the Pu distribution in seawater in the investigated areas compared to the distribution before the accident.

  2. The Thermodynamic Equation Of Seawater - 2010 (TEOS-10): implications for observational oceanography and ocean modeling

    NASA Astrophysics Data System (ADS)

    McDougall, Trevor

    2010-05-01

    The Intergovernmental Oceanographic Commission (IOC) has endorsed a new equation of state of seawater to replace the International Equation of State of 1980. The new Thermodynamic Equation of Seawater 2010 (TEOS-10 for short) has been prepared by SCOR/IAPSO Working Group 127, and from 1st January 2010, is the new worldwide standard description of seawater. This thermodynamic description of seawater provides accurate algorithms for Absolute Salinity, density, entropy, enthalpy and many other properties. The software of the new seawater standard is available on line from www.TEOS-10.org. The talk will concentrate on three main topics, namely (i) the definition and use of a new form of salinity called Absolute Salinity which takes into account the spatial variation in the composition of seawater, (ii) a thermodynamic variable that can be used to accurately represent the transport and mixing of "heat" in the ocean, and (iii) the differences between the specific volume of TEOS-10 and that of EOS-80 (the International Equation of State of seawater that has been in use since 1980). The talk will discuss the relative improvements in the accuracy of observational oceanography and ocean models that can be expected from adopting TEOS-10.

  3. The effect of composition anomalies on the conductivity and density of seawater

    NASA Astrophysics Data System (ADS)

    Pawlowicz, R. A.; Wright, D.; Millero, F. J.

    2010-12-01

    As seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. Although these changes have been ignored for 30 years, they are in fact the largest source of errors in the determination of the thermodynamic properties of real seawater using the equation of state (either EOS80 or the newer TEOS-10). Here we describe a theoretical model that relates seawater composition, conductivity, and density. A numerical implementation of the model can be used to predict density anomalies resulting from observed conductivities, carbonate-system parameters, and nutrient concentrations. Predictions of density anomalies made this way for a number of hydrographic sections are shown below. Calculations replicate direct observations of density anomalies in both laboratory experiments and in the open ocean. Theoretical analysis suggests that a hierarchy of salinity variables are required to fully describe the effects of anomalous seawater, but numerical experimentation shows that simple conversion factors can be used to relate them all in typical open-ocean situations. These results are incorporated into the new seawater manual (IOC, SCOR, and IAPSO, The International Thermodynamic Equation of Seawater - 2010: Calculation and Use of Thermodynamic Properties,UNESCO, 2010, also at www.teos-10.org) and should be useful in future attempts to understand and model global ocean circulation. Model-calculated density anomalies over several trans-oceanic sections

  4. Application of SEAWAT to select variable-density and viscosity problems

    USGS Publications Warehouse

    Dausman, Alyssa M.; Langevin, Christian D.; Thorne, Danny T.; Sukop, Michael C.

    2010-01-01

    SEAWAT is a combined version of MODFLOW and MT3DMS, designed to simulate three-dimensional, variable-density, saturated groundwater flow. The most recent version of the SEAWAT program, SEAWAT Version 4 (or SEAWAT_V4), supports equations of state for fluid density and viscosity. In SEAWAT_V4, fluid density can be calculated as a function of one or more MT3DMS species, and optionally, fluid pressure. Fluid viscosity is calculated as a function of one or more MT3DMS species, and the program also includes additional functions for representing the dependence of fluid viscosity on temperature. This report documents testing of and experimentation with SEAWAT_V4 with six previously published problems that include various combinations of density-dependent flow due to temperature variations and/or concentration variations of one or more species. Some of the problems also include variations in viscosity that result from temperature differences in water and oil. Comparisons between the results of SEAWAT_V4 and other published results are generally consistent with one another, with minor differences considered acceptable.

  5. Effect of sunlight on the infectivity of Cryptosporidium parvum in seawater.

    PubMed

    Nasser, Abid M; Telser, Lital; Nitzan, Yeshayahu

    2007-09-01

    The prevalence of pathogenic microorganisms in seawater can result in waterborne and food borne outbreaks. This study was performed to determine the effect of sunlight and salinity on the die-off of Cryptosporidium parvum. Cryptosporidium parvum oocysts, Escherichia coli, and MS2 coliphage were seeded into tap water and seawater samples and then exposed to sunlight. The die-off of C. parvum in seawater, as measured by infectivity, was greater under sunlight (-3.08 log10) than under dark conditions (-1.31 log10). While, no significant difference was recorded in the die-off of C. parvum, under dark conditions, in tap water as compared to seawater (P < 0.05), indicating that the synergistic effect of salinity and sunlight was responsible for the enhanced die-off in seawater. The die-off of MS2 coliphage and E. coli was greater than that observed for C. parvum under all tested conditions. This indicates that these microorganisms cannot serve as indicators for the presence of C. parvum oocysts in seawaters. The results of the study suggest that C. parvum can persist as infectious oocysts for a long time in seawater and can thus pose a serious hazard by direct and indirect contact with humans.

  6. Plutonium determination in seawater by inductively coupled plasma mass spectrometry: A review.

    PubMed

    Cao, Liguo; Bu, Wenting; Zheng, Jian; Pan, Shaoming; Wang, Zhongtang; Uchida, Shigeo

    2016-05-01

    Knowing the concentration and isotopic ratio of Pu in seawater is of critical importance for assessing Pu contamination and investigating oceanic processes. In recent decades, the concentration of (239+240)Pu in seawater, particularly for surface seawater, has presented an exponential decreasing trend with time; thus determination of Pu in seawater has become a challenge nowadays. Here, we have summarized and critically discussed a variety of reported analytical methods for Pu determination in seawater sample based on inductively coupled plasma mass spectrometry (ICP-MS) analytical technique for rapid ultra-trace detection of Pu. Generally, pretreatments for seawater sample include co-precipitation, valence adjustment and chemical separation and purification procedures, all of which are comprehensively reviewed. Overall, the selected anion-exchange, extraction resins and operation condition are important for decontamination of interference from matrix elements and achieving satisfactory chemical yields. In addition, other mass spectrometric and radiometric detections are briefly addressed and compared with the focus on assessing ICP-MS. Finally, we discuss some issues and prospects in determination and application of Pu isotopes in seawater samples for future research. PMID:26946007

  7. Different Planctomycetes diversity patterns in latitudinal surface seawater of the open sea and in sediment.

    PubMed

    Shu, Qinglong; Jiao, Nianzhi

    2008-04-01

    The 16S rRNA gene approach was applied to investigate the diversity of Planctomycetes in latitudinal surface seawater of the Western Pacific Ocean. The results revealed that the Pirellula-Rhodopirellula-Blastopirellula clade dominated the Planctomycetes community at all surface seawater sites while the minority genera Gemmata and Planctomyces were only found at sites H5 and H2 respectively. Although the clone frequency of the PRB clade seemed stable (between 83.3% and 94.1%) for all surface seawater sites, the retrieved Pirellula-Rhodopirellula-Blastopirellula clade presented unexpected diversity. Interestingly, low latitude seawater appeared to have higher diversity than mid-latitudes. integral-LIBSHUFF software analysis revealed significantly different diversity patterns between in latitudinal surface seawater and in the sediment of South China Sea station M2896. Our data suggested that different hydrological and geographic features contributed to the shift of Planctomycetes diversity in marine environments. This is, to our knowledge, the first systematic assessment of Planctomycetes in latitudinal surface seawater of the open sea and the first comparison of diversity pattern between surface seawater and sediments and has broadened our understanding of Planctomycetes diversity in marine environments.

  8. Survival of the North American strain of viral hemorrhagic septicemia virus (VHSV) in filtered seawater and seawater containing ovarian fluid, crude oil and serum-enriched culture medium

    USGS Publications Warehouse

    Kocan, R.M.; Hershberger, P.K.; Elder, N.E.

    2001-01-01

     The North American strain of viral hemorrhagic septicemia virus (NA-VHSV) could be recovered for up to 40 h in natural filtered seawater (27 ppt) with a 50% loss of infectivity after approximately 10 h at 15°C. Addition of 10 ppb North Slope crude oil to the seawater had no effect on virus survival. However, when various concentrations of teleost ovarian fluid were added to seawater, virus could be recovered after 72 h at 0.01% ovarian fluid and after 96 h at 1.0%. When cell culture medium supplemented with 10% fetal bovine serum was added to the seawater, 100% of the virus could be recovered for the first 15 d and 60% of the virus remained after 36 d. These findings quantify NA-VHSV infectivity in natural seawater and demonstrate that ovarian fluid, which occurs naturally during spawning events, significantly prolongs the survival and infectivity of the virus. The extended stabilization of virus in culture medium supplemented with serum allows for low titer field samples to be collected and transported in an unfrozen state without significant loss of virus titer.

  9. Survival of the North American strain of viral hemorrhagic septicemia virus (VHSV) in filtered seawater and seawater containing ovarian fluid, crude oil and serum-enriched culture medium.

    PubMed

    Kocan, R M; Hershberger, P K; Elder, N E

    2001-01-26

    The North American strain of viral hemorrhagic septicemia virus (NA-VHSV) could be recovered for up to 40 h in natural filtered seawater (27 ppt) with a 50% loss of infectivity after approximately 10 h at 15 degrees C. Addition of 10 ppb North Slope crude oil to the seawater had no effect on virus survival. However, when various concentrations of teleost ovarian fluid were added to seawater, virus could be recovered after 72 h at 0.01% ovarian fluid and after 96 h at 1.0%. When cell culture medium supplemented with 10% fetal bovine serum was added to the seawater, 100% of the virus could be recovered for the first 15 d and 60% of the virus remained after 36 d. These findings quantify NA-VHSV infectivity in natural seawater and demonstrate that ovarian fluid, which occurs naturally during spawning events, significantly prolongs the survival and infectivity of the virus. The extended stabilization of virus in culture medium supplemented with serum allows for low titer field samples to be collected and transported in an unfrozen state without significant loss of virus titer.

  10. Preconcentration with dithiocarbamate extraction for determination of molybdenum in seawater by neutron activation analysis

    SciTech Connect

    Mok, W.M.; Wai, C.M.

    1984-01-01

    Molybdenum in seawater can be quantitatively extracted with pyrrolidinedithiocarbamate and diethyldithiocarbamate at pH 1.4 into chloroform, for neutron activation analysis. Uranium in seawater cannot be extracted at this pH, and hence eliminates the interference from the /sup 235/U(n,f)/sup 99/Mo reaction. Interferences from matrix species in seawater, such as sodium and bromine, are also removed during the extraction. The proposed method, with good accuracy and sensitivity, is suitable for the determination of molybdenum in natural waters. 10 references, 2 figures.

  11. Raman Spectroscopic Measurements of Co2 Dissolved in Seawater for Laser Remote Sensing in Water

    NASA Astrophysics Data System (ADS)

    Somekawa, Toshihiro; Fujita, Masayuki

    2016-06-01

    We examined the applicability of Raman lidar technique as a laser remote sensing tool in water. The Raman technique has already been used successfully for measurements of CO2 gas dissolved in water and bubbles. Here, the effect of seawater on CO2 Raman spectra has been evaluated. A frequency doubled Q-switched Nd:YAG laser (532 nm) was irradiated to CO2 gas dissolved in a standard seawater. In seawater, the Raman signals at 984 and 1060-1180 cm-1 from SO42- were detected, which shows no spectral interference caused by Raman signals derived from CO2.

  12. Do foraminifera accurately record seawater neodymium isotope composition?

    NASA Astrophysics Data System (ADS)

    Scrivner, Adam; Skinner, Luke; Vance, Derek

    2010-05-01

    Palaeoclimate studies involving the reconstruction of past Atlantic meridional overturning circulation increasingly employ isotopes of neodymium (Nd), measured on a variety of sample media (Frank, 2002). In the open ocean, Nd isotopes are a conservative tracer of water mass mixing and are unaffected by biological and low-temperature fractionation processes (Piepgras and Wasserburg, 1987; Lacan and Jeandel, 2005). For decades, benthic foraminifera have been widely utilised in stable isotope and geochemical studies, but have only recently begun to be exploited as a widely distributed, high-resolution Nd isotope archive (Klevenz et al., 2008), potentially circumventing the difficulties associated with other methods used to recover past deep-water Nd isotopes (Klevenz et al., 2008; Rutberg et al., 2000; Tachikawa et al., 2004). Thus far, a single pilot study (Klevenz et al., 2008) has indicated that core-top sedimentary benthic foraminifera record a Nd isotope composition in agreement with the nearest available bottom seawater data, and has suggested that this archive is potentially useful on both millennial and million-year timescales. Here we present seawater and proximal core-top foraminifer Nd isotope data for samples recovered during the 2008 "RETRO" cruise of the Marion Dufresne. The foraminifer samples comprise a depth-transect spanning 3000m of the water column in the Angola Basin and permit a direct comparison between high-resolution water column and core-top foraminiferal Nd isotope data. We use these data to assess the reliability of both planktonic and benthic foraminifera as recorders of water column neodymium isotope composition. Frank, M., 2002. Radiogenic isotopes: Tracers of past ocean circulation and erosional input, Rev. Geophys., 40 (1), 1001, doi:10.1029/2000RG000094. Klevenz, V., Vance, D., Schmidt, D.N., and Mezger, K., 2008. Neodymium isotopes in benthic foraminifera: Core-top systematics and a down-core record from the Neogene south Atlantic

  13. Triple sulfur isotope composition of Late Archean seawater sulfate

    NASA Astrophysics Data System (ADS)

    Paris, G.; Fischer, W. W.; Sessions, A. L.; Adkins, J. F.

    2013-12-01

    Multiple sulfur isotope ratios in Archean sedimentary rocks have provided powerful insights into the behavior of the ancient sulfur cycle, the redox state of fluid Earth, and the timing of the rise of atmospheric oxygen [1]. Most processes fractionate sulfur isotopes in proportion to their mass differences, but the Archean sulfur isotope record is marked by pronounced mass-independent fractionation (MIF, Δ33S≠0). The origin of these signatures has been traditionally interpreted as the result of photolysis of SO2 from short wavelength UV light, with positive Δ33S values recorded in pyrite and negative Δ33S values in sulfate-bearing phases [2]. This long-held hypothesis rests on observations of negative Δ33S from enigmatic barite occurrences from mixed volcanic sedimentary strata in Mesoarchean greenstone terrains. Despite forming the framework for understanding Archean sulfur cycle processes [3], it is largely untested [3]. It is largely untested. Consequently, the biggest challenge to our current understanding of the early sulfur cycle is a poor understanding of the isotopic composition of seawater sulfate. Sulfate evaporite minerals are absent from Archean strata and the sulfur isotope record is written entirely by measurements of pyrite. Carbonate associated sulfate (CAS) provides an important archive for assaying the isotopic composition of ancient seawater sulfate It has been exploited in many studies of Phanerozoic and Proterozoic sulfate but have been only marginally used thus far for Archean samples because of the extremely low concentration of CAS in limestones and dolomites from this era. We have developed a novel MC-ICP-MS approach to solve this problem [4]. This new method lowers the detection limit by up to three orders of magnitude for δ34S and Δ33S measurements, enabling to work on a few nmols of sulfate which represent only tens of mg of sample powders micromilled from specific carbonate textures. Two stratigraphic sections from the 2

  14. Physical and numerical modeling of seawater intrusion in coastal aquifers

    NASA Astrophysics Data System (ADS)

    Crestani, Elena; Camporese, Matteo; Salandin, Paolo

    2016-04-01

    Seawater intrusion in coastal aquifers is a worldwide problem caused, among others factors, by aquifer overexploitation, rising sea levels, and climate changes. To limit the deterioration of both surface water and groundwater quality caused by saline intrusion, in recent years many research studies have been developed to identify possible countermeasures, mainly consisting of underground barriers. In this context, physical models are fundamental to study the saltwater intrusion, since they provide benchmarks for numerical model calibrations and for the evaluation of the effectiveness of general solutions to contain the salt wedge. This work presents a laboratory experiment where seawater intrusion was reproduced in a specifically designed sand-box. The physical model, built at the University of Padova, represents the terminal part of a coastal aquifer and consists of a flume 500 cm long, 30 cm wide and 60 cm high, filled for an height of 49 cm with glass beads characterized by a d50 of 0.6 mm and a uniformity coefficient d60/d10 ≈ 1.5. The resulting porous media is homogeneous, with porosity of about 0.37 and hydraulic conductivity of about 1.3×10-3 m/s. Upstream from the sand-box, a tank filled by freshwater provides the recharge to the aquifer. The downstream tank simulates the sea and red food dye is added to the saltwater to easily visualize the salt wedge. The volume of the downstream tank is about five times the upstream one, and, due to the small filtration discharge, salt concentration variations (i.e., water density variations) due to the incoming freshwater flow are negligible. The hydraulic gradient during the tests is constant, due to the fixed water level in the two tanks. Water levels and discharged flow rate are continuously monitored. The experiment presented here had a duration of 36 h. For the first 24 h, the saltwater wedge was let to evolve until quasi stationary condition was obtained. In the last 12 h, water withdrawal was carried out at a

  15. Seawater intrusion vulnerability indicators for freshwater lenses in strip islands

    NASA Astrophysics Data System (ADS)

    Morgan, L.; Werner, A. D.

    2014-12-01

    Freshwater lenses on small islands have been described as some of the most vulnerable aquifer systems in the world. Yet, little guidance is available regarding methods for rapidly assessing the vulnerability of freshwater lenses to the potential effects of climate change. To address this gap we employ a steady-state analytic modelling approach to develop seawater intrusion (SWI) vulnerability indicator equations. The vulnerability indicator equations quantify the propensity for SWI to occur in strip islands due to both recharge change and sea-level rise (SLR) (incorporating the effect of land surface inundation (LSI)). This work extends that of Werner et al. (2012) who developed SWI vulnerability indicator equations for unconfined and confined continental aquifers, and did not consider LSI. Flux-controlled and head-controlled conceptualisations of freshwater lenses are adopted. Under flux-controlled conditions the water table is able to rise unencumbered by land surface effects. Under head-controlled conditions the head is fixed at the centre of the lens due to, for example, centrally located topographic controls, surface water features or pumping. A number of inferences about SWI vulnerability in freshwater lenses can be made from the analysis: (1) SWI vulnerability indicators for SLR (under flux-controlled conditions) are proportional to lens thickness (or volume) and the rate of LSI and inversely proportional to island width; (2) SWI vulnerability indicators for recharge change (under flux-controlled conditions) are proportional to lens thickness (or volume) and inversely proportional to recharge; (3) SLR has greater impact under head-controlled conditions rather than flux-controlled conditions, whereas the opposite is the case for LSI and recharge change. Example applications to several case studies illustrate use of the method for rapidly ranking lenses according to vulnerability, thereby allowing for prioritisation of areas where further and more detailed SWI

  16. Physical and numerical modeling of seawater intrusion in coastal aquifers

    NASA Astrophysics Data System (ADS)

    Crestani, Elena; Camporese, Matteo; Salandin, Paolo

    2016-04-01

    Seawater intrusion in coastal aquifers is a worldwide problem caused, among others factors, by aquifer overexploitation, rising sea levels, and climate changes. To limit the deterioration of both surface water and groundwater quality caused by saline intrusion, in recent years many research studies have been developed to identify possible countermeasures, mainly consisting of underground barriers. In this context, physical models are fundamental to study the saltwater intrusion, since they provide benchmarks for numerical model calibrations and for the evaluation of the effectiveness of general solutions to contain the salt wedge. This work presents a laboratory experiment where seawater intrusion was reproduced in a specifically designed sand-box. The physical model, built at the University of Padova, represents the terminal part of a coastal aquifer and consists of a flume 500 cm long, 30 cm wide and 60 cm high, filled for an height of 49 cm with glass beads characterized by a d50 of 0.6 mm and a uniformity coefficient d60/d10 ≈ 1.5. The resulting porous media is homogeneous, with porosity of about 0.37 and hydraulic conductivity of about 1.3×10‑3 m/s. Upstream from the sand-box, a tank filled by freshwater provides the recharge to the aquifer. The downstream tank simulates the sea and red food dye is added to the saltwater to easily visualize the salt wedge. The volume of the downstream tank is about five times the upstream one, and, due to the small filtration discharge, salt concentration variations (i.e., water density variations) due to the incoming freshwater flow are negligible. The hydraulic gradient during the tests is constant, due to the fixed water level in the two tanks. Water levels and discharged flow rate are continuously monitored. The experiment presented here had a duration of 36 h. For the first 24 h, the saltwater wedge was let to evolve until quasi stationary condition was obtained. In the last 12 h, water withdrawal was carried out at

  17. Effect of temperature on seawater desalination-water quality analyses for desalinated seawater for its use as drinking and irrigation water.

    PubMed

    Guler, Enver; Ozakdag, Deniz; Arda, Muserref; Yuksel, Mithat; Kabay, Nalan

    2010-08-01

    The effect of feed seawater temperature on the quality of product water in a reverse osmosis process was investigated using typical seawater at Urla Bay, Izmir region, Turkey. The tests were carried out at different feed seawater temperatures (11-23 degrees C) using two RO modules with one membrane element each. A number of variables, including pH, conductivity, total dissolved solids, salinity, rejection percentage of a number of ions (Na+, K+, Ca2+, Mg2+, Cl(-), HCO3(-), and SO4(2-)), and the levels of boron and turbidities in collected permeates, were measured. The suitability of these permeates as irrigation and drinking water was checked by comparison with water quality standards.

  18. The hazards of eruptions through lakes and seawater

    USGS Publications Warehouse

    Mastin, L.G.; Witter, J.B.

    2000-01-01

    Eruptions through crater lakes or shallow seawater, referred to here as subaqueous eruptions, present hazards from hydromagmatic explosions, such as base surges, lahars, and tsunamis, which may not exist at volcanoes on dry land. We have systematically compiled information from eruptions through surface water in order to understand the circumstances under which these hazards occur and what disastrous effects they have caused in the past. Subaqueous eruptions represent only 8% of all recorded eruptions but have produced about 20% of all fatalities associated with volcanic activity in historical time. Excluding eruptions that have resulted in about a hundred deaths or less, lahars have killed people in the largest number of historical subaqueous eruptions (8), followed by pyroclastic flows (excluding base surges; 5) tsunamis (4), and base surges (2). Subaqueous eruptions have produced lahars primarily on high (>1000 m), steep-sided volcanoes containing small (<1 km diameter) crater lakes. Tsunamis and other water waves have caused death or destroyed man-made structures only at submarine volcanoes and at Lake Taal in the Philippines. In spite of evidence that magma-water mixing makes eruptions more explosive, such explosions and their associated base surges have caused fewer deaths, and have been implicated in fewer eruptions involving large numbers of fatalities than lahars and tsunamis. The latter hazards are more deadly because they travel much farther from a volcano and inundate coastal areas and stream valleys that tend to be densely settled.

  19. Radionuclides in sediments and seawater at Rongelap Atoll

    SciTech Connect

    Noshkin, V.E.; Robison, W.L.; Eagle, R.J.; Brunk, J.L.

    1998-03-01

    The present concentrations and distributions of long-lived, man-made radionuclides in Rongelap Atoll lagoon surface sediments, based on samples collected and analyzed in this report. The radionuclides were associated with debris generated with the 1954 Bravo thermonuclear test at Bikini Atoll. Presently, only {sup 90}Sr and the transuranic radionuclides are found associated with the surface sediments in any quantity. Other radionuclides, including {sup 60}Co and {sup 137} Cs, are virtually absent and have either decayed or migrated from the deposits to the overlying seawater. Present inventories of {sup 241}Am and {sup 249+240}Pu in the surface layer at Rongelap are estimated to be 3% of the respective inventories in surface sediments from Bikini Atoll. There is a continuous slow release of the transuranics from the sediments back to the water column. The inventories will only slowly change with time unless the chemical-physical processes that now regulate this release to the water column are changed or altered.

  20. 'Rare biosphere' bacteria as key phenanthrene degraders in coastal seawaters.

    PubMed

    Sauret, Caroline; Séverin, Tatiana; Vétion, Gilles; Guigue, Catherine; Goutx, Madeleine; Pujo-Pay, Mireille; Conan, Pascal; Fagervold, Sonja K; Ghiglione, Jean-François

    2014-11-01

    By coupling DNA-SIP and pyrosequencing approaches, we identified Cycloclasticus sp. as a keystone degrader of polycyclic aromatic hydrocarbons (PAH) despite being a member of the 'rare biosphere' in NW Mediterranean seawaters. We discovered novel PAH-degrading bacteria (Oceanibaculum sp., Sneathiella sp.) and we identified other groups already known to possess this function (Alteromonas sp., Paracoccus sp.). Together with Cycloclasticus sp., these groups contributed to potential in situ phenanthrene degradation at a rate >0.5 mg l(-1) day(-1), sufficient to account for a considerable part of PAH degradation. Further, we characterized the PAH-tolerant bacterial communities, which were much more diverse in the polluted site by comparison to unpolluted marine references. PAH-tolerant bacteria were also members of the rare biosphere, such as Glaciecola sp. Collectively, these data show the complex interactions between PAH-degraders and PAH-tolerant bacteria and provide new insights for the understanding of the functional ecology of marine bacteria in polluted waters.

  1. SEAWAT-based simulation of axisymmetric heat transport.

    PubMed

    Vandenbohede, Alexander; Louwyck, Andy; Vlamynck, Nele

    2014-01-01

    Simulation of heat transport has its applications in geothermal exploitation of aquifers and the analysis of temperature dependent chemical reactions. Under homogeneous conditions and in the absence of a regional hydraulic gradient, groundwater flow and heat transport from or to a well exhibit radial symmetry, and governing equations are reduced by one dimension (1D) which increases computational efficiency importantly. Solute transport codes can simulate heat transport and input parameters may be modified such that the Cartesian geometry can handle radial flow. In this article, SEAWAT is evaluated as simulator for heat transport under radial flow conditions. The 1971, 1D analytical solution of Gelhar and Collins is used to compare axisymmetric transport with retardation (i.e., as a result of thermal equilibrium between fluid and solid) and a large diffusion (conduction). It is shown that an axisymmetric simulation compares well with a fully three dimensional (3D) simulation of an aquifer thermal energy storage systems. The influence of grid discretization, solver parameters, and advection solution is illustrated. Because of the high diffusion to simulate conduction, convergence criterion for heat transport must be set much smaller (10(-10) ) than for solute transport (10(-6) ). Grid discretization should be considered carefully, in particular the subdivision of the screen interval. On the other hand, different methods to calculate the pumping or injection rate distribution over different nodes of a multilayer well lead to small differences only.

  2. Biogeography of bacterioplankton in the tropical seawaters of Singapore.

    PubMed

    Lau, Stanley C K; Zhang, Rui; Brodie, Eoin L; Piceno, Yvette M; Andersen, Gary; Liu, Wen-Tso

    2013-05-01

    Knowledge about the biogeography of marine bacterioplankton on the global scale in general and in Southeast Asia in particular has been scarce. This study investigated the biogeography of bacterioplankton community in Singapore seawaters. Twelve stations around Singapore island were sampled on different schedules over 1 year. Using PCR-DNA fingerprinting, DNA cloning and sequencing, and microarray hybridization of the 16S rRNA genes, we observed clear spatial variations of bacterioplankton diversity within the small area of the Singapore seas. Water samples collected from the Singapore Strait (south) throughout the year were dominated by DNA sequences affiliated with Cyanobacteria and Alphaproteobacteria that were believed to be associated with the influx of water from the open seas in Southeast Asia. On the contrary, water in the relatively polluted Johor Strait (north) were dominated by Betaproteobacteria, Gammaproteobacteria, and Bacteroidetes and that were presumably associated with river discharge and the relatively eutrophic conditions of the waterway. Bacterioplankton diversity was temporally stable, except for the episodic surge of Pseudoalteromonas, associated with algal blooms. Overall, these results provide valuable insights into the diversity of bacterioplankton communities in Singapore seas and the possible influences of hydrological conditions and anthropogenic activities on the dynamics of the communities.

  3. Biotransformation of potentially persistent alkylphenols in natural seawater.

    PubMed

    Lofthus, Synnøve; Almås, Inger K; Evans, Peter; Pelz, Oliver; Brakstad, Odd Gunnar

    2016-08-01

    Produced water (PW) discharged to the marine environment may contain both natural substances and industrial chemicals that are potentially persistent, bioaccumulating and toxic (PBT). Identification of substances as PBT is dependent upon accurate assessment of biodegradation rates, but these measurements can be impeded where substances exhibit inherently low solubility in water. Examples of substances of this kind include some alkylated phenols (APs). Biotransformation of three APs, suspected to be PBT compounds in PW, was investigated by adopting a new methodology in which they were immobilized to hydrophobic adsorbents submerged in natural seawater. These compounds were not ready biodegradable by conventional screening biochemical oxygen demand (BOD) methods at high concentrations (2 mg/L). However, potential biodegradability for two of the three APs were demonstrated by the immobilization method at low concentrations (appr. 100 μg/L), with biotransformation half-lives <50 days. Thus, standard screening tests should be supplemented by biodegradation methods suited for testing of poorly soluble substances before the persistence of potential PBT substances are defined. PMID:27176941

  4. Systems studies on the extraction of uranium from seawater

    SciTech Connect

    Driscoll, M.J.; Best, F.R.

    1981-11-01

    This report summarizes the work done at MIT during FY 1981 on the overall system design of a uranium-from-seawater facility. It consists of a sequence of seven major chapters, each of which was originally prepared as a stand-alone internal progress report. These chapters trace the historical progression of the MIT effort, from an early concern with scoping calculations to define the practical boundaries of a design envelope, as constrained by elementary economic and energy balance considerations, through a parallel evaluation of actively-pumped and passive current-driven concepts, and thence to quantification of the features of a second generation system based on a shipboard-mounted, actively-pumped concept designed around the use of thin beds of powdered ion exchange resin supported by cloth fiber cylinders (similar to the baghouse flyash filters used on power station offgas). An assessment of the apparently inherent limitations of even thin settled-bed sorber media then led to selection of an expanded bed (in the form of an ion exchange wool), which would permit an order of magnitude increase in flow loading, as a desirable advance. Thus the final two chapters evaluate ways in which this approach could be implemented, and the resulting performance levels which could be attained. Overall, U/sub 3/O/sub 8/ production costs under 200 $/lb appear to be within reach if a high capacity (several thousand ppM U) ion exchange wool can be developed.

  5. Evaluation of media for monitoring fecal streptococci in seawater.

    PubMed Central

    Yoshpe-Purer, Y

    1989-01-01

    The selectivity of KF streptococcus agar (KF) for monitoring fecal streptococci (FS) in seawater was examined in 234 samples of Mediterranean water and compared with the selectivity of M-Enterococcus agar (M-Ent) for 124 samples and with bile-esculin-azide agar (BEA) for 17 samples. KF was found to be unsuitable for marine water because Vibrio alginolyticus and other gram-negative bacilli indigenous to this environment grew well on it and produced red colonies identical to those of FS. In 26% of samples, some with high counts of red colonies on the membrane filters (MF), there were no streptococci, only gram-negative bacilli and staphylococci, and in an additional 23.1% the streptococci constituted less than 50% of the "typical" red colonies on the MF. V. alginolyticus also produced FS-like colonies on MF incubated on BEA but was not isolated from MF incubated on M-Ent. Although staphylococci grew and produced FS-like colonies on all three media, M-Ent was the most selective since no gram-negative bacilli were isolated from MF incubated on it. PMID:2782876

  6. Hunnebotn: a seawater basin transformed by natural and anthropogenic processes

    NASA Astrophysics Data System (ADS)

    Ström, Tomm-Espen; Klaveness, Dag

    2003-04-01

    The lake Hunnebotn ( A=1 km2, z max=11 m) has become separated from the sea by isostasis, but a 1.5-m-deep channel is held open by periodic dredging. Water exchange is minor due to the small tidal range (21 cm) and the length of the channel (1.8 km), but there may be an inflow of seawater at spring tides. The terrestrial watershed runoff may be fertilized by sewage and agricultural runoff despite some measures taken to prevent this. Historical and new records of biological communities indicate variations in sensitivity to different phases of the isolation and eutrophication process. The native oyster was most sensitive and disappeared first. Later, the eelgrass disappeared possibly due to overgrowth by epiphytic algae, and finally there was a massive littoral-sublittoral invasion of green algae. The lake should not be left in this condition, for aesthetic reasons and because marine inlets and eutrophic brackish water may serve as refugia for spore populations of toxic microalgae. Improving surface water quality will require better control of anthropogenic sources, but bursts and leaks of nutrients from the anoxic monimolimnion cannot be controlled.

  7. Seawater strontium isotopes at the Cretaceous-Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Macdougall, J. D.; Martin, E.

    1988-01-01

    Anomalously high values of Seawater Sr-87/Sr-86 near the Cretaceous-Tertiary (K-T) boundary have been reported. However, few of the data from the literature are from a single continuous section, and perhaps the most complete study of the boundary region, from a shallow marine limestone sequence in Alabama, showed elevated Sr-87/Sr-86 but no pronounced spike. Thus, in order to investigate the cause of the change in strontium isotopic composition, it is important to determine the exact nature and magnitude of the increase by studying in detail continuous sections through the boundary. If there is indeed a Sr isotope spike at the K-T boundary, it requires the addition of a large amount of radiogenic Sr to the oceans over a short time period, a phenomenon that may be linked to other large-scale environmental disturbances which occurred at that time. In order to address this question, a high-resolution strontium isotope study of foraminifera from three Deep Sea Drilling Project (DSDP) cores which recovered the K-T boundary section: Site 356 in the South Atlantic, Site 384 in the North Atlantic and Site 577 from the Shatsky Rise in the Pacific was initiated. The isotope measurements are being made on either single or small numbers of forams carefully picked and identified and in most cases examined by SEM before analysis. Because this work is not yet complete, conclusions drawn here must be viewed as tentative. They are briefly discussed.

  8. SEAWAT-based simulation of axisymmetric heat transport.

    PubMed

    Vandenbohede, Alexander; Louwyck, Andy; Vlamynck, Nele

    2014-01-01

    Simulation of heat transport has its applications in geothermal exploitation of aquifers and the analysis of temperature dependent chemical reactions. Under homogeneous conditions and in the absence of a regional hydraulic gradient, groundwater flow and heat transport from or to a well exhibit radial symmetry, and governing equations are reduced by one dimension (1D) which increases computational efficiency importantly. Solute transport codes can simulate heat transport and input parameters may be modified such that the Cartesian geometry can handle radial flow. In this article, SEAWAT is evaluated as simulator for heat transport under radial flow conditions. The 1971, 1D analytical solution of Gelhar and Collins is used to compare axisymmetric transport with retardation (i.e., as a result of thermal equilibrium between fluid and solid) and a large diffusion (conduction). It is shown that an axisymmetric simulation compares well with a fully three dimensional (3D) simulation of an aquifer thermal energy storage systems. The influence of grid discretization, solver parameters, and advection solution is illustrated. Because of the high diffusion to simulate conduction, convergence criterion for heat transport must be set much smaller (10(-10) ) than for solute transport (10(-6) ). Grid discretization should be considered carefully, in particular the subdivision of the screen interval. On the other hand, different methods to calculate the pumping or injection rate distribution over different nodes of a multilayer well lead to small differences only. PMID:24571415

  9. Aragonite coating solutions (ACS) based on artificial seawater

    NASA Astrophysics Data System (ADS)

    Tas, A. Cuneyt

    2015-03-01

    Aragonite (CaCO3, calcium carbonate) is an abundant biomaterial of marine life. It is the dominant inorganic phase of coral reefs, mollusc bivalve shells and the stalactites or stalagmites of geological sediments. Inorganic and initially precipitate-free aragonite coating solutions (ACS) of pH 7.4 were developed in this study to deposit monolayers of aragonite spherules or ooids on biomaterial (e.g., UHMWPE, ultrahigh molecular weight polyethylene) surfaces soaked in ACS at 30 °C. The ACS solutions of this study have been developed for the surface engineering of synthetic biomaterials. The abiotic ACS solutions, enriched with calcium and bicarbonate ions at different concentrations, essentially mimicked the artificial seawater composition and started to deposit aragonite after a long (4 h) incubation period at the tropical sea surface temperature of 30 °C. While numerous techniques for the solution deposition of calcium hydroxyapatite (Ca10(PO4)6(OH)2), of low thermodynamic solubility, on synthetic biomaterials have been demonstrated, procedures related to the solution-based surface deposition of high solubility aragonite remained uncommon. Monolayers of aragonite ooids deposited at 30 °C on UHMWPE substrates soaked in organic-free ACS solutions were found to possess nano-structures similar to the mortar-and-brick-type botryoids observed in biogenic marine shells. Samples were characterized using SEM, XRD, FTIR, ICP-AES and contact angle goniometry.

  10. 76 FR 14953 - Notice of Availability of Draft Environmental Impact Statement for the Proposed Honolulu Seawater...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... the Proposed Honolulu Seawater Air Conditioning Project, Honolulu, HI AGENCY: Department of the Army...); Building 230; Fort Shafter, HI 96858-5440. Comments may also be submitted via e-mail to...

  11. Color correlation for the recognition of Vibrio cholerae O1 in seawater

    NASA Astrophysics Data System (ADS)

    Mourino-Perez, Rosa R.; Alvarez-Borrego, Josue

    1999-07-01

    Application of color correlation optical systems for the recognition of Vibrio cholerae 01 in seawater samples with matched filters and phase only filters recorded in holographic plates in three channels (RGB).

  12. Continuous Underway Seawater Measurements of Biogenic Volatile Organic Compounds in the Western Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Zoerb, M.; Kim, M.; Bertram, T. H.

    2014-12-01

    The products of isoprene and terpene oxidation have been shown to contribute significantly to secondary aerosol production rates over continental regions, where the emission rates have been well characterized. Significantly less is known about the emission of isoprene and monoterpenes from marine sources. We discuss the development of a chemical ionization mass spectrometer (CIMS) employing benzene reagent ion chemistry for the selective detection of biogenic volatile organic compounds. The CIMS was coupled to a seawater equilibrator for the measurement of dissolved gases in surface seawater. This system was deployed aboard the R/V Knorr during the Western Atlantic Climate Study II in Spring 2014. Here, we report surface seawater (5 m depth) concentrations of dimethyl sulfide, isoprene, and alpha-pinene. The concentration measurements are discussed in terms of surface seawater temperature, nutrient availability, and primary productivity.

  13. The influence of the distribution of sea-water conductivity on the ocean induced magnetic field

    NASA Astrophysics Data System (ADS)

    Saynisch, Jan; Irrgang, Christopher; Hagedoorn, Jan; Thomas, Maik

    2016-04-01

    The variability of oceanic contributions to Earth's magnetic field ranges from sub-daily scales to thousands of years. To study the sensitivity and the range of oceanic magnetic signals, an induction model is coupled to an ocean general circulation model. In the presented study, the sensitivity of the induction process to spatial and temporal variations in sea-water conductivity is investigated. In current calculations of ocean induced magnetic fields, a realistic distribution of sea-water conductivity is often neglected. We shown that assuming an ocean-wide constant conductivity is insufficient to accurately capture the spatial and, more important, the temporal variability of the magnetic signal. Using a realistic global sea-water conductivity distribution changes the temporal variability of the magnetic field up to 45%. Vertical gradients in sea-water conductivity prove to be a key factor for the variability of the oceanic induced magnetic field.

  14. A solvent extraction technique for the isotopic measurement of dissolved copper in seawater.

    PubMed

    Thompson, Claire M; Ellwood, Michael J; Wille, Martin

    2013-05-01

    Stable copper (Cu) isotope geochemistry provides a new perspective for investigating and understanding Cu speciation and biogeochemical Cu cycling in seawater. In this work, sample preparation for isotopic analysis employed solvent-extraction with amino pyrollidine dithiocarbamate/diethyl dithiocarbamate (APDC/DDC), coupled with a nitric acid back-extraction, to concentrate Cu from seawater. This was followed by Cu-purification using anion-exchange. This straightforward technique is high yielding and fractionation free for Cu and allows precise measurement of the seawater Cu isotopic composition using multi-collector inductively coupled plasma mass-spectrometry. A deep-sea profile measured in the oligotrophic north Tasman Sea shows fractionation in the Cu isotopic signature in the photic zone but is relatively homogenised at depth. A minima in the Cu isotopic profile correlates with the chlorophyll a maximum at the site. These results indicate that a range of processes are likely to fractionate stable Cu isotopes in seawater. PMID:23601981

  15. A solvent extraction technique for the isotopic measurement of dissolved copper in seawater.

    PubMed

    Thompson, Claire M; Ellwood, Michael J; Wille, Martin

    2013-05-01

    Stable copper (Cu) isotope geochemistry provides a new perspective for investigating and understanding Cu speciation and biogeochemical Cu cycling in seawater. In this work, sample preparation for isotopic analysis employed solvent-extraction with amino pyrollidine dithiocarbamate/diethyl dithiocarbamate (APDC/DDC), coupled with a nitric acid back-extraction, to concentrate Cu from seawater. This was followed by Cu-purification using anion-exchange. This straightforward technique is high yielding and fractionation free for Cu and allows precise measurement of the seawater Cu isotopic composition using multi-collector inductively coupled plasma mass-spectrometry. A deep-sea profile measured in the oligotrophic north Tasman Sea shows fractionation in the Cu isotopic signature in the photic zone but is relatively homogenised at depth. A minima in the Cu isotopic profile correlates with the chlorophyll a maximum at the site. These results indicate that a range of processes are likely to fractionate stable Cu isotopes in seawater.

  16. Effect of seawater environmental exposure on fatigue properties of polyethylene pipe

    SciTech Connect

    Tipton, D G

    1980-10-01

    One laboratory study at NIT was reported to show an unexpected decrease in crystallinity for a polyethylene material exposed to fatigue loading in a synthetic seawater solution. High density polyethylene Sclairpipe, from the OTEC-1 cold water pipe, was evaluated for resistance to corrosion fatigue in natural seawater. Intermediate crystallinity measurements (via bulk density) showed no effect of corrosion fatigue exposure. Heat of fusion (a relative indicator of crystallinity) also showed no effect of the exposure. Seawater exposure produced no significant change in tensile strength. One failure was observed during the corrosion fatigue tests and was attributed to porosity observed by fractography. These data suggest that high density polyethylene is not significantly sensitive to degradation of fatigue strength in natural seawater.

  17. Dating of saline groundwater from several Israeli aquifers, indication for paleo seawater intrusion

    NASA Astrophysics Data System (ADS)

    Yechieli, Yoseph; Zilberbrand, Michael; Burg, Avihu; Weinstein, Yishai

    2016-04-01

    This study deals with dating of saline groundwater, with salinity closed to that of seawater (mostly >75% seawater), in order to estimate the timing of past events of seawater intrusion. Such dating was seldom conducted before since, in most cases, even the most saline water samples have a significant component of fresh water. Dating of saline groundwater was conducted in two of the main aquifers in Israel (the Coastal Aquifer and the Mountain Aquifer). In the Coastal Aquifer, most of the saline water was found to be young (>50 years, tritium containing, ~60 PMC) indicating recent seawater intrusion. However, in some of the deeper sub-aquifers, older saline water was found (5-10 PMC, i.e. older than ~10,000 years), implying penetration of seawater at older time. Complementary age determinations were conducted on the fresh groundwater, some of which were found to be very old. In the Mountain Aquifer, old saline water bodies were found in several locations. Estimation of the age of the different end members (fresh and saline) showed that the seawater component is older than 30,000 year, probably beyond radiocarbon dating. The isotopic values of this old seawater component is similar to that of the present seawater (e.g. δ18O of ~1.5%0 and 1.8%0 in old and recent seawater) which implies that the intrusion took place in similar sea conditions to that of the present ones. An attempt to determine the age of this old seawater will be done with noble gases. Numerical simulations were conducted with FEFLOW in order to examine the flow regime in the different parts of the coastal aquifer. The preliminary steady state simulations fit quite well with ages of saline groundwater. Transient simulations are planned to be conducted in the next stage in order to simulate the effect of sea level changes (e.g. the rise of 120 meters at the end of the glacial period) on the rate of seawater intrusion into the coastal aquifers. Due to the limitation of the radiocarbon methods, samples

  18. Determination of thorium in seawater by neutron activation analysis and mass spectrometry

    SciTech Connect

    Huh, Chih-An

    1987-01-01

    The recent development of neutron activation analysis and mass spectrometric methods for the determination of /sup 232/Th in seawater has made possible rapid sampling and analysis of this long-lived, non-radiogenic thorium isotope on small-volume samples. The marine geochemical utility of /sup 232/Th, whose concentration in seawater is extremely low, warrants the development of these sensitive techniques. The analytical methods and some results are presented and discussed in this article. 24 refs., 3 figs.

  19. Artificial Seawater Media Facilitate Cultivating Members of the Microbial Majority from the Gulf of Mexico

    PubMed Central

    Pitre, David M.; Weckhorst, Jessica Lee; Lanclos, V. Celeste; Webber, Austen T.

    2016-01-01

    ABSTRACT High-throughput cultivation studies have been successful at bringing numerous important marine bacterioplankton lineages into culture, yet these frequently utilize natural seawater media that can hamper portability, reproducibility, and downstream characterization efforts. Here we report the results of seven experiments with a set of newly developed artificial seawater media and evaluation of cultivation success via comparison with community sequencing data from the inocula. Eighty-two new isolates represent highly important marine clades, including SAR116, OM60/NOR5, SAR92, Roseobacter, and SAR11. For many, isolation with an artificial seawater medium is unprecedented, and several organisms are also the first of their type from the Gulf of Mexico. Community analysis revealed that many isolates were among the 20 most abundant organisms in their source inoculum. This method will expand the accessibility of bacterioplankton cultivation experiments and improve repeatability by avoiding normal compositional changes in natural seawater. IMPORTANCE The difficulty in cultivating many microbial taxa vexes researchers intent on understanding the contributions of these organisms to natural systems, particularly when these organisms are numerically abundant, and many cultivation attempts recover only rare taxa. Efforts to improve this conundrum with marine bacterioplankton have been successful with natural seawater media, but that approach suffers from a number of drawbacks and there have been no comparable artificial alternatives created in the laboratory. This work demonstrates that a newly developed suite of artificial-seawater media can successfully cultivate many of the most abundant taxa from seawater samples and many taxa previously only cultivated with natural-seawater media. This methodology therefore significantly simplifies efforts to cultivate bacterioplankton and greatly improves our ability to perform physiological characterization of cultures

  20. Artificial Seawater Media Facilitate Cultivating Members of the Microbial Majority from the Gulf of Mexico.

    PubMed

    Henson, Michael W; Pitre, David M; Weckhorst, Jessica Lee; Lanclos, V Celeste; Webber, Austen T; Thrash, J Cameron

    2016-01-01

    High-throughput cultivation studies have been successful at bringing numerous important marine bacterioplankton lineages into culture, yet these frequently utilize natural seawater media that can hamper portability, reproducibility, and downstream characterization efforts. Here we report the results of seven experiments with a set of newly developed artificial seawater media and evaluation of cultivation success via comparison with community sequencing data from the inocula. Eighty-two new isolates represent highly important marine clades, including SAR116, OM60/NOR5, SAR92, Roseobacter, and SAR11. For many, isolation with an artificial seawater medium is unprecedented, and several organisms are also the first of their type from the Gulf of Mexico. Community analysis revealed that many isolates were among the 20 most abundant organisms in their source inoculum. This method will expand the accessibility of bacterioplankton cultivation experiments and improve repeatability by avoiding normal compositional changes in natural seawater. IMPORTANCE The difficulty in cultivating many microbial taxa vexes researchers intent on understanding the contributions of these organisms to natural systems, particularly when these organisms are numerically abundant, and many cultivation attempts recover only rare taxa. Efforts to improve this conundrum with marine bacterioplankton have been successful with natural seawater media, but that approach suffers from a number of drawbacks and there have been no comparable artificial alternatives created in the laboratory. This work demonstrates that a newly developed suite of artificial-seawater media can successfully cultivate many of the most abundant taxa from seawater samples and many taxa previously only cultivated with natural-seawater media. This methodology therefore significantly simplifies efforts to cultivate bacterioplankton and greatly improves our ability to perform physiological characterization of cultures postisolation

  1. Study on the determination of trace methyl mercury in seawater by gas chromatography

    NASA Astrophysics Data System (ADS)

    Wang, Zhongzhu; Cui, Xianzhou

    1990-03-01

    Sample seawater containing trace methyl mercury was acidified and adsorbed on hydrosulfo-cotton, washed with hydrochloric acid, extracted by benzene and dried, and then determined by a gas chromatograph with electron capture detector. This method, which can detect a minimum concentration of 0.1×10-10%, can be used to monitor the 10-10% content of methyl mercury in seawater.

  2. Surfactant induced complex formation and their effects on the interfacial properties of seawater.

    PubMed

    Guzmán, Eduardo; Santini, Eva; Benedetti, Alessandro; Ravera, Francesca; Ferrari, Michele; Liggieri, Libero

    2014-11-01

    The effect of a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), on the interfacial properties of seawater has been studied by dynamic and equilibrium surface tension and by dilational rheology essays. Important modifications of the surface tension and dilational rheology response have been observed already at the very low CTAB concentrations, where the effects due to the high ionic strength are negligible. The comparison with the effects of CTAB in different seawater models, or in natural seawater fractions, points out the establishment of strong interactions between the surfactant molecules and the lipophilic fraction of organic material dispersed/dissolved in seawater, affecting the interfacial activity of the molecules. Considering the biochemical richness of seawater, these results can be explained assuming interaction mechanisms and adsorption schemes similar to those speculated for protein and other macromolecules in the presence of surfactants, which in fact show similar features. Thus already at the low concentrations the surfactant molecules form highly surface-active complexes with part of the organic fraction of seawater. At the larger surfactant concentrations these complexes compete for adsorption with an excess of free CTAB molecules which, according to the thermodynamic conditions, are most favoured to occupy the liquid interface. The results of this study underline the important role of the sea organic content in enhancing the surface-activity of surfactants, which is relevant for a deeper understand of the direct and indirect effects of these types of pollutants on the physico-chemical environment in the sea coastal areas and develop mitigation strategies.

  3. Graphene-based Recyclable Photo-Absorbers for High-Efficiency Seawater Desalination.

    PubMed

    Wang, Xiangqing; Ou, Gang; Wang, Ning; Wu, Hui

    2016-04-13

    Today's scientific advances in water desalination dramatically increase our ability to transform seawater into fresh water. As an important source of renewable energy, solar power holds great potential to drive the desalination of seawater. Previously, solar assisted evaporation systems usually relied on highly concentrated sunlight or were not suitable to treat seawater or wastewater, severely limiting the large scale application of solar evaporation technology. Thus, a new strategy is urgently required in order to overcome these problems. In this study, we developed a solar thermal evaporation system based on reduced graphene oxide (rGO) decorated with magnetic nanoparticles (MNPs). Because this material can absorb over 95% of sunlight, we achieved high evaporation efficiency up to 70% under only 1 kW m(-2) irradiation. Moreover, it could be separated from seawater under the action of magnetic force by decorated with MNPs. Thus, this system provides an advantage of recyclability, which can significantly reduce the material consumptions. Additionally, by using photoabsorbing bulk or layer materials, the deposition of solutes offen occurs in pores of materials during seawater desalination, leading to the decrease of efficiency. However, this problem can be easily solved by using MNPs, which suggests this system can be used in not only pure water system but also high-salinity wastewater system. This study shows good prospects of graphene-based materials for seawater desalination and high-salinity wastewater treatment.

  4. Uranium determination in seawater by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Misra, N. L.; Dhara, S.; Mudher, K. D. Singh

    2006-11-01

    A study regarding uranium determination in seawater by total reflection X-ray fluorescence (TXRF) spectrometry is reported. Uranium, present in seawater in concentration of about 3.3 ng/mL, was selectively extracted in diethyl ether and determined by TXRF after its preconcentration by evaporation and subsequent dissolution in a small volume of 1.5% suprapure HNO 3. Yttrium was used as an internal standard. Before using diethyl ether for selective extraction of uranium from seawater, its extraction behavior for different elements was studied using a multielement standard solution having elemental concentrations in 5 ng/mL levels. It was observed that the extraction efficiency of diethyl ether for uranium was about 100% whereas for other elements it was negligible. The detection limit of TXRF method for uranium in seawater samples after pre-concentration step approaches to 67 pg/mL. The concentrations of uranium in seawater samples determined by TXRF are in good agreement with the values reported in the literature. The method shows a precision within 5% (1 σ). The study reveals that TXRF can be used as a fast analytical technique for the determination of uranium in seawater.

  5. The evaporation path of seawater and the coprecipitation of Br- and K+ with halite

    NASA Technical Reports Server (NTRS)

    McCaffrey, M. A.; Lazar, B.; Holland, H. D.

    1987-01-01

    Brines and salt were sampled at the Morton Bahamas solar salt production facility on Great Inagua Island in the Bahamas. The brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies. At Inagua, calcium carbonate begins to precipitate at a brine concentration factor of 1.8 times that of seawater. Gypsum begins to precipitate at a brine concentration of 3.8 times seawater, and halite at a concentration factor of 10.6. Three of the most concentrated brines from Inagua (40 times seawater) were evaporated further in the laboratory. Magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater, and potassium-bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater. The distribution of coefficients of Br- and K+ between brines and halite were determined by combining analytical data for the Inagua brines with measurements of the Br- and K+ content of halites from Inagua and of halite which had precipitated from Inagua brines during storage. The observed average value of DBr- is 0.032, in good agreement with some of the previous measurements. The measured values of DK+ are highly variable (0.001 to 0.021); DK+ for halite precipitated early in the halite facies is in the vicinity of 0.015.

  6. Seasonal Levels of the Vibrio Predator Bacteriovorax in Atlantic, Pacific, and Gulf Coast Seawater

    PubMed Central

    Richards, Gary P.; Watson, Michael A.; Boyd, E. Fidelma; Burkhardt, William; Lau, Ronald; Uknalis, Joseph; Fay, Johnna P.

    2013-01-01

    Bacteriovorax were quantified in US Atlantic, Gulf, and Pacific seawater to determine baseline levels of these predatory bacteria and possible seasonal fluctuations in levels. Surface seawater was analyzed monthly for 1 year from Kailua-Kona, Hawaii; the Gulf Coast of Alabama; and four sites along the Delaware Bay. Screening for Bacteriovorax was performed on lawns of V. parahaemolyticus host cells. Direct testing of 7.5 mL portions of seawater from the Atlantic, Pacific, and Gulf coasts gave mean annual counts ≤12.2 PFU. Spikes in counts were observed at 3 out of 4 sites along the Delaware Bay 1 week after Hurricane Sandy. A comparison of summer versus winter counts showed significantly more Bacteriovorax (P ≤ 0.0001) in the Delaware Bay during the summer and significantly more (P ≤ 0.0001) in the Gulf during the winter, but no significant seasonal differences (P > 0.05) for Hawaiian seawater. Bacteriovorax counts only correlated with seawater salinity and temperature at one Delaware site (r = 0.79 and r = 0.65, resp.). There was a relatively strong negative correlation between temperature and Bacteriovorax levels (r = −0.585) for Gulf seawater. Selected isolates were sequenced and identified by phylogenetic analysis as Bacteriovorax clusters IX, X, XI, and XII. PMID:24454382

  7. [Residue characteristics and distributions of perfluorinated compounds in surface seawater along Shenzhen coastline].

    PubMed

    Chen, Qing-Wu; Zhang, Hong; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo

    2012-06-01

    In order to explore the residue characteristics and distributions of 15 perfluorinated compounds (PFCs) in 18 surface seawater samples along Shenzhen coastline, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with solid phase extraction enrichment was applied in this research. The results indicated that residue level of PFCs in coastal surface seawater samples was significantly affected by human activities. Sigma PFCs residue levels in surface seawater from Shenzhen west coast, which locates below the estuary of Pearl River and Donghao River, are much higher than those from the east coast, which has low development and sparse population (P<0.05). Under natural conditions, sigma PFCs residue levels in coastal surface seawater samples from Shenzhen Bays are higher than those out of bays. The major residue species in surface seawater samples along Shenzhen coast were medium- and short-chain PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanoic acid and perfluoropentanoic acid. Their similar environmental behavior (P<0.05, P<0.01) is likely associated with the production process of PFCs-related products. Furthermore, cluster analysis results show that PFOS (R2 = 0.4092) level can be used as a representative parameter for evaluating PFCs contamination status in surface seawater along Shenzhen coast.

  8. Seawater spray injury to Quercus acutissima leaves: crystal deposition, stomatal clogging, and chloroplast degeneration.

    PubMed

    Kim, Ki Woo; Koo, Kyosang; Kim, Pan-Gi

    2011-05-01

    Effects of seawater spray on leaf structure were investigated in Quercus acutissima by electron microscopy and X-ray microanalysis. Two-year-old seedlings of Q. acutissima were sprayed with seawater and kept in a greenhouse maintained at 25°C. The most recognizable symptoms of seawater-sprayed seedlings included leaf necrosis, crystal deposition, stomatal clogging, and chloroplast degeneration. Field emission scanning electron microscopy revealed that the leaf surface was covered with additional layers of remnants of seawater spray. Composed of sodium and chloride, cube-shaped crystals (halite) were prevalently found on trichomes and epidermis, and formed aggregates. Meanwhile, wedge-shaped crystals were deposited on epidermis and consisted of calcium and sulfur. As a result of stomatal clogging by crystal deposition on the abaxial surface, it was conceivable that plant respiration became severely hampered. Transmission electron microscopy showed degenerated cytoplasm of seawater-sprayed leaves. It was common to observe severe plasmolysis and disrupted chloroplasts with a reduced number of thylakoids in grana. These results indicate that foliar applications of seawater were sufficient to induce necrosis of Q. acutissima seedlings as an abiotic disturbance factor. PMID:20931628

  9. Cultivation of oleaginous Rhodotorula mucilaginosa in airlift bioreactor by using seawater.

    PubMed

    Yen, Hong-Wei; Liao, Yu-Ting; Liu, Yi Xian

    2016-02-01

    The enormous water resource consumption is a concern to the scale-up fermentation process, especially for those cheap fermentation commodities, such as microbial oils as the feedstock for biodiesel production. The direct cultivation of oleaginous Rhodotorula mucilaginosa in a 5-L airlift bioreactor using seawater instead of pure water led to a slightly lower biomass being achieved, at 17.2 compared to 18.1 g/L, respectively. Nevertheless, a higher lipid content of 65 ± 5% was measured in the batch using seawater as compared to the pure water batch. Both the salinity and osmotic pressure decreased as the cultivation time increased in the seawater batch, and these effects may contribute to the high tolerance for salinity. No effects were observed for the seawater on the fatty acid profiles. The major components for both batches using seawater and pure water were C16:0 (palmitic acid), C18:1 (oleic acid) and C18:2 (linoleic acid), which together accounted for over 85% of total lipids. The results of this study indicated that seawater could be a suitable option for scaling up the growth of oleaginous R. mucilaginosa, especially from the perspective of water resource utilization.

  10. Long-Term Viscoelastic Response of E-glass/Bismaleimide Composite in Seawater Environment

    NASA Astrophysics Data System (ADS)

    Yian, Zhao; Zhiying, Wang; Keey, Seah Leong; Boay, Chai Gin

    2015-12-01

    The effect of seawater absorption on the long-term viscoelastic response of E-glass/BMI composite is presented in this paper. The diffusion of seawater into the composite shows a two-stage behavior, dominated by Fickian diffusion initially and followed by polymeric relaxation. The Glass transition temperature (Tg) of the composite with seawater absorption is considerably lowered due to the plasticization effect. However the effect of water absorption at 50 °C is found to be reversible after drying process. The time-temperature superposition (TTS) was performed based on the results of Dynamic Mechanical Analysis to construct the master curve of storage modulus. The shift factors exhibit Arrhenius behavior when temperature is well below Tg and Vogel-Fulcher-Tammann (VFT) like behavior when temperature gets close to glass transition region. As a result, a semi-empirical formulation is proposed to account for the seawater absorption effect in predicting long-term viscoelastic response of BMI composites based on temperature dependent storage modulus and TTS. The predicted master curves show that the degradation of storage modulus accelerates with both seawater exposure and increasing temperature. The proposed formulation can be applied to predict the long-term durability of any thermorheologically simple composite materials in seawater environment.

  11. Chemometrics for the classification and calibration of seawater using the H+ affinity spectrum.

    PubMed

    Kortazar, L; Sáez, J; Astigarraga, E; Goienaga, N; Fernández, L

    2013-11-15

    In 1819 Alexander Marcet proposed that seawater contains small amounts of all soluble substances and that the relative abundances of some of them were constant. This hypothesis is nowadays known as Marcet's Principle or the principle of constancy of the composition of seawater. Based on this principle, the present research tried to prove that it is possible to detect polluted seawater samples using the seawater H(+) affinity spectrum by the application of the possibilities provided by chemometric tools. Seawater samples were classified using the principal component analysis (PCA) of the HBound spectra of the samples. It was concluded that the sampling points location does not have any influence in the cluster formation, while the season in which they were collected is significant. On the other hand, the seawater composition was calibrated using estuary water samples of different salinities. Once the major constituents were measured, the data analysis concluded that it is possible to make a calibration of the HBound spectrum vs. any of these constituents by means of partial least square (PLS) regression. Thus, the experimental evidence collected in this work confirms that it is possible to detect polluted sea or estuary water samples using these chemometric tools and the H(+) affinity spectrum because with polluted samples these multivariate methods lead to incoherent results. So, suspect polluted zones may be monitored in a simple way with a low cost method and spending much less time. PMID:24148380

  12. Impact of variable seawater conductivity on motional induction simulated with an ocean general circulation model

    NASA Astrophysics Data System (ADS)

    Irrgang, C.; Saynisch, J.; Thomas, M.

    2016-01-01

    Carrying high concentrations of dissolved salt, ocean water is a good electrical conductor. As seawater flows through the Earth's ambient geomagnetic field, electric fields are generated, which in turn induce secondary magnetic fields. In current models for ocean-induced magnetic fields, a realistic consideration of seawater conductivity is often neglected and the effect on the variability of the ocean-induced magnetic field unknown. To model magnetic fields that are induced by non-tidal global ocean currents, an electromagnetic induction model is implemented into the Ocean Model for Circulation and Tides (OMCT). This provides the opportunity to not only model ocean-induced magnetic signals but also to assess the impact of oceanographic phenomena on the induction process. In this paper, the sensitivity of the induction process due to spatial and temporal variations in seawater conductivity is investigated. It is shown that assuming an ocean-wide uniform conductivity is insufficient to accurately capture the temporal variability of the magnetic signal. Using instead a realistic global seawater conductivity distribution increases the temporal variability of the magnetic field up to 45 %. Especially vertical gradients in seawater conductivity prove to be a key factor for the variability of the ocean-induced magnetic field. However, temporal variations of seawater conductivity only marginally affect the magnetic signal.

  13. Treatment of seawater immersion-complicated open-knee joint fracture.

    PubMed

    Ai, J G; Zhao, F; Gao, Z M; Dai, W; Zhang, L; Chen, H B; Zhou, J G

    2014-01-01

    The current study aimed to select suitable remedies for seawater immersion-complicated open-knee joint fracture by exploring the effects of different treatment methods. Forty adult rabbits weighing 2.20 ± 0.25 kg were divided equally into internal fracture fixation group (A), seawater-immersed group with primary internal fixation (B), seawater-immersed group with secondary internal fixation (C), and seawater-immersed group with external fixation (D), using the random-digit table method. Open-femoral internal condylar fracture models were established. Group A was left untreated for 2 h, whereas the other three groups were subjected to seawater immersion for 2 h. Afterwards, groups A and B underwent debridement and steel plate and screw internal fixation. Group C underwent debridement and external fixation, which was followed by secondary steel plate and screw internal fixation after the wound healed. Group D underwent transarticular arthrodesis. Wound infection, joint functional rehabilitation, and radiological and histopathological changes in fracture healing in each group were assessed. The results showed that delayed internal fixation effectively reduces the infection rate of seawater immersion-complicated open fracture and benefits joint function rehabilitation. PMID:25117308

  14. Graphene-based Recyclable Photo-Absorbers for High-Efficiency Seawater Desalination.

    PubMed

    Wang, Xiangqing; Ou, Gang; Wang, Ning; Wu, Hui

    2016-04-13

    Today's scientific advances in water desalination dramatically increase our ability to transform seawater into fresh water. As an important source of renewable energy, solar power holds great potential to drive the desalination of seawater. Previously, solar assisted evaporation systems usually relied on highly concentrated sunlight or were not suitable to treat seawater or wastewater, severely limiting the large scale application of solar evaporation technology. Thus, a new strategy is urgently required in order to overcome these problems. In this study, we developed a solar thermal evaporation system based on reduced graphene oxide (rGO) decorated with magnetic nanoparticles (MNPs). Because this material can absorb over 95% of sunlight, we achieved high evaporation efficiency up to 70% under only 1 kW m(-2) irradiation. Moreover, it could be separated from seawater under the action of magnetic force by decorated with MNPs. Thus, this system provides an advantage of recyclability, which can significantly reduce the material consumptions. Additionally, by using photoabsorbing bulk or layer materials, the deposition of solutes offen occurs in pores of materials during seawater desalination, leading to the decrease of efficiency. However, this problem can be easily solved by using MNPs, which suggests this system can be used in not only pure water system but also high-salinity wastewater system. This study shows good prospects of graphene-based materials for seawater desalination and high-salinity wastewater treatment. PMID:27019007

  15. Microbial communities related to biodegradation of dispersed Macondo oil at low seawater temperature with Norwegian coastal seawater

    PubMed Central

    Brakstad, Odd G; Throne-Holst, Mimmi; Netzer, Roman; Stoeckel, Donald M; Atlas, Ronald M

    2015-01-01

    The Deepwater Horizon (DWH) accident in 2010 created a deepwater plume of small oil droplets from a deepwater well in the Mississippi Canyon lease block 252 (‘Macondo oil’). A novel laboratory system was used in the current study to investigate biodegradation of Macondo oil dispersions (10 μm or 30 μm median droplet sizes) at low oil concentrations (2 mg l−1) in coastal Norwegian seawater at a temperature of 4–5°C. Whole metagenome analyses showed that oil biodegradation was associated with the successive increased abundances of Gammaproteobacteria, while Alphaproteobacteria (Pelagibacter) became dominant at the end of the experiment. Colwellia and Oceanospirillales were related to n-alkane biodegradation, while particularly Cycloclasticus and Marinobacter were associated with degradation of aromatic hydrocarbons (HCs). The larger oil droplet dispersions resulted in delayed sequential changes of Oceanospirillales and Cycloclasticus, related with slower degradation of alkanes and aromatic HCs. The bacterial successions associated with oil biodegradation showed both similarities and differences when compared with the results from DWH field samples and laboratory studies performed with deepwater from the Gulf of Mexico. PMID:26485443

  16. Microbial communities related to biodegradation of dispersed Macondo oil at low seawater temperature with Norwegian coastal seawater.

    PubMed

    Brakstad, Odd G; Throne-Holst, Mimmi; Netzer, Roman; Stoeckel, Donald M; Atlas, Ronald M

    2015-11-01

    The Deepwater Horizon (DWH) accident in 2010 created a deepwater plume of small oil droplets from a deepwater well in the Mississippi Canyon lease block 252 ('Macondo oil'). A novel laboratory system was used in the current study to investigate biodegradation of Macondo oil dispersions (10 μm or 30 μm median droplet sizes) at low oil concentrations (2 mg l(-1)) in coastal Norwegian seawater at a temperature of 4-5°C. Whole metagenome analyses showed that oil biodegradation was associated with the successive increased abundances of Gammaproteobacteria, while Alphaproteobacteria (Pelagibacter) became dominant at the end of the experiment. Colwellia and Oceanospirillales were related to n-alkane biodegradation, while particularly Cycloclasticus and Marinobacter were associated with degradation of aromatic hydrocarbons (HCs). The larger oil droplet dispersions resulted in delayed sequential changes of Oceanospirillales and Cycloclasticus, related with slower degradation of alkanes and aromatic HCs. The bacterial successions associated with oil biodegradation showed both similarities and differences when compared with the results from DWH field samples and laboratory studies performed with deepwater from the Gulf of Mexico. PMID:26485443

  17. Dynamics of bacterial populations during bench-scale bioremediation of oily seawater and desert soil bioaugmented with coastal microbial mats.

    PubMed

    Ali, Nidaa; Dashti, Narjes; Salamah, Samar; Sorkhoh, Naser; Al-Awadhi, Husain; Radwan, Samir

    2016-03-01

    This study describes a bench-scale attempt to bioremediate Kuwaiti, oily water and soil samples through bioaugmentation with coastal microbial mats rich in hydrocarbonoclastic bacterioflora. Seawater and desert soil samples were artificially polluted with 1% weathered oil, and bioaugmented with microbial mat suspensions. Oil removal and microbial community dynamics were monitored. In batch cultures, oil removal was more effective in soil than in seawater. Hydrocarbonoclastic bacteria associated with mat samples colonized soil more readily than seawater. The predominant oil degrading bacterium in seawater batches was the autochthonous seawater species Marinobacter hydrocarbonoclasticus. The main oil degraders in the inoculated soil samples, on the other hand, were a mixture of the autochthonous mat and desert soil bacteria; Xanthobacter tagetidis, Pseudomonas geniculata, Olivibacter ginsengisoli and others. More bacterial diversity prevailed in seawater during continuous than batch bioremediation. Out of seven hydrocarbonoclastic bacterial species isolated from those cultures, only one, Mycobacterium chlorophenolicum, was of mat origin. This result too confirms that most of the autochthonous mat bacteria failed to colonize seawater. Also culture-independent analysis of seawater from continuous cultures revealed high-bacterial diversity. Many of the bacteria belonged to the Alphaproteobacteria, Flavobacteria and Gammaproteobacteria, and were hydrocarbonoclastic. Optimal biostimulation practices for continuous culture bioremediation of seawater via mat bioaugmentation were adding the highest possible oil concentration as one lot in the beginning of bioremediation, addition of vitamins, and slowing down the seawater flow rate. PMID:26751253

  18. Cardiac responses to elevated seawater temperature in Atlantic salmon

    PubMed Central

    2014-01-01

    Background Atlantic salmon aquaculture operations in the Northern hemisphere experience large seasonal fluctuations in seawater temperature. With summer temperatures often peaking around 18-20°C there is growing concern about the effects on fish health and performance. Since the heart has a major role in the physiological plasticity and acclimation to different thermal conditions in fish, we wanted to investigate how three and eight weeks exposure of adult Atlantic salmon to 19°C, previously shown to significantly reduce growth performance, affected expression of relevant genes and proteins in cardiac tissues under experimental conditions. Results Transcriptional responses in cardiac tissues after three and eight weeks exposure to 19°C (compared to thermal preference, 14°C) were analyzed with cDNA microarrays and validated by expression analysis of selected genes and proteins using real-time qPCR and immunofluorescence microscopy. Up-regulation of heat shock proteins and cell signaling genes may indicate involvement of the unfolded protein response in long-term acclimation to elevated temperature. Increased immunofluorescence staining of inducible nitric oxide synthase in spongy and compact myocardium as well as increased staining of vascular endothelial growth factor in epicardium could reflect induced vascularization and vasodilation, possibly related to increased oxygen demand. Increased staining of collagen I in the compact myocardium of 19°C fish may be indicative of a remodeling of connective tissue with long-term warm acclimation. Finally, higher abundance of transcripts for genes involved in innate cellular immunity and lower abundance of transcripts for humoral immune components implied altered immune competence in response to elevated temperature. Conclusions Long-term exposure of Atlantic salmon to 19°C resulted in cardiac gene and protein expression changes indicating that the unfolded protein response, vascularization, remodeling of connective

  19. Xanthomarina gelatinilytica gen. nov., sp. nov., isolated from seawater.

    PubMed

    Vaidya, Bhumika; Kumar, Ravinder; Sharma, Gunjan; Srinivas, Tanuku Naga Radha; Kumar, Pinnaka Anil

    2015-11-01

    A novel Gram-stain-negative, rod-shaped, yellow-pigmented, non-sporulating, non-motile bacterium, designated strain AK20T, was isolated from seawater collected from Kochi city, Kerala state, India. Colonies on marine agar were circular, yellow, shiny, translucent, 2-3 mm in diameter, convex and with entire margin. Flexirubin-type pigment was present. The fatty acids were dominated by iso-branched units with a high abundance of iso-C15:0, iso-C15:1 G, iso-C17:0 3-OH, summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH) and iso-C15:0 3-OH. Polar lipids included phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified phospholipids and four unidentified lipids. Menaquinone 6 (MK-6) was the predominant respiratory quinone. The DNA G+C content of strain AK20T was 38.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain AK20T was closely related to Formosa spongicola A2T and Bizionia paragorgiae KMM 6029T (pair-wise sequence similarities of 95.9 and 95.7%, respectively), forming a distinct branch within the family Flavobacteriaceae and clustering with the clade comprising species of the genus Bizionia. Based on phenotypic and chemotaxonomic characteristics and phylogenetic analysis, strain AK20T is different from the existing genera in the family Flavobacteriaceae, and is therefore considered to represent a novel species of a new genus, for which the name Xanthomarina gelatinilytica gen. nov., sp. nov. is proposed. The type strain of Xanthomarina gelatinilytica is AK20T ( = MTCC 11705T = JCM 18821T). PMID:26956595

  20. Forward osmosis niches in seawater desalination and wastewater reuse.

    PubMed

    Valladares Linares, R; Li, Z; Sarp, S; Bucs, Sz S; Amy, G; Vrouwenvelder, J S

    2014-12-01

    This review focuses on the present status of forward osmosis (FO) niches in two main areas: seawater desalination and wastewater reuse. Specific applications for desalination and impaired-quality water treatment and reuse are described, as well as the benefits, advantages, challenges, costs and knowledge gaps on FO hybrid systems are discussed. FO can play a role as a bridge to integrate upstream and downstream water treatment processes, to reduce the energy consumption of the entire desalination or water recovery and reuse processes, thus achieving a sustainable solution for the water-energy nexus. FO hybrid membrane systems showed to have advantages over traditional membrane process like high pressure reverse osmosis and nanofiltration for desalination and wastewater treatment: (i) chemical storage and feed water systems may be reduced for capital, operational and maintenance cost, (ii) water quality is improved, (iii) reduced process piping costs, (iv) more flexible treatment units, and (v) higher overall sustainability of the desalination and wastewater treatment process. Nevertheless, major challenges make FO systems not yet a commercially viable technology, the most critical being the development of a high flux membrane, capable of maintaining an elevated salt rejection and a reduced internal concentration polarization effect, and the availability of appropriate draw solutions (cost effective and non-toxic), which can be recirculated via an efficient recovery process. This review article highlights the features of hybrid FO systems and specifically provides the state-of-the-art applications in the water industry in a novel classification and based on the latest developments toward scaling up these systems. PMID:25201336

  1. Exploring novel hormones essential for seawater adaptation in teleost fish.

    PubMed

    Takei, Yoshio

    2008-05-15

    Marine fish are dehydrated in hyperosmotic seawater (SW), but maintain water balance by drinking surrounding SW if they are capable of excreting the excess ions, particularly Na(+) and Cl(-), absorbed with water by the intestine. An integrative approach is essential for understanding the mechanisms for SW adaptation, in which hormones play pivotal roles. Comparative genomic analyses have shown that hormones that have Na(+)-extruding and vasodepressor properties are greatly diversified in teleost fish. Physiological studies at molecular to organismal levels have revealed that these diversified hormones are much more potent and efficacious in teleost fish than in mammals and are important for survival in SW and for maintenance of low arterial pressure in a gravity-free aquatic environment. This is typified by the natriuretic peptide (NP) family, which is diversified into seven members (ANP, BNP, VNP and CNP1, 2, 3 and 4) and exerts potent hyponatremic and vasodepressor actions in marine fish. Another example is the guanylin family, which consists of three paralogs (guanylin, uroguanylin and renoguanylin), and stimulates Cl(-) secretion into the intestinal lumen and activates the absorptive-type Na-K-2Cl cotransporter by local luminocrine actions. The most recent addition is the adrenomedullin (AM) family, which has five members (AM1, 2, 3, 4 and 5), with AM2 and AM5 showing the most potent or efficacious vasodepressor and osmoregulatory effects among known hormones in teleost fish. Accumulating evidence strongly indicates that members of these diversified hormone families play essential roles in SW adaptation in teleost fish. In this short review, the author has attempted to propose a novel approach for identification of new hormones that are important for SW adaptation using comparative genomic and functional studies. The author has also suggested potential hormone families that are diversified in teleost fish and appear to be involved in SW adaptation through their

  2. Vacuum membrane distillation of seawater reverse osmosis brines.

    PubMed

    Mericq, Jean-Pierre; Laborie, Stéphanie; Cabassud, Corinne

    2010-10-01

    Seawater desalination by Reverse Osmosis (RO) is an interesting solution for drinking water production. However, because of limitation by the osmotic pressure, a high recovery factor is not attainable. Consequently, large volumes of brines are discharged into the sea and the flow rate produced (permeate) is limited. In this paper, Vacuum Membrane Distillation (VMD) is considered as a complementary process to RO to further concentrate RO brines and increase the global recovery of the process. VMD is an evaporative technology that uses a membrane to support the liquid-vapour interface and enhance the contact area between liquid and vapour in comparison with conventional distillation. This study focuses on VMD for the treatment of RO brines. Simulations were performed to optimise the operating conditions and were completed by bench-scale experiments using actual RO brines and synthetic solutions up to a salt concentration of 300 g L(-1). Operating conditions such as a highly permeable membrane, high feed temperature, low permeate pressure and a turbulent fluid regime allowed high permeate fluxes to be obtained even for a very high salt concentration (300 g L(-1)). For the membrane studied, temperature and concentration polarisation were shown to have little effect on permeate flux. After 6 to 8 h, no organic fouling or biofouling was observed for RO brines. At high salt concentrations, scaling occurred (mainly due to calcium precipitation) but had only a limited impact on the permeate flux (24% decrease for a permeate specific volume of 43L m(-2) for the highest concentration of salt). Calcium carbonate and calcium sulphate precipitated first due to their low solubility and formed mixed crystal deposits on the membrane surface. These phenomena only occurred on the membrane surface and did not totally cover the pores. The crystals were easily removed simply by washing the membrane with water. A global recovery factor of 89% can be obtained by coupling RO and VMD.

  3. Forward osmosis niches in seawater desalination and wastewater reuse.

    PubMed

    Valladares Linares, R; Li, Z; Sarp, S; Bucs, Sz S; Amy, G; Vrouwenvelder, J S

    2014-12-01

    This review focuses on the present status of forward osmosis (FO) niches in two main areas: seawater desalination and wastewater reuse. Specific applications for desalination and impaired-quality water treatment and reuse are described, as well as the benefits, advantages, challenges, costs and knowledge gaps on FO hybrid systems are discussed. FO can play a role as a bridge to integrate upstream and downstream water treatment processes, to reduce the energy consumption of the entire desalination or water recovery and reuse processes, thus achieving a sustainable solution for the water-energy nexus. FO hybrid membrane systems showed to have advantages over traditional membrane process like high pressure reverse osmosis and nanofiltration for desalination and wastewater treatment: (i) chemical storage and feed water systems may be reduced for capital, operational and maintenance cost, (ii) water quality is improved, (iii) reduced process piping costs, (iv) more flexible treatment units, and (v) higher overall sustainability of the desalination and wastewater treatment process. Nevertheless, major challenges make FO systems not yet a commercially viable technology, the most critical being the development of a high flux membrane, capable of maintaining an elevated salt rejection and a reduced internal concentration polarization effect, and the availability of appropriate draw solutions (cost effective and non-toxic), which can be recirculated via an efficient recovery process. This review article highlights the features of hybrid FO systems and specifically provides the state-of-the-art applications in the water industry in a novel classification and based on the latest developments toward scaling up these systems.

  4. Nucleation of metastable aragonite CaCO3 in seawater

    DOE PAGES

    Sun, Wenhao; Jayaraman, Saivenkataraman; Chen, Wei; Persson, Kristin A.; Ceder, Gerbrand

    2015-03-04

    Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metastable structures. Crystallization of metastable phases is particularly accessible via low-temperature solution-based routes, such as chimie douce and hydrothermal synthesis, but although the chemistry of the solution plays a crucial role in governing which polymorph forms, how it does so is poorly understood. Here, we demonstrate an ab initio technique to quantify thermodynamic parameters ofmore » surfaces and bulks in equilibrium with an aqueous environment, enabling the calculation of nucleation barriers of competing polymorphs as a function of solution chemistry, thereby predicting the solution conditions governing polymorph selection. We apply this approach to resolve the long-standing “calcite–aragonite problem”––the observation that calcium carbonate precipitates as the metastable aragonite polymorph in marine environments, rather than the stable phase calcite––which is of tremendous relevance to biomineralization, carbon sequestration, paleogeochemistry, and the vulnerability of marine life to ocean acidification. We identify a direct relationship between the calcite surface energy and solution Mg–Ca ion concentrations, showing that the calcite nucleation barrier surpasses that of metastable aragonite in solutions with Mg:Ca ratios consistent with modern seawater, allowing aragonite to dominate the kinetics of nucleation. Our ability to quantify how solution parameters distinguish between polymorphs marks an important step toward the ab initio prediction of materials synthesis pathways in solution.« less

  5. Kordia antarctica sp. nov., isolated from Antarctic seawater.

    PubMed

    Baek, Kiwoon; Choi, Ahyoung; Kang, Ilnam; Lee, Kiyoung; Cho, Jang-Cheon

    2013-10-01

    A Gram-staining-negative, chemoheterotrophic, yellow-pigmented, non-motile, flexirubin-negative, facultatively anaerobic bacterium, designated strain IMCC3317(T), was isolated from a coastal seawater sample from the Antarctic Penninsula. Optimal growth of strain IMCC3317(T) was observed at 20 °C, pH 8.0 and in the presence of 2-3 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain IMCC3317(T) belonged to the genus Kordia and was closely related to Kordia algicida OT-1(T) (96.7 % sequence similarity) and Kordia periserrulae IMCC1412(T) (96.1 % sequence similarity). The major fatty acids were 10-methyl C16 : 0 and/or iso-C16 : 1ω9c, iso-C17 : 0 3-OH, iso-C15 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 35.1 mol%. The strain contained menaquinone-6 (MK-6) as the respiratory quinone. The polar lipids detected in the strain were phosphatidylethanolamine and unknown aminophospholipids, aminolipids and polar lipids. On the basis of phylogenetic distinction and differential phenotypic characteristics, it is suggested that strain IMCC3317(T) ( = KCTC 32292(T) = NBRC 109401(T)) be assigned to the genus Kordia as the type strain of a novel species, for which the name Kordia antarctica sp. nov. is proposed.

  6. Nucleation of metastable aragonite CaCO3 in seawater

    PubMed Central

    Sun, Wenhao; Jayaraman, Saivenkataraman; Chen, Wei; Persson, Kristin A.; Ceder, Gerbrand

    2015-01-01

    Predicting the conditions in which a compound adopts a metastable structure when it crystallizes out of solution is an unsolved and fundamental problem in materials synthesis, and one which, if understood and harnessed, could enable the rational design of synthesis pathways toward or away from metastable structures. Crystallization of metastable phases is particularly accessible via low-temperature solution-based routes, such as chimie douce and hydrothermal synthesis, but although the chemistry of the solution plays a crucial role in governing which polymorph forms, how it does so is poorly understood. Here, we demonstrate an ab initio technique to quantify thermodynamic parameters of surfaces and bulks in equilibrium with an aqueous environment, enabling the calculation of nucleation barriers of competing polymorphs as a function of solution chemistry, thereby predicting the solution conditions governing polymorph selection. We apply this approach to resolve the long-standing “calcite–aragonite problem”––the observation that calcium carbonate precipitates as the metastable aragonite polymorph in marine environments, rather than the stable phase calcite––which is of tremendous relevance to biomineralization, carbon sequestration, paleogeochemistry, and the vulnerability of marine life to ocean acidification. We identify a direct relationship between the calcite surface energy and solution Mg–Ca ion concentrations, showing that the calcite nucleation barrier surpasses that of metastable aragonite in solutions with Mg:Ca ratios consistent with modern seawater, allowing aragonite to dominate the kinetics of nucleation. Our ability to quantify how solution parameters distinguish between polymorphs marks an important step toward the ab initio prediction of materials synthesis pathways in solution. PMID:25739963

  7. Exploring novel hormones essential for seawater adaptation in teleost fish.

    PubMed

    Takei, Yoshio

    2008-05-15

    Marine fish are dehydrated in hyperosmotic seawater (SW), but maintain water balance by drinking surrounding SW if they are capable of excreting the excess ions, particularly Na(+) and Cl(-), absorbed with water by the intestine. An integrative approach is essential for understanding the mechanisms for SW adaptation, in which hormones play pivotal roles. Comparative genomic analyses have shown that hormones that have Na(+)-extruding and vasodepressor properties are greatly diversified in teleost fish. Physiological studies at molecular to organismal levels have revealed that these diversified hormones are much more potent and efficacious in teleost fish than in mammals and are important for survival in SW and for maintenance of low arterial pressure in a gravity-free aquatic environment. This is typified by the natriuretic peptide (NP) family, which is diversified into seven members (ANP, BNP, VNP and CNP1, 2, 3 and 4) and exerts potent hyponatremic and vasodepressor actions in marine fish. Another example is the guanylin family, which consists of three paralogs (guanylin, uroguanylin and renoguanylin), and stimulates Cl(-) secretion into the intestinal lumen and activates the absorptive-type Na-K-2Cl cotransporter by local luminocrine actions. The most recent addition is the adrenomedullin (AM) family, which has five members (AM1, 2, 3, 4 and 5), with AM2 and AM5 showing the most potent or efficacious vasodepressor and osmoregulatory effects among known hormones in teleost fish. Accumulating evidence strongly indicates that members of these diversified hormone families play essential roles in SW adaptation in teleost fish. In this short review, the author has attempted to propose a novel approach for identification of new hormones that are important for SW adaptation using comparative genomic and functional studies. The author has also suggested potential hormone families that are diversified in teleost fish and appear to be involved in SW adaptation through their

  8. Mechanisms for Photoinactivation of Enterococcus faecalis in Seawater

    PubMed Central

    Sassoubre, Lauren M.; Nelson, Kara L.

    2012-01-01

    Field studies in fresh and marine waters consistently show diel fluctuations in concentrations of enterococci, indicators of water quality. We investigated sunlight inactivation of Enterococcus faecalis to gain insight into photoinactivation mechanisms and cellular responses to photostress. E. faecalis bacteria were exposed to natural sunlight in clear, filtered seawater under both oxic and anoxic conditions to test the relative importance of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. Multiple methods were used to assess changes in bacterial concentration, including cultivation, quantitative PCR (qPCR), propidium monoazide (PMA)-qPCR, LIVE/DEAD staining using propidium iodide (PI), and cellular activity, including ATP concentrations and expression of the superoxide dismutase-encoding gene, sodA. Photoinactivation, based on numbers of cultivable cells, was faster in oxic than in anoxic microcosms exposed to sunlight, suggesting that oxygen-mediated photoinactivation dominated. There was little change in qPCR signal over the course of the experiment, demonstrating that the nucleic acid targets were not damaged to a significant extent. The PMA-qPCR signal was also fairly stable, consistent with the observation that the fraction of PI-permeable cells was constant. Thus, damage to the membrane was minimal. Microbial ATP concentrations decreased in all microcosms, particularly the sunlit oxic microcosms. The increase in relative expression of the sodA gene in the sunlit oxic microcosms suggests that cells were actively responding to oxidative stress. Dark repair was not observed. This research furthers our understanding of photoinactivation mechanisms and the conditions under which diel fluctuations in enterococci can be expected in natural and engineered systems. PMID:22941072

  9. Cell Culture Isolation of Piscine Nodavirus (Betanodavirus) in Fish-Rearing Seawater.

    PubMed

    Nishi, Shinnosuke; Yamashita, Hirofumi; Kawato, Yasuhiko; Nakai, Toshihiro

    2016-04-01

    Piscine nodavirus (betanodavirus) is the causative agent of viral nervous necrosis (VNN) in a variety of cultured fish species, particularly marine fish. In the present study, we developed a sensitive method for cell culture isolation of the virus from seawater and applied the method to a spontaneous fish-rearing environment. The virus in seawater was concentrated by an iron-based flocculation method and subjected to isolation with E-11 cells. A real-time reverse transcriptase PCR (RT-PCR) assay was used to quantify the virus in water. After spiking into seawater was performed, a betanodavirus strain (red spotted grouper nervous necrosis virus [RGNNV] genotype) was effectively recovered in the E-11 cells at a detection limit of approximately 10(5)copies (equivalent to 10(2)50% tissue culture infective doses [TCID50])/liter seawater. In an experimental infection of juvenile sevenband grouper (Epinephelus septemfasciatus) with the virus, the virus was isolated from the drainage of a fish-rearing tank when the virus level in water was at least approximately 10(5)copies/liter. The application of this method to seven band grouper-rearing floating net pens, where VNN prevailed, resulted in the successful isolation of the virus from seawater. No differences were found in the partial sequences of the coat protein gene (RNA2) between the clinical virus isolates of dead fish and the cell-cultured virus isolates from seawater, and the viruses were identified as RGNNV. The infection experiment showed that the virus isolates from seawater were virulent to seven band grouper. These results showed direct evidence of the horizontal transmission of betanodavirus via rearing water in marine aquaculture. PMID:26896128

  10. Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

    SciTech Connect

    Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana; Strivens, Jonathan E.; Gill, Gary

    2015-11-19

    Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8) of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.

  11. Seawater Intrusion and groundwater quality of the coastal area in Tripoli region, Libya

    NASA Astrophysics Data System (ADS)

    Abdalla, Rashid; Rinder, Thomas; Dietzel, Martin; Leis, Albrecht

    2010-05-01

    In Libya groundwater is the main source of freshwater, providing a vital supplement to surface water sources. Groundwater availability and quality are however, vulnerable both to climate change and over-abstraction. In Libyan cities where the water table has lowered there has been a consequent impact on agricultural activities. Groundwater aquifers are either renewable or non-renewable. The renewable aquifers are those located in the north coastal strip with high precipitation rates. The large non-renewable sedimentary groundwater basins cover extensive areas in the central and southern parts of Libya and contribute large quantities of freshwater for local use, industrial and agricultural development. Seawater intrusion is a problem in the coastal areas of Libya. Most productive agricultural fields are in the northern coastal areas of the country where irrigation predominantly relies on groundwater. Seawater has moved inland because of heavy exploitation of the Miocene-Quaternary aquifer in order to meet the increasing water demand. The physical and chemical parameters of groundwater such as electrical conductivity, pH, temperature and individual ion content were determined. Most of the wells showed high values of electrical conductivity. The increase of water salinity is directly related to the extreme pumping of shallow coastal aquifers and movement of seawater towards inland. In some samples the increase of salinity corresponds to the ions abundant in seawater. In those solutions molar ratios of Cl/Br indicate influence of seawater intrusion. According to mixing calculations between fresh groundwater of the study area and Mediterranean seawater, the estimated concentration of seawater ranges from 10 to 15 wt%.

  12. Seawater intrusion in fractured coastal aquifers: A preliminary numerical investigation using a fractured Henry problem

    NASA Astrophysics Data System (ADS)

    Sebben, Megan L.; Werner, Adrian D.; Graf, Thomas

    2015-11-01

    Despite that fractured coastal aquifers are widespread, the influence of fracture characteristics on seawater intrusion (SWI) has not been explored in previous studies. This research uses numerical modelling in a first step towards understanding the influence of fracture orientation, location and density on the extent of seawater and accompanying patterns of groundwater discharge in an idealised coastal aquifer. Specifically, aquifers containing single fractures or networks of regularly spaced fractures are studied using modified forms of the Henry SWI benchmark problem. The applicability of equivalent porous media (EPM) models for representing simple fracture networks in steady-state simulations of SWI is tested. The results indicate that the influence of fractures on SWI is likely to be mixed, ranging from enhancement to reduction in seawater extent and the width of the mixing zone. For the conceptual models considered here, vertical fractures in contact with the seawater wedge increase the width of the mixing zone, whereas vertical fractures inland of the wedge have minimal impact on the seawater distribution. Horizontal fractures in the lower part of the aquifer force the wedge seaward, whereas horizontal fractures located within the zone of freshwater discharge enhance the wedge. Inclined fractures roughly parallel to the seawater-freshwater interface increase the landward extent of seawater and fractures perpendicular to the interface inhibit the wedge. The results show that EPM models are likely inadequate for inferring salinity distributions in most of the fractured cases, although the EPM approach may be suitable for orthogonal fracture networks if fracture density is high and appropriate dispersivity values can be determined.

  13. Deep-sea coral aragonite as a recorder for the neodymium isotopic composition of seawater

    NASA Astrophysics Data System (ADS)

    van de Flierdt, Tina; Robinson, Laura F.; Adkins, Jess F.

    2010-11-01

    Deep-sea corals have been shown to be useful archives of rapid changes in ocean chemistry during the last glacial cycle. Their aragonitic skeleton can be absolutely dated by U-Th data, freeing radiocarbon to be used as a water-mass proxy. For certain species of deep-sea corals, the growth rate allows time resolution that is comparable to ice cores. An additional proxy is needed to exploit this opportunity and turn radiocarbon data into rates of ocean overturning in the past. Neodymium isotopes in seawater can serve as a quasi-conservative water-mass tracer and initial results indicate that deep-sea corals may be reliable archives of seawater Nd isotopes. Here we present a systematic study exploring Nd isotopes as a water-mass proxy in deep-sea coral aragonite. We investigated five different genera of modern deep-sea corals ( Caryophyllia, Desmophyllum, Enallopsamia, Flabellum, Lophelia), from global locations covering a large potential range of Nd isotopic compositions. Comparison with ambient seawater measurements yields excellent agreement and suggests that deep-sea corals are reliable archives for seawater Nd isotopes. A parallel study of Nd concentrations in these corals yields distribution coefficients for Nd between seawater and coral aragonite of 1-10, omitting one particular genus ( Enallopsamia). The corals and seawater did however not come from exactly the same location, and further investigations are needed to reach robust conclusions on the incorporation of Nd into deep-sea coral aragonite. Lastly, we studied the viability of extracting the Nd isotope signal from fossil deep-sea corals by carrying out stepwise cleaning experiments. Our results show that physical removal of the ferromanganese coating and chemical pre-cleaning have the highest impact on Nd concentrations, but that oxidative/reductive cleaning is also needed to acquire a seawater Nd isotope signal.

  14. Microbial ureolysis in the seawater-catalysed urine phosphorus recovery system: Kinetic study and reactor verification.

    PubMed

    Tang, Wen-Tao; Dai, Ji; Liu, Rulong; Chen, Guang-Hao

    2015-12-15

    Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery. PMID:26378727

  15. Variable response of three Trifolium repens ecotypes to soil flooding by seawater

    PubMed Central

    White, Anissia C.; Colmer, Timothy D.; Cawthray, Greg R.; Hanley, Mick E.

    2014-01-01

    Background and Aims Despite concerns about the impact of rising sea levels and storm surge events on coastal ecosystems, there is remarkably little information on the response of terrestrial coastal plant species to seawater inundation. The aim of this study was to elucidate responses of a glycophyte (white clover, Trifolium repens) to short-duration soil flooding by seawater and recovery following leaching of salts. Methods Using plants cultivated from parent ecotypes collected from a natural soil salinity gradient, the impact of short-duration seawater soil flooding (8 or 24 h) on short-term changes in leaf salt ion and organic solute concentrations was examined, together with longer term impacts on plant growth (stolon elongation) and flowering. Key Results There was substantial Cl– and Na+ accumulation in leaves, especially for plants subjected to 24 h soil flooding with seawater, but no consistent variation linked to parent plant provenance. Proline and sucrose concentrations also increased in plants following seawater flooding of the soil. Plant growth and flowering were reduced by longer soil immersion times (seawater flooding followed by drainage and freshwater inputs), but plants originating from more saline soil responded less negatively than those from lower salinity soil. Conclusions The accumulation of proline and sucrose indicates a potential for solute accumulation as a response to the osmotic imbalance caused by salt ions, while variation in growth and flowering responses between ecotypes points to a natural adaptive capacity for tolerance of short-duration seawater soil flooding in T. repens. Consequently, it is suggested that selection for tolerant ecotypes is possible should the predicted increase in frequency of storm surge flooding events occur. PMID:24942000

  16. Constrains on the Uranium Isotopic Composition of Seawater and Implications for Coral U/Th Geochronology

    NASA Astrophysics Data System (ADS)

    Chutcharavan, P. M.; Dutton, A.; Ellwood, M. J.

    2015-12-01

    Coral U-series geochronology is an important tool for calibrating records of sea level change during the late Quaternary and coral 14C dates for the radiocarbon timescale. However, coralline aragonite is highly susceptible to diagenesis, and samples must be carefully screened to ensure a specimen is unaltered. One method used to accept or reject U-series ages is the initial coral 234U/238U activity ratio, which reflects the 234U/238U activity of seawater at the time of coral skeleton formation. Due to the long residence time of uranium in the ocean (~400,000 years), researchers often assume that seawater 234U/238U has remained constant throughout the late Pleistocene. Coral specimens whose U-series ages yield an initial 234U/238U value that is significantly different than modern seawater are considered altered. Several studies have demonstrated that coral initial 234U/238U and, hence, seawater 234U/238U may have varied significantly on glacial-interglacial timescales, but the cause of this variability is subject to debate. To evaluate the pattern and mechanisms of 234U/238U variability in seawater over the last glacial cycle, we draw upon a compilation of U-series measurements of shallow and deep water corals to better define the observed variability. Observed trends from the coral record will be assessed using a simple two-box model of the ocean to determine how changes to the ocean's uranium isotope budget during glacial cycles can explain shifts in seawater 234U/238U. An improved understanding the evolution of seawater 234U/238U composition will enable more robust interpretations of both closed-system and open-system ages for corals. Such interpretations of U-series ages are essential to the development of robust chronologies for climate and sea level change and for improving the calibration of the radiocarbon timescale.

  17. 17β-Estradiol administration attenuates seawater aspiration-induced acute lung injury in rats.

    PubMed

    Fan, Qixin; Zhao, Pengtao; Li, Jiahuan; Xie, Xiaoyan; Xu, Min; Zhang, Yong; Mu, Deguang; Li, Wangping; Sun, Ruilin; Liu, Wei; Nan, Yandong; Zhang, Bo; Jin, Faguang; Li, Zhichao

    2011-12-01

    There is very little evidence on the value of administering estrogen in cases of seawater drowning which can induce acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Therefore, this study aimed to investigate whether 17β-estradiol (E2) treatment can attenuate seawater aspiration-induced ALI in rats. In the experiment, ALI was induced by endotracheal instillation of seawater (4mL/kg) and the rats were then given intraperitoneal injection of E2 (5mg/kg) 20min after seawater instillation. Finally, the changes of arterial blood gases which contained hydrogen ion concentration (pH), arterial oxygen tension (PaO(2)) and arterial carbon dioxide tension (PaCO(2)) were measured and the measurement of extravascular lung water (EVLW) was observed. The pulmonary histological changes were evaluated by hematoxylin-eosin stain. The expression of aquaporins (AQPs) 1, AQP5, and estrogen receptor-β (ERβ) was measured by western blotting and immunohistochemical methods. The results showed that compared with normal saline water, seawater aspiration induced more serious ALI in rats which was markedly alleviated by E2 treatment. Meanwhile, the ERβ in lung tissues was activated after E2 administration. The seawater aspiration group also presented with severe pulmonary edema which was paralleled with over expressed AQP1 and AQP5. However, the up-regulation of AQP1 and AQP5 was suppressed by the administration of E2, resulting in an attenuation of lung edema. In conclusion, E2 treatment could effectively attenuate seawater aspiration-induced acute lung injury in rats by the down-regulation of AQP1 and AQP5.

  18. Cell Culture Isolation of Piscine Nodavirus (Betanodavirus) in Fish-Rearing Seawater

    PubMed Central

    Nishi, Shinnosuke; Yamashita, Hirofumi; Kawato, Yasuhiko

    2016-01-01

    Piscine nodavirus (betanodavirus) is the causative agent of viral nervous necrosis (VNN) in a variety of cultured fish species, particularly marine fish. In the present study, we developed a sensitive method for cell culture isolation of the virus from seawater and applied the method to a spontaneous fish-rearing environment. The virus in seawater was concentrated by an iron-based flocculation method and subjected to isolation with E-11 cells. A real-time reverse transcriptase PCR (RT-PCR) assay was used to quantify the virus in water. After spiking into seawater was performed, a betanodavirus strain (redspotted grouper nervous necrosis virus [RGNNV] genotype) was effectively recovered in the E-11 cells at a detection limit of approximately 105 copies (equivalent to 102 50% tissue culture infective doses [TCID50])/liter seawater. In an experimental infection of juvenile sevenband grouper (Epinephelus septemfasciatus) with the virus, the virus was isolated from the drainage of a fish-rearing tank when the virus level in water was at least approximately 105 copies/liter. The application of this method to sevenband grouper-rearing floating net pens, where VNN prevailed, resulted in the successful isolation of the virus from seawater. No differences were found in the partial sequences of the coat protein gene (RNA2) between the clinical virus isolates of dead fish and the cell-cultured virus isolates from seawater, and the viruses were identified as RGNNV. The infection experiment showed that the virus isolates from seawater were virulent to sevenband grouper. These results showed direct evidence of the horizontal transmission of betanodavirus via rearing water in marine aquaculture. PMID:26896128

  19. Benthic marine calcifiers coexist with CaCO3-undersaturated seawater worldwide

    NASA Astrophysics Data System (ADS)

    Lebrato, M.; Andersson, A. J.; Ries, J. B.; Aronson, R. B.; Lamare, M. D.; Koeve, W.; Oschlies, A.; Iglesias-Rodriguez, M. D.; Thatje, S.; Amsler, M.; Vos, S. C.; Jones, D. O. B.; Ruhl, H. A.; Gates, A. R.; McClintock, J. B.

    2016-07-01

    Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO3) minerals have raised concerns about the consequences to marine organisms that build CaCO3 structures. A large proportion of benthic marine calcifiers incorporate Mg2+ into their skeletons (Mg-calcite), which, in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO3 structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg-calcite mineralogy (ΩMg-x) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ ΩMg-x. This analysis shows that 24% of the studied benthic calcifiers currently experience seawater mineral undersaturation (ΩMg-x < 1). As a result of ongoing anthropogenic ocean acidification over the next 200 to 3000 years, the predicted decrease in seawater mineral saturation will expose approximately 57% of all studied benthic calcifying species to seawater undersaturation. These observations reveal a surprisingly high proportion of benthic marine calcifiers exposed to seawater that is undersaturated with respect to their skeletal mineralogy, underscoring the importance of using species-specific seawater mineral saturation states when investigating the impact of CO2-induced ocean acidification on benthic marine calcification.

  20. Evaluation of Seawater Intrusion Potential into a Coastal Underground Oil Storage Cavern in Korea

    NASA Astrophysics Data System (ADS)

    Lee, E.; Lim, J.; Moon, H.; Lee, K.

    2010-12-01

    Underground oil storage caverns have been operated in Korea since 1990s, and the facility at Yeosu, south coast of Korea, is one of the largest underground oil storage facilities in Korea. Hydrologic and water quality monitoring of the facility has been performed to find out whether the facility maintains secure containment condition and long-term stability. Recently, seawater intrusion into the base of the storage cavern was suspected based on the long-term monitoring of water levels and chemical analyses of seepage water pumped out from cavern bottom. The sudden decrease of water pressure during the construction of storage tunnel seems to cause the inland movement of saline water. In this study, numerical analysis was performed to estimate the potential of seawater intrusion into underground oil storage cavern using a three dimensional groundwater simulation model, FEFLOW (Diersch, 2005). The geometry of the cavern and water curtain was represented by using the implemented functions. The groundwater flow field and seawater intrusion in response to construction activity was also estimated. The simulation results were validated by comparing EC and salinity of seepage water monitoring data. Sensitivity analyses on hydraulic conductivity and water pressure from the water curtain or injection well were also conducted. Relatively high groundwater level was observed at this site due to the low hydraulic conductivity of base rock and high altitude of the mountains. Therefore, the amount of intruded seawater does not seem to be significant. However, apparent decrease of water level was observed along the main fracture zone and seawater could be intruded along these paths. Simulation results show that the seawater intrusion to the cavern is mainly controlled by the fracture zone, which would be the main channel of groundwater movement. The injection of fresh water to the injection wells along the coast may retard the intrusion of seawater.

  1. Microbial ureolysis in the seawater-catalysed urine phosphorus recovery system: Kinetic study and reactor verification.

    PubMed

    Tang, Wen-Tao; Dai, Ji; Liu, Rulong; Chen, Guang-Hao

    2015-12-15

    Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery.

  2. Synthesis of Naphthalimidedioxime Ligand-Containing Fibers for Uranium Adsorption from Seawater

    DOE PAGES

    Chatterjee, Sabornie; Bryantsev, Vyacheslav S.; Brown, Suree; Johnson, J. Casey; Grant, Christopher D.; Mayes, Richard T.; Hay, Benjamin P.; Dai, Sheng; Saito, Tomonori

    2015-12-16

    Uranium exists as uranyl carbonates (primarily as [UO2(CO3)3]4-) at a low concentration of 3.3 ppb, in seawater. Due to the ocean's vast volume, the total amount of uranium in seawater has been estimated at 4.5 billion tons or nearly 1000 times more than land-based resources. This large surplus provides attractive solution to supply nuclear fuel feeds in future. However, the presence of a variety of competing metal ions and the low concentration of uranium in seawater make the extraction of uranium from seawater challenging. The goal of this work is to develop adsorbent fibers that can recover uranium from themore » slightly alkaline (pH 8.0 - 8.3) seawater. In this process, radiation-induced graft polymerization (RIGP) is used where fibers are prepared by irradiating and treating polyethylene (PE) with different bulk ratios of vinyl benzyl chloride (VBC) and methacrylic acid (MAA) or itaconic acid. Furthermore, chemical modifications of these fibers were performed via two step processes, where novel bisimidoxime ligands are incorporated into fibers. These ligands contain imidedioxime, which is known to be a uranium-philic functionality. Also, the core structures of these ligands containing three donor atoms facilitate the formation of chelates with uranyl ion in seawater. Density functional theory (DFT) calculations were performed to quantify the binding strength with the uranyl ion. The adsorbent showed moderate to high uranium (~35-50 g-U/kg adsorbent) adsorption capacity in a model seawater with a uranium concentration of 6 ppm at pH 8.0 8.3.« less

  3. Synthesis of Naphthalimidedioxime Ligand-Containing Fibers for Uranium Adsorption from Seawater

    SciTech Connect

    Chatterjee, Sabornie; Bryantsev, Vyacheslav S.; Brown, Suree; Johnson, J. Casey; Grant, Christopher D.; Mayes, Richard T.; Hay, Benjamin P.; Dai, Sheng; Saito, Tomonori

    2015-12-16

    Uranium exists as uranyl carbonates (primarily as [UO2(CO3)3]4-) at a low concentration of 3.3 ppb, in seawater. Due to the ocean's vast volume, the total amount of uranium in seawater has been estimated at 4.5 billion tons or nearly 1000 times more than land-based resources. This large surplus provides attractive solution to supply nuclear fuel feeds in future. However, the presence of a variety of competing metal ions and the low concentration of uranium in seawater make the extraction of uranium from seawater challenging. The goal of this work is to develop adsorbent fibers that can recover uranium from the slightly alkaline (pH 8.0 - 8.3) seawater. In this process, radiation-induced graft polymerization (RIGP) is used where fibers are prepared by irradiating and treating polyethylene (PE) with different bulk ratios of vinyl benzyl chloride (VBC) and methacrylic acid (MAA) or itaconic acid. Furthermore, chemical modifications of these fibers were performed via two step processes, where novel bisimidoxime ligands are incorporated into fibers. These ligands contain imidedioxime, which is known to be a uranium-philic functionality. Also, the core structures of these ligands containing three donor atoms facilitate the formation of chelates with uranyl ion in seawater. Density functional theory (DFT) calculations were performed to quantify the binding strength with the uranyl ion. The adsorbent showed moderate to high uranium (~35-50 g-U/kg adsorbent) adsorption capacity in a model seawater with a uranium concentration of 6 ppm at pH 8.0 8.3.

  4. A comparison of recent Standard Seawater and Quality Evaluation of the Standard Seawater supplied in a bottle

    NASA Astrophysics Data System (ADS)

    Kawano, Takeshi; Takatsuki, Yasushi; Imai, Jun; Aoyama, Michio

    The results of IAPSO Standard Seawater (SSW) comparisons are presented for batches P 132 to P 140. We try to match up our data with the previous result of comparison experiment to make the newest "offset table". According to the newest "offset table" proposed in this study, the standard deviation of the batch to batch differences among batches P 132 to P 140 is calculated to be 0.3 × 10-3 in salinity. This value is smaller than the value reported in the previous studies. The quality of SSW, from the point of view of batch to batch differences, has improved recently. The SSW batch P 138 and P 140 were stored in bottles made from borosilicate glass and closed with chemically resistant plastic stoppers, while batches P 133 to P 137 and P 139 were stored in glass ampoules. We measured 30 bottles of P 138 and P 140 along with several ampoules of other batches in order to check the quality, those are, within-batch difference and batch-to-batch difference. The standard deviations (1σ) of 30 repeat measurements on P 138 and P 140 were both 0.3 × 10-3 in salinity. The difference between label-delived and measured salinity of P 138 referred to batch P 137 was -0.1 × 10-3 and that of P 140 reffered to batch P 139 was -0.5 × 10-3 in salinity. These values are comparable with other batches stored in a traditional glass ampoules. This result shows that SSW in a shot-bottle is, at least as for P 138 and P 140 at this moment, almost equivalent to SSW in a glass ampoule in quality.

  5. User's guide to SEAWAT; a computer program for simulation of three-dimensional variable-density ground-water flow

    USGS Publications Warehouse

    Guo, Weixing; Langevin, C.D.

    2002-01-01

    This report documents a computer program (SEAWAT) that simulates variable-density, transient, ground-water flow in three dimensions. The source code for SEAWAT was developed by combining MODFLOW and MT3DMS into a single program that solves the coupled flow and solute-transport equations. The SEAWAT code follows a modular structure, and thus, new capabilities can be added with only minor modifications to the main program. SEAWAT reads and writes standard MODFLOW and MT3DMS data sets, although some extra input may be required for some SEAWAT simulations. This means that many of the existing pre- and post-processors can be used to create input data sets and analyze simulation results. Users familiar with MODFLOW and MT3DMS should have little difficulty applying SEAWAT to problems of variable-density ground-water flow.

  6. Decadal variability in seawater pH in the West Pacific: Evidence from coral δ11B records

    NASA Astrophysics Data System (ADS)

    Wei, Gangjian; Wang, Zhibing; Ke, Ting; Liu, Ying; Deng, Wenfeng; Chen, Xuefei; Xu, Jifeng; Zeng, Ti; Xie, Luhua

    2015-11-01

    Long-term seawater pH records are essential for evaluating the rates of ocean acidification (OA) driven by anthropogenic emissions. Widespread, natural decadal variability in seawater pH superimposes on the long-term anthropogenic variations, likely influencing the OA rates estimated from the pH records. Here, we report a record of annual seawater pH estimated using the δ11B proxy over the past 159 years reconstructed from a Porites coral collected to the east of Hainan Island in the northern South China Sea (SCS). By coupling this time series with previously reported long-term seawater pH records in the West Pacific, the decadal variability in seawater pH records and its possible driving mechanisms were investigated. The results indicate that large decadal variability in seawater pH has occurred off eastern Hainan Island over the past 159 years, in agreement with previous records. The Qiongdong upwelling system, which controls nutrient supplies, regulates surface water productivity, and is driven by the East Asian summer monsoon, is the primary control of this decadal variability, while terrestrial inputs appear not influence significantly. Meanwhile the impacts of the Pacific Decadal Oscillation (PDO) and the El Nino and Southern Oscillation (ENSO) systems on seawater pH off eastern Hainan Island is likely limited. In contrast, the PDO is the main factor to influence the decadal seawater pH variability offshore the East Australia, while the mechanism controlling the decadal seawater pH variability in Guam is not clear yet. Meanwhile, The rate of decrease in seawater pH estimated from coral records are significantly different in different regions and over different time spans, which may reflect a combination of natural decadal variability in seawater pH and long-term variations. Therefore, understanding the mechanisms driving natural variability in seawater pH is important for improving estimates of ocean acidification rates driven by anthropogenic emissions.

  7. Environmental concerns of desalinating seawater using reverse osmosis.

    PubMed

    Tularam, Gurudeo Anand; Ilahee, Mahbub

    2007-08-01

    This Critical Review on environmental concerns of desalination plants suggests that planning and monitoring stages are critical aspects of successful management and operation of plants. The site for the desalination plants should be selected carefully and should be away from residential areas particularly for forward planning for possible future expansions. The concerning issues identified are noise pollution, visual pollution, reduction in recreational fishing and swimming areas, emission of materials into the atmosphere, the brine discharge and types of disposal methods used are the main cause of pollution. The reverse osmosis (RO) method is the preferred option in modern times especially when fossil fuels are becoming expensive. The RO has other positives such as better efficiency (30-50%) when compared with distillation type plants (10-30%). However, the RO membranes are susceptible to fouling and scaling and as such they need to be cleaned with chemicals regularly that may be toxic to receiving waters. The input and output water in desalination plants have to be pre and post treated, respectively. This involves treating for pH, coagulants, Cl, Cu, organics, CO(2), H(2)S and hypoxia. The by-product of the plant is mainly brine with concentration at times twice that of seawater. This discharge also includes traces of various chemicals used in cleaning including any anticorrosion products used in the plant and has to be treated to acceptable levels of each chemical before discharge but acceptable levels vary depending on receiving waters and state regulations. The discharge of the brine is usually done by a long pipe far into the sea or at the coastline. Either way the high density of the discharge reaches the bottom layers of receiving waters and may affect marine life particularly at the bottom layers or boundaries. The longer term effects of such discharge concentrate has not been documented but it is possible that small traces of toxic substances used in the

  8. Probing the record of seawater carbonate chemistry in coccolithophore calcite

    NASA Astrophysics Data System (ADS)

    Candelier, Yael; Minoletti, Fabrice; Hermoso, Michael

    2013-04-01

    Previous works on the biogeochemistry of the ubiquist coccolithophore Calcidiscus leptoporus quantified an oxygen isotope fractionation of about -2.2 ‰ with respect to equilibrium. New cultures experiments and core top study of this taxon enable the calibration of the temperature dependance recorded in δ18O of this coccolith providing a new tool to decipher surfaces water temperatures through the Cenozoic. These findings, concordant in the two approaches show a reduced range of vital effect (-1.1 ‰ ). Other cultured and isolated species (Gephyrocapsa oceanica, Emiliania huxleyi and C.pelagicus) show similar patterns that raise the question of a possible overestimation of isotopic disequilibria in coccolith calcite. A promising research topic in palaeoceanography consists of exploiting interspecific isotopic fractionation because species respond differently to ambient changes in carbonate system chemistry. While E.huxleyi or G.oceanica are isotopically sensitive to changes in dissolved inorganic carbon speciation or concentration, others such as C.leptoporus remains almost unaffected. This may indicate that in addition to traditional δ18O temperature proxy, coccolith interspecific isotopic offsets can provide an innovative means to constrain the carbonate chemistry of the mixed-layer. We investigated this hypothesis with a study case of the last Pleistocene deglaciation that appears to be a good candidate by his abrupt changes in temperatures, oxygen isotope composition of seawater and atmospheric pCO2. While numerous studies have investigated climate changes at high latitudes, we present here the first coccoliths-based isotopic record of mixed-layer temperature at the border of North Atlantic Subtropical Gyre (southwards of the polar front). From Site DSDP 607 we successfully isolated fractions of coccolithophore species C.leptoporus, G.oceanica, E. huxleyi and C.pelagicus over the last 17 kyr. Oxygen isotope variations from these fractions exhibit a shift of

  9. Environmental concerns of desalinating seawater using reverse osmosis.

    PubMed

    Tularam, Gurudeo Anand; Ilahee, Mahbub

    2007-08-01

    This Critical Review on environmental concerns of desalination plants suggests that planning and monitoring stages are critical aspects of successful management and operation of plants. The site for the desalination plants should be selected carefully and should be away from residential areas particularly for forward planning for possible future expansions. The concerning issues identified are noise pollution, visual pollution, reduction in recreational fishing and swimming areas, emission of materials into the atmosphere, the brine discharge and types of disposal methods used are the main cause of pollution. The reverse osmosis (RO) method is the preferred option in modern times especially when fossil fuels are becoming expensive. The RO has other positives such as better efficiency (30-50%) when compared with distillation type plants (10-30%). However, the RO membranes are susceptible to fouling and scaling and as such they need to be cleaned with chemicals regularly that may be toxic to receiving waters. The input and output water in desalination plants have to be pre and post treated, respectively. This involves treating for pH, coagulants, Cl, Cu, organics, CO(2), H(2)S and hypoxia. The by-product of the plant is mainly brine with concentration at times twice that of seawater. This discharge also includes traces of various chemicals used in cleaning including any anticorrosion products used in the plant and has to be treated to acceptable levels of each chemical before discharge but acceptable levels vary depending on receiving waters and state regulations. The discharge of the brine is usually done by a long pipe far into the sea or at the coastline. Either way the high density of the discharge reaches the bottom layers of receiving waters and may affect marine life particularly at the bottom layers or boundaries. The longer term effects of such discharge concentrate has not been documented but it is possible that small traces of toxic substances used in the

  10. Dissolved Gases in Seawater and Sediments (Paper 7R0315)

    NASA Astrophysics Data System (ADS)

    Key, R. M.

    1987-07-01

    the photooxidative daylight loss of oxygen from near-surface tropical waters (Gieskes and Kraay, 1982), isotopic fractionation between fresh and seawater and the atmosphere (Benson and Krause, 1984) , edge effects on chemistry in the 02 minimum zone (Mullins et al., 1985), and the relationship between oxygen and other biogeochemical properties (Pak, 1984; Blizard and Pak, 1984; Lewitus and Broenkow, 1985).

  11. SEAWAT Version 4: A Computer Program for Simulation of Multi-Species Solute and Heat Transport

    USGS Publications Warehouse

    Langevin, Christian D.; Thorne, Daniel T.; Dausman, Alyssa M.; Sukop, Michael C.; Guo, Weixing

    2008-01-01

    The SEAWAT program is a coupled version of MODFLOW and MT3DMS designed to simulate three-dimensional, variable-density, saturated ground-water flow. Flexible equations were added to the program to allow fluid density to be calculated as a function of one or more MT3DMS species. Fluid density may also be calculated as a function of fluid pressure. The effect of fluid viscosity variations on ground-water flow was included as an option. Fluid viscosity can be calculated as a function of one or more MT3DMS species, and the program includes additional functions for representing the dependence on temperature. Although MT3DMS and SEAWAT are not explicitly designed to simulate heat transport, temperature can be simulated as one of the species by entering appropriate transport coefficients. For example, the process of heat conduction is mathematically analogous to Fickian diffusion. Heat conduction can be represented in SEAWAT by assigning a thermal diffusivity for the temperature species (instead of a molecular diffusion coefficient for a solute species). Heat exchange with the solid matrix can be treated in a similar manner by using the mathematically equivalent process of solute sorption. By combining flexible equations for fluid density and viscosity with multi-species transport, SEAWAT Version 4 represents variable-density ground-water flow coupled with multi-species solute and heat transport. SEAWAT Version 4 is based on MODFLOW-2000 and MT3DMS and retains all of the functionality of SEAWAT-2000. SEAWAT Version 4 also supports new simulation options for coupling flow and transport, and for representing constant-head boundaries. In previous versions of SEAWAT, the flow equation was solved for every transport timestep, regardless of whether or not there was a large change in fluid density. A new option was implemented in SEAWAT Version 4 that allows users to control how often the flow field is updated. New options were also implemented for representing constant

  12. Precise determination of cadmium isotope fractionation in seawater by double spike MC-ICPMS

    NASA Astrophysics Data System (ADS)

    Ripperger, S.; Rehkämper, M.

    2007-02-01

    A new technique has been developed for the accurate and precise determination of the stable Cd isotope composition of seawater. The method utilizes a 110Cd- 111Cd double spike, and it involves separation of Cd from seawater by column chromatography and isotopic analyses by multiple collector inductively coupled plasma mass spectrometry. As a by-product, it also generates precise Cd concentration data. Repeated analyses of three pure Cd reference materials and three seawater samples yielded reproducibilities of about ±1.0 to ±1.6 ɛ114/110Cd (2 SD), based on measurements that each consumed about ˜8 ng of natural Cd ( ɛ114/110Cd is the deviation of the 114Cd/ 110Cd isotope ratio of a sample from the standard in parts per 10,000). This demonstrates that the new double spike technique is superior to published methods of Cd isotope analyses, with regard to the acquisition of precise data for samples of limited size. Additional experiments showed that as little as 1-5 ng of seawater Cd could be analyzed with a precision of about ±2 to ±6 ɛ114/110Cd (2 SD). The accuracy of the seawater isotope data was ascertained by experiments in which a Cd-free seawater matrix was doped with small quantities of isotopically well-characterized Cd. Repeated mass scans that were carried out on purified Cd fractions of several samples furthermore demonstrated the absence of significant spectral interferences. The isotope data that were acquired for the three seawater samples reveal, for the first time, small but resolvable Cd isotope fractionations in the marine environment. Cadmium-rich intermediate water from the North Pacific was found to have an isotope composition of ɛ114/110Cd = 3.2 ± 1.0. In contrast, Cd-depleted seawater from the upper water column of the Atlantic and Arctic Oceans displayed isotope compositions of ɛ114/110Cd = 6.4 ± 1.1 and 6.6 ± 1.6, respectively. These observations are in accord with the interpretation that the isotope effects are due to the

  13. Measurement of the Dielectric Constant of Seawater at L-Band: Techniques and Measurements

    NASA Technical Reports Server (NTRS)

    Lang, R.; Utku, C.; Tarkocin, Y.; LeVine, D.

    2009-01-01

    Satellite instruments, that will monitor salinity from space in the near future, require an accurate relationship between salinity/temperature and seawater dielectric constant. This paper will review measurements that were made of the dielectric constant of seawater during the past several years. The objective of the measurements is to determine the dependence of the dielectric constant of seawater on salinity and on temperature, more accurately than in the past. by taking advantage of modem instrumentation. The measurements of seawater permittivity have been performed as a function of salinity and temperature using a transmission resonant cavity technique. The measurements have been made in the salinity range of 10 to 38 psu and in the temperature range of IOU C to 35 C. These results will be useful in algorithm development for sensor systems such as SMOS and Aquarius. The measurement system consists of a brass microwave cavity that is resonant at 1.413 GHz. The seawater is introduced into the cavity through a capillary glass tube having an inner diameter of 0.1 mm. The diameter of the tube has been made very small so that the amount of seawater introduced in the cavity is small - thus maintaining the sensitivity of the measurements and allowing the use of perturbation theory predicting the seawater permittivity. The change in resonant frequency and the change in cavity Q can be used to determine the real and imaginary pare of the dielectric constant of seawater introduced into the slender tube. The microwave measurements are made by an HPS722D network analyzer. The cavity has been immersed in a uateriethylene-glycol bath which is connected to a Lauda circulator. The circulator keeps the brass cavity at a temperature constant to within 0.01 degrees. The system is automated using a Visual Basic program to control the analyzer and to collect the data. The results of the dielectric constant measurements of seawater will be presented. The measurement results will be

  14. δ44/40Ca variations of seawater from Cenozoic and Mesozoic fossil corals

    NASA Astrophysics Data System (ADS)

    Gothmann, A. O.; Higgins, J. A.; Blättler, C. L.; Stolarski, J.; Adkins, J. F.; Bender, M. L.

    2013-12-01

    Numerous archives including fossil carbonates, marine barite, and authigenic phosphates have shown that the Ca-isotope composition of seawater has varied throughout the Phanerozoic. Such changes are thought to be driven by oscillations between calcite seas and aragonite seas, with relatively heavy seawater δ44/40Ca occurring when aragonite deposition is favored and relatively light seawater δ44/40Ca when calcite deposition is favored[1,2]. While the Ca-isotope composition of Neogene and Late Paleogene seawater has been fairly well characterized, current records lack redundancy for ages >35Ma, and are sparsely sampled during the Late Mesozoic and Early Cenozoic. Fossil scleractinian corals may be good candidates for supplementing existing records of seawater Ca isotopes. Although the coral Ca-isotope effect has been shown to be somewhat variable between different taxa, it has also been shown that the Ca-isotope composition of scleractinians exhibits a weak temperature dependence, and is essentially independent of salinity and calcification rate[3]. We measured a suite of ~35 well-preserved fossil corals for Ca isotopes, ranging in age from Jurassic through Recent. We find that the δ44/40Ca seawater composition reconstructed from Neogene-age fossil corals is broadly consistent with existing records. However, Cretaceous and Late Jurassic fossil corals are ~1.1‰ lighter in δ44/40Ca than modern corals. The Cretaceous and Jurassic data support a record from Cretaceous-age authigenic phosphates, but indicate a δ44/40Ca of seawater that is ~0.8‰ lower than that inferred from fossil brachiopods and belemnites of similar ages. We are uncertain which record may best reflect the isotopic composition of seawater, but the differences between these reconstructions have implications for our current understanding of calcite and aragonite seas, and for the global calcium cycle. It is also possible that part of the depletion observed in Jurassic and Cretaceous age corals

  15. Sea-level rise impacts on seawater intrusion in coastal aquifers: Review and integration

    NASA Astrophysics Data System (ADS)

    Ketabchi, Hamed; Mahmoodzadeh, Davood; Ataie-Ashtiani, Behzad; Simmons, Craig T.

    2016-04-01

    Sea-level rise (SLR) influences groundwater hydraulics and in particular seawater intrusion (SWI) in many coastal aquifers. The quantification of the combined and relative impacts of influential factors on SWI has not previously been considered in coastal aquifers. In the present study, a systematic review of the available literature on this topic is first provided. Then, the potential remaining challenges are scrutinized. Open questions on the effects of more realistic complexities such as gradual SLR, parameter uncertainties, and the associated influences in decision-making models are issues requiring further investigation. We assess and quantify the seawater toe location under the impacts of SLR in combination with recharge rate variations, land-surface inundation (LSI) due to SLR, aquifer bed slope variation, and changing landward boundary conditions (LWBCs). This is the first study to include all of these factors in a single analysis framework. Both analytical and numerical models are used for these sensitivity assessments. It is demonstrated that (1) LSI caused by SLR has a significant incremental impact on the seawater toe location, especially in the flatter coasts and the flux-controlled (FC) LWBCs, however this impact is less than the reported orders of magnitude differences which were estimated using only analytical solutions; (2) LWBCs significantly influence the SLR impacts under almost all conditions considered in this study; (3) The main controlling factors of seawater toe location are the magnitudes of fresh groundwater discharge to sea and recharge rate. Regional freshwater flux entering from the landward boundary and the groundwater hydraulic gradient are the major contributors of fresh groundwater discharge to sea for both FC and head-controlled (HC) systems, respectively; (4) A larger response of the aquifer and larger seawater toe location changes are demonstrable for a larger ratio of the aquifer thickness to the aquifer length particularly in

  16. Effect of different seawater Mg2 + concentrations on calcification in two benthic foraminifers

    PubMed Central

    Mewes, Antje; Langer, Gerald; de Nooijer, Lennart Jan; Bijma, Jelle; Reichart, Gert-Jan

    2014-01-01

    Magnesium, incorporated in foraminiferal calcite (Mg/CaCC), is used intensively to reconstruct past seawater temperatures but, in addition to temperature, the Mg/CaCC of foraminiferal tests also depends on the ratio of Mg and Ca in seawater (Mg/CaSW). The physiological mechanisms responsible for these proxy relationships are still unknown. This culture study investigates the impact of different seawater [Mg2 +] on calcification in two benthic foraminiferal species precipitating contrasting Mg/CaCC: Ammonia aomoriensis, producing low-Mg calcite and Amphistegina lessonii, producing intermediate-Mg calcite. Foraminiferal growth and test thickness were determined and, Mg/Ca was analyzed using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Results show that at present-day seawater Mg/CaSW of ~ 5, both species have highest growth rates, reflecting their adaptation to modern seawater element concentrations. Test thickness is not significantly affected by different Mg/CaSW. The relationship between Mg/CaSW and Mg/CaCC shows a distinct positive y-axis intercept, possibly reflecting at least two processes involved in foraminiferal biomineralization. The associated Mg partition (DMg) changes non-linearly with increasing Mg/CaSW, hence suggesting that the DMg is best described by an exponential function approaching an asymptote. PMID:26089590

  17. The critical point and two-phase boundary of seawater, 200–500°C

    USGS Publications Warehouse

    Bischoff, James L.; Rosenbauer, Robert J.

    1984-01-01

    The two-phase boundary of seawater was determined by isothermal decompression of fully condensed seawater in the range of 200–500°C. The pressure at which phase separation occurred for each isotherm was determined by a comparison of the refractive index of fluid removed from the top and bottom of the reaction vessel. The critical point was determined to be in the range of 403–406°C, 285–302 bar and was located by the inflection in the two-phase boundary and by the relative volume of fluid and vapor as a function of temperature. The two-phase boundary of 3.2% NaCl solution was found to coincide exactly with that of seawater over the range tested in the present study. The boundary for both is described by a single seventh-order polynomial equation. The two-phase boundary defines the maximum temperature of seawater circulating at depth in the oceanic crust. Thus the boundary puts a limit of about 390°C for seawater circulating near the seafloor at active ocean ridges (2.5 km water depth), and about 465°C at the top of a magma chamber occurring at 2 km below the seafloor.

  18. Fossil fish teeth as proxies for seawater Sr and Nd isotopes

    NASA Astrophysics Data System (ADS)

    Martin, E. E.; Haley, B. A.

    2000-03-01

    We analyzed Nd and Sr isotopic compositions of Neogene fossil fish teeth from two sites in the Pacific in order to determine the effect of cleaning protocols and burial diagenesis on the preservation of seawater isotopic values. Sr is incorporated into the teeth at the time of growth; thus Sr isotopes are potentially valuable for chemostratigraphy. Nd isotopes are potential conservative tracers of paleocirculation; however, Nd is incorporated post-mortem, and may record diagenetic pore waters rather than seawater. We evaluated samples from two sites (site 807A, Ontong Java Plateau and site 786A, Izu-Bonin Arc) that were exposed to similar bottom waters, but have distinct lithologies and pore water chemistries. The Sr isotopic values of the fish teeth appear to accurately reflect contemporaneous seawater at both sites. The excellent correlation between the Nd isotopic values of teeth from the two sites suggests that the Nd is incorporated while the teeth are in chemical equilibrium with seawater, and that the signal is preserved over geologic timescales and subsequent burial. These data also corroborate paleoseawater Nd isotopic compositions derived from Pacific ferromanganese crusts that were recovered from similar water depths (Ling et al., 1997). This corroboration strongly suggests that both materials preserve seawater Nd isotope values. Variations in Pacific deepwater ɛ Nd values are consistent with predictions for the shoaling of the Isthmus of Panama and the subsequent initiation of nonradiogenic North Atlantic Deep Water that entered the Pacific via the Antarctic Circumpolar Current.

  19. Effect of phytoplankton biomass in seawater on chemical properties of sea spray aerosols.

    PubMed

    Park, Jiyeon; Kim, Dohyung; Lee, Kwangyul; Han, Seunghee; Kim, Hyunji; Williams, Leah R; Joo, Hung Soo; Park, Kihong

    2016-09-15

    This study is to investigate the effect of biological seawater properties on sea spray aerosols (SSA). Concentrations of chlorophyll-a and bacteria were measured at coastal site in Korea in fall and summer seasons. Also, aerosol mass spectrometer (AMS) was used to determine chemical constituents (organics, sulfate, nitrate, ammonium, and chloride) of non-refractory submicrometer aerosols sprayed from seawaters using a bubble bursting system. The average concentration of chlorophyll-a in seawater in fall was 1.75±0.78μg/l, whereas it significantly increased to 5.11±2.16μg/l in summer. It was found that the fraction of organics in the submicrometer SSA was higher in summer (68%) than fall (49%), and that the organic fraction in the SSA increased as the concentration of chlorophyll-a increased in seawater, suggesting that the high phytoplankton biomass in seawater could lead to the enhancement of organic species in the SSA.

  20. Distribution of cadmium in the pearl oyster following exposure to cadmium in seawater

    SciTech Connect

    Francesconi, K.A. )

    1989-08-01

    Laboratory studies on the uptake of cadmium from seawater have shown that bivalve molluscs readily accumulated cadmium from this medium and that the relative concentrations of cadmium between viscera and muscle were always the same as those found in natural populations. These results suggested that in the natural environment seawater was a major source of cadmium for bivalve molluscs. Results of a recent study have indicated that seawater is not always the major contributor of cadmium to bivalve molluscs. These authors reported high levels of cadmium in the pearl oyster Pinctada albina albina, collected from Shark Bay in Western Australia, and noted that there was no correlation between cadmium concentrations in the oysters and cadmium concentrations in the surrounding seawater. Australia is one of several countries which have a maximum permissible level of cadmium in molluscs. The possibility that the pearl oyster, and perhaps other molluscs as well, may accumulate cadmium preferentially in different tissues depending upon the source of cadmium has important implications in the area of contaminants in marine foodstuffs. The present study reports the uptake and distribution of cadmium within P. albina albina when subjected to cadmium in seawater alone.

  1. Differential Decay of Wastewater Bacteria and Change of Microbial Communities in Beach Sand and Seawater Microcosms.

    PubMed

    Zhang, Qian; He, Xia; Yan, Tao

    2015-07-21

    Laboratory microcosm experiments were conducted to determine the decay kinetics of wastewater bacteria and the change of microbial communities in beach sand and seawater. Cultivation-based methods showed that common fecal indicator bacteria (FIBs; Escherichia coli, enterococci, and Clostridium perfringens) exhibited biphasic decay patterns in all microcosms. Enterococci and C. perfringens, but not E. coli, showed significantly smaller decay rates in beach sand than in seawater. Cultivation-independent qPCR quantification of 16S rRNA gene also showed significantly slower decrease of total bacterial densities in beach sand than in seawater. Microbial community analysis by next-generation sequencing (NGS) further illustrated that the decreasing relative abundance of wastewater bacteria was contrasted by the increase in indigenous beach sand and seawater microbiota, and the overall microbial community dynamics corresponded well with the decay of individual FIB populations. In summary, the differential decay of wastewater bacteria in beach sand and in seawater provides a kinetic explanation to the often-observed higher abundance of FIBs in beach sand, and the NGS-based microbial community analysis can provide valuable insights to understanding the fate of wastewater bacteria in the context of indigenous microbial communities in natural environments.

  2. The long-term impact of magnesium in seawater on foraminiferal mineralogy: Mechanism and consequences

    NASA Astrophysics Data System (ADS)

    Dijk, I.; Nooijer, L. J.; Hart, M. B.; Reichart, G.-J.

    2016-03-01

    Foraminifera are unicellular protists, primarily known for their calcium carbonate shells that provide an extensive fossil record. This record, ranging from Cambrian to present shows both major shifts and gradual changes in the relative occurrence of taxa producing different polymorphs of carbonate. Here we present evidence for coupling between shifts in calcite- versus aragonite-producing species and periods with, respectively, low and high seawater Mg/Ca throughout the Phanerozoic. During periods when seawater Mg/Ca is <2 mol/mol, low-Mg calcite-producing species dominate the foraminiferal community. Vice versa, high-Mg calcite- and aragonite-producing species are more abundant during periods with relatively high seawater Mg/Ca. This alteration in dominance of the phase precipitated is due to selective recovery of groups producing the favorable polymorph after shifts from calcite to aragonite seas. In addition, relatively high extinction rates of species producing the mineral phase not favored by the seawater Mg/Ca of that time may be responsible for this alteration. These results imply that the current high seawater Mg/Ca will, in the long term, favor prevalence of high-Mg and aragonite-producing foraminifera over calcite-producing taxa, possibly shifting the balance toward a community in which calcite production is less dominant.

  3. A Comparative study on the nonspecific immunity of juvenile Litopenaeus vannamei ever inhabiting freshwater and seawater

    NASA Astrophysics Data System (ADS)

    Jia, Xuying; Ding, Sen; Wang, Fang; Dong, Shuanglin

    2014-06-01

    A study on the nonspecific immunity of Litopenaeus vannamei ever inhabiting freshwater and seawater was carried out at different molt stages by comparing their total hemocyte count (THC) and respiratory burst (RB) and activity of phenol oxidase (PO), nitric oxide synthase (NOS) and lysozyme (LY). Two-way ANOVA showed that salinity and molt stage independently affected THC and RB and the activity of PO, NOS and LY of juvenile L. vannamei significantly ( P < 0.05). The THC and RB and the activity of NOS gradually increased from the post-molt stages (A and B) to the pre-molt stages (D0-D3), which were common in shrimps inhabiting freshwater and seawater. The activity of PO peaked at the inter-molt stage (C), and touched the lowest at the post-molt stage in freshwater and pre-molt stage in seawater. The activity of LY was stable over the molt cycle. The RB and the activity of PO, NOS and LY of juvenile L. vannamei were significantly lower in freshwater than in seawater; whereas THC was significantly higher in freshwater than in seawater ( P < 0.05). It was concluded that the post-molt stage (especially stage A) was critical to shrimp culture, which should be intensively attended when L. vannamei was cultured in freshwater.

  4. Identification of disinfection by-products in freshwater and seawater swimming pools and evaluation of genotoxicity.

    PubMed

    Manasfi, Tarek; De Méo, Michel; Coulomb, Bruno; Di Giorgio, Carole; Boudenne, Jean-Luc

    2016-03-01

    Exposure to disinfection byproducts (DBPs) in swimming pools has been linked to adverse health effects. Numerous DBPs that occur in swimming pools are genotoxic and carcinogenic. This toxicity is of a greater concern in the case of brominated DBPs that have been shown to have substantially greater toxicities than their chlorinated analogs. In chlorinated seawater swimming pools, brominated DBPs are formed due to the high content of bromide. Nevertheless, very little data is reported about DBP occurrence and mutagenicity of water in these pools. In the present study, three seawater and one freshwater swimming pools located in Southeastern France were investigated to determine qualitatively and quantitatively their DBP contents. An evaluation of the genotoxic properties of water samples of the freshwater pool and a seawater pool was conducted through the Salmonella assay (Ames test). The predominant DBPs identified in the freshwater pool were chlorinated species and included trichloroacetic acid, chloral hydrate, dichloroacetonitrile, 1,1,1-trichloropropanone and chloroform. In the seawater pools, brominated DBPs were the predominant species and included dibromoacetic acid, bromoform and dibromoacetonitile. Bromal hydrate levels were also reported. In both types of pools, haloacetic acids were the most prevalent chemical class among the analyzed DBP classes. The distribution of other DBP classes varied depending on the type of pool. As to genotoxicity, the results of Ames test showed higher mutagenicity in the freshwater pool as a consequence of its considerably higher DBP contents in comparison to the tested seawater pool.

  5. Alloy 31, a new 6 moly stainless steel with improved corrosion resistance in seawater

    SciTech Connect

    Jasner, M.; Heubner, U.

    1995-10-01

    Alloy 31--UNS N08031--31Ni-27Cr-6.5Mo-1.2Cu-0.2N-balance iron--is an advanced 6 Mo stainless steel with increased chromium and nickel, contents for seawater service. In hot seawater the pitting potential of alloy 31 remains high up to 90 C (194 F). Investigations of resistance to crevice corrosion in real piping systems in natural seawater, both North Sea and Baltic Sea, show that the threshold conditions for alloy 31 in chlorinated seawater (North Sea) are at 40 C and 1 ppm chlorine well superior to the 6 Mo stainless grades being currently in use. In addition, alloy 31 shows an excellent resistance to corrosion versus both hot reducing media (e.g. H{sub 2}SO{sub 4}) and hot oxidizing media (e.g. HNO{sub 3}). The combination of high resistance to localized corrosion vs. hot chloride-bearing cooling waters including seawater and aggressive oxidizing and reducing hot corrosive media is a unique feature of alloy 31. Alloy 31 is recommended for the construction of heat exchangers, process coolers and piping systems. The material is supplied in a number of semifinished products such as seamless and welded pipes, fittings, flanges, forged bars, plate, sheet, strip, wire and prefabricated piping systems.

  6. Origins of seawater intrusion in a coastal aquifer - A case study of the Pajaro Valley, California

    USGS Publications Warehouse

    Bond, L.D.; Bredehoeft, J.D.

    1987-01-01

    Seawater may enter and contaminate stratified coastal aquifers through a number of different pathways. These pathways and their relative contribution are examined in the Pajaro Valley, California, a coastal area with extensive groundwater development. This study considers three pathways of possible intrusion of the primary confined aquifer: (1) onshore leakage from brackish sources, the estuary and sloughs, through the confining layer; (2) near-shore leakage from the ocean through the confining layer; and (3) offshore flow from the ocean through the submarine canyon outcrop of the aquifer. Groundwater flow and seawater intrusion are simulated using an areal, two-dimensional solute-transport computer model. This analysis indicates that leakage through confining layers is the principal mechanism of recharge to the aquifer. Although lateral flow through the offshore outcrop contaminates the aquifer, as a whole, at a higher rate, vertical leakage through the sea floor initially is the main pathway of seawater intrusion to the onshore portion of the aquifer. It is likely that leakage generally is the dominant mechanism of recharge and initial cause of seawater intrusion for poorly-confined, stratified coastal aquifers. This analysis suggests that a significant time interval follows the initial observation of seawater intrusion, during which remedial action can be taken to control lateral flow through the offshore outcrop, which ultimately will be the largest component of future intrusion in these aquifers. ?? 1987.

  7. Differential Decay of Wastewater Bacteria and Change of Microbial Communities in Beach Sand and Seawater Microcosms.

    PubMed

    Zhang, Qian; He, Xia; Yan, Tao

    2015-07-21

    Laboratory microcosm experiments were conducted to determine the decay kinetics of wastewater bacteria and the change of microbial communities in beach sand and seawater. Cultivation-based methods showed that common fecal indicator bacteria (FIBs; Escherichia coli, enterococci, and Clostridium perfringens) exhibited biphasic decay patterns in all microcosms. Enterococci and C. perfringens, but not E. coli, showed significantly smaller decay rates in beach sand than in seawater. Cultivation-independent qPCR quantification of 16S rRNA gene also showed significantly slower decrease of total bacterial densities in beach sand than in seawater. Microbial community analysis by next-generation sequencing (NGS) further illustrated that the decreasing relative abundance of wastewater bacteria was contrasted by the increase in indigenous beach sand and seawater microbiota, and the overall microbial community dynamics corresponded well with the decay of individual FIB populations. In summary, the differential decay of wastewater bacteria in beach sand and in seawater provides a kinetic explanation to the often-observed higher abundance of FIBs in beach sand, and the NGS-based microbial community analysis can provide valuable insights to understanding the fate of wastewater bacteria in the context of indigenous microbial communities in natural environments. PMID:26125493

  8. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    PubMed

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems. PMID:27304868

  9. Pitting corrosion behavior of 316L stainless steels in tropical seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Acuna, N.; Solis, W.; Aldana, J.; Festy, D.

    1996-10-01

    The open circuit potential (OCP) and the pitting potential of 316L stainless steel (SS) have been determined as a function of the immersion time in tropical seawater. An increase in the noble direction of the OCP for short exposures was observed. After certain time occasional fall and rise of the OCP values was observed. Pitting potentials measurements shows that a relatively small increase in the seawater temperature can increase the susceptibility to localized corrosion of this alloy. Little or no effect of the exposure time on the pitting potential was observed. SEM observation shows that the steel surface was colonized by bacteria an microalgae which forms an heterogeneous biofilm on the steel surface which probably have an influence on the corrosion behavior of 316 L SS in seawater.

  10. Status of trace metals in surface seawater of the Gulf of Aqaba, Saudi Arabia.

    PubMed

    Al-Taani, Ahmed A; Batayneh, Awni; Nazzal, Yousef; Ghrefat, Habes; Elawadi, Eslam; Zaman, Haider

    2014-09-15

    The Gulf of Aqaba (GoA) is of significant ecological value with unique ecosystems that host one of the most diverse coral communities in the world. However, these marine environments and biodiversity have been threatened by growing human activities. We investigated the levels and distributions of trace metals in surface seawater across the eastern coast of the Saudi GoA. Zn, Cu, Fe, B and Se in addition to total dissolved solids and seawater temperature exhibited decreasing trends northwards. While Mn, Cd, As and Pb showed higher average levels in the northern GoA. Metal input in waters is dependent on the adjacent geologic materials. The spatial variability of metals in water is also related to wave action, prevailing wind direction, and atmospheric dry deposition from adjacent arid lands. Also, water discharged from thermal desalination plants, mineral dust from fertilizer and cement factories are potential contributors of metals to seawater water, particularly, in the northern GoA.

  11. Seawater strontium and Sr/Ca variability in the Atlantic and Pacific oceans

    NASA Astrophysics Data System (ADS)

    de Villiers, Stephanie

    1999-09-01

    Seawater Sr and Sr/Ca exhibit spatial gradients of 2-3% globally, with the deep ocean more enriched relative to the surface. In latitudinal transects, the highest surface values are found at high latitudes and associated with areas of upwelling. A pronounced upper ocean vertical Sr gradient is attributable to the production of celestite skeletons by surface-dwelling acantharia, coupled to a shallow dissolution cycle. The upper ocean residence time of Sr with respect to celestite cycling is much shorter than its global oceanic residence time. Although the magnitude of seawater Sr/Ca variability is relatively small, it is significant with respect to high-precision paleoceanographic applications. Sr/Ca gradients in the contemporary ocean also complicates evaluating Quaternary changes in seawater Sr/Ca that may have resulted from other processes, such as aragonite recrystallization during sea-level low stands.

  12. Microstructure and mechanical properties of recycled aggregate concrete in seawater environment.

    PubMed

    Yue, Pengjun; Tan, Zhuoying; Guo, Zhiying

    2013-01-01

    This study aims to conduct research about the microstructure and basic properties of recycled aggregate concrete under seawater corrosion. Concrete specimens were fabricated and tested with different replacement percentages of 0%, 30%, and 60% after immersing in seawater for 4, 8, 12, and 16 months, respectively. The basic properties of recycled aggregate concrete (RAC) including the compressive strength, the elastic modulus, and chloride penetration depth were explicitly investigated. And the microstructure of recycled concrete aggregate (RCA) was revealed to find the seawater corrosion by using scanning electron microscope (SEM). The results showed that higher amount of the RCA means more porosity and less strength, which could lower both the compressive strength and resistance to chloride penetration. This research could be a guide in theoretical and numerical analysis for the design of RAC structures. PMID:24453830

  13. Dolomitization in a mixing zone of near-seawater composition, Late Pleistocene, northeastern Yucatan Peninsula

    USGS Publications Warehouse

    Ward, W. C.; Halley, Robert B.

    1985-01-01

    18O compositions of Yucatecan dolomite and of modern ground water suggest dolomite precipitation from mixed water ranging from about 75% seawater, 25% freshwater to nearly all seawater. (Isotope analyses are for the most stable calcian dolomites; more soluble, calcium-rich dolomite presumably is analyzed with calcite and thought to be isotopically lighter than the less soluble dolomite.) In the cement sequence, the most stable dolomite is followed by more soluble dolomite as ground water becomes less saline. Isotope analyses, together with position of dolomite in the cement sequence, suggest the most stable calcian dolomite (including limpid dolomite) precipitated from mixed water with large proportions of seawater, and the less stable, more calcian dolomite precipitated from fresher mixed water.

  14. Standardized seawater rearing of chinook salmon smolts to evaluate hatchery practices showed low statistical power

    USGS Publications Warehouse

    Palmisano, Aldo N.; Elder, N.E.

    2001-01-01

    We examined, under standardized conditions, seawater survival of chinook salmon Oncorhynchus tshawytscha at the smolt stage to evaluate the experimental hatchery practices applied to their rearing. The experimental rearing practices included rearing fish at different densities; attempting to control bacterial kidney disease with broodstock segregation, erythromycin injection, and an experimental diet; rearing fish on different water sources; and freeze branding the fish. After application of experimental rearing practices in hatcheries, smolts were transported to a rearing facility for about 2-3 months of seawater rearing. Of 16 experiments, 4 yielded statistically significant differences in seawater survival. In general we found that high variability among replicates, plus the low numbers of replicates available, resulted in low statistical power. We recommend including four or five replicates and using ?? = 0.10 in 1-tailed tests of hatchery experiments to try to increase the statistical power to 0.80.

  15. Seawater test results of Open-Cycle Ocean Thermal Energy Conversion (OC-OTEC) components

    NASA Astrophysics Data System (ADS)

    Zangrando, F.; Bharathan, D.; Link, H.; Panchal, C. B.

    Key components of open-cycle ocean thermal energy conversion systems- the flash evaporator, mist eliminator, passive predeaerator, two surface condenser stages, and two direct-contact condenser stages- have been tested using seawater. These components operate at lower steam pressures and higher inlet noncondensable gas concentrations than do conventional power plant heat exchangers. The rate of heat exchanged between the evaporator and the condenser is on the order of 1.25MW-thermal, requiring a warm seawater flow of about 0.1 cu m/s; the cold seawater flow is on the order of half the warm water flow. In addition to characterizing the performance of the various components, the system has produced potable water from condensation of the steam produced in the evaporator. The information obtained in these tests is being used to design a larger scale experiment in which net power production is expected to be demonstrate for the first time using OC-OTEC technology.

  16. Lithium isotope history of Cenozoic seawater: changes in silicate weathering and reverse weathering.

    PubMed

    Misra, Sambuddha; Froelich, Philip N

    2012-02-17

    Weathering of uplifted continental rocks consumes carbon dioxide and transports cations to the oceans, thereby playing a critical role in controlling both seawater chemistry and climate. However, there are few archives of seawater chemical change that reveal shifts in global tectonic forces connecting Earth ocean-climate processes. We present a 68-million-year record of lithium isotopes in seawater (δ(7)Li(SW)) reconstructed from planktonic foraminifera. From the Paleocene (60 million years ago) to the present, δ(7)Li(SW) rose by 9 per mil (‰), requiring large changes in continental weathering and seafloor reverse weathering that are consistent with increased tectonic uplift, more rapid continental denudation, increasingly incongruent continental weathering (lower chemical weathering intensity), and more rapid CO(2) drawdown. A 5‰ drop in δ(7)Li(SW) across the Cretaceous-Paleogene boundary cannot be produced by an impactor or by Deccan trap volcanism, suggesting large-scale continental denudation.

  17. The impact of atmospheric aerosols on trace metal chemistry in open ocean surface seawater. 2. Copper

    SciTech Connect

    Maring, H.B.; Duce, R.A. )

    1989-01-15

    Atmospheric deposition contributes copper to the surface ocean. The biogeochemical importance and fate of this copper is poorly understood for open ocean regions. Atmospheric aerosols collected at Enewetak Atoll, in the tropical North Pacific, were exposed to seawater and artificial rainwater in laboratory experiments. Aerosol copper during the high-dust season at Enewetak Atoll is made up of aluminosilicate, oceanic, and possibly soil organic matter components. During the low-dust season, marine aerosols collected at Enewetak is soluble in seawater. Dissolved organic matter and possibly cations in seawater increase the dissolution of aerosol copper. The net atmospheric flux of soluble copper to the tropical North Pacific surface waters as does upwelling to eastern North Pacific surface waters. Atmospheric copper deposition, which appears to be primarily of natural origin, may be the most important input of copper to the surface waters of the central gyre of the North Pacific.

  18. Seawater-Assisted Self-Healing of Catechol Polymers via Hydrogen Bonding and Coordination Interactions.

    PubMed

    Li, Jincai; Ejima, Hirotaka; Yoshie, Naoko

    2016-07-27

    It is highly desirable to prevent crack formation in polymeric materials at an early stage and to extend their lifespan, particularly when repairs to these materials would be difficult for humans. Here, we designed and synthesized catechol-functionalized polymers that can self-heal in seawater through hydrogen bonding and coordination. These bioinspired acrylate polymers are originally viscous materials, but after coordination with environmentally safe, common metal cations in seawater, namely, Ca(2+) and Mg(2+), the mechanical properties of the polymers were greatly enhanced from viscous to tough, hard materials. Reduced swelling in seawater compared with deionized water owing to the higher osmotic pressure resulted in greater toughness (∼5 MPa) and self-healing efficiencies (∼80%). PMID:27377859

  19. Occurrence of ground water and potential for seawater intrusion, Island County, Washington

    USGS Publications Warehouse

    Jones, M.A.

    1985-01-01

    The data from a study of groundwater availability and quality in Island County, Washington, are presented. Increased groundwater withdrawals associated with the population increase in Island County have caused concern about groundwater availability and potential seawater intrusion. The most widely used aquifer lies near sea level. Locally, available data indicate that one or more water-bearing zones lie above the sea-level aquifer. Pumpage in 1979 was about 1.67 billion gallons, about 90% of which was pumped from the sea-level aquifer. Most large producing wells in the county have pumping water levels near or below sea level, so that if pumping continues for a long enough time, seawater intrusion would result. Chloride concentrations in water samples taken in July 1978, April 1980 and August 1980 indicate that seawater intrusion is occurring in northeastern and southern Camano Island and in central Whidbey island. (USGS)

  20. Comparison of techniques for preserving dissolved nutrients in open-ocean seawater samples

    SciTech Connect

    Morse, J. W.; Hunt, M.; Zullig, J.; Mucci, A.; Mendez, T.

    1981-12-01

    A survey of recent literature on methods for preserving nutrients indicates that the major factors which have been considered are: filtration and type of filter, material and history of storage containers, the influence of light, storage temperature and how it is achieved, the effectiveness of various acids, poisons, and preservatives, and the source of the sample. No comprehensive studies of open ocean seawater were found. A comprehensive study of nutrient preservation techniques was conducted on surface and deep seawater samples collected in the Gulf Stream east of Miami, Florida. No preservation techniques were found to be satisfactory for near-surface open ocean seawater. Results for deep water samples are found to be substantially better. The degree of preservation was not substantially improved by complex techniques involving freezing and chemical additives. Storage of filtered samples in aged polyethylene bottles at 2/sup 0/C in the dark is recommended for samples that must be stored. (LEW)

  1. Mitigation of biofouling using electromagnetic fields in tubular heat exchangers-condensers cooled by seawater.

    PubMed

    Trueba, Alfredo; García, Sergio; Otero, Félix M

    2014-01-01

    Electromagnetic field (EMF) treatment is presented as an alternative physical treatment for the mitigation of biofouling adhered to the tubes of a heat exchanger-condenser cooled by seawater. During an experimental phase, a fouling biofilm was allowed to grow until experimental variables indicated that its growth had stabilised. Subsequently, EMF treatment was applied to seawater to eliminate the biofilm and to maintain the achieved cleanliness. The results showed that EMFs precipitated ions dissolved in the seawater. As a consequence of the application of EMFs, erosion altered the intermolecular bonding of extracellular polymers, causing the destruction of the biofilm matrix and its detachment from the inner surface of the heat exchanger-condenser tubes. This detachment led to the partial removal of a mature biofilm and a partial recovery of the efficiency lost in the heat transfer process by using a physical treatment that is harmless to the marine environment.

  2. Recovery of uranium from seawater-status of technology and needed future research and development

    SciTech Connect

    Kelmers, A. D.

    1980-01-01

    A survey of recent publications concerning uranium recovery from seawater shows that considerable experimental work in this area is currently under way in Japan, less in European countries. Repeated screening programs have identified hydrous titanium oxide as the most promising candidate adsorbent; however, many of its properties, such as distribution coefficient, selectivity, loading, and possibly stability, appear to fall far short of those required for a practical recovery system. In addition, various evaluations of the energy efficiency of pumped or tidal power schemes for contacting the sorbent and seawater are in serious disagreement. Needed future research and development tasks have been identified. A fundamental development program to achieve significantly improved adsorbent properties would be required to permit economical recovery of uranium from seawater. Unresolved engineering aspects of such recovery systems are also identified and discussed. 63 references.

  3. Microstructure and Mechanical Properties of Recycled Aggregate Concrete in Seawater Environment

    PubMed Central

    Yue, Pengjun; Tan, Zhuoying; Guo, Zhiying

    2013-01-01

    This study aims to conduct research about the microstructure and basic properties of recycled aggregate concrete under seawater corrosion. Concrete specimens were fabricated and tested with different replacement percentages of 0%, 30%, and 60% after immersing in seawater for 4, 8, 12, and 16 months, respectively. The basic properties of recycled aggregate concrete (RAC) including the compressive strength, the elastic modulus, and chloride penetration depth were explicitly investigated. And the microstructure of recycled concrete aggregate (RCA) was revealed to find the seawater corrosion by using scanning electron microscope (SEM). The results showed that higher amount of the RCA means more porosity and less strength, which could lower both the compressive strength and resistance to chloride penetration. This research could be a guide in theoretical and numerical analysis for the design of RAC structures. PMID:24453830

  4. Osmoregulation and salinity tolerance in the Antarctic midge, Belgica antarctica: seawater exposure confers enhanced tolerance to freezing and dehydration.

    PubMed

    Elnitsky, Michael A; Benoit, Joshua B; Lopez-Martinez, Giancarlo; Denlinger, David L; Lee, Richard E

    2009-09-01

    Summer storms along the Antarctic Peninsula can cause microhabitats of the terrestrial midge Belgica antarctica to become periodically inundated with seawater from tidal spray. As microhabitats dry, larvae may be exposed to increasing concentrations of seawater. Alternatively, as a result of melting snow or following rain, larvae may be immersed in freshwater for extended periods. The present study assessed the tolerance and physiological response of B. antarctica larvae to salinity exposure, and examined the effect of seawater acclimation on their subsequent tolerance of freezing, dehydration and heat shock. Midge larvae tolerated extended exposure to hyperosmotic seawater; nearly 50% of larvae survived a 10-day exposure to 1000 mOsm kg(-1) seawater and approximately 25% of larvae survived 6 days in 2000 mOsm kg(-1) seawater. Exposure to seawater drastically reduced larval body water content and increased hemolymph osmolality. By contrast, immersion in freshwater did not affect water content or hemolymph osmolality. Hyperosmotic seawater exposure, and the accompanying osmotic dehydration, resulted in a significant correlation between the rate of oxygen consumption and larval water content and induced the de novo synthesis and accumulation of several organic osmolytes. A 3-day exposure of larvae to hyperosmotic seawater increased freezing tolerance relative to freshwater-acclimated larvae. Even after rehydration, the freezing survival of larvae acclimated to seawater was greater than freshwater-acclimated larvae. Additionally, seawater exposure increased the subsequent tolerance of larvae to dehydration. Our results further illustrate the similarities between these related, yet distinct, forms of osmotic stress and add to the suite of physiological responses used by larvae to enhance survival in the harsh and unpredictable Antarctic environment. PMID:19684222

  5. Assessing the pollution risk of a groundwater source field at western Laizhou Bay under seawater intrusion.

    PubMed

    Zeng, Xiankui; Wu, Jichun; Wang, Dong; Zhu, Xiaobin

    2016-07-01

    Coastal areas have great significance for human living, economy and society development in the world. With the rapid increase of pressures from human activities and climate change, the safety of groundwater resource is under the threat of seawater intrusion in coastal areas. The area of Laizhou Bay is one of the most serious seawater intruded areas in China, since seawater intrusion phenomenon was firstly recognized in the middle of 1970s. This study assessed the pollution risk of a groundwater source filed of western Laizhou Bay area by inferring the probability distribution of groundwater Cl(-) concentration. The numerical model of seawater intrusion process is built by using SEAWAT4. The parameter uncertainty of this model is evaluated by Markov Chain Monte Carlo (MCMC) simulation, and DREAM(ZS) is used as sampling algorithm. Then, the predictive distribution of Cl(-) concentration at groundwater source field is inferred by using the samples of model parameters obtained from MCMC. After that, the pollution risk of groundwater source filed is assessed by the predictive quantiles of Cl(-) concentration. The results of model calibration and verification demonstrate that the DREAM(ZS) based MCMC is efficient and reliable to estimate model parameters under current observation. Under the condition of 95% confidence level, the groundwater source point will not be polluted by seawater intrusion in future five years (2015-2019). In addition, the 2.5% and 97.5% predictive quantiles show that the Cl(-) concentration of groundwater source field always vary between 175mg/l and 200mg/l.

  6. Comparative decay of Catellicoccus marimmalium and enterococci in beach sand and seawater.

    PubMed

    Brown, Kendra I; Boehm, Alexandria B

    2015-10-15

    Most studies characterize microbial source tracking (MST) target performance using sensitivity and specificity metrics. However, it is important to also consider the temporal stability of MST targets in relation to regulated microbial pollutants. Differences among bacterial target stabilities may lead to erroneous conclusions about sources of contamination. The present study evaluates the relative stability of MST targets and fecal indicator organisms using the gull/pigeon-associated Catellicoccus marimammalium (CAT) marker and enterococci (ENT). The decay rates of CAT and ENT measured by culture (cENT) and QPCR (tENT) were compared in sand and seawater laboratory microcosms under environmentally relevant conditions (subject to tidal wetting versus no wetting in sand, and sunlit versus dark conditions in seawater). Bacterial targets were more persistent in beach sand than in seawater with decay rates on the order of 0.01-0.1 per day and 1 to 10 per day, respectively. Targets were more persistent in unwetted compared to wetted sand, and dark compared to sunlit seawater. During the first 8 days of the sand experiment, the decay rate k of CAT was greater than that of cENT. The decay rates of CAT, tENT, and cENT were similar in sand after day 8 and in dark seawater. In sunlit seawater, the decay rates were different between targets with kcENT > kCAT > ktENT. The decay rates presented here are useful for fate and transport models and also inform the use of MST marker concentrations to infer ENT sources in the environment.

  7. Flux patterns and membrane fouling propensity during desalination of seawater by forward osmosis.

    PubMed

    Li, Zhen-Yu; Yangali-Quintanilla, Victor; Valladares-Linares, Rodrigo; Li, Qingyu; Zhan, Tong; Amy, Gary

    2012-01-01

    The membrane fouling propensity of natural seawater during forward osmosis was studied. Seawater from the Red Sea was used as the feed in a forward osmosis process while a 2M sodium chloride solution was used as the draw solution. The process was conducted in a semi-batch mode under two crossflow velocities, 16.7 cm/s and 4.2 cm/s. For the first time reported, silica scaling was found to be the dominant inorganic fouling (scaling) on the surface of membrane active layer during seawater forward osmosis. Polymerization of dissolved silica was the major mechanism for the formation of silica scaling. After ten batches of seawater forward osmosis, the membrane surface was covered by a fouling layer of assorted polymerized silica clusters and natural organic matter, especially biopolymers. Moreover, the absorbed biopolymers also provided bacterial attachment sites. The accumulated organic fouling could be partially removed by water flushing while the polymerized silica was difficult to remove. The rate of flux decline was about 53% with a crossflow velocity of 16.7 cm/s while reaching more than 70% with a crossflow velocity of 4.2 cm/s. Both concentration polarization and fouling played roles in the decrease of flux. The salt rejection was stable at about 98% during seawater forward osmosis. In addition, an almost complete rejection of natural organic matter was attained. The results from this study are valuable for the design and development of a successful protocol for a pretreatment process before seawater forward osmosis and a cleaning method for fouled membranes.

  8. Enumeration, isolation, and characterization of n(2)-fixing bacteria from seawater.

    PubMed

    Guerinot, M L; Colwell, R R

    1985-08-01

    Marine pelagic N(2)-fixing bacteria have not, in general, been identified or quantified, since low or negligible rates of N(2) fixation have been recorded for seawater when blue-green algae (cyanobacteria) are absent. In the study reported here, marine N(2)-fixing bacteria were found in all samples of seawater collected and were analyzed by using a most-probable-number (MPN) method. Two different media were used which allowed growth of microaerophiles, as well as that of aerobes and facultative anaerobes. MPN values obtained for N(2)-fixing bacteria ranged from 0.4 to 1 x 10 per liter for water collected off the coast of Puerto Rico and from 2 to 5.5 x 10 per liter for Chesapeake Bay water. Over 100 strains of N(2)-fixing bacteria were isolated from the MPN tubes and classified, yielding four major groups of NaCl-requiring bacteria based on biochemical characteristics. Results of differential filtration studies indicate that N(2)-fixing bacteria may be associated with phytoplankton. In addition, when N(2)-fixing bacteria were inoculated into unfiltered seawater and incubated in situ, nitrogenase activity could be detected within 1 h. However, no nitrogenase activity was detected in uninoculated seawater or when bacteria were incubated in 0.2-mum-filtered (phytoplankton-free) seawater. The ability of these isolates to fix N(2) at ambient conditions in seawater and the large variety of N(2)-fixing bacteria isolated and identified lead to the conclusion that N(2) fixation in the ocean may occur to a greater degree than previously believed. PMID:16346855

  9. Influence of osmoregulation processes on starvation survival of Escherichia coli in seawater.

    PubMed Central

    Munro, P M; Gauthier, M J; Breittmayer, V A; Bongiovanni, J

    1989-01-01

    The adaptation of enteric bacteria in seawater has previously been described in terms of nutrient starvation. In the present paper, we bring experimental arguments suggesting that survival of these microorganisms could also depend on their ability to overcome the effects of osmotic stress. We analyzed the influence of osmoregulatory mechanisms (potassium transport, transport and accumulation of organic osmolytes) on the survival of Escherichia coli in seawater microcosms by using mutants lacking components of the osmotic stress response. Long-term protection was afforded to cells by growth in a medium whose osmotic pressure was increased by either NaCl, LiCl, or saccharose. Achievement of the protection state depended at least partly on osmoregulatory mechanisms, but differed when these were activated or induced during prior growth or in resting cells suspended in phosphate buffer or in seawater. When achieved during growth, K+ transport, glycine-betaine (GBT) synthesis or transport, and trehalose synthesis helped increase the ability to survive in seawater. Protection by GBT was also obtained with resting cells in a phosphate buffer at high osmotic pressure. However, when added only to the seawater, GBT did not change the survival ability of cells no matter what their osmoregulation potential. These results showed that the survival of E. coli cells in seawater depends, at least partly, on whether they possess certain genes which enable them to regulate osmotic pressure and whether they can be stimulated to express those genes before or after their release into the environment. This expression requires nutrients as the substrates from which the corresponding gene products are made. PMID:2675763

  10. Serpentinization of Sintered Olivine during Seawater Percolation Experiments

    NASA Astrophysics Data System (ADS)

    Luquot, L.; Andreani, M.; Godard, M.; Gouze, P.; Gibert, B.; Lods, G.

    2010-12-01

    Hydration of the mantle lithosphere exposed at slow spreading ridges leads to significant changes of the rock rheological, geophysical, mineralogical and geochemical properties, and to the production of large amounts of H2 and CH4, and of complex carbon molecules that support primitive ecosystems. The onset and efficiency of these hydrothermal processes requires penetration and renewal of fluids at the mineral-fluid interface. However, the mechanisms and the depth of fluid penetration are still poorly understood. Moreover, serpentinization is exovolumic, if a mass-conservative system is assumed, or chemical elements are leached out to conserve rock volume. Thus, the durability and extent of serpentinisation depends of the system capacity to create space and/or to drive mass transfers. In order to investigate these hydrodynamic and chemical mechanisms, we did a series of laboratory experiments during which seawater was injected in sintered San Carlos olivine samples at conditions representative of low temperature ultramafic hydrothermal systems. The percolation-reaction experiments were carried out using the ICARE 2 experimental bench at a confined pressure of 19 MPa and a temperature of 190°C; water flow was set at a constant specific discharge of 0.06 mL/h. During experiments (up to 23 days), permeability decreases continuously although the high Si concentrations in outlet fluids indicate steady olivine dissolution. Fluids are also depleted in Fe and Mg, suggesting precipitation of Fe- and Mg-rich mineral phases; SEM and AEM/TEM analyses of the reacted samples allowed to characterize hematite and poorly crystallized serpentine, both formed at the expense of olivine. Mass balance calculations indicate that, on average, 15 wt. % olivine was dissolved while the same mass of serpentine (+/- brucite) was formed; concurrently, porosity decreased from ~ 12% to 5 %. We infer that the structure of the newly formed serpentine resulted in the clogging of fluid paths and

  11. Serpentinization of Olivine by Seawater: A Flow-Through Experiment

    NASA Astrophysics Data System (ADS)

    Gouze, P.; Luquot, L.; Andreani, M.; Godard, M.; Gibert, B.

    2011-12-01

    The mantle exposed at slow spreading ridges is pervasively serpentinized, down to ca. 5km according to geophysical data. The onset and durability of this hydration process require efficient penetration and renewal of fluids at the mineral-fluid interface. However, the mechanisms of fluid penetration are still poorly understood. Moreover, serpentinization is exovolumic, if a mass-conservative system is assumed, or chemical elements are leached out to conserve rock volume. Thus, the extent of serpentinization depends of the system capacity to create space and/or to drive mass transfers. In order to investigate these hydrodynamic and chemical mechanisms, we did a laboratory experiment during which seawater was injected in a sintered San Carlos olivine sample at conditions representative of low temperature ultramafic hydrothermal systems. The percolation-reaction experiment was carried out at 19 MPa and 190°C; the initial water flow was set at 0.2 mL/h then decreased down to 0.06 mL/h after 8 days. During the experiment (23 days), permeability decreased continuously. The composition of the outlet fluid varied strongly during the first 24h of the experiment, then reached equilibrium values. The high Si concentrations in outlet fluids indicated steady olivine dissolution, while their low Fe and Mg concentrations suggested precipitation of Fe- and Mg-rich mineral phases. The reacted sample acquired a reddish brown color, indicating oxidation reactions occurred. Optical observation and SEM imaging revealed the presence of a soft white material filling the pores of the reacted sample. It was identified as a poorly crystallized serpentine type material by AEM/TEM analyses. This proto-serpentine is intimately associated to <100 nm Fe-oxide patches (probably hematite) growing on the olivine surface. We interpret the precipitation of this proto-serpentine together with Fe-oxides throughout the sample as marking the early stages of serpentinization. The fluid composition not

  12. Adsorbent materials development and testing for the extraction of uranium from seawater

    SciTech Connect

    Felker, L.K.; Dai, S.; Hay, B.P.; Janke, C.J.; Mayes, R.T.; Sun, X.; Tsouris, C.

    2013-07-01

    The extraction of uranium from seawater has been the focus of a research project for the U.S. Department of Energy to develop amidoxime functional group adsorbents using radiation-induced graphing on polymer-based fiber materials and subsequent chemical conversion of the radical sites to form the desired adsorbent material. Materials with promising uranium adsorption capacities were prepared through a series of parametric studies on radiation dose, time, temperature, graphing solutions, and properties of the base polymer materials. A laboratory screening protocol was developed to determine the uranium adsorption capacity to identify the most promising candidate materials for seawater testing. (authors)

  13. Effect of seawater-sewage cross-transplants on bacterial metabolism and diversity.

    PubMed

    Xu, Jie; Jing, Hongmei; Kong, Liangliang; Sun, Mingming; Harrison, Paul J; Liu, Hongbin

    2013-07-01

    Bioassays experiments were conducted to determine the metabolic and community composition response of bacteria to transplants between relatively pristine coastal seawater and sewage-impacted seawater. There were four treatments: (1) pristine seawater bacteria + pristine seawater (Pb + Pw), (2) sewage-impacted bacteria + sewage-impacted water (Sb + Sw), (3) pristine seawater bacteria + sewage-impacted water (Pb + Sw), and (4) sewage-impacted bacteria + pristine seawater (Sb + Pw). Sewage-derived DOC was more labile and readily utilized by bacteria, which favored the growth of high nucleic acid (HNA) bacteria, resulting in high bacterial production (BP, 113 ± 4.92 to 130 ± 15.8 μg C l(-1) day(-1)) and low respiration rate (BR, <67 ± 11.3 μg C l(-1) day(-1)), as well as high bacterial growth efficiency (BGE, 0.68 ± 0.09 to 0.71 ± 0.05). In contrast, at the relatively pristine site, bacteria utilized natural marine-derived dissolved organic matter (DOM) at the expense of lowering their growth efficiency (BGE, <0.32 ± 0.02) with low BP (<62 ± 6.3 μg C l(-1) day(-1)) and high BR 133 ± 14.2 μg C l(-1) day(-1)). Sewage DOM input appeared to alter the partitioning of carbon between respiration and production of bacteria, resulting in a shift toward higher BGE, which would not enhance oxygen consumption. Taxonomic classification based on 454 pyrosequencing reads of the 16S rRNA gene amplicons revealed that changes in bacterial community structure occurred when seawater bacteria were transferred to the eutrophic sewage-impacted water. Sewage DOM fueled the growth of Gammma-proteobacteria and Epsilson-proteobacteria and reduced the bacterial richness, but the changes in the community were not apparent when sewage-impacted bacteria were transferred to pristine seawater. PMID:23494574

  14. Thermal infrared emissivity spectrum and its characteristics of crude oil slick covered seawater.

    PubMed

    Xiong, Pan; Gu, Xing-Fai; Yu, Taol; Meng, Qing-Yan; Li, Jia-Guoi; Shi, Ji-xiang; Cheng, Yang; Wang, Liang; Liu, Wen-Song; Liu, Qi-Yuei; Zhao, Li-Min

    2014-11-01

    Detecting oil slick covered seawater surface using the thermal infrared remote sensing technology exists the advantages such as: oil spill detection with thermal infrared spectrum can be performed in the nighttime which is superior to visible spectrum, the thermal infrared spectrum is superior to detect the radiation characteristics of both the oil slick and the seawater compared to the mid-wavelength infrared spectrum and which have great potential to detect the oil slick thickness. And the emissivity is the ratio of the radiation of an object at a given temperature in normal range of the temperature (260-320 K) and the blackbody radiation under the same temperature , the emissivity of an object is unrelated to the temperature, but only is dependent with the wavelength and material properties. Using the seawater taken from Bohai Bay and crude oil taken from Gudao oil production plant of Shengli Oilfield in Dongying city of Shandong Province, an experiment was designed to study the characteristics and mechanism of thermal infrared emissivity spectrum of artificial crude oil slick covered seawater surface with its thickness. During the experiment, crude oil was continuously dropped into the seawater to generate artificial oil slick with different thicknesses. By adding each drop of crude oil, we measured the reflectivity of the oil slick in the thermal infrared spectrum with the Fourier transform infrared spectrometer (102F) and then calculated its thermal infrared emissivity. The results show that the thermal infrared emissivity of oil slick changes significantly with its thickness when oil slick is relatively thin (20-120 μm), which provides an effective means for detecting the existence of offshore thin oil slick In the spectrum ranges from 8 to 10 μm and from 13. 2 to 14 μm, there is a steady emissivity difference between the seawater and thin oil slick with thickness of 20 μm. The emissivity of oil slick changes marginally with oil slick thickness and

  15. Mercury distribution in seawater of Kagoshima Bay near the active Volcano, Mt. Sakurajima in Japan.

    PubMed

    Ando, Tetsuo; Yamamoto, Megumi; Tomiyasu, Takashi; Tsuji, Mayumi; Akiba, Suminori

    2010-04-01

    Kagoshima bay has a highly active volcano in its center. In the filtered seawater and suspended matter collected from 200-m deep fumaroles at the bottom of the inner bay, the geometric mean concentrations of total mercury were 7.6 and 65.0 ng/L, respectively. The surface seawater collected at the inner bay had a higher concentration of mercury when compared to that in the bay entrance (average: 1.0 vs. 0.5 ng/L). In July, however, no such difference was observed. The fumaroles seem to contribute to relatively high concentrations of mercury in the inner bay except in summer, when thermal cline is formed.

  16. An evaluation of microbial growth and corrosion of 316L SS in glycol/seawater mixtures

    NASA Technical Reports Server (NTRS)

    Lee, Jason S.; Ray, Richard I.; Lowe, Kristine L.; Jones-Meehan, Joanne; Little, Brenda J.

    2003-01-01

    Glycol/seawater mixtures containing > 50% glycol inhibit corrosion of 316L stainless steel and do not support bacterial growth. The results indicate bacteria are able to use low concentrations of glycol (10%) as a growth medium, but bacterial growth decreased with increasing glycol concentration. Pitting potential, determined by anodic polarization, was used to evaluate susceptibility of 316L SS to corrosion in seawater-contaminated glycol. Mixture containing a minimum concentration of 50% propylene glycol-based coolant inhibited pitting corrosion. A slightly higher minimum concentration (55%) was needed for corrosion protection in ethylene glycol mixtures.

  17. Seawater strontium isotopes, Acid rain, and the cretaceous-tertiary boundary.

    PubMed

    Macdougall, J D

    1988-01-29

    A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in seawater at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the seawater strontium isotope record at other times may reflect similar episodes.

  18. A mass spectrometer with a membrane interface for oil concentration monitoring in seawater

    NASA Astrophysics Data System (ADS)

    Gorbatskii, V. V.; Elokhin, V. A.; Nikolaev, V. I.; Ershov, T. D.; Elizarov, A. Yu.

    2016-08-01

    An immersion mass spectrometer with a membrane interface was used for oil detection and oil concentration measurements in seawater by measuring in situ the concentrations of three hydrocarbons: benzene, toluene, and xylene in the region of the specialized Primorsk oil loading seaport in the Gulf of Finland. The recorded mass spectra demonstrated the possibility of measuring the oil concentration in seawater and determining the grade of oil products. The use of a mass spectrometer with a membrane separator interface allows measurements of hydrocarbon concentration with high accuracy, which is currently not provided in commercially available monitors.

  19. Research on the Attenuation Characteristics of Some Inorganic Salts in Seawater

    NASA Astrophysics Data System (ADS)

    Han, X.; Peng, Y.; Zhang, Y.; Ma, Z.; Wang, J.

    2015-10-01

    Seawater is a complex multicomponent system, which involves varieties of organic, inorganic, dissolved and suspended substances. However, the main components dissolved in seawater are the inorganic salts such as NaCl, MgCl2, KCl, NaHCO3, and MgSO4. These elements make different contributions to the spectra of absorption and scattering in water. In this paper, the spectra of different aqueous solutions were measured in the region from 200 to 1200 nm; the attenuation characteristics of aqueous solutions were studied at wavelengths of 450, 532, and 633 nm, respectively; the relationships between attenuation coefficient and the conductivity in different concentrations were also studied.

  20. Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment

    NASA Astrophysics Data System (ADS)

    de Souza, Cláudio M. D.; Carneiro, Cristine E. A.; Baú, João Paulo T.; da Costa, Antonio C. S.; Ivashita, Flávio F.; Paesano, Andrea; di Mauro, Eduardo; de Santana, Henrique; Holm, Nils G.; Neubeck, Anna; Zaia, Cássia T. B. V.; Zaia, Dimas A. M.

    2013-04-01

    In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pHPZC decreased and the pHIEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not +II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM-EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch

  1. Synthesis of goethite in solutions of artificial seawater and amino acids: a prebiotic chemistry study

    NASA Astrophysics Data System (ADS)

    Carneiro, Cristine E. A.; Ivashita, Flávio F.; de Souza, Ivan Granemann; de Souza, Cláudio M. D.; Paesano, Andrea; da Costa, Antonio C. S.; di Mauro, Eduardo; de Santana, Henrique; Zaia, Cássia T. B. V.; Zaia, Dimas A. M.

    2013-04-01

    This study investigated the synthesis of goethite under conditions resembling those of the prebiotic Earth. The artificial seawater used contains all the major elements as well as amino acids (α-Ala, β-Ala, Gly, Cys, AIB) that could be found on the prebiotic Earth. The spectroscopic methods (FT-IR, EPR, Raman), scanning electron microscopy (SEM) and X-ray diffraction showed that in any condition Gly and Cys favoured the formation of goethite, artificial seawater plus β-Ala and distilled water plus AIB favoured the formation of hematite and for the other synthesis a mixture of goethite and hematite were obtained. Thus in general no protein amino acids (β-Ala, AIB) favoured the formation of hematite. As shown by surface enhanced Raman spectroscopy (SERS) spectra the interaction between Cys and Fe3+ of goethite is very complex, involving decomposition of Cys producing sulphur, as well as interaction of carboxylic group with Fe3+. SERS spectra also showed that amino/CN and C-CH3 groups of α-Ala are interacting with Fe3+ of goethite. For the other samples the shifting of several bands was observed. However, it was not possible to say which amino acid groups are interacting with Fe3+. The pH at point of zero charge of goethites increased with artificial seawater and decreased with amino acids. SEM images showed when only goethite was synthesized the images of the samples were acicular and when only hematite was synthesized the images of the samples were spherical. SEM images for the synthesis of goethite with Cys were spherical crystal aggregates with radiating acicular crystals. The highest resonance line intensities were obtained for the samples where only hematite was obtained. Electron paramagnetic resonance (EPR) and Mössbauer spectra showed for the synthesis of goethite with artificial seawater an isomorphic substitution of iron by seawater cations. Mössbauer spectra also showed that for the synthesis goethite in distilled water plus Gly only goethite was

  2. Seawater strontium isotopes, acid rain, and the Cretaceous-Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Macdougall, J. D.

    1988-01-01

    A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in seawater at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the seawater strontium isotope record at other times may reflect similar episodes.

  3. Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida

    NASA Astrophysics Data System (ADS)

    de Nooijer, L. J.; Langer, G.; Nehrke, G.; Bijma, J.

    2009-11-01

    To analyze the relation between seawater uptake and calcification, we incubated juveniles of the benthic foraminifer Ammonia tepida with various fluorescent probes and visualised them afterwards with confocal laser scanning microscopy. Vesicle membranes, Ca ions and vacuole fluids were followed with various tracers and showed for the first time that endocytosis of seawater is part of the calcification process in Ammonia tepida. Data on the intracellular Ca ion cycling allowed for calculating a preliminary cellular Ca budget during foraminiferal calcification. This showed that the free calcium involved in the production of a new chamber cannot be sufficient and suggests that foraminifera may precipitate their calcite from an amorphous precursor.

  4. Variations in Cenozoic seawater uranium reconstructed from well preserved aragonitic fossil corals

    NASA Astrophysics Data System (ADS)

    Gothmann, A. O.; Higgins, J. A.; Bender, M. L.; Stolarski, J.; Adkins, J. F.; McKeon, R. E.; Farley, K. A.; Wang, X.; Planavsky, N.

    2015-12-01

    U/Ca ratios were measured in a subset (n ≈ 30) of well preserved scleractinian fossil corals previously described by Gothmann et al. (2015) in order to investigate Cenozoic changes in seawater [U]. He/U dating studies and measurements of 234U/238U and δ238/235U provide constraints on fossil coral U preservation. He/U ages also demonstrate the ability of well preserved coral aragonite to retain most of its radiogenic He over million year timescales. We find that fossil coral U/Ca has increased by a factor of ~4 between the Early Cenozoic and today. This number is calculated from the change in seawater [Ca2+] implied by brine inclusions and other proxies, and the assumption that the U/Ca in shallow water corals equals the seawater ratio. The change cannot be attributed to a dependence of coral U uptake on seawater pH or [CO32-] (e.g., Inoue et al., 2011), which would lead to a decrease in U/Ca going forward in time. Instead, we suggest that seawater [U] has increased since the Early Cenozoic. Possible explanations for the inferred change include: (1) a small decrease in uranium uptake in suboxic and anoxic sediments over the Cenozoic, (2) a decrease in the rate of low-temperature hydrothermal alteration, and associated U uptake, over the Cenozoic, and (3) a decrease in U removal from seawater resulting from an increase in UO2-CO3 complexation, as originally suggested by Broecker (1971). References: Broecker, W. S. (1971) A Kinetic Model for the Chemical Composition of Sea Water. Quaternary Research, 1, 188-207. Gothmann, A.M., Stolarski, J., Adkins, J.F., Dennis, K.J., Schrag, D.P., Schoene, B., Bender, M.L. (2015) Fossil corals as an archive of secular variations in seawater chemistry. Geochimica et Cosmochimica Acta, 160, 188-208. Inoue, M., Suwa, R., Suzuki, A., Sakai, K., and Kawahata, H., (2011) Effects of seawater pH on growth and skeletal U/Ca ratios of Acropora digitifera coral polyps. Geophysical Research Letters 38, 12801-12804.

  5. Salt-Tectonics Plays Major Role in Contributing High Seawater Salinity in Arabian/persian Gulf: a Constant Constrain on Seawater Desalination

    NASA Astrophysics Data System (ADS)

    Zaigham, N. A.; Aburizaiza, O. S.; Nayyar, Z. A.; Mahar, G. A.; Siddique, A.

    2012-12-01

    Literature research indicates that Arabian/Persian Gulf is the second smallest and saltiest marine body in the world. In general, it is believed that anomalously high salinity of the Gulf is due to low precipitation, high rate of evaporation and limited freshwater pouring from rivers of Iraq and Iran. But present research study has identified that the geotectonic setup and the associated resulting active salt-tectonic processes are mainly causing constant enhancement of salinity in Arabian/Persian Gulf. The results indicate presence of numerous penetrations of salt domes, plugs and other diapiric structures almost all over the bottom and surrounding coastline areas, particularly coastal-belt of Iran, Strait of Hormuz and coastal areas of Qatar and UAE, which are the main inherent contributors for high salinity in seawater of the Gulf. Other factors, like, low precipitation, high evaporation, poor freshwater pouring of Iraq and Iran rivers and discharging back of highly concentrated brines, etc., are further augmenting Gulf's high-salinity. From the assessed salinity environment, it is inferred that present level of salinity will be 'higher to highest' in future affecting considerably the desalination activities in time to come. As the level of seawater salinity plays an important role for the efficient and cost effective seawater desalination activities, the present priorities should be reevaluated for efficient and sustainable water from desalination of highly salted-water of Arabian/Persian Gulf.

  6. Leaching heavy metals from the surface soil of reclaimed tidal flat by alternating seawater inundation and air drying.

    PubMed

    Guo, Shi-Hong; Liu, Zhen-Ling; Li, Qu-Sheng; Yang, Ping; Wang, Li-Li; He, Bao-Yan; Xu, Zhi-Min; Ye, Jin-Shao; Zeng, Eddy Y

    2016-08-01

    Leaching experiments were conducted in a greenhouse to simulate seawater leaching combined with alternating seawater inundation and air drying. We investigated the heavy metal release of soils caused by changes associated with seawater inundation/air drying cycles in the reclaimed soils. After the treatment, the contents of all heavy metals (Cd, Pb, Cr, and Cu), except Zn, in surface soil significantly decreased (P < 0.05), with removal rates ranging from 10% to 51%. The amounts of the exchangeable, carbonate, reducible, and oxidizable fractions also significantly decreased (P < 0.05). Moreover, prolonged seawater inundation enhanced the release of heavy metals. Measurement of diffusive gradients in thin films indicated that seawater inundation significantly increased the re-mobility of heavy metals. During seawater inundation, iron oxide reduction induced the release of heavy metals in the reducible fraction. Decomposition of organic matter, and complexation with dissolved organic carbon decreased the amount of heavy metals in the oxidizable fraction. Furthermore, complexation of chloride ions and competition of cations during seawater inundation and/or leaching decreased the levels of heavy metals in the exchangeable fraction. By contrast, air drying significantly enhanced the concentration of heavy metals in the exchangeable fraction. Therefore, the removal of heavy metals in the exchangeable fraction can be enhanced during subsequent leaching with seawater.

  7. Effects of seawater on elongated duration of ground motion as well as variation in its amplitude for offshore earthquakes

    NASA Astrophysics Data System (ADS)

    Todoriki, Masaru; Furumura, Takashi; Maeda, Takuto

    2016-10-01

    We investigated the effects of seawater on the propagation of seismic waves using a three-dimensional (3D) finite-difference-method (FDM) simulation of seismic wave propagation following offshore earthquakes. When using a one-dimensional (1D) layered structure, the simulation results showed strong S- to P-wave conversion at the sea bottom; accordingly, S-wave energy was dramatically decreased by the seawater layer. This seawater de-amplification effect had strong frequency dependence, therefore resembling a low-pass filter in which the cut-off frequency and damping coefficients were defined by the thickness of the seawater layer. The seawater also acted to elongate the duration of Rayleigh wave packet. The importance of the seawater layer in modelling offshore earthquakes was further demonstrated by a simulation using a realistic 3D velocity structure model with and without seawater for a shallow (h = 14 km) outer-rise Nankai Trough event, the 2004 SE Off Kii Peninsula earthquake (Mw = 7.2). Synthetic seismograms generated by the model when seawater was included were in accordance with observed seismograms for long-term longer-period motions, particularly those in the shape of Rayleigh waves.

  8. Leaching heavy metals from the surface soil of reclaimed tidal flat by alternating seawater inundation and air drying.

    PubMed

    Guo, Shi-Hong; Liu, Zhen-Ling; Li, Qu-Sheng; Yang, Ping; Wang, Li-Li; He, Bao-Yan; Xu, Zhi-Min; Ye, Jin-Shao; Zeng, Eddy Y

    2016-08-01

    Leaching experiments were conducted in a greenhouse to simulate seawater leaching combined with alternating seawater inundation and air drying. We investigated the heavy metal release of soils caused by changes associated with seawater inundation/air drying cycles in the reclaimed soils. After the treatment, the contents of all heavy metals (Cd, Pb, Cr, and Cu), except Zn, in surface soil significantly decreased (P < 0.05), with removal rates ranging from 10% to 51%. The amounts of the exchangeable, carbonate, reducible, and oxidizable fractions also significantly decreased (P < 0.05). Moreover, prolonged seawater inundation enhanced the release of heavy metals. Measurement of diffusive gradients in thin films indicated that seawater inundation significantly increased the re-mobility of heavy metals. During seawater inundation, iron oxide reduction induced the release of heavy metals in the reducible fraction. Decomposition of organic matter, and complexation with dissolved organic carbon decreased the amount of heavy metals in the oxidizable fraction. Furthermore, complexation of chloride ions and competition of cations during seawater inundation and/or leaching decreased the levels of heavy metals in the exchangeable fraction. By contrast, air drying significantly enhanced the concentration of heavy metals in the exchangeable fraction. Therefore, the removal of heavy metals in the exchangeable fraction can be enhanced during subsequent leaching with seawater. PMID:27236846

  9. Rapid determination of strontium-90 by solid phase extraction using DGA Resin® for seawater monitoring

    NASA Astrophysics Data System (ADS)

    Tazoe, H.; Obata, H.; Yamagata, T.; Karube, Z.; Yamada, M.

    2015-12-01

    Strontium-90 concentrations in seawater exceeding the background level have been observed at the accidents of nuclear facilities, such as Chernobyl and Fukushima. However, analytical procedure for strontium-90 in seawater is still quite complicated and challenging. Here we show a simple and rapid analytical technique for the determination of strontium-90 in seawater samples without time-consuming separation of strontium from calcium. The separation with DGA Resin® is used to determine the abundance of strontium-90, which selectively collects yttrium-90, progeny of strontium-90. Naturally occurring radioactive nuclides (such as potassium, lead, bismuth, uranium, and thorium) and anthropogenic radionuclides (such as cesium, barium, lanthanum, and cerium) were separated from yttrium. Through a sample separation procedure, a high chemical yield of yttrium-90 was achieved at 93.9 % for seawater. The result of IAEA 443 certified seawater analysis was in good agreement with the certified value. At 20 hrs counting a lower detection limit of 1.5 mBq L-1 was obtained from 3 L of seawater. The proposed method can finish analyzing 8 samples per day, which is a reasonably fast throughput in actual seawater monitoring. Reproducibility was found to be 3.4 % according to 10 separate analyses of natural seawater samples from the vicinity of Fukushima Daiichi Nuclear Power Plant in September 2013.

  10. Trace metals pollution in seawater and groundwater in the ship breaking area of Sitakund Upazilla, Chittagong, Bangladesh.

    PubMed

    Hasan, Asma Binta; Kabir, Sohail; Selim Reza, A H M; Zaman, Mohammad Nazim; Ahsan, Mohammad Aminul; Akbor, Mohammad Ahedul; Rashid, Mohammad Mamunur

    2013-06-15

    This study reveals potential accumulation of trace metals in the sea and groundwater due to ship breaking activities which take place along the Bay of Bengal in Sitakund Upazilla, Chittagong, Bangladesh. When compared with WHO and Bangladesh domestic standards for water quality, it is revealed that seawater was strongly polluted by Fe and Hg, moderately by Mn and Al, and slightly by Pb and Cd. Groundwater was strongly polluted by Fe, Pb and Hg, moderately by Mn and Al, and slightly by As. Trace element concentrations of all seawater samples exceeded the average concentration of elements in the Earth's seawater. The application of Principal Components Analysis identified two sources of pollution-marine and ship breaking. The mechanism of groundwater pollution inferred that if seawater is polluted, nearby groundwater is also polluted with trace metals due to the influence of seawater intrusion.

  11. Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

    PubMed

    Wang, Rui Xuan; Wang, AnLi; Wang, Jiang Yong

    2014-11-01

    A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar.

  12. Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

    PubMed

    Wang, Rui Xuan; Wang, AnLi; Wang, Jiang Yong

    2014-11-01

    A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar. PMID:25133348

  13. Preparation of Pt deposited nanotubular TiO{sub 2} as cathodes for enhanced photoelectrochemical hydrogen production using seawater electrolytes

    SciTech Connect

    Nam, Wonsik; Oh, Seichang; Joo, Hyunku; Yoon, Jaekyung

    2011-11-15

    The purpose of this study was to develop effective cathodes to increase the production of hydrogen and use the seawater, an abundant resource in the earth as the electrolyte in photoelectrochemical systems. In order to fabricate the Pt/TiO{sub 2} cathodes, various contents of the Pt precursor (0-0.4 wt%) deposited by the electrodeposition method were used. On the basis of the hydrogen evolution rate, 0.2 wt% Pt/TiO{sub 2} was observed to exhibit the best performance among the various Pt/TiO{sub 2} cathodes with the natural seawater and two concentrated seawater electrolytes obtained from single (nanofiltration) and combined membrane (nanofiltration and reverse osmosis) processes. The surface characterizations exhibited that crystal structures and morphological properties of Pt and TiO{sub 2} found the results of XRD pattern and SEM/TEM images, respectively. - Graphical abstract: On the basis of photoelectrochemical hydrogen production, 0.2 wt% Pt/TiO{sub 2} was observed to exhibit the best performance among the various Pt/TIO{sub 2} cathodes with natural seawater. In comparison of hydrogen evolution rate with various seawater electrolytes, 0.2 wt% Pt/TiO{sub 2} was found to show the better performance as cathode with the concentrated seawater electrolytes obtained from membrane. Highlights: > Pt deposited TiO{sub 2} electrodes are used as cathode in PEC H{sub 2} production. > Natural and concentrated seawater by membranes are used as electrolytes in PEC. > Pt/TiO{sub 2} shows a good performance as cathode with seawater electrolytes. > H{sub 2} evolution rate increases with more concentrated seawater electrolyte. > Highly saline seawater is useful resource for H{sub 2} production.

  14. Role of microbial and phytoplanktonic communities in the control of seawater viscosity off East Antarctica (30-80° E)

    NASA Astrophysics Data System (ADS)

    Seuront, Laurent; Leterme, Sophie C.; Seymour, Justin R.; Mitchell, James G.; Ashcroft, Daniel; Noble, Warwick; Thomson, Paul G.; Davidson, Andrew T.; van den Enden, Rick; Scott, Fiona J.; Wright, Simon W.; Schapira, Mathilde; Chapperon, Coraline; Cribb, Nardi

    2010-05-01

    Despite the long-standing belief that seawater viscosity is driven by temperature and salinity, biologically increased seawater viscosity has repeatedly been reported in relation to phytoplankton exudates in shallow, productive coastal waters. Here, seawater viscosity was investigated in relation to microbial and phytoplanktonic communities off the coast of East Antarctica along latitudinal transects located between 30°E and 80°E in sub-surface waters and at the deep chlorophyll maximum (DCM). The physical component of seawater viscosity observed along each transects ranged from 1.80 to 1.95 cP, while the actual seawater viscosity ranged from 1.85 to 3.69 cP. This resulted in biologically increased seawater viscosity reaching up to 84.9% in sub-surface waters and 77.6% at the DCM. Significant positive correlations were found between elevated seawater viscosity and (i) bacterial abundance in sub-surface waters and (ii) chlorophyll a concentration and the abundance of flow cytometrically-defined auto- and heterotrophic protists at the DCM. Among the 12 groups and 108 species of protists identified under light microscopy, dinoflagellates and more specifically Alexandrium tamarense and Prorocentrum sp. were the main contributors to the patterns observed for elevated seawater viscosity. Our observations, which generalised the link previously identified between seawater viscosity and phytoplankton composition and standing stock to the Southern Ocean, are the first demonstration of increases in seawater viscosity linked to marine bacterial communities, and suggest that the microbially-increased viscosity might quantitatively be at least as important as the one related to phytoplankton secretion.

  15. Optimal Planning and Design of Seawater RO Brine Outfalls under Environmental Uncertainty

    NASA Astrophysics Data System (ADS)

    Maalouf, S.; Yeh, W. W.

    2012-12-01

    Seawater reverse osmosis (SWRO) desalination has emerged as the technology of choice, adopted in most arid and semi-arid coastal regions around the world to alleviate shortages in freshwater supply. Depleted traditional water resources, population growth, frequent droughts in these regions and climate change, are among a myriad of factors that have forced coastal communities to seek alternative reliable sources of potable water. The abundance of seawater (about 97% of the volume of water on earth) makes SWRO desalination an attractive supply source of potable water for coastal communities. SWRO desalination plants, however, create hypersaline brine disposal challenges. These challenges are due to elevated Total Dissolved Solids (TDS) concentration levels, of about twice of that of the receiving seawater body, and densities that are higher than the ambient seawater density. We present a model that is applied to optimize the design of a SWRO brine discharge system. We also address the need to develop a simulation-optimization framework that can be used to find the least-cost design of a multiport marine outfall system, while meeting regulatory constraints. Given the uncertainty of some of the input parameters, such as current speed, wind speed and ambient temperature, we demonstrate how one of these parameters is treated as a random variable in the development of the simulation-optimization framework. Finally, we present numerical results of a real-world problem.

  16. Experiments on oxygen desorption from surface warm seawater under open-cycle ocean thermal energy conversion

    SciTech Connect

    Pesaran, A.A. )

    1992-11-01

    This paper presents the results of scoping deaeration experiments conducted with warm surface seawater under open-cycle ocean thermal energy conversion (OC-OTEC) conditions. Concentrations of dissolved oxygen in seawater at three locations (in the supply water, water leaving the predeaerator, and discharge water from an evaporator) were measured and used to estimate oxygen desorption levels. The results suggest that 7 percent to 60 percent of the dissolved oxygen in the supply water was desorbed from seawater in the predeaerator for pressures ranging from 35 to 9 kPa. Bubble injection in the upcomer increased the oxygen desorption rate by 20 percent to 60 percent. The data also indicated that at typical OC-OTEC evaporator pressures, when flash evaporation in the evaporator occurred, 75 percent to 95 percent of the dissolved oxygen was desorbed overall from the warm seawater. The results were used to find the impact of a single-stage predeaeration scheme on the power to remove noncondensable gases in an OC-OTEC plant.

  17. A precise method for the analysis of d18O of dissolved inorganic phosphate in seawater

    USGS Publications Warehouse

    McLaughlin, K.; Silva, S.; Kendall, C.; Stuart-Williams, Hilary; Paytan, A.

    2004-01-01

    A method for preparation and analysis of the oxygen isotope composition (d18O) of dissolved inorganic phosphate (DIP) has been developed and preliminary results for water samples from various locations are reported. Phosphate is extracted from seawater samples by coprecipitation with magnesium hydroxide. Phosphate is further purified through a series of precipitations and resin separation and is ultimately converted to silver phosphate. Silver phosphate samples are pyrolitically decomposed to carbon monoxide and analyzed for d18O. Silver phosphate samples weighing 0.7 mg (3.5 mol oxygen) can be analyzed routinely with an average standard deviation of about 0.3. There is no isotope fractionation during extraction and blanks are negligible within analytical error. Reproducibility was determined for both laboratory standards and natural samples by multiple analyses. A comparison between filtered and unfiltered natural seawater samples was also conducted and no appreciable difference was observed for the samples tested. The d18O values of DIP in seawater determined using this method range from 18.6 to 22.3, suggesting small but detectable natural variability in seawater. For the San Francisco Bay estuary DIP d18O is more variable, ranging from 11.4 near the San Joaquin River to 20.1 near the Golden Gate Bridge, and was well correlated with salinity, phosphate concentration, and d18O of water.

  18. Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

  19. Cysteine containing dipeptides show a metal specificity that matches the composition of seawater.

    PubMed

    Belmonte, Luca; Rossetto, Daniele; Forlin, Michele; Scintilla, Simone; Bonfio, Claudia; Mansy, Sheref S

    2016-07-27

    Model prebiotic dipeptide sequences were identified by bioinformatics and DFT and molecular dynamics calculations. The peptides were then synthesized and evaluated for metal affinity and specificity. Cysteine containing dipeptides were not associated with metal affinities that followed the Irving-Williams series but did follow the concentration trends found in seawater. PMID:27182665

  20. Critical crevice temperature for high-alloyed stainless steels in chlorinated seawater applications

    SciTech Connect

    Steinsmo, U.; Rogne, T.; Drugli, J.M.; Gartland, P.O.

    1997-01-01

    Eleven high-alloyed stainless steels (SS) were tested for application in chlorinated seawater. Critical crevice temperatures (CCT) were determined using a potentiostatic test method. Results were evaluated in terms of the critical crevice index (CCI) value of the alloys and compared to results of duplicate specimens in other tests.

  1. Localized corrosion probability in stainless steels after cathodic protection in seawater

    SciTech Connect

    Salvago, G.; Bollini, G.

    1999-04-01

    Growth of calcareous deposits on stainless steels (SS) exposed to seawater under cathodic protection (CP) conditions was examined. CP was performed by galvanic coupling with iron, zinc, or magnesium anodes. The influence of the galvanic coupling period on the temporal evolution of localized corrosion susceptibility was examined for various SS with CP removed. The study was carried out using a statistical approach with 33 SS samples from the same group. Temporal evolutions of corrosion potential distributions and breakdown potential distributions were determined. Visual and microscopic observations were compared with the localized corrosion risk evaluated from the superimposition of corrosion potential distributions with breakdown potential distributions. Galvanic coupling of SS with iron anodes in seawater did not lead to growth of calcareous deposits, and protection failed soon after galvanic coupling was removed. Galvanic coupling with zinc anodes in seawater led to growth of a light layer of aragonite, and the protection persisted for >3 weeks after the coupling was removed. Galvanic coupling with magnesium anodes in seawater led to growth of thick calcareous deposits of a different composition. Protection persisted for >1 year after the galvanic couple was removed.

  2. Accelerated decolorization of reactive azo dyes under saline conditions by bacteria isolated from Arabian seawater sediment.

    PubMed

    Khalid, Azeem; Kausar, Farzana; Arshad, Muhammad; Mahmood, Tariq; Ahmed, Iftikhar

    2012-12-01

    Presence of huge amount of salts in the wastewater of textile dyeing industry is one of the major limiting factors in the development of an effective biotreatment system for the removal of azo dyes from textile effluents. Bacterial spp. capable of thriving under high salt conditions could be employed for the treatment of saline dyecontaminated textile wastewaters. The present study was aimed at isolating the most efficient bacterial strains capable of decolorizing azo dyes under high saline conditions. Fiftyeight bacterial strains were isolated from seawater, seawater sediment, and saline soil, using mineral salt medium enriched with 100 mg l−1 Reactive Black-5 azo dye and 50 g NaCl l−1 salt concentration. Bacterial strains KS23 (Psychrobacter alimentarius) and KS26 (Staphylococcus equorum) isolated from seawater sediment were able to decolorize three reactive dyes including Reactive Black 5, Reactive Golden Ovifix, and Reactive Blue BRS very efficiently in liquid medium over a wide range of salt concentration (0-100 g NaCl l)⁻¹. Time required for complete decolorization of 100 mg dye l ⁻¹ varied with the type of dye and salt concentration. In general, there was an inverse linear relationship between the velocity of the decolorization reaction (V) and salt concentration. This study suggested that bacteria isolated from saline conditions such as seawater sediment could be used in designing a bioreactor for the treatment of textile effluent containing high concentration of salts.

  3. Measurement of cosmogenic (32)p and (33)p activities in rainwater and seawater.

    PubMed

    Benitez-Nelson, C R; Buesseler, K O

    1998-01-01

    We have developed a new method for the collection, purification, and measurement of natural levels of (32)P and (33)P in rain, marine particulates, and dissolved constituents of seawater. (32)P and (33)P activities were measured using a recently developed ultra-low-level liquid scintillation counter. Measurement by liquid scintillation counting allows, for the first time, simultaneous measurement of both (32)P and (33)P. Furthermore, (33)P activities are measured with high efficiency (>50%), regardless of the amount of stable phosphorus in the sample. Liquid scintillation also produces energy specific β spectra which has enabled us to identify previously unrecognized β-emitting contaminants in natural samples. In order to remove these contaminants, new methods of purification have been developed which utilize a series of precipitations and anion and cation exchange columns. Rainwater and dissolved seawater samples were extracted from large volumes of rain- and seawater, 5-20 and >5000 L, respectively, using iron-impregnated polypropylene filters. On these filters, it was possible to load between 25 and 30% Fe(OH)(3) by weight, over twice that loaded on previously utilized materials. Using our collection, purification, and liquid scintillation counting techniques, it was possible to obtain specific (32)P and (33)P activities with less than 10% error (2σ) in rainwater and 20% error (2σ) in seawater.

  4. 77 FR 59904 - Takes of Marine Mammals Incidental to Specified Activities; Pile Driving for Honolulu Seawater...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... implementing regulations, NMFS issued a notice in the Federal Register on July 24, 2012 (77 FR 43259... description of the specified activity may be found in NMFS' proposed IHA notice in the Federal Register (77 FR... offshore seawater discharge pipe, a land-based pump station, and a land-based chilled water...

  5. Mobilization of technetium from reduced sediments under seawater inundation and intrusion scenarios.

    PubMed

    Eagling, Jane; Worsfold, Paul J; Blake, William H; Keith-Roach, Miranda J

    2012-11-01

    Predicted sea level rise would increase the vulnerability of low lying coastal legacy nuclear sites to inundation and intrusion with oxygenated seawater. This could have a significant impact on the mobility of redox-sensitive radionuclides such as Tc. Here, batch and column experiments were used to simulate and investigate the effect of these processes on the mobilization of Tc from sediments under a range of geochemically reduced conditions. Batch experiments showed that only a small proportion of Tc was rapidly (within 5 days) released from the sediments into seawater and groundwater. The subsequent Tc release was slowest and ultimately limited to the greatest extent (17%) in initially Fe-reducing sediments, when they were reoxidized in seawater. Thus, the cycling of iron and the impact of the water chemistry on iron mineralogy were important for hindering Tc release. Column experiments showed that iron minerals were less effective at retarding Tc release under flow-through conditions. Kinetically controlled and solubility limited Fe dissolution led to ongoing Tc release from the sediments; i.e. the retarding effect of iron phases was temporary, and significantly more Tc was mobilized (79-93%) compared with the batch experiments (17-45%). These results demonstrate the potential for Tc(IV) to be oxidized and mobilized from sediments at coastal nuclear sites resulting from predicted intrusion and inundation with oxic seawater.

  6. Efficient purification and concentration of viruses from a large body of high turbidity seawater.

    PubMed

    Sun, Guowei; Xiao, Jinzhou; Wang, Hongming; Gong, Chaowen; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2014-01-01

    Marine viruses are the most abundant entities in the ocean and play crucial roles in the marine ecological system. However, understanding of viral diversity on large scale depends on efficient and reliable viral purification and concentration techniques. Here, we report on developing an efficient method to purify and concentrate viruses from large body of high turbidity seawater. The developed method characterizes with high viral recovery efficiency, high concentration factor, high viral particle densities and high-throughput, and is reliable for viral concentration from high turbidity seawater. Recovered viral particles were used directly for subsequent analysis by epifluorescence microscopy, transmission electron microscopy and metagenomic sequencing. Three points are essential for this method:•The sampled seawater (>150 L) was initially divided into two parts, water fraction and settled matter fraction, after natural sedimentation.•Both viruses in the water fraction concentrated by tangential flow filtration (TFF) and viruses isolated from the settled matter fraction were considered as the whole viral community in high turbidity seawater.•The viral concentrates were re-concentrated by using centrifugal filter device in order to obtain high density of viral particles.

  7. Loma salmonae (Protozoa: Microspora) infections in seawater reared coho salmon Oncorhynchus kisutch

    USGS Publications Warehouse

    Kent, M.L.; Elliott, D.G.; Groff, J.M.; Hedrick, R.P.

    1989-01-01

    Loma salmonae (Putz et al., 1965) infections were observed in five groups of coho salmon, Oncorhynchus kisutch, reared in seawater net-pens in Washington State, U.S.A. in 1984–1986. Ultrastructural characteristics, size of spores, tissues and host infected, and geographical location identified the microsporidium as Loma salmonae. Preserved spores measured 4.4×2.3 (4–5.6×2–2.4) μm and exhibited 14–17 turns of the polar filament. Infections were evident in the gills of some fish before seawater entry, but few parasites were observed and they caused little tissue damage. Infections observed in fish after transfer to seawater were associated with significant pathological changes in the gills. A mixed inflammatory infiltrate was associated with ruptured microsporidian xenomas within the vessels and interstitium of the primary lamellae. Microsporidian spores were dispersed throughout the lesions and were often seen inside phagocytes. The parasite was also observed in the heart, spleen, kidney and pseudobranchs; however, the inflammatory lesions were common only in the heart.Monthly examination of fish after transfer to seawater showed peak prevalences (33–65%) of gill infections during the summer. Although moribund fish were often infected with other pathogens, the high prevalence of L. salmonae infections and the severity of the lesions it caused, suggested that this parasite significantly contributed to the recurrent summer mortalities observed at this net-pen site.

  8. The Analysis of Seawater: A Laboratory-Centered Learning Project in General Chemistry.

    ERIC Educational Resources Information Center

    Selco, Jodye I.; Roberts, Julian L., Jr.; Wacks, Daniel B.

    2003-01-01

    Describes a sea-water analysis project that introduces qualitative and quantitative analysis methods and laboratory methods such as gravimetric analysis, potentiometric titration, ion-selective electrodes, and the use of calibration curves. Uses a problem-based cooperative teaching approach. (Contains 24 references.) (YDS)

  9. Uranium Recovery from Seawater: Development of Fiber Adsorbents Prepared via Atom-Transfer Radical Polymerization

    SciTech Connect

    Saito, Tomonori; Brown, Suree; Chatterjee, Sabornie; Kim, Jungseung; Tsouris, Costas; Mayes, Richard T; Kuo, Li-Jung; Gill, Gary; Oyola, Yatsandra; Janke, Christopher James; Dai, Sheng

    2014-01-01

    A novel adsorbent preparation method using atom-transfer radical polymerization (ATRP) combined with radiation-induced graft polymerization (RIGP) was developed to synthesize an adsorbent for uranium recovery from seawater. The ATRP method allowed a much higher degree of grafting on the adsorbent fibers (595 2818%) than that allowed by RIGP alone. The adsorbents were prepared with varied composition of amidoxime groups and hydrophilic acrylate groups. The successful preparation revealed that both ligand density and hydrophilicity were critical for optimal performance of the adsorbents. Adsorbents synthesized in this study showed a relatively high performance (141 179 mg/g at 49 62 % adsorption) in laboratory screening tests using a uranium concentration of ~6 ppm. This performance is much higher than that of known commercial adsorbents. However, actual seawater experiment showed impeded performance compared to the recently reported high-surface-area-fiber adsorbents, due to slow adsorption kinetics. The impeded performance motivated an investigation of the effect of hydrophilic block addition on the graft chain terminus. The addition of hydrophilic block on the graft chain terminus nearly doubled the uranium adsorption capacity in seawater, from 1.56 mg/g to 3.02 mg/g. The investigation revealed the importance of polymer chain conformation, in addition to ligand and hydrophilic group ratio, for advanced adsorbent synthesis for uranium recovery from seawater.

  10. An investigation on NO removal by wet scrubbing using NaClO2 seawater solution.

    PubMed

    Han, Zhitao; Yang, Shaolong; Zheng, Dekang; Pan, Xinxiang; Yan, Zhijun

    2016-01-01

    The experiments were conducted to investigate the NO removal by wet scrubbing using NaClO2 seawater solution in a cyclic scrubbing mode. Results show that, when the concentration of NaClO2 in scrubbing solution is higher than 10 mM, a complete removal of NO can be achieved during the cyclic scrubbing process. The breakthrough time for seawater with 15 mM NaClO2 is enhanced by 34.3 % compared with that for NaClO2 freshwater. The extension of the breakthrough time for NaClO2 seawater is mainly ascribed to the improved utilization of NaClO2 in the solution. The good buffering ability of seawater could suppress the acidic decomposition of NaClO2 into ClO2 effectively. The analysis of reaction products indicates that the main anions in the spent liquor are chloride ions and nitrate ions. The calculation of NaClO2 utilization according to the ion chromatography also agrees well with the experimental results of breakthrough times. PMID:27386234

  11. Transition from freshwater to seawater reshapes the skin-associated microbiota of Atlantic salmon

    PubMed Central

    Lokesh, Jep; Kiron, Viswanath

    2016-01-01

    Knowledge concerning shifts in microbiota is important in order to elucidate the perturbations in the mucosal barrier during the transitional life stages of the host. In the present study, a 16S rRNA gene sequencing technique was employed to examine the compositional changes and presumptive functions of the skin-associated bacterial communities of Atlantic salmon reared under controlled laboratory conditions and transferred from freshwater to seawater. Proteobacteria was the dominant phylum in salmon from both freshwater (45%) and seawater (above 89%). Bacteroidetes, Actinobacteria, Firmicutes, Cyanobacteria and Verrucomicrobia were the most abundant phyla in salmon from freshwater. The transition to seawater influenced the OTU richness and evenness. The high abundance (~62%) of the genus Oleispira made Proteobacteria the most significantly abundant phylum in salmon from seawater. The predictive functional profile suggested that the communities had the ability to extract energy from amino acids in order to maintain their metabolism and scavenge and biosynthesise compounds to make structural changes and carry out signalling for their survival. These findings need to be further explored in relation to metabolic processes, the fish genotype, and the environment. PMID:26806545

  12. Efficient purification and concentration of viruses from a large body of high turbidity seawater

    PubMed Central

    Sun, Guowei; Xiao, Jinzhou; Wang, Hongming; Gong, Chaowen; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2014-01-01

    Marine viruses are the most abundant entities in the ocean and play crucial roles in the marine ecological system. However, understanding of viral diversity on large scale depends on efficient and reliable viral purification and concentration techniques. Here, we report on developing an efficient method to purify and concentrate viruses from large body of high turbidity seawater. The developed method characterizes with high viral recovery efficiency, high concentration factor, high viral particle densities and high-throughput, and is reliable for viral concentration from high turbidity seawater. Recovered viral particles were used directly for subsequent analysis by epifluorescence microscopy, transmission electron microscopy and metagenomic sequencing. Three points are essential for this method:•The sampled seawater (>150 L) was initially divided into two parts, water fraction and settled matter fraction, after natural sedimentation.•Both viruses in the water fraction concentrated by tangential flow filtration (TFF) and viruses isolated from the settled matter fraction were considered as the whole viral community in high turbidity seawater.•The viral concentrates were re-concentrated by using centrifugal filter device in order to obtain high density of viral particles. PMID:26150953

  13. Simulation-Optimization Model for Seawater Intrusion Management at Pingtung Coastal Area, Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, P. S.; Chiu, Y.

    2015-12-01

    In 1970's, the agriculture and aquaculture were rapidly developed at Pingtung coastal area in southern Taiwan. The groundwater aquifers were over-pumped and caused the seawater intrusion. In order to remedy the contaminated groundwater and find the best strategies of groundwater usage, a management model to search the optimal groundwater operational strategies is developed in this study. The objective function is to minimize the total amount of injection water and a set of constraints are applied to ensure the groundwater levels and concentrations are satisfied. A three-dimension density-dependent flow and transport simulation model, called SEAWAT developed by U.S. Geological Survey, is selected to simulate the phenomenon of seawater intrusion. The simulation model is well calibrated by the field measurements and replaced by the surrogate model of trained artificial neural networks (ANNs) to reduce the computational time. The ANNs are embedded in the management model to link the simulation and optimization models, and the global optimizer of differential evolution (DE) is applied for solving the management model. The optimal results show that the fully trained ANNs could substitute the original simulation model and reduce much computational time. Under appropriate setting of objective function and constraints, DE can find the optimal injection rates at predefined barriers. The concentrations at the target locations could decrease more than 50 percent within the planning horizon of 20 years. Keywords : Seawater intrusion, groundwater management, numerical model, artificial neural networks, differential evolution

  14. MEMBRANE FILTER PROCEDURE FOR ENUMERATING THE COMPONENT GENERA OF THE COLIFORM GROUP IN SEAWATER

    EPA Science Inventory

    A facile, quantitative, membrane filter procedure (mC) for defining the distribution of coliform populations in seawater according to the component genera was developed. The procedure, which utilizes a series of in situ substrate tests to obviate the picking of colonies for ident...

  15. Relaxed selection causes microevolution of seawater osmoregulation and gene expression in landlocked Alewives

    USGS Publications Warehouse

    Velotta, Jonathan P.; McCormick, Stephen D.; O'Neill, Rachel J.; Schultz, Eric T.

    2014-01-01

    Ecological transitions from marine to freshwater environments have been important in the creation of diversity among fishes. Evolutionary changes associated with these transitions likely involve modifications of osmoregulatory function. In particular, relaxed selection on hypo-osmoregulation should strongly affect animals that transition into novel freshwater environments. We used populations of the Alewife (Alosa pseudoharengus) to study evolutionary shifts in hypo-osmoregulatory capacity and ion regulation associated with freshwater transitions. Alewives are ancestrally anadromous, but multiple populations in Connecticut have been independently restricted to freshwater lakes; these landlocked populations complete their entire life cycle in freshwater. Juvenile landlocked and anadromous Alewives were exposed to three salinities (1, 20 and 30 ppt) in small enclosures within the lake. We detected strong differentiation between life history forms: landlocked Alewives exhibited reduced seawater tolerance and hypo-osmoregulatory performance compared to anadromous Alewives. Furthermore, gill Na+/K+-ATPase activity and transcription of genes for seawater osmoregulation (NKCC—Na+/K+/2Cl− cotransporter and CFTR—cystic fibrosis transmembrane conductance regulator) exhibited reduced responsiveness to seawater challenge. Our study demonstrates that adaptations of marine-derived species to completely freshwater life cycles involve partial loss of seawater osmoregulatory performance mediated through changes to ion regulation in the gill.

  16. Design Criteria, Operating Conditions, and Nickel-Iron Hydroxide Catalyst Materials for Selective Seawater Electrolysis.

    PubMed

    Dionigi, Fabio; Reier, Tobias; Pawolek, Zarina; Gliech, Manuel; Strasser, Peter

    2016-05-10

    Seawater is an abundant water resource on our planet and its direct electrolysis has the advantage that it would not compete with activities demanding fresh water. Oxygen selectivity is challenging when performing seawater electrolysis owing to competing chloride oxidation reactions. In this work we propose a design criterion based on thermodynamic and kinetic considerations that identifies alkaline conditions as preferable to obtain high selectivity for the oxygen evolution reaction. The criterion states that catalysts sustaining the desired operating current with an overpotential <480 mV in alkaline pH possess the best chance to achieve 100 % oxygen/hydrogen selectivity. NiFe layered double hydroxide is shown to satisfy this criterion at pH 13 in seawater-mimicking electrolyte. The catalyst was synthesized by a solvothermal method and the activity, surface redox chemistry, and stability were tested electrochemically in alkaline and near-neutral conditions (borate buffer at pH 9.2) and under both fresh seawater conditions. The Tafel slope at low current densities is not influenced by pH or presence of chloride. On the other hand, the addition of chloride ions has an influence in the temporal evolution of the nickel reduction peak and on both the activity and stability at high current densities at pH 9.2. Faradaic efficiency close to 100 % under the operating conditions predicted by our design criteria was proven using in situ electrochemical mass spectrometry.

  17. Photochemical formation of hydroxyl radical in red-soil-polluted seawater - effects of dissolved organic compounds

    NASA Astrophysics Data System (ADS)

    Uehara, M.; Arakaki, T.

    2006-12-01

    Development of pineapple farmlands and construction of recreational facilities caused runoff of red soil into the coastal ocean (locally termed as red soil pollution) in the north of Okinawa Island, Japan. Red soil is acidic and contains a few percent of iron oxide. We were interested in the formation of hydroxyl radical (·OH), the most potent oxidant in the environment, from the photo-Fenton reaction (reaction between Fe(II) and HOOH) in red-soil-polluted seawater. Various artificial seawater solutions were prepared by adding red soil, HOOH, and/or humic acid to clean seawater, and were used for photochemical experiments. Commercially available humic acid was used to represent natural organic compounds. All the solutions were filtered through 0.45 micron filter before conducting photochemical experiments. Comparisons among the solutions indicated that dissolved chemicals from the red-soil only slightly increased the OH radical photoformation. Photoformation rates of OH radicals of the HOOH + red soil solutions were similar to the calculated rates from direct photolysis of HOOH. Furthermore, addition of humic acid to the HOOH + red soil solutions did not significantly enhance the photo-Fenton reaction, suggesting that Fe(II), even if it had been formed, did not react with HOOH to form OH radicals at detectable level in seawater.

  18. REE/Fe variations in hydrothermal sediments: Implications for the REE content of seawater

    SciTech Connect

    Olivarez, A.M.; Owen, R.M. )

    1989-03-01

    Seafloor hydrothermal vent solutions exhibit rare earth element (REE) enrichments ranging between one to three orders of magnitude greater than average seawater. To assess the impact of these hydrothermal inputs on ocean chemistry, the authors have examined he behavior of REEs for hydrothermal sediments collected adjacent to two Pacific spreading ridge sites: the East Pacific Rise at 19{degree}S, and the Southern Juan de Fuca Ridge at 45{degree}N. In general, the REE/Fe ratios for both proximal and distal hydrothermal sediments are greater than vent solutions by a factor of 2 to 500, and these ratios increase with increasing distance away from the ridge axis. An evaluation of these results in the context of previous models of REE behavior indicates that, in fact, seawater experiences a net depletion in REEs as a result of hydrothermal activity. This is due primarily to the large scavenging capacity of iron oxyhydroxides which precipitate from these solutions. Such an interpretation explains why the REE content of seawater collected in the vicinity of hydrothermal vents is anomalously lower than normal seawater sampled from a comparable depth.

  19. Lithium sorption properties of HMnO in seawater and wastewater.

    PubMed

    Park, HyunJu; Singhal, Naresh; Jho, Eun Hea

    2015-12-15

    The lithium concentration in seawater is 0.17 mg/L, which is very low, but the overall quantity is approximately 2.5 × 10(14) kg. Therefore, seawater, which contains a vast amount of lithium, could be a major alternative source that might supply the rising demand for lithium. This research was undertaken to evaluate the feasibility of a manganese oxide (HMnO) adsorbent, which was produced after leaching lithium from lithium manganese oxide, for lithium collection from seawater. The HMnO was synthesized and deformed to a plastic after wet blending of manganese oxide and lithium hydroxide, and subsequently, the influence of pH, sorption isotherms, sorption rates, sorption energies, and effects of the co-ions were measured. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° indicated that the nature of the lithium sorption was both spontaneous and endothermic. The used HMnO could be regenerated by washing it with an HCl solution. The results demonstrated that HMnO could be effectively used for the collection of lithium from seawater with good selectivity. PMID:26447943

  20. Low-Sulfate Seawater Injection into Oil Reservoir to Avoid Scaling Problem

    NASA Astrophysics Data System (ADS)

    Merdhah, Amer Badr Bin; Mohd Yassin, Abu Azam

    This study presents the results of laboratory experiments carried out to investigate the formation of calcium, strontium and barium sulfates from mixing Angsi seawater or low sulfate seawater with the following sulfate contents (75, 50, 25, 5 and 1%) and formation water contain high concentration of calcium, strontium and barium ions at various temperatures (40-90°C) and atmospheric pressure. The knowledge of solubility of common oil field scale formation and how their solubilities are affected by changes in salinity and temperatures is also studied. Results show a large of precipitation occurred in all jars containing seawater while the amount of precipitation decreased when the low sulfate seawater was used. At higher temperatures the mass of precipitation of CaSO4 and SrSO4 scales increases and the mass of precipitation of BaSO4 scale decreases since the solubilities of CaSO4 and SrSO4 scales decreases and the solubility of BaSO4 increases with increasing temperature. It can be concluded that even at sulfate content of 1% there may still be a scaling problem.

  1. Complete Genome Sequence of Photobacterium sp. Strain J15, Isolated from Seawater of Southwestern Johor, Malaysia

    PubMed Central

    Roslan, Noordiyanah Nadhirah; Oslan, Siti Nurbaya; Baharum, Syarul Nataqain; Leow, Thean Chor

    2016-01-01

    Here, we report the genome sequences of Photobacterium sp. strain J15, isolated from seawater in Johor, Malaysia, with the ability to produce lipase and asparaginase. The PacBio genome sequence analysis of Photobacterium sp. strain J15 generated revealed its potential in producing enzymes with different catalytic functions. PMID:27469962

  2. Corrosion of carbon steel by bacteria from North Sea offshore seawater injection systems: laboratory investigation.

    PubMed

    Stipanicev, Marko; Turcu, Florin; Esnault, Loïc; Rosas, Omar; Basseguy, Régine; Sztyler, Magdalena; Beech, Iwona B

    2014-06-01

    Influence of sulfidogenic bacteria, from a North Sea seawater injection system, on the corrosion of S235JR carbon steel was studied in a flow bioreactor; operating anaerobically for 100days with either inoculated or filtrated seawater. Deposits formed on steel placed in reactors contained magnesium and calcium minerals plus iron sulfide. The dominant biofilm-forming organism was an anaerobic bacterium, genus Caminicella, known to produce hydrogen sulfide and carbon dioxide. Open Circuit Potentials (OCP) of steel in the reactors was, for nearly the entire test duration, in the range -800seawater though they varied significantly on both reactors. Initial and final corrosion rates were virtually identical, namely initial 1/(Rp/Ω)=2×10(-6)±5×10(-7) and final 1/(Rp/Ω)=1.1×10(-5)±2.5×10(-6). Measured data, including electrochemical noise transients and statistical parameters (0.0545), suggested pitting on steel samples within the inoculated environment. However, the actual degree of corrosion could neither be directly correlated with the electrochemical data and nor with the steel corrosion in the filtrated seawater environment. Further laboratory tests are thought to clarify the noticed apparent discrepancies.

  3. Corrosion coupon testing in natural waters: A case history dealing with reverse osmosis desalination of seawater

    SciTech Connect

    Kain, R.M.; Adamson, W.L.; Weber, B.

    1997-12-31

    This paper describes a series of corrosion tests performed to determine the general and localized corrosion behavior of two stainless alloys (UNS S31603 and UNS N08367) and 70/30 CuNi (UNS C71500) in three aqueous environments associated with advanced reverse osmosis (TO) desalination of natural seawater. In addition to seawater (the RO feed stock), the other environments included a 2nd-pass RO brine with lower chloride content and total dissolved solids than raw seawater, and an ultrapure 3rd-pass permeate. Two ASTM standards were reviewed for guidance in the design of the experiment. Since testing could be conducted in an operating prototype RO system, the test program followed the general procedures for an in-plant corrosion tests described by ASTM G4-95: Standard Guide for Conducting Corrosion Coupon Tests in Field Applications. This standard, along with G78-95: Standard Guide for Crevice Corrosion Testing of Iron-Base and Nickel-Base Alloys in Seawater and Other Chloride-Containing Environments, provided guidance in the selection of test specimens and mounting fixtures as well as crevice formers utilized. The G78-95 standard guide also provided considerations associated with the interpretation of the crevice corrosion test results.

  4. Global variability of chromium isotopes in seawater demonstrated by Pacific, Atlantic, and Arctic Ocean samples

    NASA Astrophysics Data System (ADS)

    Scheiderich, Kathleen; Amini, Marghaleray; Holmden, Chris; Francois, Roger

    2015-08-01

    Seawater chromium (Cr) isotope and concentration data are presented from multiple sites in the Arctic Ocean, and three locations in the Atlantic and Pacific Oceans. A 2400-m profile illustrates the heterogeneity of δ53Cr in the Arctic Ocean with depth and water-mass source (Pacific vs. Atlantic). The highest δ53Cr values occur in Pacific-sourced waters, which also have the lowest Cr concentration. Chromium concentration and δ53Cr data from these locations, in conjunction with published data for the South Atlantic Ocean, yield a simple logarithmic function, as predicted by Rayleigh fractionation in a closed system. The observed Cr isotope signature is hypothesized to arise from fractionation during the reduction of Cr(VI) in surface waters and oxygen minimum zones, scavenging of isotopically light Cr(III) to deeper water and sediment, and subsequent release of this seawater-derived Cr(III) back into seawater, either as organic complexes with Cr(III) or after oxidation to Cr(VI). The isotopic fractionation factor (ε) associated with Cr cycling in seawater is estimated to be - 0.80 ± 0.03 ‰ (2 σ). Samples from the sea-ice affected Surface Mixed Layer of the Arctic Ocean (∼10 m depth) deviate from the general trend, and samples proximal to rivers illustrate geographic variation in δ53Cr values for continental runoff, but prompt loss of this signature away from the source.

  5. Complete Genome Sequence of Photobacterium sp. Strain J15, Isolated from Seawater of Southwestern Johor, Malaysia.

    PubMed

    Roslan, Noordiyanah Nadhirah; Sabri, Suriana; Oslan, Siti Nurbaya; Baharum, Syarul Nataqain; Leow, Thean Chor

    2016-01-01

    Here, we report the genome sequences of Photobacterium sp. strain J15, isolated from seawater in Johor, Malaysia, with the ability to produce lipase and asparaginase. The PacBio genome sequence analysis of Photobacterium sp. strain J15 generated revealed its potential in producing enzymes with different catalytic functions. PMID:27469962

  6. Lithium sorption properties of HMnO in seawater and wastewater.

    PubMed

    Park, HyunJu; Singhal, Naresh; Jho, Eun Hea

    2015-12-15

    The lithium concentration in seawater is 0.17 mg/L, which is very low, but the overall quantity is approximately 2.5 × 10(14) kg. Therefore, seawater, which contains a vast amount of lithium, could be a major alternative source that might supply the rising demand for lithium. This research was undertaken to evaluate the feasibility of a manganese oxide (HMnO) adsorbent, which was produced after leaching lithium from lithium manganese oxide, for lithium collection from seawater. The HMnO was synthesized and deformed to a plastic after wet blending of manganese oxide and lithium hydroxide, and subsequently, the influence of pH, sorption isotherms, sorption rates, sorption energies, and effects of the co-ions were measured. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° indicated that the nature of the lithium sorption was both spontaneous and endothermic. The used HMnO could be regenerated by washing it with an HCl solution. The results demonstrated that HMnO could be effectively used for the collection of lithium from seawater with good selectivity.

  7. Refrigerated seawater depuration for reducing Vibrio parahaemolyticus contamination in pacific oyster (Crassostrea gigas).

    PubMed

    Su, Yi-Cheng; Yang, Qianru; Häse, Claudia

    2010-06-01

    The efficacy of refrigerated-seawater depuration for reducing Vibrio parahaemolyticus levels in Pacific oyster (Crassostrea gigas) was investigated. Raw Pacific oysters were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus (10(5) to 10(6) most probable number [MPN] per g) and depurated with refrigerated seawater (5 degrees C) in a laboratory-scale recirculation system equipped with a 15-W gamma UV sterilizer. Depuration with refrigerated seawater for 96 h reduced V. parahaemolyticus populations by >3.0 log MPN/g in oysters harvested in the winter. However, 144 h of depuration at 5 degrees C was required to achieve a 3-log reduction in oysters harvested in the summer. Depuration with refrigerated seawater at 5 degrees C for up to 144 h caused no significant fatality in the Pacific oyster and could be applied as a postharvest treatment to reduce V. parahaemolyticus contamination in Pacific oysters. Further studies are needed to validate the efficacy of the depuration process for reducing naturally accumulated V. parahaemolyticus in oysters.

  8. Effects of Bloom-Forming Algae on Fouling of Integrated Membrane Systems in Seawater Desalination

    ERIC Educational Resources Information Center

    Ladner, David Allen

    2009-01-01

    Combining low- and high-pressure membranes into an integrated membrane system is an effective treatment strategy for seawater desalination. Low-pressure microfiltration (MF) and ultrafiltration (UF) membranes remove particulate material, colloids, and high-molecular-weight organics leaving a relatively foulant-free salt solution for treatment by…

  9. Performance level of an autonomous system of continuous monitoring of radioactivity in seawater.

    PubMed

    van Put, P; Debauche, A; De Lellis, C; Adam, V

    2004-01-01

    Following the recognition of their usefulness by the authorities and the scientific community, automatic water monitoring networks were developed again to be able to measure seawater. For that purpose, they had to be fully autonomous, with low power consumption (solar panel power supply), wireless communicating (satellite, GSM, radio) and very sensitive (a few Bq/m3). PMID:15162870

  10. Effect of seawater transfer on CYP1A gene expression in rainbow trout gills.

    PubMed

    Leguen, I; Odjo, N; Le Bras, Y; Luthringer, B; Baron, D; Monod, G; Prunet, P

    2010-06-01

    During the transfer of rainbow trout from freshwater to seawater, the gills have to switch from an ion-absorption epithelium to an ion-secretion epithelium in order to maintain equilibrium of their hydromineral balance. After a change to ambient salinity, several gill modifications have already been demonstrated, including ion transporters. In order to identify new branchial mechanisms implicated in seawater acclimation, we carried out an extensive analysis of gene expression in gills using microarray technology. This strategy allowed us to show that CYP1A gene expression was up-regulated in the gills after salinity transfer. This increase was confirmed by real-time reverse transcription PCR. Furthermore, measurements of CYP1A enzyme activity (EROD) showed a significant increase after transfer to seawater. Immunohistochemistry analysis in the gills revealed that cells with a higher expression of CYP1A protein were principally pillar cells and those in the primary lamellae not in contact with the external medium. The results of this study suggest for the first time that CYP1A may be implicated in the seawater acclimation of the gills of rainbow trout.

  11. Design Criteria, Operating Conditions, and Nickel-Iron Hydroxide Catalyst Materials for Selective Seawater Electrolysis.

    PubMed

    Dionigi, Fabio; Reier, Tobias; Pawolek, Zarina; Gliech, Manuel; Strasser, Peter

    2016-05-10

    Seawater is an abundant water resource on our planet and its direct electrolysis has the advantage that it would not compete with activities demanding fresh water. Oxygen selectivity is challenging when performing seawater electrolysis owing to competing chloride oxidation reactions. In this work we propose a design criterion based on thermodynamic and kinetic considerations that identifies alkaline conditions as preferable to obtain high selectivity for the oxygen evolution reaction. The criterion states that catalysts sustaining the desired operating current with an overpotential <480 mV in alkaline pH possess the best chance to achieve 100 % oxygen/hydrogen selectivity. NiFe layered double hydroxide is shown to satisfy this criterion at pH 13 in seawater-mimicking electrolyte. The catalyst was synthesized by a solvothermal method and the activity, surface redox chemistry, and stability were tested electrochemically in alkaline and near-neutral conditions (borate buffer at pH 9.2) and under both fresh seawater conditions. The Tafel slope at low current densities is not influenced by pH or presence of chloride. On the other hand, the addition of chloride ions has an influence in the temporal evolution of the nickel reduction peak and on both the activity and stability at high current densities at pH 9.2. Faradaic efficiency close to 100 % under the operating conditions predicted by our design criteria was proven using in situ electrochemical mass spectrometry. PMID:27010750

  12. Sulphide production and corrosion in seawaters during exposure to FAME diesel.

    PubMed

    Lee, Jason S; Ray, Richard I; Little, Brenda J; Duncan, Kathleen E; Oldham, Athenia L; Davidova, Irene A; Suflita, Joseph M

    2012-01-01

    Experiments were designed to evaluate the corrosion-related consequences of storing/transporting fatty acid methyl ester (FAME) alternative diesel fuel in contact with natural seawater. Coastal Key West, FL (KW), and Persian Gulf (PG) seawaters, representing an oligotrophic and a more organic- and inorganic mineral-rich environment, respectively, were used in 60 day incubations with unprotected carbon steel. The original microflora of the two seawaters were similar with respect to major taxonomic groups but with markedly different species. After exposure to FAME diesel, the microflora of the waters changed substantially, with Clostridiales (Firmicutes) becoming dominant in both. Despite low numbers of sulphate-reducing bacteria in the original waters and after FAME diesel exposure, sulphide levels and corrosion increased markedly due to microbial sulphide production. Corrosion morphology was in the form of isolated pits surrounded by an intact, passive surface with the deepest pits associated with the fuel/seawater interface in the KW exposure. In the presence of FAME diesel, the highest corrosion rates measured by linear polarization occurred in the KW exposure correlating with significantly higher concentrations of sulphur and chlorine (presumed sulphide and chloride, respectively) in the corrosion products. PMID:22594394

  13. [Variation characteristics and controlling factors of heavy metals in the South Yellow Sea surface seawaters].

    PubMed

    He, Zhi-Peng; Song, Jin-Ming; Zhang, Nai-Xing; Xu, Ya-Yan; Zheng, Guo-Xia; Zhang, Peng

    2008-05-01

    Based on the 8 cruises data of surface seawater heavy metals and other related environmental factors from 1997 to 2004 of the South Yellow Sea (SYS), distribution patterns, mechanisms controlling the distributions and pollution levels of heavy metals (As, Cd, Cu, Hg, Pb, Zn) were studied with the data of 2003-10, and 8-year-fluctuation trends of heavy metals were also discussed. The average concentrations of heavy metals in surface seawater were 2.33, 0.078, 1.41, 0.003 6, 0.37, 6.21 microg/L respectively. The average concentrations showed a relatively stable trend in 8 years, except Zn's distinct upward tendency. The distribution patterns corresponded to the distance away from the coastline,that was, the content of heavy metals (except Pb) was low in central area while high inshore. Those were responses of human activity in the marginal sea, however, in some local areas, Pb was controlled by atmospheric deposition, Cd was relative to pH and salinity, Hg was related to organic carbon, Cu and Zn were influenced by runoff and drainage, and the resuspending of sediments played important roles on the content and distribution of As. Compared to the Marine Water Quality Standard of China, heavy metals indicated that SYS was a first class sea, and Ecological Risk Index analysis showed that SYS was a low ecological risk sea. In conclusion, seawater quality of heavy metals in SYS surface seawater is relatively good in general.

  14. Surface functionalized nanostructured ceramic sorbents for the effective collection and recovery of uranium from seawater.

    PubMed

    Chouyyok, Wilaiwan; Pittman, Jonathan W; Warner, Marvin G; Nell, Kara M; Clubb, Donald C; Gill, Gary A; Addleman, R Shane

    2016-07-28

    The ability to collect uranium from seawater offers the potential for a nearly limitless fuel supply for nuclear energy. We evaluated the use of functionalized nanostructured sorbents for the collection and recovery of uranium from seawater. Extraction of trace minerals from seawater and brines is challenging due to the high ionic strength of seawater, low mineral concentrations, and fouling of surfaces over time. We demonstrate that rationally assembled sorbent materials that integrate high affinity surface chemistry and high surface area nanostructures into an application relevant micro/macro structure enables collection performance that far exceeds typical sorbent materials. High surface area nanostructured silica with surface chemistries composed of phosphonic acid, phosphonates, 3,4 hydroxypyridinone, and EDTA showed superior performance for uranium collection. A few phosphorous-based commercial resins, specifically Diphonix and Ln Resin, also performed well. We demonstrate an effective and environmentally benign method of stripping the uranium from the high affinity sorbents using inexpensive nontoxic carbonate solutions. The cyclic use of preferred sorbents and acidic reconditioning of materials was shown to improve performance. Composite thin films composed of the nanostructured sorbents and a porous polymer binder are shown to have excellent kinetics and good capacity while providing an effective processing configuration for trace mineral recovery from solutions. Initial work using the composite thin films shows significant improvements in processing capacity over the previously reported sorbent materials. PMID:27184739

  15. Cenozoic Seawater Sr/Ca ratios: Implications for coral reef development through ocean de-acidification

    NASA Astrophysics Data System (ADS)

    Sosdian, S. M.; Grossman, E. L.; Lear, C. H.; Tao, K.; Rosenthal, Y.

    2010-12-01

    Records of seawater chemistry help constrain the temporal variation in geochemical processes that impact the global carbon cycle and global climate across Earth’s history. To date, various attempts to reconstruct Cenozoic seawater Sr/Ca ratios have produced markedly different results, with estimated Paleogene seawater Sr/Ca ranging from ~50% higher than today to 70% lower. We reconstruct seawater Sr/Ca using Eocene to Pliocene fossil mollusks collected from US Gulf Coast (Mississippi, Alabama, and Florida). We use Conus spp. and Turritella, taxa for which the Sr/Ca distribution coefficients have been determined as a function of temperature in modern specimens [1, 2]. Specimens were serially sampled perpendicular to growth to produce seasonal records of Sr/Ca. Fossil Conus shells show pronounced seasonal Sr/Ca cycles with a strong inverse correlation between Sr/Ca and δ18O, similar to those observed in modern specimens [1]. The fossil Turritella also show similar Sr/Ca cyclicity as modern specimens [2]. We calculate seawater Sr/Ca ratios using our Sr/Ca record, modern Sr/Ca-temperature calibrations for Conus and Turritella [1, 2], and a paleotemperature record based on oxygen isotopes from the same samples [3]. Seawater Sr/Ca increased from ~11.5 to 13.9 mmol/mol between the mid-Eocene (42 Ma) and early Oligocene (33 Ma) and decreased substantially from the mid-Miocene (11 mmol/mol) to the Pliocene (9 mmol/mol) and modern (8.5 mmol/mol). A mass balance model of variations in seawater Sr concentrations suggests a long-term decrease through the Neogene, which we attribute to a significant increase in the proportion of aragonite versus calcite deposition in shallow waters. The largest change is coincident with the proliferation of coral reefs, which occurred after the calcite-aragonite sea transition, and was likely ultimately driven by ocean de-acidification. [1] Sosdian et al. (2006) Geochemistry, Geophysics, Geosystems (G3) 7, Q11023, doi:10.1029/2005GC001233; [2

  16. High-precision measurements of seawater Pb isotope compositions by double spike thermal ionization mass spectrometry.

    PubMed

    Paul, Maxence; Bridgestock, Luke; Rehkämper, Mark; van DeFlierdt, Tina; Weiss, Dominik

    2015-03-10

    A new method for the determination of seawater Pb isotope compositions and concentrations was developed, which combines and optimizes previously published protocols for the separation and isotopic analysis of this element. For isotopic analysis, the procedure involves initial separation of Pb from 1 to 2L of seawater by co-precipitation with Mg hydroxide and further purification by a two stage anion exchange procedure. The Pb isotope measurements are subsequently carried out by thermal ionization mass spectrometry using a (207)Pb-(204)Pb double spike for correction of instrumental mass fractionation. These methods are associated with a total procedural Pb blank of 28±21 pg (1sd) and typical Pb recoveries of 40-60%. The Pb concentrations are determined by isotope dilution (ID) on 50 mL of seawater, using a simplified version of above methods. Analyses of multiple aliquots of six seawater samples yield a reproducibility of about ±1 to ±10% (1sd) for Pb concentrations of between 7 and 50 pmol/kg, where precision was primarily limited by the uncertainty of the blank correction (12±4 pg; 1sd). For the Pb isotope analyses, typical reproducibilities (±2sd) of 700-1500 ppm and 1000-2000 ppm were achieved for (207)Pb/(206)Pb, (208)Pb/(206)Pb and (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)Pb, respectively. These results are superior to literature data that were obtained using plasma source mass spectrometry and they are at least a factor of five more precise for ratios involving the minor (204)Pb isotope. Both Pb concentration and isotope data, furthermore, show good agreement with published results for two seawater intercomparison samples of the GEOTRACES program. Finally, the new methods were applied to a seawater depth profile from the eastern South Atlantic. Both Pb contents and isotope compositions display a smooth evolution with depth, and no obvious outliers. Compared to previous Pb isotope data for seawater, the (206)Pb/(204)Pb ratios are well correlated

  17. Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

    DOE PAGES

    Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana; Strivens, Jonathan E.; Gill, Gary

    2015-11-19

    Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8)more » of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

  18. The Gravitational Effect of the Ocean Density Contrast for a Depth-Dependent Seawater Density Model

    NASA Astrophysics Data System (ADS)

    Novak, P.; Tenzer, R.; Gladkikh, V.

    2010-12-01

    In geophysical studies investigating the lithosphere structure, the topographic and consolidated crust density contrast stripping corrections are computed and applied to observed gravity data. The gravitational field generated by the ocean density contrast represents a significant amount of the signal to be modelled and subsequently subtracted from the gravity field. The ocean density contrast is typically calculated as the difference between the mean density values of the Earth’s crust and seawater. The currently available global geopotential models and the global elevation and bathymetry (ocean bottom depth) data allow modelling the topography corrected and bathymetry stripped gravity field quantities to a very high spectral resolution (up to degree 2159 of spherical harmonics) using methods for a spherical harmonic analysis and synthesis of the gravity field. The approximation of the actual seawater density distribution by the mean value yields relative errors up to 2% in computed values of the bathymetric stripping corrections. To reduce these errors, we adopt a depth-dependent theoretical model of the seawater density distribution to account for increasing seawater density with pressure/depth. The smaller lateral seawater density variations due to salinity and temperature and other oceanographic factors are not taken into consideration. The approximation of the seawater density by the depth-dependent density model reduces the maximum errors to less than 0.6%. The corresponding depth-averaged errors are below 0.1%. The depth-dependent seawater density model is facilitated in the forward modelling of the bathymetric stripping corrections. The expressions for computing the gravitational field quantities generated by the depth-dependent ocean density contrast are formulated in the spectral representation by means of the spherical bathymetric functions. These newly derived expressions are used to compute globally the bathymetric stripping corrections. The

  19. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization

    NASA Astrophysics Data System (ADS)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen

    2016-04-01

    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  20. Geophysical and geochemical studies to delineate seawater intrusion in Bagoush area, Northwestern coast, Egypt

    NASA Astrophysics Data System (ADS)

    Eissa, Mustafa A.; Mahmoud, Hussein Hosni; Shouakar-Stash, Orfan; El-Shiekh, Abdelfattah; Parker, Beth

    2016-09-01

    Coastal aquifers are the main source for sustainable freshwater in many arid and semi-arid regions around the earth. In such regions, groundwater extraction far exceeds the natural replenishment rates due to additional demands on groundwater resources especially in the last few decades. The characterization of the seawater intrusion in the Baghoush area along the northwestern coast of Egypt assesses the risk of seawater intrusion for the purpose of managing the groundwater resources in coastal areas. The (SI) in the oolitic Pleistocene aquifer is affected by several natural factors, including the drainage patterns, geological structures, distance from the sea and the manipulation of groundwater. Electrical Resistivity Tomography (ERT) has been implemented to identify the geometry of the brackish/saline water interface and to map the distribution of brackish water zone floating over the denser saline water. Seven 2-D resistivity imaging profiles were conducted using a Wenner array with different electrode distance spacings. The inverse resistivity models of these profiles indicate that these profiles are composed of three zones: the upper dry zone, the middle brackish water zone, and the lower saline water zone. The thickness of the brackish groundwater zone decreases toward the sea and the resistivity decreases with depth due to increase in water salinity. Water table along these profiles decreases from south to north, which indicates that groundwater flow is from south (inland) to north (sea). Groundwater chemistry and stable isotopes were used to determine the fresh groundwater recharge source(s), to identify mixing of different groundwaters, to evaluate seawater intrusion zone along the coast, and to investigate the upwelling of deep saline groundwater underneath the brackish zone. The recharge of fresh groundwater originates from the mountain watershed located upstream as well as the annual rainfall; however, seawater is the main source of groundwater

  1. Hydrogeochemical investigation of seawater intrusion into confined aquifer in Liepaja city

    NASA Astrophysics Data System (ADS)

    Bikse, Janis; Retike, Inga; Delina, Aija; Babre, Alise; Kalvans, Andis

    2015-04-01

    Large scale pumping of groundwater has caused seawater intrusion into Upper Devonian Famenian multi aquifer (D3fm), particularly Muri - Zagare aquifer (D3mr-zg) in the Liepaja city area, and intrusion is developing towards water supply wells which are located inland to the south-east from Liepaja City. In this study attempt has been made to determine seawater intrusion rate and current hydrogeochemical conditions in Muri - Zagare confined aquifer using data on chemical composition of groundwater samples, taken from exploration and monitoring wells. Dataset of major ions and trace elements were used acquired from monitoring wells, project wells and water supply wells dated from 1960.-ies to year 2013. Various techniques are used for better understanding of seawater intrusion development, its current state and possible further development, including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) and probability graphs. Probability graph revealed that it is possible to distinguish fresh, brackish and saline water by electrical conductivity (EC) threshold. Seawater influence can be detected up to 4 km inland from the Baltic Sea coast. Analysis of hydrogeochemical data reveal great influence of cation exchange processes on groundwater chemical composition. Besides seawater intrusion, signs of intrusion from subjacent aquifer (Devonian akmene-jonisku) were detected from analysis. Majority of samples showed manganese, sodium, potassium and calcium ion correlation with Cl- indicating that these components can be enriched during freshwater and seawater mixing. This study revealed that is possible to distinguish brackish water from freshwater by using Ca/Cl, Mg/Cl and K/Cl ionic ratios. PCA and HCA statistical analysis proved their usability in investigation of seawater intrusion process as they can distinguish different groups of water from chemical composition point of view. The research is supported by the European Union through the ESF

  2. The major-ion composition of Cenozoic seawater: the past 36 million years from fluid inclusions in marine halite

    USGS Publications Warehouse

    Brennan, Sean T.; Lowenstein, Tim K.; Cendon, Dioni I.

    2013-01-01

    Fluid inclusions from ten Cenozoic (Eocene-Miocene) marine halites are used to quantify the major-ion composition (Mg2+, Ca2+, K+, Na+, SO42−, and Cl−) of seawater over the past 36 My. Criteria used to determine a seawater origin of the halites include: (1) stratigraphic, sedimentologic, and paleontologic observations; (2) Br− in halite; (3) δ34S of sulfate minerals; (4) 87Sr/86Sr of carbonates and sulfates; and (5) fluid inclusion brine compositions and evaporation paths, which must overlap from geographically separated basins of the same age to confirm a “global” seawater chemical signal. Changes in the major-ion chemistry of Cenozoic seawater record the end of a systematic, long term (>150 My) shift from the Ca2+-rich, Mg2+- and SO42−-poor seawater of the Mesozoic (“CaCl2 seas”) to the “MgSO4 seas” (with higher Mg2+ and SO42−>Ca2+) of the Cenozoic. The major ion composition of Cenozoic seawater is calculated for the Eocene-Oligocene (36-34 Ma), Serravallian-Tortonian (13.5-11.8 Ma) and the Messinian (6-5 Ma), assuming chlorinity (565 mmolal), salinity, and the K+ concentration (11 mmolal) are constant and the same as in modern seawater. Fluid inclusions from Cenozoic marine halites show that the concentrations of Mg2+and SO42− have increased in seawater over the past 36 My and the concentration of Ca2+ has decreased. Mg2+ concentrations increased from 36 mmolal in Eocene-Oligocene seawater (36-34 Ma) to 55 mmolal in modern seawater. The Mg2+/Ca2+ ratio of seawater has risen from ∼2.3 at the end of the Eocene, to 3.4 and 4.0, respectively, at 13.5 to 11.8 Ma and 6 to 5 Ma, and to 5 in modern seawater. Eocene-Oligocene seawater (36-34 Ma) has estimated ranges of SO42− = 14–23 mmolal and Ca2+ = 11–20 mmolal. If the (Ca2+)(SO42−) product is assumed to be the same as in modern seawater (∼300 mmolal2), Eocene-Oligocene seawater had Ca2+ ∼16 mmolal and SO42− ∼19 mmolal. The same estimates of Ca2+ and SO42− for Serravallian

  3. The evolution process of seawater intrusion in Laizhou Bay, and its linkage to climate change and human activity

    NASA Astrophysics Data System (ADS)

    xu, X.

    2013-12-01

    Seawater Intrusion is that seawater or saltwater intrude into the continent along the aquifer.Under the effects of the natural and artificial factors, the hydrodynamic conditions of aquifer in the coastal area has been changed ,which break the equilibrium between the seawater and the freshwater, hence the salt-fresh interface moves on the continent. Sea-level rise due to climate change and the paleoseawater hosting in marine strata combined with a rising population density in the Laizhou Bay have led to higher stresses on coastal water resources, and the risk of seawater intrusion has increased. Despite comprehensive seawater intrusion research and prevention measures are developed, the effects of climate change and human activity on seawater intrusion is still unclear. Therefore to reveal how climate change and human activity impact on seawater intrusion and to mathematical quantify it is important to establish reasonable prevention and control of seawater intrusion measures. Laizhou Bay is the region suffering from the geo-hazard of sea (saline) water intrusion most seriously in China, and is divided into seawater intrusion area, saline water (paleo-sea water) intrusion area and sea-saline water intrusion area The area of seawter intrusion in Laizhou Bay nearly 4,000 km2. And the seawater intrusion disasters in Laizhou bay can be divided into five stage from 1976 to now, which is Initial stage (1976-1979),Developing stage (1980-1985), Deterioration stage(1987-1989), Release stage (1990-2000)and Differentiation stage (2000-). The impact of human activities is shown as seawater intrusion in the linear growth trend. With the rapid economic development, the increase in abstraction from aquifers results in a serious imbalance between the seawater and freshwater interface, and the risk of seawater intrusion has increased. Taking into account of the climate change and human activity factors and seawater intrusion evaluation factors, such as the intensity of Cl

  4. Speciation of americium in seawater and accumulation in the marine sponge Aplysina cavernicola.

    PubMed

    Maloubier, Melody; Michel, Hervé; Solari, Pier Lorenzo; Moisy, Philippe; Tribalat, Marie-Aude; Oberhaensli, François R; Dechraoui Bottein, Marie Yasmine; Thomas, Olivier P; Monfort, Marguerite; Moulin, Christophe; Den Auwer, Christophe

    2015-12-21

    The fate of radionuclides in the environment is a cause of great concern for modern society, seen especially in 2011 after the Fukushima accident. Among the environmental compartments, seawater covers most of the earth's surface and may be directly or indirectly impacted. The interaction between radionuclides and the marine compartment is therefore essential for better understanding the transfer mechanisms from the hydrosphere to the biosphere. This information allows for the evaluation of the impact on humans via our interaction with the biotope that has been largely undocumented up to now. In this report, we attempt to make a link between the speciation of heavy elements in natural seawater and their uptake by a model marine organism. More specifically, because the interaction of actinides with marine invertebrates has been poorly studied, the accumulation in a representative member of the Mediterranean coralligenous habitat, the sponge Aplysina cavernicola, was investigated and its uptake curve exposed to a radiotracer (241)Am was estimated using a high-purity Ge gamma spectrometer. But in order to go beyond the phenomenological accumulation rate, the speciation of americium(III) in seawater must be assessed. The speciation of (241)Am (and natural europium as its chemically stable surrogate) in seawater was determined using a combination of different techniques: Time-Resolved Laser-Induced Fluorescence (TRLIF), Extended X-ray Absorption Fine Structure (EXAFS) at the LIII edge, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM) and the resulting data were compared with the speciation modeling. In seawater, the americium(III) complex (as well as the corresponding europium complex, although with conformational differences) was identified as a ternary sodium biscarbonato complex, whose formula can be tentatively written as NaAm(CO3)2·nH2O. It is therefore this chemical form of americium that is

  5. Microbial community response to seawater amendment in low-salinity tidal sediments.

    PubMed

    Edmonds, Jennifer W; Weston, Nathaniel B; Joye, Samantha B; Mou, Xiaozhen; Moran, Mary Ann

    2009-10-01

    Rising sea levels and excessive water withdrawals upstream are making previously freshwater coastal ecosystems saline. Plant and animal responses to variation in the freshwater-saline interface have been well studied in the coastal zone; however, microbial community structure and functional response to seawater intrusion remains relatively unexplored. Here, we used molecular approaches to evaluate the response of the prokaryotic community to controlled changes in porewater salinity levels in freshwater sediments from the Altamaha River, Georgia, USA. This work is a companion to a previously published study describing results from an experiment using laboratory flow-through sediment core bioreactors to document biogeochemical changes as porewater salinity was increased from 0 to 10 over 35 days. As reported in Weston et al. (Biogeochemistry, 77:375-408, 62), porewater chemistry was monitored, and cores were sacrificed at 0, 9, 15, and 35 days, at which time we completed terminal restriction fragment length polymorphism and 16S rRNA clone library analyses of sediment microbial communities. The biogeochemical study documented changes in mineralization pathways in response to artificial seawater additions, with a decline in methanogenesis, a transient increase in iron reduction, and finally a dominance of sulfate reduction. Here, we report that, despite these dramatic and significant changes in microbial activity at the biogeochemical level, no significant differences were found between microbial community composition of control vs. seawater-amended treatments for either Bacterial or Archaeal members. Further, taxa in the seawater-amended treatment community did not become more "marine-like" through time. Our experiment suggests that, as seawater intrudes into freshwater sediments, observed changes in metabolic activity and carbon mineralization on the time scale of weeks are driven more by shifts in gene expression and regulation than by changes in the composition of

  6. Iodine-129 and iodine-127 in European seawaters and in precipitation from Northern Germany.

    PubMed

    Michel, R; Daraoui, A; Gorny, M; Jakob, D; Sachse, R; Tosch, L; Nies, H; Goroncy, I; Herrmann, J; Synal, H-A; Stocker, M; Alfimov, V

    2012-03-01

    In order to obtain a comprehensive survey on the consequences of the marine (129)I discharges from the European reprocessing plants La Hague and Sellafield, the distribution of (129)I and (127)I in surface waters of the North Sea, the English Channel, the Irish Sea, and the Northeast Atlantic was studied using accelerator mass spectrometry for (129)I and ICP-MS for (127)I. Samples of seawater were taken in the German Bight in May, September, and November 2005 and in the entire North Sea and the English Channel in August 2005. Further samples were obtained from the Irish Sea in June and August 2006 and from Arctic waters between Spitsbergen and Southern Norway in September 2005. (129)I is a conservative tracer in seawater. The concentrations of (127)I are relatively constant with exceptions of coastal areas with high biological activity and of areas influenced by influx from rivers and the Baltic Sea. The variability of the (129)I/(127)I isotopic ratios is exclusively determined by admixture of (129)I released from the reprocessing facilities Sellafield and La Hague to the seawater. The (129)I/(127)I ratios were between 4 × 10(-9)and 3 × 10(-6): at least 3 orders of magnitude higher than the natural equilibrium isotopic ratio 1.5 × 10(-12). (129)I/(127)I ratios of a few times 10(-10) were only found in seawater from the Indian Ocean and from the Pacific at Hawaii. Comparison of the results obtained for seawater with those of a measurement of airborne iodine species and with iodine isotopes in precipitation in Northern Germany demonstrates the transfer of (129)I and (127)I from the sea into the atmosphere and the dominating role of the marine discharges for the atmospheric fallout of (129)I in Western Europe. The results are discussed with the goal to estimate the relevance of the marine discharges for the contamination of the continental areas.

  7. New Dielectric Measurement Data to Determine the Permittivity of Seawater at 1.4313 Hz

    NASA Technical Reports Server (NTRS)

    Lang, R.; Zhou, Y.; Utku, C.; Levine, D.

    2012-01-01

    This paper describes the new measurements - made in 2010-2011 - of the dielectric constant of seawater at 1.413 GHz using a resonant cavity technique. The purpose of these measurements is to develop an accurate relationship concerning the dependence of the dielectric constant of seawater on temperature and salinity for use by the Aquarius inversion algorithm. Aquarius is a NASA/CONAE satellite mission launched in June of 2011 with the primary mission of measuring global sea surface salinity with a 1.413 GHz radiometer to an accuracy of 0.2 psu. A brass microwave cavity resonant at 1.413 GHz has been used to measure the dielectric constant of seawater. The seawater is introduced into the cavity through a capillary glass tube having an inner diameter of 0.1 mm. The change of resonant frequency and the cavity Q value are used to determine the real and imaginary parts of the dielectric constant of seawater. Measurements are automated with Visual Basic software developed at the George Washington University. In this paper, new results from measurements made since September 2010 will be presented for salinities of 30, 35 and 38 psu with a temperature range of 0 C to 35 C in intervals of 5 C. These measurements are more accurate than earlier measurements made in 2008. The new results will be compared to the Klein-Swift (KS) and Meissner-Wentz (MW) model functions. The importance of an accurate model function will be illustrated by using these model functions to invert the Aquarius brightness temperature to retrieve the salinity values. The salinity values will be compared to co-located in situ data collected by Argo buoys.

  8. Acidified seawater impacts sea urchin larvae pH regulatory systems relevant for calcification

    PubMed Central

    Stumpp, Meike; Hu, Marian Y.; Melzner, Frank; Gutowska, Magdalena A.; Dorey, Narimane; Himmerkus, Nina; Holtmann, Wiebke C.; Dupont, Sam T.; Thorndyke, Michael C.; Bleich, Markus

    2012-01-01

    Calcifying echinoid larvae respond to changes in seawater carbonate chemistry with reduced growth and developmental delay. To date, no information exists on how ocean acidification acts on pH homeostasis in echinoderm larvae. Understanding acid–base regulatory capacities is important because intracellular formation and maintenance of the calcium carbonate skeleton is dependent on pH homeostasis. Using H+-selective microelectrodes and the pH-sensitive fluorescent dye BCECF, we conducted in vivo measurements of extracellular and intracellular pH (pHe and pHi) in echinoderm larvae. We exposed pluteus larvae to a range of seawater CO2 conditions and demonstrated that the extracellular compartment surrounding the calcifying primary mesenchyme cells (PMCs) conforms to the surrounding seawater with respect to pH during exposure to elevated seawater pCO2. Using FITC dextran conjugates, we demonstrate that sea urchin larvae have a leaky integument. PMCs and spicules are therefore directly exposed to strong changes in pHe whenever seawater pH changes. However, measurements of pHi demonstrated that PMCs are able to fully compensate an induced intracellular acidosis. This was highly dependent on Na+ and HCO3−, suggesting a bicarbonate buffer mechanism involving secondary active Na+-dependent membrane transport proteins. We suggest that, under ocean acidification, maintained pHi enables calcification to proceed despite decreased pHe. However, this probably causes enhanced costs. Increased costs for calcification or cellular homeostasis can be one of the main factors leading to modifications in energy partitioning, which then impacts growth and, ultimately, results in increased mortality of echinoid larvae during the pelagic life stage. PMID:23077257

  9. The airborne lava-seawater interaction plume at Kilauea Volcano, Hawai'i

    USGS Publications Warehouse

    Edmonds, M.; Gerlach, T.M.

    2006-01-01

    Lava flows into the sea at Kīlauea Volcano, Hawaiʻi, and generates an airborne gas and aerosol plume. Water (H2O), hydrogen chloride (HCl), carbon dioxide (CO2), nitrogen dioxide (NO2) and sulphur dioxide (SO2) gases were quantified in the plume in 2004–2005, using Open Path Fourier Transform infra-red Spectroscopy. The molar abundances of these species and thermodynamic modelling are used to discuss their generation. The range in molar HCl / H2O confirms that HCl is generated when seawater is boiled dry and magnesium salts are hydrolysed (as proposed by [T.M. Gerlach, J.L. Krumhansl, R.O. Fournier, J. Kjargaard, Acid rain from the heating and evaporation of seawater by molten lava: a new volcanic hazard, EOS (Trans. Am. Geophys. Un.) 70 (1989) 1421–1422]), in contrast to models of Na-metasomatism. Airborne droplets of boiled seawater brine form nucleii for subsequent H2O and HCl condensation, which acidifies the droplets and liberates CO2 gas from bicarbonate and carbonate. NO2 is derived from the thermal decomposition of nitrates in coastal seawater, which takes place as the lava heats droplets of boiled seawater brine to 350–400 °C. SO2 is derived from the degassing of subaerial lava flows on the coastal plain. The calculated mass flux of HCl from a moderate-sized ocean entry significantly increases the total HCl emission at Kīlauea (including magmatic sources) and is comparable to industrial HCl emitters in the United States. For larger lava ocean entries, the flux of HCl will cause intense local environmental hazards, such as high localised HCl concentrations and acid rain.

  10. Speciation of americium in seawater and accumulation in the marine sponge Aplysina cavernicola.

    PubMed

    Maloubier, Melody; Michel, Hervé; Solari, Pier Lorenzo; Moisy, Philippe; Tribalat, Marie-Aude; Oberhaensli, François R; Dechraoui Bottein, Marie Yasmine; Thomas, Olivier P; Monfort, Marguerite; Moulin, Christophe; Den Auwer, Christophe

    2015-12-21

    The fate of radionuclides in the environment is a cause of great concern for modern society, seen especially in 2011 after the Fukushima accident. Among the environmental compartments, seawater covers most of the earth's surface and may be directly or indirectly impacted. The interaction between radionuclides and the marine compartment is therefore essential for better understanding the transfer mechanisms from the hydrosphere to the biosphere. This information allows for the evaluation of the impact on humans via our interaction with the biotope that has been largely undocumented up to now. In this report, we attempt to make a link between the speciation of heavy elements in natural seawater and their uptake by a model marine organism. More specifically, because the interaction of actinides with marine invertebrates has been poorly studied, the accumulation in a representative member of the Mediterranean coralligenous habitat, the sponge Aplysina cavernicola, was investigated and its uptake curve exposed to a radiotracer (241)Am was estimated using a high-purity Ge gamma spectrometer. But in order to go beyond the phenomenological accumulation rate, the speciation of americium(III) in seawater must be assessed. The speciation of (241)Am (and natural europium as its chemically stable surrogate) in seawater was determined using a combination of different techniques: Time-Resolved Laser-Induced Fluorescence (TRLIF), Extended X-ray Absorption Fine Structure (EXAFS) at the LIII edge, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM) and the resulting data were compared with the speciation modeling. In seawater, the americium(III) complex (as well as the corresponding europium complex, although with conformational differences) was identified as a ternary sodium biscarbonato complex, whose formula can be tentatively written as NaAm(CO3)2·nH2O. It is therefore this chemical form of americium that is

  11. Substrate Use of Pseudovibrio sp. Growing in Ultra-Oligotrophic Seawater

    PubMed Central

    Schwedt, Anne; Seidel, Michael; Dittmar, Thorsten; Simon, Meinhard; Bondarev, Vladimir; Romano, Stefano; Lavik, Gaute; Schulz-Vogt, Heide N.

    2015-01-01

    Marine planktonic bacteria often live in habitats with extremely low concentrations of dissolved organic matter (DOM). To study the use of trace amounts of DOM by the facultatively oligotrophic Pseudovibrio sp. FO-BEG1, we investigated the composition of artificial and natural seawater before and after growth. We determined the concentrations of dissolved organic carbon (DOC), total dissolved nitrogen (TDN), free and hydrolysable amino acids, and the molecular composition of DOM by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The DOC concentration of the artificial seawater we used for cultivation was 4.4 μmol C L-1, which was eight times lower compared to the natural oligotrophic seawater we used for parallel experiments (36 μmol C L -1). During the three-week duration of the experiment, cell numbers increased from 40 cells mL-1 to 2x104 cells mL -1 in artificial and to 3x105 cells mL -1 in natural seawater. No nitrogen fixation and minor CO2 fixation (< 1% of cellular carbon) was observed. Our data show that in both media, amino acids were not the main substrate for growth. Instead, FT-ICR-MS analysis revealed usage of a variety of different dissolved organic molecules, belonging to a wide range of chemical compound groups, also containing nitrogen. The present study shows that marine heterotrophic bacteria are able to proliferate with even lower DOC concentrations than available in natural ultra-oligotrophic seawater, using unexpected organic compounds to fuel their energy, carbon and nitrogen requirements. PMID:25826215

  12. Precipitation and Seawater Isotopic Variability from Hawaii to the equator: the 2014-2015 ENSO cycle

    NASA Astrophysics Data System (ADS)

    Cobb, K. M.; Conroy, J. L.; Moerman, J. W.; Bosma, C.; Everitt, L.; Stevenson, S.; Noone, D. C.; Grothe, P. R.; Schneider, N.; Merrifield, M. A.; Farnsworth, M.

    2015-12-01

    An increasing number of paleoclimate reconstructions rely on the isotopic variability of precipitation or seawater as a proxy for past hydrological variability, even though modern-day water isotope variability is poorly constrained by observations. Nowhere is this more apparent than in the tropical Pacific, where paleo-water isotope reconstructions imply that anthropogenic climate change has driven dramatic shifts in the isotopic composition of surface waters (Nurhati et al., 2009), yet water isotope observations in this region are virtually non-existent. Here we present a new set of weekly seawater and daily precipitation isotope observations along a meridional gradient in the tropical Pacific, spanning from Hawaii (21N, 158W) to Palmyra Island (6N, 162W) to Christmas Island (2N, 157W), that spans the development and growth of the current ENSO cycle that began in 2014. We use a suite of high-quality in situ observations of ocean conditions (salinity, temperature) as well as surface meteorological measurements (relative humidity, precipitation amount, wind speed and direction) to provide an interpretive framework for the observed isotopic variations, with a focus on the expression of seasonal to interannual features in the dataset. A complementary dataset of precipitation and seawater isotopes from across the equator in the tropical Pacific basin provides additional diagnostic context. We also compare our observed isotopic variations to output from numerical simulations of precipitation and seawater isotopes in the tropical Pacific. We discuss the implications of our findings for the design of long-term monitoring programs in the tropical Pacific, as well as the interpretation of proxy-based reconstructions of seawater and precipitation water isotopes.

  13. Characterizing seawater oxygen isotopic variability in a regional ocean modeling framework: Implications for coral proxy records

    NASA Astrophysics Data System (ADS)

    Stevenson, S.; Powell, B. S.; Merrifield, M. A.; Cobb, K. M.; Nusbaumer, J.; Noone, D.

    2015-11-01

    Reconstructions of the El Niño-Southern Oscillation (ENSO) are often created using the oxygen isotopic ratio in tropical coral skeletons (δ18O). However, coral δ18O can be difficult to interpret quantitatively, as it reflects changes in both temperature and the δ18O value of seawater. Small-scale (10-100 km) processes affecting local temperature and seawater δ18O are also poorly quantified and contribute an unknown amount to intercoral δ18O offsets. A new version of the Regional Ocean Modeling System capable of directly simulating seawater δ18O (isoROMS) is therefore presented to address these issues. The model is used to simulate δ18O variations over the 1979-2009 period throughout the Pacific at coarse (O(50 km)) resolution, in addition to 10 km downscaling experiments covering the central equatorial Pacific Line Islands, a preferred site for paleo-ENSO reconstruction from corals. A major impact of downscaling at the Line Islands is the ability to resolve fronts associated with tropical instability waves (TIWs), which generate large excursions in both temperature and seawater δ18O at Palmyra Atoll (5.9°N, 162.1°W). TIW-related sea surface temperature gradients are smaller at neighboring Christmas Island (1.9°N, 157.5°W), but the interaction of mesoscale features with the steep island topography nonetheless generates cross-island temperature differences of up to 1°C. These nonlinear processes alter the slope of the salinity:seawater δ18O relationship at Palmyra and Christmas, as well as affect the relation between coral δ18O and indices of ENSO variability. Consideration of the full physical oceanographic context of reef environments is therefore crucial for improving δ18O-based ENSO reconstructions.

  14. L-band Dielectric Constant Measurements of Seawater (Oral presentation and SMOS Poster)

    NASA Technical Reports Server (NTRS)

    Lang, Roger H.; Utku, Cuneyt; LeVine, David M.

    2003-01-01

    This paper describes a resonant cavity technique for the measurement of the dielectric constant of seawater as a function of its salinity. Accurate relationships between salinity and dielectric constant (which determines emissivity) are needed for sensor systems such as SMOS and Aquarius that will monitor salinity from space in the near future. The purpose of the new measurements is to establish the dependence of the dielectric constant of seawater on salinity in contemporary units (e.g. psu) and to take advantage of modern instrumentation to increase the accuracy of these measurements. The measurement device is a brass cylindrical cavity 16cm in diameter and 7cm in height. The seawater is introduced into the cavity through a slender glass tube having an inner diameter of 0.1 mm. By assuming that this small amount of seawater slightly perturbs the internal fields in the cavity, perturbation theory can be employed. A simple formula results relating the real part of the dielectric constant to the change in resonant frequency of the cavity. In a similar manner, the imaginary part of the dielectric constant is related to the change in the cavity s Q. The expected accuracy of the cavity technique is better than 1% for the real part and 1 to 2% for the imaginary part. Presently, measurements of methanol have been made and agree with precision measurements in the literature to within 1% in both real and imaginary parts. Measurements have been made of the dielectric constant of seawater samples from Ocean Scientific in the United Kingdom with salinities of 10, 30, 35 and 38 psu. All measurements were made at room temperature. Plans to make measurements at a range of temperatures and salinities will be discussed.

  15. Aerobic methanotrophic communities at the Red Sea brine-seawater interface

    PubMed Central

    Abdallah, Rehab Z.; Adel, Mustafa; Ouf, Amged; Sayed, Ahmed; Ghazy, Mohamed A.; Alam, Intikhab; Essack, Magbubah; Lafi, Feras F.; Bajic, Vladimir B.; El-Dorry, Hamza; Siam, Rania

    2014-01-01

    The central rift of the Red Sea contains 25 brine pools with different physicochemical conditions, dictating the diversity and abundance of the microbial community. Three of these pools, the Atlantis II, Kebrit and Discovery Deeps, are uniquely characterized by a high concentration of hydrocarbons. The brine-seawater interface, described as an anoxic-oxic (brine-seawater) boundary, is characterized by a high methane concentration, thus favoring aerobic methane oxidation. The current study analyzed the aerobic free–living methane-oxidizing bacterial communities that potentially contribute to methane oxidation at the brine-seawater interfaces of the three aforementioned brine pools, using metagenomic pyrosequencing, 16S rRNA pyrotags and pmoA library constructs. The sequencing of 16S rRNA pyrotags revealed that these interfaces are characterized by high microbial community diversity. Signatures of aerobic methane-oxidizing bacteria were detected in the Atlantis II Interface (ATII-I) and the Kebrit Deep Upper (KB-U) and Lower (KB-L) brine-seawater interfaces. Through phylogenetic analysis of pmoA, we further demonstrated that the ATII-I aerobic methanotroph community is highly diverse. We propose four ATII-I pmoA clusters. Most importantly, cluster 2 groups with marine methane seep methanotrophs, and cluster 4 represent a unique lineage of an uncultured bacterium with divergent alkane monooxygenases. Moreover, non-metric multidimensional scaling (NMDS) based on the ordination of putative enzymes involved in methane metabolism showed that the Kebrit interface layers were distinct from the ATII-I and DD-I brine-seawater interfaces. PMID:25295031

  16. Light Penetration in Seawater Polluted by Dispersed Oil: Results of Radiative Transfer Modelling

    NASA Astrophysics Data System (ADS)

    Haule, K.; Darecki, M.; Toczek, H.

    2015-11-01

    The downwelling light in seawater is shaped by natural seawater constituents as well as by some external substances which can occur locally and temporally. In this study we focused on dispersed oil droplets which can be found in seawater after an oil spill or in the consequence of intensive shipping, oil extraction and transportation. We applied our modified radiative transfer model based on Monte Carlo code to evaluate the magnitude of potential influence of dispersed oil droplets on the downwelling irradiance and the depth of the euphotic zone. Our model was validated on the basis of in situ measurements for natural (unpolluted) seawater in the Southern Baltic Sea, resulting in less than 5% uncertainty. The optical properties of dispersed Petrobaltic crude oil were calculated on the basis of Mie theory and involved into radiative transfer model. We found that the changes in downwelling light caused by dispersed oil depend on several factors such as oil droplet concentration, size distribution, and the penetration depth (i.e. vertical range of oil droplets occurrence below sea surface). Petrobaltic oil droplets of submicron sizes and penetration depth of 5 m showed a potentially detectable reduction in the depth of the euphotic zone of 5.5% at the concentration of only 10 ppb. Micrometer-sized droplets needed 10 times higher concentration to give a similar effect. Our radiative transfer model provided data to analyse and discuss the influence of each factor separately. This study contributes to the understanding of the change in visible light penetration in seawater affected by dispersed oil.

  17. Diachronous seawater retreat from the southwestern margin of the Tarim Basin in the late Eocene

    NASA Astrophysics Data System (ADS)

    Sun, Jimin; Windley, Brian F.; Zhang, Zhiliang; Fu, Bihong; Li, Shihu

    2016-02-01

    In contrast to the present hyper-arid inland basin surrounded by the high mountains of Central Asia, the western Tarim Basin was once connected with the Tajik Basin at least in the late Eocene, when an epicontinental sea extended from the western Tarim Basin to Europe. Western Tarim is a key site for studying the retreat of seawater, which was likely caused by the northward indentation of the Pamir arc and facilitated by the climatic cooling and eustatic sea level change in the Cenozoic. Here we present a new magnetostratigraphic record from the Tarim Basin that provides evidence of diachronous seawater retreat from its southwestern margin. We studied about 1360 m of well-exposed Eocene-Oligocene strata at Keliyang in the folded foreland of the West Kunlun orogen. Until now, the age of the strata has only been minimally constrained by the presence of late mid-Eocene marine fossils. Our biostratigraphic and magnetostratigraphic results demonstrate that the age of the sedimentary sequence ranges from ∼46 Ma to ∼26 Ma (mid-Eocene to late-Oligocene) and the seawater retreat at Keliyang took place at ∼40 Ma. Considering the stepwise northward indentation and uplift of the Pamir orogen, together with the other previous results, we propose that seawater retreat from the southwestern margin of the Tarim Basin was diachronous in the late Eocene ranging from 47 Ma to 40 Ma. The regional indentation, uplift and erosion of the Pamir orogen played the dominant and important role in controlling the seawater retreat from the southwestern margin of the Tarim Basin.

  18. Intestinal Na+ and Cl- levels control drinking behavior in the seawater-adapted eel Anguilla japonica

    PubMed

    Ando; Nagashima

    1996-01-01

    To analyze drinking mechanisms in seawater teleosts, seawater-adapted eels were used as a model system. When the intestine of the eel was perfused with iso-osmotic mannitol, the eels drank sea water. However, when the perfusion medium was switched to iso-osmotic NaCl, seawater drinking was depressed. This depression was observed even after blocking NaCl absorption across the intestine by replacement of the perfusate with choline chloride or by treatment with furosemide, an inhibitor of NaCl and water absorption across the eel intestine. Furthermore, depression of drinking rate preceded an increase in urine flow by over 1 h. These results indicate that this depression is not due to a recovery of blood volume and suggest that intestinal Cl- itself inhibits drinking. Direct action of luminal Cl- on drinking behavior was further supported by the observation that perfusion with iso-osmotic NMDG-HCl, Tris-HCl, choline chloride and RbCl all inhibited seawater drinking. When NaCl in the perfusion medium was replaced with sodium acetate, sodium butyrate, sodium methylsulfate or NaSCN, the drinking rate was enhanced threefold, suggesting that Na+ itself stimulates drinking in the absence of Cl-. In the present study, concentrations of Na+ and Cl- in the swallowed fluid were also measured simultaneously. As the drinking rate was enhanced, the Na+ and Cl- concentrations in the gastrointestinal fluid were increased. On the basis of these results, it seems possible that high concentrations of Cl- in the intestine reduce the drinking rate, thus lowering esophageal Cl- concentration due to desalination of the ingested sea water. When Cl- concentration in the intestine falls below a certain level, Na+ will stimulate seawater drinking again.

  19. Determination of CCl 3F and CCl 2F 2 in seawater and air

    NASA Astrophysics Data System (ADS)

    Bullister, J. L.; Weiss, R. F.

    1988-05-01

    An improved analytical technique has been developed for the rapid and accurate shipboard measurement of two anthropogenically produced chlorofluorocarbons (CFCs), CCl 3F (F-11) and CCl 2F 2 (F-12) in air and seawater. Gas samples (dry air or standard) are injected into a stream of purified gas and then concentrated in a low temperature trap. Seawater samples collected in oceanographic Niskin bottles are transferred into glass syringes for storage until analysis. An aliquot of approximately 30 cm 3 of seawater is introduced into a glass stripping chamber where the dissolved gases are purged with purified gas, and the evolved CFCs are concentrated in the same cold trap. The trap is subsequently isolated and heated, and the CFCs are automatically transferred by a stream of carrier gas into a precolumn and then a chromatographic separating column. The CCl 3F and CCl 2F 2 peaks are detected by an electron capture detector (ECD) and their areas are integrated digitally. CFC amounts are calculated using fitted calibration curves, generated by injection of various multiple aliquots of gas standard containing known concentrations of CFCs. Preliminary concentration values for these compounds are printed at the completion of each analysis. Total analysis time for air and water samples is < 10 min, allowing detailed vertical profiles of the concentrations of these compounds in the water column and concentrations in the overlying atmosphere to be determined within a few hours of the completion of a hydrographic station. Typical relative standard deviations for analyses of CCl 3F and CCl 2F 2 in near-surface seawater containing equilibrium levels of these compounds are approximately 1%. Limits of detection for both compounds in 30 cm 3 seawater samples are about 0.005 × 10 -12 mol kg -1.

  20. Seawater recharge into oceanic crust: IODP Exp 327 Site U1363 Grizzly Bare outcrop

    NASA Astrophysics Data System (ADS)

    Wheat, C. Geoffrey; Hulme, Samuel M.; Fisher, Andrew T.; Orcutt, Beth N.; Becker, Keir

    2013-06-01

    Systematic differences in sediment thermal and pore water chemical profiles from Integrated Ocean Drilling Program Site U1363 document mixing and reaction within the basaltic crust adjacent to Grizzly Bare outcrop, a site of hydrothermal recharge into 3.6 My-old basaltic crust. A transect of seven holes was drilled ~50 m to ~750 m away from the base of the outcrop. Temperatures at the sediment-basement interface increase from ~6°C to >30°C with increasing distance from the outcrop, and heat flow is suppressed within several hundred meters from the outcrop. Calculated fluid compositions at the sediment-basement interface are generally explained by mixing between bottom seawater and altered crustal basement fluids, with a composition similar but not identical to fluids from seeps at Baby Bare outcrop, located ~45 km to the northeast. Reactions within upper basement and overlying sediment affect a variety of ions (Mn, Fe, Mo, Si, PO43-, V, and U) and δ13DIC, indicating a diagenetic influence and diffusive exchange with overlying sediment pore waters. The apparent 14C age of basal pore fluids is much older than bottom seawater. Collectively, these results are consistent with seawater recharge at Grizzly Bare outcrop; however, there are strong gradients in fluid composition within 50 m of the outcrop, providing evidence for complex flow paths and vigorous mixing of young, recently recharged seawater with much older, more reacted basement fluid. The proximity of these altered fluids to the edge of the outcrop raises the possibility for fluid seepage from the outcrop in addition to seawater recharge.

  1. Comparing Organic Aerosol Composition from Marine Biogenic Sources to Seawater and to Physical Sea Spray Models

    NASA Astrophysics Data System (ADS)

    Russell, L. M.; Frossard, A. A.; Sanchez, K.; Massoli, P.; Elliott, S.; Burrows, S. M.; Bates, T. S.; Quinn, P.

    2015-12-01

    In much of the marine atmosphere, organic components in aerosol particles have many sources other than sea spray that contribute organic constituents. For this reason, physical sea spray models provide an important technique for studying the organic composition of particles from marine biogenic sources. The organic composition of particles produced by two different physical sea spray models were measured in three open ocean seawater types: (i) Coastal California in the northeastern Pacific, which is influenced by wind-driven, large-scale upwelling leading to productive or eutrophic (nutrient-rich) seawater and high chl-a concentrations, (ii) George's Bank in the northwestern Atlantic, which is also influenced by nutrient upwelling and eutrophic seawater with phytoplankton productivity and high chl-a concentrations, and (iii) the Sargasso Sea in the subtropical western Atlantic, which is oligotrophic and nutrient-limited, reflected in low phytoplankton productivity and low chl-a concentrations. Fourier transform infrared spectroscopy provides information about the functional group composition that represents the marine organic fraction more completely than is possible with techniques that measure non-refractory mass (vaporizable at 650°C). After separating biogenic marine particles from those from other sources, the measured compositions of atmospheric marine aerosol particles from three ocean regions is 65±12% hydroxyl, 21±9% alkane, 6±6% amine, and 7±8% carboxylic acid functional groups. The organic composition of atmospheric primary marine (ocean-derived) aerosol particles is nearly identical to model generated primary marine aerosol particles from bubbled seawater. Variability in productive and non-productive seawater may be caused by the presence of surfactants that can stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components without substantial changes in overall group composition

  2. Improvement of the analysis of the biochemical oxygen demand (BOD) of Mediterranean seawater by seeding control.

    PubMed

    Simon, F Xavier; Penru, Ywann; Guastalli, Andrea R; Llorens, Joan; Baig, Sylvie

    2011-07-15

    Biochemical oxygen demand (BOD) is a useful parameter for assessing the biodegradability of dissolved organic matter in water. At the same time, this parameter is used to evaluate the efficiency with which certain processes remove biodegradable natural organic matter (NOM). However, the values of BOD in seawater are very low (around 2 mgO(2)L(-1)) and the methods used for its analysis are poorly developed. The increasing attention given to seawater desalination in the Mediterranean environment, and related phenomena such as reverse osmosis membrane biofouling, have stimulated interest in seawater BOD close to the Spanish coast. In this study the BOD analysis protocol was refined by introduction of a new step in which a critical quantity of autochthonous microorganisms, measured as adenosine triphosphate, is added. For the samples analyzed, this improvement allowed us to obtain reliable and replicable BOD measurements, standardized with solutions of glucose-glutamic acid and acetate. After 7 days of analysis duration, more than 80% of ultimate BOD is achieved, which in the case of easily biodegradable compounds represents nearly a 60% of the theoretical oxygen demand. BOD(7) obtained from the Mediterranean Sea found to be 2.0±0.3 mgO(2)L(-1) but this value decreased with seawater storage time due to the rapid consumption of labile compounds. No significant differences were found between two samples points located on the Spanish coast, since their organic matter content was similar. Finally, the determination of seawater BOD without the use of inoculum may lead to an underestimation of BOD.

  3. Enhancing uranium uptake by amidoxime adsorbent in seawater: An investigation for optimum alkaline conditioning parameters

    DOE PAGES

    Das, Sadananda; Tsouris, Costas; Zhang, Chenxi; Brown, Suree; Janke, Christopher James; Mayes, Richard T.; Kuo, Li -Jung; Gill, Gary; Dai, Sheng; Kim, J.; et al

    2015-09-07

    A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 °C). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentration ofmore » ~7–8 ppm and pH 8. Fourier transform infrared spectroscopy and solid-state NMR analyses indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 °C resulted in an increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. The scanning electron microscopy showed that long

  4. Enhancing uranium uptake by amidoxime adsorbent in seawater: An investigation for optimum alkaline conditioning parameters

    SciTech Connect

    Das, Sadananda; Tsouris, Costas; Zhang, Chenxi; Brown, Suree; Janke, Christopher James; Mayes, Richard T.; Kuo, Li -Jung; Gill, Gary; Dai, Sheng; Kim, J.; Oyola, Y.; Wood, J. R.

    2015-09-07

    A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 °C). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentration of ~7–8 ppm and pH 8. Fourier transform infrared spectroscopy and solid-state NMR analyses indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 °C resulted in an increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. The scanning electron microscopy showed that long conditioning

  5. PCB impairs smoltification and seawater performance in anadromous Arctic charr (Salvelinus alpinus)

    USGS Publications Warehouse

    Jorgensen, E.H.; Aas-Hansen, O.; Maule, A.G.; Strand, J.E.T.; Vijayan, M.M.

    2004-01-01

    The impacts of polychlorinated biphenyl (PCB) exposure on smoltification and subsequent seawater performance were investigated in hatchery-reared, anadromous Arctic charr (Salvelinus alpinus). The fish were subjected to a 2-month summer seawater residence, after which they were orally dosed with 0 (Control, C), 1 (Low Dose, LD) or 100 mg Aroclor 1254 kg-1 body mass (High Dose, HD) in November. They were then held in fresh water, without being fed (to mimic their natural overwintering in freshwater), until they had smolted in June the next year. The smolts were then transferred to seawater and fed to mimic their summer feeding residence in seawater, followed by a period without food in freshwater from August until maturation in October. Compared with C and LD charr, the HD charr had either a transient or a permanent reduction in plasma growth hormone, insulin-like growth factor-1, and thyroxin and triiodothyronine titers during the period of smoltification. These hormonal alterations in the HD charr corresponded with impaired hyposmoregulatory ability in May and June, as well as reduced growth rate and survival after transference to seawater. Consequently, fewer fish in the HD group matured in October compared to the other two treatments. The HD fish had a liver PCB concentration ranging between 14 and 42 mg kg-1 wet mass, whereas there were similar, and very low, liver PCB concentrations in LD and C fish throughout the smolting period. Our findings suggest that PCB might compromise mechanisms important for fitness in a fish species living in an extreme environment. ?? 2004 Elsevier Inc. All rights reserved.

  6. Improvement of the analysis of the biochemical oxygen demand (BOD) of Mediterranean seawater by seeding control.

    PubMed

    Simon, F Xavier; Penru, Ywann; Guastalli, Andrea R; Llorens, Joan; Baig, Sylvie

    2011-07-15

    Biochemical oxygen demand (BOD) is a useful parameter for assessing the biodegradability of dissolved organic matter in water. At the same time, this parameter is used to evaluate the efficiency with which certain processes remove biodegradable natural organic matter (NOM). However, the values of BOD in seawater are very low (around 2 mgO(2)L(-1)) and the methods used for its analysis are poorly developed. The increasing attention given to seawater desalination in the Mediterranean environment, and related phenomena such as reverse osmosis membrane biofouling, have stimulated interest in seawater BOD close to the Spanish coast. In this study the BOD analysis protocol was refined by introduction of a new step in which a critical quantity of autochthonous microorganisms, measured as adenosine triphosphate, is added. For the samples analyzed, this improvement allowed us to obtain reliable and replicable BOD measurements, standardized with solutions of glucose-glutamic acid and acetate. After 7 days of analysis duration, more than 80% of ultimate BOD is achieved, which in the case of easily biodegradable compounds represents nearly a 60% of the theoretical oxygen demand. BOD(7) obtained from the Mediterranean Sea found to be 2.0±0.3 mgO(2)L(-1) but this value decreased with seawater storage time due to the rapid consumption of labile compounds. No significant differences were found between two samples points located on the Spanish coast, since their organic matter content was similar. Finally, the determination of seawater BOD without the use of inoculum may lead to an underestimation of BOD. PMID:21645736

  7. Detection of marine toxins, brevetoxin-3 and saxitoxin, in seawater using neuronal networks.

    PubMed

    Kulagina, Nadezhda V; Mikulski, Christina M; Gray, Samuel; Ma, Wu; Doucette, Gregory J; Ramsdell, John S; Pancrazio, Joseph J

    2006-01-15

    There is a need for assay systems that can detect known and unanticipated neurotoxins associated with harmful algal blooms. The present work describes our attempt to monitor the presence of brevetoxin-3 (PbTx-3) and saxitoxin (STX) in a seawater matrix using the neuronal network biosensor (NNB). The NNB relies on cultured mammalian neurons grown over microelectrode arrays, where the inherent bioelectrical activity of the network manifested as extracellular action potentials can be monitored noninvasively. Spinal cord neuronal networks were prepared from embryonic mice and the mean spike rate across the network was analyzed before and during exposure to the toxins. Extracellular action potentials from the network are highly sensitive not only to purified STX and PbTx-3, but also when in combination with matrixes such as natural seawater and algal growth medium. Detection limits for STX and PbTx-3, respectively, are 0.031 and 0.33 nM in recording buffer and 0.076 and 0.48 nM in the presence of 25-fold-diluted seawater. Our results demonstrated that neuronal networks could be used for analysis of Alexandrium fundyense (STX-producer) and Karenia brevis (PbTx-producer) algal samples lysed directly in the seawater-based growth medium and appropriately diluted with HEPES-buffered recording medium. The cultured network responded by changes in mean spike rate to the presence of STX-or PbTx-producing algae but not to the samples of two non-STX and non-PbTx isolates of the same algal genera. This work provides evidence that the NNB has the capacity to rapidly detect toxins associated with cells of toxic algal species or as dissolved forms present in seawater and hasthe potential for monitoring toxin levels during harmful algal blooms. PMID:16468405

  8. Petroleum hydrocarbon contaminations in the intertidal seawater after the Hebei Spirit oil spill--effect of tidal cycle on the TPH concentrations and the chromatographic characterization of seawater extracts.

    PubMed

    Kim, Moonkoo; Hong, Sang Hee; Won, Jongho; Yim, Un Hyuk; Jung, Jee-Hyun; Ha, Sung Yong; An, Joon Geon; Joo, Changkyu; Kim, Eunsic; Han, Gi Myung; Baek, Seongho; Choi, Hyun-Woo; Shim, Won Joon

    2013-02-01

    In December 2007, the oil tanker Hebei Spirit released approximately 12,547,000 L of crude oil off the west coast of Korea, impacting more than 375 km of coastline. The seawater TPH concentrations immediately after the spill ranged from 1.5 to 7310 μg L⁻¹, with an average of 732 μg L⁻¹. The concentrations appeared to decrease drastically to 2.0-224 μg L⁻¹ in one month after the spill. The TPH concentrations in seawater fluctuated with time thereafter because of the remobilization of oil by continuing shoreline cleanup activities and subsequent wave/tidal actions. Seawater TPH concentrations were much higher during high tide than during low tide due to the resuspension of stranded oil. The variation of TPH levels in seawater also matched the spring-neap tidal cycle in the study areas for the first three weeks of the study. Comparisons of the gas chromatograms of the seawater with the water accommodated fraction and the cargo oil indicated that seawater samples were contaminated mainly by the dispersed droplets of spilled oil. One year of monitoring revealed that the oil content in seawater had clearly decreased at most sites, although some regional fluctuations of oil contamination were noted until June 2008.

  9. Occurrence and air-seawater exchange of brominated flame retardants and Dechlorane Plus in the North Sea

    NASA Astrophysics Data System (ADS)

    Möller, Axel; Xie, Zhiyong; Caba, Armando; Sturm, Renate; Ebinghaus, Ralf

    2012-01-01

    The occurrence, spatial and seasonal concentration variations in air and seawater and the air-seawater exchange of polybrominated diphenyl ethers (PBDEs), alternate brominated flame retardants (BFRs) and Dechlorane Plus (DP) were studied in the German part of the North Sea in 2010. BDE-209 and DP were found to be the dominating compounds, both in the atmosphere and in seawater. Sum PBDEs (∑ 10PBDEs) ranged from 0.31 to 10.7 pg m -3 in the atmosphere and from not detected (n.d.) to 10.5 pg L -1 in seawater, respectively. DP ra