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Sample records for aged sea salt

  1. Sea Water Ageing of GFRP Composites and the Dissolved salts

    NASA Astrophysics Data System (ADS)

    Chakraverty, A. P.; Mohanty, U. K.; Mishra, S. C.; Satapathy, A.

    2015-02-01

    This paper houses the effect of sea water immersion on glass fibre reinforced polymer (GFRP) composites. The major sources of interest are study of sea water absorption, penetration of the dissolved salts, details of chemical and physical bonds at the interface, variations of mechanical properties and study of failure mechanisms as revealed through SEM fractographs. Eighteen ply GFRP composites are immersed in sea water for a period of one year in steps of two months durations. It is revealed that the moisture absorption transforms from a Fickian to non-Fickian behavior with lapse of time. The dissolved salt 'K' shows highest depth of penetration after one year of immersion while 'Na' shows a least depth of penetration, as revealed from the EDS spectra. It is also revealed that 'Ca' seems to have a sudden burst in the rate of penetration even surpassing that of 'K'. This trend can be attributed to the combined effect of ionic mobility of the various dissolved salts and the probable interaction between 'K' and the -OH group of epoxy resin. This interaction between dissolved 'K' and the -OH group in the polymer could have arrested the further advancement of 'K' salts in the polymer, resulting in comparatively high rates of 'Ca' penetration. The mechanical properties such as inter laminar shear stress (ILSS), stress and strain at rupture, glass transition temperature (Tg) and elastic modulus show a decreasing trend with the increased duration of immersion. As revealed from the SEM fractographs pot- holing, fiber pull-out, matrix crack etc. are seen to be the major reason for failure of the immersed samples under load.

  2. Changes in shape and composition of sea-salt particles upon aging in an urban atmosphere

    NASA Astrophysics Data System (ADS)

    Adachi, Kouji; Buseck, Peter R.

    2015-01-01

    Sea salt is one of the most abundant types of natural aerosol particles and significantly influences local and global climate. It is an important constituent of samples collected between June 10 and 15 in the Los Angeles area during the 2010 CalNex campaign. The sea-salt particles reacted with other species in the atmosphere and became Na-bearing aerosol (NaA) particles. Using transmission electron microscopy, we found that Na occurred in almost half of all analyzed particles (∼3500), although commonly only in minor amounts. Almost all the NaA particles contained S but not Cl, suggesting that Cl was depleted through particle formation to sulfate, nitrate, or both in the urban atmosphere. We observed both rounded and euhedral NaA particles. The rounded ones consisted mainly of aged sea salt (>12 h) that had reacted extensively with sulfate, whereas the euhedral ones occurred in samples from relatively fresh marine air. The shapes and compositions of NaA particles changed within 3 h in the urban atmosphere. Moreover, our calculations indicate that light scattering from NaA particles depends on their shapes (e.g., roughly spherical, flat, or elongated). These compositions and shapes affect hygroscopicities and light scattering, respectively, both of which influence their climate effects.

  3. Acidity decline in Antarctic ice cores during the Little Ice Age linked to changes in atmospheric nitrate and sea salt concentrations

    NASA Astrophysics Data System (ADS)

    Pasteris, Daniel; McConnell, Joseph R.; Edwards, Ross; Isaksson, Elizabeth; Albert, Mary R.

    2014-05-01

    Acidity is an important chemical variable that impacts atmospheric and snowpack chemistry. Here we describe composite time series and the spatial pattern of acidity concentration (Acy = H+ - HCO3-) during the last 2000 years across the Dronning Maud Land region of the East Antarctic Plateau using measurements in seven ice cores. Coregistered measurements of the major ion species show that sulfuric acid (H2SO4), nitric acid (HNO3), and hydrochloric acid (HCl) determine greater than 98% of the acidity value. The latter, also described as excess chloride (ExCl-), is shown mostly to be derived from postdepositional diffusion of chloride with little net gain or loss from the snowpack. A strong inverse linear relationship between nitrate concentration and inverse accumulation rate provides evidence of spatially homogenous fresh snow concentrations and reemission rates of nitrate from the snowpack across the study area. A decline in acidity during the Little Ice Age (LIA, 1500-1900 Common Era) is observed and is linked to declines in HNO3 and ExCl- during that time. The nitrate decline is found to correlate well with published methane isotope data from Antarctica (δ13CH4), indicating that it is caused by a decline in biomass burning. The decrease in ExCl- concentration during the LIA is well correlated to published sea surface temperature reconstructions in the Atlantic Ocean, which suggests increased sea salt aerosol production associated with greater sea ice extent.

  4. Scattering by solutions of major sea salts.

    PubMed

    Zhang, Xiaodong; Hu, Lianbo; Twardowski, Michael S; Sullivan, James M

    2009-10-26

    Increased scattering by seawater relative to that by pure water is primarily due to additional fluctuation of the refractive index contributed by sea salts. Salts with different ionic weight and sizes, while barely affecting the scattering that is due to density fluctuations, have a significant effect on the scattering that is due to concentration fluctuations. And this explains the major differences of their total scattering that would be observed. Scattering by solutions of NaCl, the major sea salt, is consistently about 6.7% and 4% lower than seawater of the same mass concentration and of the same refractive index, respectively. Because of ionic interactions, the molecular scattering does not follow the simple addition rule that applies to bulk inherent optical properties, with the total less than the summation of the parts. The possible values of scattering by waters of, such as, Dead Sea or Orca Basin, which have different salt composition from seawater, are discussed. PMID:19997177

  5. Neutron activation analysis of sea-, lake-, and evaporated salt

    NASA Astrophysics Data System (ADS)

    Steinhauser, G.; Sterba, J. H.; Poljanc, K.; Bichler, M.; Buchtela, K.

    2006-01-01

    Salt is essential for human nutrition. Recently, it has become popular in Europe to rather use exotic sea salt or lake salt instead of purified evaporated salt, because of an alleged higher content of trace elements. In this study the content of trace elements and their bioavailability of 19 samples of different types of salt and 1 sample of brine purification sludge were investigated using instrumental neutron activation analysis. In general, sea-, lake-, and evaporated salt are quite pure. Trace elements determined in salt were Al, Br, Co, Cr, Cs, Fe, Rb, Sc, Sr, and Zn; some of them only in individual cases. It was found that, in general, the content of trace elements in sea- or lake salt was higher than in purified salt. Nevertheless, the use of sea- or lake salt does not contribute significantly to the human needs of essential trace elements, because their concentration in salt is too low or their compounds are not bioavailable.

  6. Sea-Salt Aerosol Forecasts Compared with Wave and Sea-Salt Measurements in the Open Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Kishcha, P.; Starobinets, B.; Bozzano, R.; Pensieri, S.; Canepa, E.; Nickovie, S.; di Sarra, A.; Udisti, R.; Becagli, S.; Alpert, P.

    2012-03-01

    Sea-salt aerosol (SSA) could influence the Earth's climate acting as cloud condensation nuclei. However, there were no regular measurements of SSA in the open sea. At Tel-Aviv University, the DREAM-Salt prediction system has been producing daily forecasts of 3-D distribution of sea-salt aerosol concentrations over the Mediterranean Sea (http://wind.tau.ac.il/saltina/ salt.html). In order to evaluate the model performance in the open sea, daily modeled concentrations were compared directly with SSA measurements taken at the tiny island of Lampedusa, in the Central Mediterranean. In order to further test the robustness of the model, the model performance over the open sea was indirectly verified by comparing modeled SSA concentrations with wave height measurements collected by the ODAS Italia 1 buoy and the Llobregat buoy. Model-vs.-measurement comparisons show that the model is capable of producing realistic SSA concentrations and their day-today variations over the open sea, in accordance with observed wave height and wind speed.

  7. Nitrite toxicity of Litopenaeus vannamei in water containing low concentrations of sea salt or mixed salts

    USGS Publications Warehouse

    Sowers, A.; Young, S.P.; Isely, J.J.; Browdy, C.L.; Tomasso, J.R., Jr.

    2004-01-01

    The uptake, depuration and toxicity of environmental nitrite was characterized in Litopenaeus vannamei exposed in water containing low concentrations of artificial sea salt or mixed salts. In 2 g/L artificial sea salts, nitrite was concentrated in the hemolymph in a dose-dependent and rapid manner (steady-state in about 2 d). When exposed to nitrite in 2 g/L artificial sea salts for 4 d and then moved to a similar environment without added nitrite, complete depuration occurred within a day. Increasing salinity up to 10 g/L decreased uptake of environmental nitrite. Nitrite uptake in environments containing 2 g/L mixed salts (combination of sodium, potassium, calcium and magnesium chlorides) was similar to or lower than rates in 2 g/L artificial sea salt. Toxicity was inversely related to total dissolved salt and chloride concentrations and was highest in 2 g/L artificial sea salt (96-h medial lethal concentration = 8.4 mg/L nitrite-N). Animals that molted during the experiments did not appear to be more susceptible to nitrite than animals that did not molt. The shallow slope of the curve describing the relationship between toxicity and salinity suggests that management of nitrite toxicity in low-salinity shrimp ponds by addition of more salts may not be practical. ?? Copyright by the World Aquaculture Society 2004.

  8. Sea salt production over Bay of Bengal : Effect of salinity

    NASA Astrophysics Data System (ADS)

    K, K. N.; S K, S.; S S, B.; K, K.

    2015-12-01

    Marine aerosols constitute one of the most important natural aerosol systems globally and play an important role in global climate regulation and the marine biogenic system. One of the major constituents of the marine aerosol system is sea salt. Sea salt aerosols are produced via the bubble-bursting process resulting from whitecap generation (due to high wind speed). The resulting sea salt particles are of sub micrometre sizes and go up to a few micrometres. An increase in sea salt mass is primarily associated with increasing wind speeds. The increase in wind speed not only increases the mass concentration of the small-sized sea salt particles but also that of higher-sized particles. This behaviour is constrained by other factors like temperature and salinity. In the present work, this variability in the change in mass concentration of sea salt aerosol is studied with respect to the wind speed variation over Bay of Bengal (BoB). This work includes measurements from two field experiments held on 2006 ((ICARB) March-April) and 2012 ((CTCZ) July-August) over BoB. An analysis of the mass concentration with the wind history showed the mass concentration increasing with the increase in wind speed. Here wind history is used instead of instantaneous wind speed, because it is a good indicator of dependence of mass concentrations on wind speed. However, the cruise held in 2012 showed the size of particles constraining to 2.5 μm unlike the cruise in 2006. This difference in the size of the particles formed is majorly due to change in salinity. In 2012, the cruise was during summer monsoon season wherein the high runoff associated with high precipitation lead to reduced salinity. Whereas in 2006, the cruise was in summer season during which high evaporation lead to increase in salinity. This shows that with lower salinity the sea salt particles formed will be of smaller size. This also shows that apart from wind speed, salinity also affects the sea salt production.

  9. The Ages of the Lunar Seas

    PubMed Central

    Ronca, L. B.

    1971-01-01

    Two ages are attributed to each circular lunar sea, the age of formation of the circular basin, probably by impact, and the age of the filling of the basin by lava-like effusions. Each lunar-sea surface displays a range of geomorphic indices. This is interpreted as being due to the presence of effusions of different ages on the surface of each sea. The landing sites of Apollo 11 and 12 have geomorphic indices of value 10.3 and 8.4. The radiometric ages of the rocks are, respectively, approximately 3.65 × 109 and 3.36 × 109 years. The range of geomorphic indices on sea surfaces is from less than 5 to more than 14, which indicates that the two Apollo crafts landed on surfaces formed about in the middle of the total span of time of sea-surface formation. Using four possible relationships between geomorphic index and age, I conclude that the age of the youngest effusions is less than 3 × 109 years and the age of the oldest effusions is more than 4 × 109 years. The results of the analyses of the Russian Luna 16 samples, although preliminary, fit in this interpretation. PMID:16591925

  10. Sea salt aerosol from blowing snow on sea ice - modeling vs observation

    NASA Astrophysics Data System (ADS)

    Yang, Xin; Frey, Markus; Norris, Sarah; Brooks, Ian; Anderson, Philip; Jones, Anna; wolff, Eric; Legrand, Michel

    2016-04-01

    Blowing snow over sea ice, through a subsequent sublimation process of salt-containing blown snow particles, has been hypothesized as a significant sea salt aerosol (SSA) source in high latitudes. This mechanism has been strongly supported by a winter cruise in the Weddell Sea (during June-August 2013). The newly collected data, including both physical and chemical components, provide a unique way to test and validate the parameterisation used for describing the SSA production from blowing snow events. With updates to some key parameters such as snow salinity in a global Chemistry-transport model pTOMCAT, simulated SSA concentrations can be well compared with measured SSA data. In this presentation, I will report modeled SSA number density against collected data on board of Polarstern ship during the Weddell Sea cruise, as well as modeled SSA massive concentrations against those measured at both coastal sites such as Alert in the North and Dumont d'Urville (DDU) in the South and central Antarctic sites such as Concordia and Kohnen stations. Model experiments indicated that open ocean-sourced SSA could not explain the observed winter SSA peaks seen in most polar sites, while with sea ice-sourced SSA in the model, the winter peaks can be well improved indicating the importance of sea ice-sourced SSA as a significant contributor to the salts (Na+, Cl-) recorded in the ice core.

  11. Global scale emission and distribution of sea-spray aerosol: Sea-salt and organic enrichment

    NASA Astrophysics Data System (ADS)

    Vignati, E.; Facchini, M. C.; Rinaldi, M.; Scannell, C.; Ceburnis, D.; Sciare, J.; Kanakidou, M.; Myriokefalitakis, S.; Dentener, F.; O'Dowd, C. D.

    2010-02-01

    The chemical composition of marine aerosols as a function of their size is an important parameter for the evaluation of their impact on the global climate system. In this work we model fine particle organic matter emitted by sea spray processes and its influence on the aerosol chemical properties at the global scale using the off-line global Chemistry-Transport Model TM5. TM5 is coupled to a microphysical aerosol dynamics model providing size resolved information on particle masses and numbers. The mass of the emitted sea spray particles is partitioned between water insoluble organic matter (WIOM) and sea salt components in the accumulation mode using a function that relates the emitted organic fraction to the surface ocean chlorophyll- a concentrations. The global emission in the sub-micron size range of organic matter by sea spray process is 8.2 Tg yr -1, compared to 24 Tg fine yr -1 sea-salt emissions. When the marine sources are included, the concentrations of modelled primary particulate organic matter (POM) increase mainly over the oceans. The model predictions of WIOM and sea salt are evaluated against measurements carried out at Mace Head (Northern Hemisphere) and Amsterdam Island (Southern Hemisphere), showing that in clean marine conditions WIOM marine emissions contribute significantly to POM values.

  12. Light scattering from sea-salt aerosols at Interagency Monitoring of Protected Visual Environments (IMPROVE) sites.

    PubMed

    Lowenthal, Douglas; Kumar, Naresh

    2006-05-01

    A method is described to estimate light scattering (Bsp) by sea-salt aerosols at coastal locations in the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. Dry mass scattering efficiencies for fine and coarse sea-salt particles were based on previously measured dry sea-salt size distributions. Enhancement of sea-salt particle scattering by hygroscopic growth was based on NaCl water activity data. Sea-salt aerosol mass at the IMPROVE site in the Virgin Islands (VIIS) was estimated from strontium (Sr) concentrations in IMPROVE aerosol samples. Estimated Bsp, including contributions from sea-salt mass based on Sr, agreed well with measured Bsp at the VIIS IMPROVE site. On average, sea salt accounted for 52% of estimated Bsp at this site. Sea-salt aerosol mass cannot be reliably estimated from Sr unless its crustal enrichment factor exceeds 10. Sodium (Na) concentrations are not accurately determined by X-ray fluorescence analysis in IMPROVE samples. It is recommended that Na be measured in the fine and coarse modes by a more appropriate method, such as atomic absorption spectroscopy or ion chromatography, to account for scattering by sea-salt particles at IMPROVE sites where such contributions may be significant. PMID:16739800

  13. Sensitivity of modeled atmospheric nitrogen species to variations in sea salt emissions in the North and Baltic Sea regions

    NASA Astrophysics Data System (ADS)

    Neumann, D.; Matthias, V.; Bieser, J.; Aulinger, A.; Quante, M.

    2015-10-01

    Coarse sea salt particles are emitted ubiquitously from the oceans' surfaces by wave breaking and bubble bursting processes. These particles impact atmospheric chemistry by affecting condensation of gas-phase species and nucleation of new fine particles, particularly in regions with high air pollution. In this study, atmospheric particle concentrations are modeled for the North and Baltic Sea regions, Northwestern Europe, using the Community Multiscale Air Quality (CMAQ) modeling system and evaluated against European Monitoring and Evaluation Programme (EMEP) measurement data. As model extension, sea salt emissions are scaled by water salinity because of low salinity in large parts of the Baltic Sea and in certain river estuaries. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is separately considered. Additionally, the impact of sea salt particles on atmospheric nitrate, ammonium and sulfate concentrations is evaluated. The comparisons show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated when going inland. The introduced salinity scaling improves predicted Baltic Sea sea salt concentrations considerably. Dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to a minor increase of NH4+ and NO3- and a minor decrease of SO42- concentrations. However, the overall effect is very low and lower than the deviation from measurements. Size resolved measurements of Na+, NH4+, NO3-, and SO42- are needed for a more detailed analysis on the impact of sea salt particles.

  14. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    NASA Astrophysics Data System (ADS)

    Neumann, Daniel; Matthias, Volker; Bieser, Johannes; Aulinger, Armin; Quante, Markus

    2016-03-01

    Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ) modeling system and are compared to European Monitoring and Evaluation Programme (EMEP) measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 + NH4+ and HNO3 + NO3- and a decrease in NO3- concentrations. However, the overall effect on NH3 + NH4+ and HNO3 + NO3- concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is underestimated by the model at most

  15. Modelling artificial sea salt emission in large eddy simulations.

    PubMed

    Maalick, Z; Korhonen, H; Kokkola, H; Kühn, T; Romakkaniemi, S

    2014-12-28

    We study the dispersion of sea salt particles from artificially injected sea spray at a cloud-resolving scale. Understanding of how different aerosol processes affect particle dispersion is crucial when designing emission sources for marine cloud brightening. Compared with previous studies, we include for the first time an explicit treatment of aerosol water, which takes into account condensation, evaporation and their effect on ambient temperature. This enables us to capture the negative buoyancy caused by water evaporation from aerosols. Additionally, we use a higher model resolution to capture aerosol loss through coagulation near the source point. We find that, with a seawater flux of 15 kg s(-1), the cooling due to evaporation can be as much as 1.4 K, causing a delay in particle dispersion of 10-20 min. This delay enhances particle scavenging by a factor of 1.14 compared with simulations without aerosol water. We further show that both cooling and particle dispersion depend on the model resolution, with a maximum particle scavenging efficiency of 20% within 5 h after emission at maximum resolution of 50 m. Based on these results, we suggest further regional high-resolution studies which model several injection periods over several weeks. PMID:25404679

  16. Modelling artificial sea salt emission in large eddy simulations

    PubMed Central

    Maalick, Z.; Korhonen, H.; Kokkola, H.; Kühn, T.; Romakkaniemi, S.

    2014-01-01

    We study the dispersion of sea salt particles from artificially injected sea spray at a cloud-resolving scale. Understanding of how different aerosol processes affect particle dispersion is crucial when designing emission sources for marine cloud brightening. Compared with previous studies, we include for the first time an explicit treatment of aerosol water, which takes into account condensation, evaporation and their effect on ambient temperature. This enables us to capture the negative buoyancy caused by water evaporation from aerosols. Additionally, we use a higher model resolution to capture aerosol loss through coagulation near the source point. We find that, with a seawater flux of 15 kg s−1, the cooling due to evaporation can be as much as 1.4 K, causing a delay in particle dispersion of 10–20 min. This delay enhances particle scavenging by a factor of 1.14 compared with simulations without aerosol water. We further show that both cooling and particle dispersion depend on the model resolution, with a maximum particle scavenging efficiency of 20% within 5 h after emission at maximum resolution of 50 m. Based on these results, we suggest further regional high-resolution studies which model several injection periods over several weeks. PMID:25404679

  17. Rhode Island Salt Marshes: Elevation Capital and Resilience to Sea Level Rise

    EPA Science Inventory

    Tidal salt marsh is especially sensitive to deterioration due to the effects of accelerated sea level rise when combined with other anthropogenically linked stressors, including crab herbivory, changes in tidal hydrology, nutrient loading, dam construction, changes in temperature...

  18. 20 Years of sea-levels, accretion, and vegetation on two Long Island Sound salt marshes

    EPA Science Inventory

    The long-term 1939-2013 rate of RSLR (Relative Sea-Level Rise) at the New London, CT tide gauge is ~2.6 mm/yr, near the maximum rate of salt marsh accretion reported in eastern Long Island Sound salt marshes. Consistent with recent literature RSLR at New London has accelerated si...

  19. SIZE DISTRIBUTION OF SEA-SALT EMISSIONS AS A FUNCTION OF RELATIVE HUMIDITY

    EPA Science Inventory

    This note presents a straightforward method to correct sea-salt-emission particle-size distributions according to local relative humidity. The proposed method covers a wide range of relative humidity (0.45 to 0.99) and its derivation incorporates recent laboratory results on sea-...

  20. Process evaluation of sea salt aerosol concentrations at remote marine locations

    NASA Astrophysics Data System (ADS)

    Struthers, H.; Ekman, A. M.; Nilsson, E. D.

    2011-12-01

    Sea salt, an important natural aerosol, is generated by bubbles bursting at the surface of the ocean. Sea salt aerosol contributes significantly to the global aerosol burden and radiative budget and are a significant source of cloud condensation nuclei in remote marine areas (Monahan et al., 1986). Consequently, changes in marine aerosol abundance is expected to impact on climate forcing. Estimates of the atmospheric burden of sea salt aerosol mass derived from chemical transport and global climate models vary greatly both in the global total and the spatial distribution (Texor et al. 2006). This large uncertainty in the sea salt aerosol distribution in turn contributes to the large uncertainty in the current estimates of anthropogenic aerosol climate forcing (IPCC, 2007). To correctly attribute anthropogenic climate change and to veraciously project future climate, natural aerosols including sea salt must be understood and accurately modelled. In addition, the physical processes that determine the sea salt aerosol concentration are susceptible to modification due to climate change (Carslaw et al., 2010) which means there is the potential for feedbacks within the climate/aerosol system. Given the large uncertainties in sea salt aerosol modelling, there is an urgent need to evaluate the process description of sea salt aerosols in global models. An extremely valuable source of data for model evaluation is the long term measurements of PM10 sea salt aerosol mass available from a number of remote marine observation sites around the globe (including the GAW network). Sea salt aerosol concentrations at remote marine locations depend strongly on the surface exchange (emission and deposition) as well as entrainment or detrainment to the free troposphere. This suggests that the key parameters to consider in any analysis include the sea surface water temperature, wind speed, precipitation rate and the atmospheric stability. In this study, the sea salt aerosol observations

  1. Salt tectonics in the northeastern Nordkapp Basin, southwestern Barents Sea

    SciTech Connect

    Koyi, H.; Talbot, C.J.; Torudbakken, B.O.

    1996-12-31

    Salt structures in the northeastern Nordkapp subbasin are interpreted on reflection seismic profiles. Thickness variations indicate localized accumulation of the mother salt in Late Carboniferous-Early Permian time. Rapid sedimentation in the Early Triassic accompanied rise of salt into asymmetric salt pillows during regional extension. These pillows domed the prekinematic Permian sediments and became diapiric during the late Early-Middle Triassic, perhaps as a result of thin-skinned normal faulting decoupled by the salt from old basements faults reactivated by thick-skinned regional (northwest-southeast) extension. Variations in size, maturity, and evolution history of individual salt structures can be attributed to local differences in thickness of the initial salt layer and its burial history. Salt structures form three rows concentric to the basin margins and cover {approximately}20% of the basin area. Some salt stocks appear to overlie basement faults. Asymmetric primary, secondary, and in places tertiary, peripheral sinks indicate that salt was withdrawn mainly from the basin side of most diapirs throughout Triassic downbuilding.

  2. Reactivity of NaCl with Secondary Organic Acids: An Important Mechanism of the Chloride Depletion in Sea Salt Particles Mixed with Organic Materials

    NASA Astrophysics Data System (ADS)

    Wang, B.; Laskin, A.; Kelly, S.; Gilles, M. K.; Shilling, J. E.; Zelenyuk, A.; Wilson, J. M.; Tivanski, A.

    2012-12-01

    proposed reactions may result in the formation of organic salts and production of HCl from sea salt particles that become mixed with organic acids during atmospheric aging that occurs with transport. The process of hydration/dehydration and these reactions may modify the physical and chemical properties of aged sea salt particles.

  3. Investigations of novel unsaturated bile salts of male sea lamprey as potential chemical cues

    USGS Publications Warehouse

    Johnson, Nicholas S.; Yun, Sang-Seon; Li, Weiming

    2014-01-01

    Sulfated bile salts function as chemical cues that coordinate reproduction in sea lamprey, Petromyzon marinus. 7α, 12α, 24-trihydroxy-5α-cholan-3-one 24-sulfate (3kPZS) is the most abundant known bile salt released by sexually mature male sea lampreys and attracts ovulated females. However, previous studies showed that the male-produced pheromone consists of unidentified components in addition to 3kPZS. Here, analysis of water conditioned with mature male sea lampreys indicated the presence of 4 oxidized, unsaturated compounds with molecular weights of 466 Da, 468 Da, and 2 of 470 Da. These compounds were not detectable in water conditioned with immature male sea lampreys. By using mass spectrometry, 4 A-ring unsaturated sulfated bile salts were tentatively identified from male washings as 2 4-ene, a 1-ene, and a 1,4-diene analogs. These were synthesized to determine if they attracted ovulated female sea lampreys to spawning nests in natural streams. One of the novel synthetic bile salts, 3 keto-1-ene PZS, attracted ovulated females to the point of application at a concentration of 10-12 M. This study reveals the structural diversity of bile salts in sea lamprey, some of which have been demonstrated to be pheromonal cues.

  4. Sensitivity to deliberate sea salt seeding of marine clouds - observations and model simulations

    NASA Astrophysics Data System (ADS)

    Alterskjær, K.; Kristjánsson, J. E.; Seland, Ø.

    2012-03-01

    Sea salt seeding of marine clouds to increase their albedo is a proposed technique to counteract or slow global warming. In this study, we first investigate the susceptibility of marine clouds to sea salt injections, using observational data of cloud droplet number concentration, cloud optical depth, and liquid cloud fraction from the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on board the Aqua and Terra satellites. We then compare the derived susceptibility function to a corresponding estimate from the Norwegian Earth System Model (NorESM). Results compare well between simulations and observations, showing that stratocumulus regions off the west coast of the major continents along with large regions over the Pacific and the Indian Oceans are susceptible. At low and mid latitudes the signal is dominated by the cloud fraction. We then carry out geo-engineering experiments with a uniform increase over ocean of 10-9 kg m-2 s-1 in emissions of sea salt particles with a dry modal radius of 0.13 μm, an emission strength and areal coverage much greater than proposed in earlier studies. The increased sea salt concentrations and the resulting change in marine cloud properties lead to a globally averaged forcing of -4.8 W m-2 at the top of the atmosphere, more than cancelling the forcing associated with a doubling of CO2 concentrations. The forcing is large in areas found to be sensitive by using the susceptibility function, confirming its usefulness as an indicator of where to inject sea salt for maximum effect. Results also show that the effectiveness of sea salt seeding is reduced because the injected sea salt provides a large surface area for water vapor and gaseous sulphuric acid to condense on, thereby lowering the maximum supersaturation and suppressing the formation and lifetime of sulphate particles. In some areas, our simulations show an overall reduction in the CCN concentration and the number of activated cloud droplets decreases

  5. Sensitivity to deliberate sea salt seeding of marine clouds - observations and model simulations

    NASA Astrophysics Data System (ADS)

    Alterskjær, K.; Kristjánsson, J. E.; Seland, Ø.

    2011-10-01

    Sea salt seeding of marine clouds to increase their albedo is a proposed technique to counteract or slow global warming. In this study, we first investigate the susceptibility of marine clouds to sea salt injections, using observational data of cloud droplet number concentration, cloud optical depth, and liquid cloud fraction from the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on board the Aqua and Terra satellites. We then compare the derived susceptibility function to a corresponding estimate from the Norwegian Earth System Model (NorESM). Results compare well between simulations and observations, showing that stratocumulus regions off the west coast of the major continents along with large regions in the Pacific and the Indian Oceans are susceptible. We then carry out geo-engineering experiments with a uniform increase of 10-9 kg m-2 s-1 in emissions of sea salt particles with a modal radius of 0.13 μm. The increased sea salt concentrations and the resulting change in marine cloud properties lead to a globally averaged forcing of -4.8 W m-2 at the top of the atmosphere, more than cancelling a doubling of CO2 concentrations. The forcing is large in areas found to be sensitive by using the susceptibility function, confirming its usefulness as an indicator of where to inject sea salt for maximum effect. Results also show that the effectiveness of sea salt seeding is reduced because the injected sea salt provide a large surface area for water vapor and gaseous sulphuric acid to condense on, thereby lowering the maximum supersaturation and suppressing the formation and lifetime of sulphate particles. In some areas, our simulations show an overall reduction in the CCN concentration and the number of activated cloud droplets decreases, resulting in a positive globally averaged forcing.

  6. Multiple Year-round Atmospheric Record of DMS, DMSO, Sulfurdioxide, Sea-salt and Sulfur (MSA and Non-sea-salt Sulfate) Aerosols at Dumont d'Urville (Antarctica) (December 1998-August 2002): Implications for Ice Core Interpretation

    NASA Astrophysics Data System (ADS)

    Legrand, M.; Jourdain, B.

    2002-12-01

    Since four years, year-round measurements of DMS and DMSO (3100 samples) using a gas chromatograph were achieved at Dumont d'Urville, a coastal Antarctic site. In addition to bulk aerosol composition ((MSA, non-sea-salt sulfate (nssSO42-)) and sea-salt) made on a daily basis since 1991, year-round studies of the size-segregated aerosol composition were achieved in 2000 and 2001. Together with denuder tube sampling (HCl and HNO3) these data permit to examine summer (chloride depletion relative to sodium) and winter (sulfate depletion relative to sodium and chloride) sea-salt aerosol fractionations in more detail than previously done from the single examination of bulk aerosol chemistry, allowing a better understanding of these processes which is required to quantify the sulfate fraction related to biogenic DMS emissions. It is found that HCl is present at levels close to 130 ng m-3 in summer in this region as result of an acidification of sea-salt aerosol by HNO3. Impactor data indicate a sulfate to sodium ratio of 0.13 (sulfate to chloride ratio of 0.06) on sea-salt aerosols from May to October. This sulfate depletion relative to sodium in airborne sea-salt aerosol is less pronounced at DDU than at other coastal Antarctic sites. This difference may result from either a less extended sea ice cover which controls the formation of a sea-salt aerosol source depleted in mirabilite or warmer temperatures which decrease the intensity of the fractionation process. Based on that, accurate determination of nssSO42- indicates winter levels ranging from 10 to 30 ng m-3 with a higher value (50 ng m-3) from 1992 to 1994 when the Pinatubo volcanic cloud was present. We discuss possible effects of the nighttime oxidation of DMS (still present in winter) to explain the presence of non-sea-salt sulfate (in the absence of MSA) in these regions at that season. Over the last 4 years summer levels of DMS, DMSO and MSA exhibit a large interannual variability with high values in January

  7. On temporal wind variations forcing salt water inflows into the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Lass, H. U.; Matthäus, W.

    1996-10-01

    Salt water inflows into the Baltic Sea are important processes for maintaining the general stratification and the ventilation of the bottom water in deep basins of the central Baltic. These events occur randomly during the winter season at intervals from one to several years. This pattern changed in the mid-seventies when only weak or no major inflows were observed. During that period a steady loss of salt together with a steady increase in hydrogen sulphide concentrations was observed in the central Baltic deep water.It is generally assumed that strong westerly winds force a salt water inflow. Long time series of daily wind records at the meteorological station Arkona and sea level observations at Landsort between 1951 and 1990 have been analyzed in order to find characteristic sequences being associated with inflow events. A necessary condition for a salt water inflow is for the wind to blow from west for several tens of days. The weighted mean of the yearly cycle of the wind components for years without and with salt water inflows revealed that this condition happens usually in November and December. However, in years with inflows, a long-lasting easterly wind occurs in October and early November just before the strengthening of westerly winds. A similar sequence is observed in the yearly cycle of the mean sea level of the Baltic Sea, i.e., in years with inflows a lowering of the mean sea level precedes the increase of the sea level in November to December. Hence, major salt water inflows are very likely forced by a sequence of easterly winds in late autumn lasting for 20 30days followed by strong to very strong westerly winds of similar duration.

  8. Heterogeneous oxidation of a phosphocholine on synthetic sea salt by ozone at room temperature.

    PubMed

    Dilbeck, Christopher W; Finlayson-Pitts, Barbara J

    2013-02-14

    The ozonolysis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) adsorbed on salt mixtures as models for sea-salt particles was studied in real time using diffuse reflection infrared Fourier transform spectrometry (DRIFTS) at room temperature with and without added water vapor. The salt substrates were a mixture of MgCl(2)·6H(2)O with NaCl or a commercially available synthetic sea salt. Ozone concentrations ranged from (0.25 to 3.9) × 10(13) molecules cm(-3) (0.1-1.6 ppm). The major products identified by FTIR and confirmed using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry were the secondary ozonide (SOZ) and a phospholipid aldehyde and carboxylic acid formed by scission of the double bond. The reaction probabilities for the two substrates were similar, γ = (6-7) × 10(-7), with an estimated overall uncertainty of a factor of two. The presence of water vapor decreased the yield of SOZ relative to the products formed by C[double bond, length as m-dash]C scission, but also increased the availability of the double bond for reaction, particularly on the less hygroscopic commercial sea-salt substrate. Thus, water not only affects the mechanisms and products, but also the structure of the phospholipid on the salt in a manner that affects its reactivity. The results of these studies suggest that the reactivity and products of oxidation of unsaturated phospholipids on sea-salt particles in air will be very sensitive to the nature and phase of the substrate, the amount of water present, and whether there is phase separation between the organics and the inorganic salt mixture. PMID:23258195

  9. Removal of sulphur from the marine boundary layer by ozone oxidation in sea-salt aerosols

    NASA Astrophysics Data System (ADS)

    Sievering, H.; Boatman, J.; Gorman, E.; Kim, Y.; Anderson, L.; Ennis, G.; Luria, M.; Pandis, S.

    1992-12-01

    The contribution of ozone oxidation in sea-salt aerosols to the cycling of sulfur in the marine boundary layer (MBL) is assessed. It is shown that, due to the effects of mass transfer, the non-sea-salt SO4(2-) so generated will be predominantly associated with particles 2-9 microns in diameter and will accordingly dry-deposit at a rapid rate. Because part of the dimethyl sulfide emitted by marine organisms is converted to SO2 in the MBL, this additional removal pathway for sulfur may markedly reduce the proposed feedback between greenhouse warming, oceanic DMS emissions, and sulfate haze albedos.

  10. A comparison of sea salt emission parameterizations in northwestern Europe using a chemistry transport model setup

    NASA Astrophysics Data System (ADS)

    Neumann, Daniel; Matthias, Volker; Bieser, Johannes; Aulinger, Armin; Quante, Markus

    2016-08-01

    Atmospheric sea salt particles affect chemical and physical processes in the atmosphere. These particles provide surface area for condensation and reaction of nitrogen, sulfur, and organic species and are a vehicle for the transport of these species. Additionally, HCl is released from sea salt. Hence, sea salt has a relevant impact on air quality, particularly in coastal regions with high anthropogenic emissions, such as the North Sea region. Therefore, the integration of sea salt emissions in modeling studies in these regions is necessary. However, it was found that sea salt concentrations are not represented with the necessary accuracy in some situations.In this study, three sea salt emission parameterizations depending on different combinations of wind speed, salinity, sea surface temperature, and wave data were implemented and compared: GO03 (Gong, 2003), SP13 (Spada et al., 2013), and OV14 (Ovadnevaite et al., 2014). The aim was to identify the parameterization that most accurately predicts the sea salt mass concentrations at different distances to the source regions. For this purpose, modeled particle sodium concentrations, sodium wet deposition, and aerosol optical depth were evaluated against measurements of these parameters. Each 2-month period in winter and summer 2008 were considered for this purpose. The shortness of these periods limits generalizability of the conclusions on other years.While the GO03 emissions yielded overestimations in the PM10 concentrations at coastal stations and underestimations of those at inland stations, OV14 emissions conversely led to underestimations at coastal stations and overestimations at inland stations. Because of the differently shaped particle size distributions of the GO03 and OV14 emission cases, the deposition velocity of the coarse particles differed between both cases which yielded this distinct behavior at inland and coastal stations. The PM10 concentrations produced by the SP13 emissions generally

  11. Tagus estuary and Ria de Aveiro salt marsh dynamics and the impact of sea level rise

    NASA Astrophysics Data System (ADS)

    Valentim, J. M.; Vaz, N.; Silva, H.; Duarte, B.; Caçador, I.; Dias, J. M.

    2013-09-01

    Different characteristics of Spartina maritima found in two distinct salt marshes located in different estuaries were analysed through interpretation of their local hydrodynamic patterns, as well as the impact of sea level rise on physical processes and consequently on plant dynamics and salt marshes stability. These salt marshes are situated in two of the most important Portuguese coastal systems, Tagus estuary (Rosário salt marsh) and Ria de Aveiro lagoon (Barra salt marsh), which are dominated by physical processes that induce strong tidal currents. They were monitored during one year and plant and sediment samples of S. maritima were collected quarterly in order to determine the vegetation coverage, above and belowground biomass, organic matter and sediment moisture. Residual circulation, tidal asymmetry and tidal dissipation were determined from numerical modelling results of the MOHID 2D model that was applied to each coastal system, considering the actual sea level and a sea level rise (SLR) scenario. Results suggest that the different characteristics found for Spartina maritima in the Rosário and the Barra salt marshes may be related with the diverse hydrodynamic conditions identified for each salt marsh. Consequently, the exploration of SLR scenario predictions indicates how these salt marshes could evolve in the future, showing that the important changes in these hydrodynamic parameters under climate change context might induce significant modifications in the salt marshes dynamics and stability. SLR scenario could lead to changes in nutrients and sediments patterns around the salt marshes and thus vegetation coverage percentage would be affected. Additionally, as a consequence of flood duration increase, sediment moisture will increase causing a stress condition to plants. Hence, the ratio below/aboveground biomass might increase, becoming critical to plants survival under conditions of accelerated sea level rise. Accordingly, both SLR and expected

  12. Sea salt dependent electrical conduction in polar ice

    SciTech Connect

    Moore, J.; Paren, J. ); Oerter, H. )

    1992-12-10

    A 45 m length of ice core from Dolleman Island, Antarctic Peninsula has been dielectrically analyzed at 5 cm resolution using the dielectric profiling (DEP) technique. The core has also been chemically analyzed for major ionic impurities. A statistical analysis of the measurements shows that the LF (low frequency) conductivity is determined both by neutral salt and acid concentrations. The statistical relationships have been compared with results from laboratory experiments on ice doped with HF (hydrogen fluoride). Salts (probably dispersed throughout the ice fabric) determine the dielectric conductivity. The salt conduction mechanism is probably due to Bjerrum L defects alone, created by the incorporation of chloride ions in the lattice. Samples of ice from beneath the Filchner-Ronne Ice Shelf were also measured and display a similar conduction mechanism below a solubility limit of about 400 [mu]M of chloride. The temperature dependence of the neutral salt, acid and pure ice contributions to the LF conductivity of natural ice between [approximately] 70[degrees]C and 0[degrees]C is discussed. These results allow a comprehensive comparison of dielectric and chemical data from natural ice.

  13. Drilling below the salt in the Western Mediterranean Sea: the GOLD project

    NASA Astrophysics Data System (ADS)

    Rabineau, M.; Droxler, A. W.; Kuroda, J.; Eguchi, N.; Aslanian, D.; Alain, K.; Gorini, C.

    2011-12-01

    In recent years the Gulf of Lion within the western Mediterranean Sea has become a unique natural laboratory to study both the evolution and interaction of deep processes (geodynamics, tectonics, subsidence, isostasy) and surficial processes (river behavior, sedimentary fluxes, sea-level changes, climatic impacts). We present the three main objectives for the GOLD deep drilling project at the foot of the continental slope (2400 m water depth) in the Gulf of Lion, the only place where the complete high-resolution history of the last 30 Ma of Mediterranean history is recorded in some 7.7 km of sedimentary archive 1) For the substratum: the upper continental crust thins to less than 5 km, and changes laterally to a relatively thin crust with high velocities whose precise nature is still undetermined (Gailler et al., 2009). The aim of the drilling is to reach this crucial zone, which is essential for the understanding of margin formation and the evolution of sedimentary basin (Aslanian et al., 2009). 2) The drilling will allow the dating and characterization of the impact of climate variations on sedimentation in the deep basin. For the Miocene and older sediments the drilling, will yield information about the nature, paleoenvironments and age of deposits enabling an astronomically-tuned Neogene time scale to be refined for the period of Aquitanian through Langhian interval. The Messinian extreme event represents a unique crisis in Earth history. It is a unique case to study the impact of sea-level drop (more than 1000 m, one order of magnitude greater than Late Quaternary glaciations) on sedimentary river behavior, deltaic and evaporitic deposition and ensuing biotic crisis. Deep drilling with the R/V Chikyu is the only way to go through the complete series of evaporites in the Provence Basin, sample the initiation and evolution of the crises, the first deposits related to the lowering of sea-level on the one hand and to the salinity crisis on the other. 3) The

  14. Relation between surface topography and sea-salt snow chemistry from Princess Elizabeth Land, East Antarctica

    NASA Astrophysics Data System (ADS)

    Mahalinganathan, K.; Thamban, M.; Laluraj, C. M.; Redkar, B. L.

    2011-10-01

    Previous studies on variability of sea-salt records in Antarctic snow have established an unambiguous relationship with the proximity to the sea and have been directly correlated with the site specific features like elevation and distance from the coast. On the other hand, variations in Cl-/Na+ ratio in have been attributed with the reaction mechanisms involving atmospheric acids. In the present study, annual records of Na+, Cl- and SO42- records were investigated using snow cores along a 180 km coast to inland transect in Princess Elizabeth Land, East Antarctica. Exceptionally high Na+ concentrations varying between 1000 and 2000 μg l-1 were observed within 50 km of the transect. Large variations in Cl-/Na+ ratio were observed within 50 km from the coast. A rapid increase in the elevation (0-1115 m) was noticed up to 50 km from the coast, whereas a steady elevation change (1115-2200 m) occurred between 50 and 180 km. The largest slope of the entire transect was observed (33.7 m km-1) between 20 and 30 km and records from this area correspondingly revealed extensive modifications in snow sea-salt chemistry, with Cl-/Na+ ratios as low as 0.2. Statistical analysis showed a strong association between the slope of the ice sheet and variation of the sea-salt ions along the transect. While distance from coast accounted for some variability, the altitude by itself seem to have no significant control on the distribution of sea-salt ions. We suggest that the degree of slope of the ice sheet on the coastal regions of Antarctica could have a major influence the sea-salt chemistry.

  15. Relation between surface topography and sea-salt snow chemistry from Princess Elizabeth Land, East Antarctica

    NASA Astrophysics Data System (ADS)

    Mahalinganathan, K.; Thamban, M.; Laluraj, C. M.; Redkar, B. L.

    2012-04-01

    Previous studies on Antarctic snow have established an unambiguous correlation between variability of sea-salt records and site specific features like elevation and proximity to the sea. On the other hand, variations of Cl-/Na+ ratios in snow have been attributed to the reaction mechanisms involving atmospheric acids. In the present study, the annual records of Na+, Cl- and SO42- were investigated using snow cores along a 180 km coast to inland transect in Princess Elizabeth Land, East Antarctica. Exceptionally high Na+ concentrations and large variations in Cl-/Na+ ratios were observed up to 50 km (∼1100 m elevation) of the transect. The steepest slope in the entire transect (49.3 m km-1) was between 20 and 30 km and the sea-salt records in snow from this area revealed extensive modifications, with Cl-/Na+ ratios as low as 0.2. Statistical analysis showed a strong association between the slope and variations in Cl-/Na+ ratios along the transect (r = -0.676, 99% confidence level). While distance from the coast accounted for some variability, the altitude by itself has no significant control over the sea-salt ion variability. However, the steep slopes influence the deposition of sea-salt aerosols in snow. The wind redistribution of snow due to the steep slopes on the coastal escarpment increases the concentration of Na+, resulting in a low Cl-/Na+ ratios. We propose that the slope variations in the coastal regions of Antarctica could significantly influence the sea-salt chemistry of snow.

  16. Salt distribution in the Norwegian-Danish Basin, Central North Sea

    NASA Astrophysics Data System (ADS)

    Sassier, Caroline; Jarsve, Erlend; Heeremans, Michel; Mansour Abdelmalak, Mohamed; Faleide, Jan Inge; Helge Gabrielsen, Roy

    2014-05-01

    Salt tectonics have extensively been studied in most parts of the Central North Sea. However, few studies have been done in the Norwegian side of the Norwegian-Danish Basin. In this contribution, we report a new regional analysis of the salt patterns across the offshore Norwegian-Danish Basin. We have mapped the regional distribution of salt structures in the Norwegian-Danish Basin using both old and recent 2D seismic reflection profiles tied to wells. The salt-thickness map shows three distinct salt structures patterns: (1) NW-SE trending salt walls in the northern part of the basin; the spacing between the walls vary between 7 to 12 km; (2) a dense and irregular distribution of salt diapirs in the southern part of the studied area; (3) an irregular pattern of sparse but big salt diapirs in the eastern part of the basin. This domain is characterized by numerous turtle structures associated with salt diapirs. Reflection seismic cross-sections show that most salt structures only pierce the Triassic sedimentary strata whereas only few salt structures reach the seabed. Rotated fault blocks indicate a gliding vergence towards the South in the eastern part of the basin and towards the SE in the western side of the Norwegian-Danish Basin. No mature or compressive salt structures, except some squeezed salt diapirs, are observed in the topographic lows of the basin. The initiation of salt tectonics started during the early Middle Triassic in the entire basin; salt tectonics reactivations were recorded during the Middle Jurassic, Paleogene, and prior to the Quaternary but are not homogeneous across the basin. Salt movements inferred from our study are in good agreement with previous studies. The trend of salt walls (domain 1) indicates a NE-SW extension which is not compatible with N-S trending pre-salt faults. Instead, the strong Triassic subsidence towards the SW has most likely controlled the formation of the salt walls. The salt was initially thicker in domain 2 that

  17. Superposed Neogene extension, contraction, and salt canopy emplacement in the Yemeni Red Sea

    SciTech Connect

    Heaton, R.C.; Jackson, M.P.A.; Bamahmoud, M.; Nani, A.S.O.

    1996-12-31

    Although the Neogene Red Sea basin has been intensively examined as the type example of a young, narrow ocean, salt tectonics there has been neglected. The Yemeni part of the Red Sea exhibits a wide array of salt tectonic features within a small area. Above the rift section, a middle Miocene evaporite layer, originally 1.5-2 km thick, is the source for autochthonous and allochthonous salt structures. In the middle-late Miocene, evaporite-clastic overburden, halite, and anhydrite layers 50-350 m thick assisted deformation by providing several levels for decollement. Four southward-narrowing tectonics zones trend subparallel to the basin axis. Areas of extension in the easternmost Roller Zone, severe shortening in the central Canopy Zone, and mild shortening in the western Anticline Zone all narrow then pinch out at roughly the same latitude. This convergence suggests that extension and contraction are linked by various salt layers and by transfer structures transecting the tectonic zones. Extension, contraction, and coeval salt canopy emplacement were superposed, mostly between 8 and 5 Ma. The presence of allochthonous salt sheets casts doubt on previous estimates of salt 5 km thick in the southern Red Sea. Fault scarp asperities in the basin floor may have acted as buttresses against which contraction was initiated. The wide variety of salt structures may be due to the weakness and anisotropy of the partially evaporitic overburden and to high geothermal gradients (up to 77{degrees}C/km). These factors enhanced the deformation driven by gravity spreading and sedimentary differential loading.

  18. Investigating primary marine aerosol properties: CCN activity of sea salt and mixed particles

    NASA Astrophysics Data System (ADS)

    King, S. M.; Butcher, A. C.; Rosenoern, T.; Coz, E.; Lieke, K. I.; de Leeuw, G.; Nilsson, E. D.; Bilde, M.

    2012-04-01

    Sea salt particles ejected as a result of bubbles bursting from artificial seawater in a closed stainless steel tank were sampled for size distribution, morphology, and cloud condensation nucleus (CCN) activity. The two-component artificial seawater consisted of salt, either NaCl or sea salt, and one organic compound in deionized water. Several organic molecules representative of oceanic organic matter were investigated. Bubbles were generated either by aeration through a porous diffuser or by water jet impingement on the surface of the artificial seawater. The effect of bubble lifetime, which was controlled by varying the depth of the diffuser in the water column, on particle size and CCN activity was investigated and was found to be insignificant for the organic compounds studied. The CCN activities of particles produced from diffuser-generated bubbles were generally governed by the high hygroscopicity of salt, such that activation was indistinguishable from that of salt, except in the case of very low mass ratio of salt to organic matter in the seawater solution. There was, however, a considerable decrease in CCN activity for particles produced from jet impingement on seawater that had a salinity of 10‰ and contained 0.45 mM of sodium laurate, an organic surfactant. The production of a thick foam layer from impingement may explain the difference in activation and supports hypotheses that particle production from the two methods of generating bubbles is not similar. Accurate conclusions from observed CCN activities of particles from artificial seawater containing organic matter require knowledge of the CCN activity of the inorganic component, especially as a small amount of the inorganic can heavily influence activation. Therefore, the CCN activity of both artificial sea salt and NaCl were measured and compared. Part of the discrepancy observed between the CCN activities of the two salts may be due to morphological differences, which were investigated using

  19. Size Distribution of Sea-Salt Emissions as a Function of Relative Humidity

    NASA Astrophysics Data System (ADS)

    Zhang, K. M.; Knipping, E. M.; Wexler, A. S.; Bhave, P. V.; Tonnesen, G. S.

    2004-12-01

    Here we introduced a simple method for correcting sea-salt particle-size distributions as a function of relative humidity. Distinct from previous approaches, our derivation uses particle size at formation as the reference state rather than dry particle size. The correction factors, corresponding to the size at formation and the size at 80% RH, are given as polynomial functions of local relative humidity which are straightforward to implement. Without major compromises, the correction factors are thermodynamically accurate and can be applied between 0.45 and 0.99 RH. Since the thermodynamic properties of sea-salt electrolytes are weakly dependent on ambient temperature, these factors can be regarded as temperature independent. The correction factor w.r.t. to the size at 80% RH is in excellent agreement with those from Fitzgerald's and Gerber's growth equations; while the correction factor w.r.t. the size at formation has the advantage of being independent of dry size and relative humidity at formation. The resultant sea-salt emissions can be used directly in atmospheric model simulations at urban, regional and global scales without further correction. Application of this method to several common open-ocean and surf-zone sea-salt-particle source functions is described.

  20. Final Report, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone"

    SciTech Connect

    B. J. Finlayson-Pitts

    2005-06-20

    This document is a final report for the project DE-FG03-98ER62578, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone". It includes a technical summary, collaborations, educational contributions and the peer-reviewed scientific publications that have resulted from this research.

  1. Tropical salt marsh succession as sea-level indicator during Heinrich events

    NASA Astrophysics Data System (ADS)

    González, Catalina; Dupont, Lydie M.

    2009-05-01

    Centennial-millennial dynamics of tropical salt marsh vegetation are documented in the pollen record from marine core MD03-2622, Cariaco Basin, Venezuela, which spans the glacial period between 63 and 29 ka. Five rapid and abrupt expansions of salt marsh vegetation are linked with North Atlantic Heinrich events (HEs). Within each event, a recurrent pattern - starting with species of Chenopodiaceae, followed by grasses, and subsequently by Cyperaceae species - suggests a successional process that is determined by the close relationship between sea-level and community dynamics. The salt tolerant Chenopodiaceae, at the base of each sequence, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE stadials, causing erosion of marsh sediments, and continued recruitment of pioneer species (Chenopodiaceae), which are the only ones capable of tolerating the rapid rate of disturbance. Once, as sea-level drops or as rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species (graminoids). The increment of marsh height as a result of autochthonous sediment accumulation reduces the extent of hypersaline environments, and allows the establishment of mesohaline species. These results add to the scarce knowledge on tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes occurring simultaneously with Antarctica climate variations.

  2. Influence of sea level rise on the dynamics of salt inflows in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hordoir, Robinson; Axell, Lars; Löptien, Ulrike; Dietze, Heiner; Kuznetsov, Ivan

    2015-10-01

    The Baltic Sea is a marginal sea, located in a highly industrialized region in Central Northern Europe. Saltwater inflows from the North Sea and associated ventilation of the deep exert crucial control on the entire Baltic Sea ecosystem. This study explores the impact of anticipated sea level changes on the dynamics of those inflows. We use a numerical oceanic general circulation model covering both the Baltic and the North Sea. The model successfully retraces the essential ventilation dynamics throughout the period 1961-2007. A suite of idealized experiments suggests that rising sea level is associated with intensified ventilation as saltwater inflows become stronger, longer, and more frequent. Expressed quantitatively as a salinity increase in the deep central Baltic Sea, we find that a sea level rise of 1 m triggers a saltening of more than 1 PSU. This substantial increase in ventilation is the consequence of the increasing cross section in the Danish Straits amplified by a reduction of vertical mixing.

  3. Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing

    NASA Astrophysics Data System (ADS)

    Ueda, S.; Hirose, Y.; Miura, K.; Okochi, H.

    2014-02-01

    Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, Japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 μm diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or Cl. Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without Cl. However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in

  4. Self-accelerated development of salt karst during flash floods along the Dead Sea Coast, Israel

    NASA Astrophysics Data System (ADS)

    Avni, Yoav; Lensky, Nadav; Dente, Elad; Shviro, Maayan; Arav, Reuma; Gavrieli, Ittai; Yechieli, Yoseph; Abelson, Meir; Lutzky, Hallel; Filin, Sagi; Haviv, Itai; Baer, Gidon

    2016-01-01

    We document and analyze the rapid development of a real-time karst system within the subsurface salt layers of the Ze'elim Fan, Dead Sea, Israel by a multidisciplinary study that combines interferometric synthetic aperture radar and light detection and ranging measurements, sinkhole mapping, time-lapse camera monitoring, groundwater level measurements and chemical and isotopic analyses of surface runoff and groundwater. The >1 m/yr drop of Dead Sea water level and the subsequent change in the adjacent groundwater system since the 1960s resulted in flushing of the coastal aquifer by fresh groundwater, subsurface salt dissolution, gradual land subsidence and formation of sinkholes. Since 2010 this process accelerated dramatically as flash floods at the Ze'elim Fan were drained by newly formed sinkholes. During and immediately after these flood events the dissolution rates of the subsurface salt layer increased dramatically, the overlying ground surface subsided, a large number of sinkholes developed over short time periods (hours to days), and salt-saturated water resurged downstream. Groundwater flow velocities increased by more than 2 orders of magnitudes compared to previously measured velocities along the Dead Sea. The process is self-accelerating as salt dissolution enhances subsidence and sinkhole formation, which in turn increase the ponding areas of flood water and generate additional draining conduits to the subsurface. The rapid terrain response is predominantly due to the highly soluble salt. It is enhanced by the shallow depth of the salt layer, the low competence of the newly exposed unconsolidated overburden and the moderate topographic gradients of the Ze'elim Fan.

  5. Unraveling the hydrocarbon charge potential of the Nordkapp Basin, Barents Sea: An integrated approach to reduce exploration risk in complex salt basins

    NASA Astrophysics Data System (ADS)

    Schenk, Oliver; Shtukert, Olga; Bishop, Andrew; Kornpihl, Kristijan; Milne, Graham

    2014-05-01

    The Nordkapp Basin, Barents Sea, is an intra-continental syn-rift basin containing many complex salt structures. The salt is late-Carboniferous to Early Permian in age, with regional extension in the Triassic initiating the salt movement resulting in formation of sub- and mini-basins with significant subsidence (especially in the northeastern part of the basin). Subsequent tectonic phases allowed growth and distortion of salt diapirs that were later affected by uplift and erosion during Tertiary resulting in the formation of salt-related traps in Triassic and Lower Jurassic strata. During Plio-Pleistocene, glacial erosion removed additional Mesozoic and Cenozoic strata. This basin is regarded as a frontier salt province. A small hydrocarbon discovery (Pandora well) in the southwestern part of the basin points to the presence several functioning petroleum systems. The primary play type is related to salt traps below overhangs. Such structures are however, very difficult to image with conventional seismic techniques due to i) generation of multiples from sea floor and top of shallow salt bodies and ii) seismic shadow zones within the salt (possibly resulting from shale and carbonate stringers) which cause severe diffractions so that prospective areas adjacent to the salt remain elusive. Arctic exploration is expensive and the ability to focus on the highest potential targets is essential. A unique solution to this challenging subsurface Arctic environment was developed by integrating petroleum system modeling with full azimuth broadband seismic acquisition and processing. This integrated approach allows intelligent location of seismic surveys over structures which have the maximum chance of success of hydrocarbon charge. Petroleum system modeling was conducted for four seismic sections. Salt was reconstructed according to the diapiric evolution presented in Nilsen et al. (1995) and Koyi et al. (1995). Episodes of major erosion were assigned to Tertiary (tectonic) and

  6. Basin-edge diapirism and updip salt flow in Zechstein of southern North Sea

    SciTech Connect

    Jenyon, M.K.

    1985-01-01

    Some unusual and interesting structural geometries have been recognized on seismic lines recorded in the United Kingdom sector of the southern Permian basin of the North Sea. They seem to be the result of diapirism at the northern edge of the (Upper Permian) Zechstein salt basin, and involve the preservation of a 75 km (47 mi) long prism of a younger Mesozoic sequence replaced elsewhere by the widespread Jurassic/Cretaceous late Kimmerian unconformity. It is suggested that the diapiric features described are due to the movement of salt toward the basin edge having been dammed by a change in facies from basinal halite to shelf lithologies over a short distance.

  7. Basin-edge diapirism and updip salt flow in Zechstein of southern North Sea

    SciTech Connect

    Jenyon, M.K.

    1985-12-01

    Some unusual and interesting structural geometries have been recognized on seismic lines recorded in the United Kingdom sector the southern Permian basin of the North Sea. They seem to be the result of diapirism at the northern edge of the (Upper Permian) Zechstein salt basin, and involve the preservation of a 75 km (47 mi) long prism of a younger Mesozoic sequence replaced elsewhere by the widespread Jurassic/Cretaceous late Kimmerian unconformity. It is suggested that the diapiric features described are due to the movement of salt toward the basin edge having been dammed by a change in facies from basinal halite to shelf lithologies over a short distance. 13 figures.

  8. Arctic Sea Salt Aerosol from Blowing Snow and Sea Ice Surfaces - a Missing Natural Source in Winter

    NASA Astrophysics Data System (ADS)

    Frey, M. M.; Norris, S. J.; Brooks, I. M.; Nishimura, K.; Jones, A. E.

    2015-12-01

    Atmospheric particles in the polar regions consist mostly of sea salt aerosol (SSA). SSA plays an important role in regional climate change through influencing the surface energy balance either directly or indirectly via cloud formation. SSA irradiated by sunlight also releases very reactive halogen radicals, which control concentrations of ozone, a pollutant and greenhouse gas. However, models under-predict SSA concentrations in the Arctic during winter pointing to a missing source. It has been recently suggested that salty blowing snow above sea ice, which is evaporating, to be that source as it may produce more SSA than equivalent areas of open ocean. Participation in the 'Norwegian Young Sea Ice Cruise (N-ICE 2015)' on board the research vessel `Lance' allowed to test this hypothesis in the Arctic sea ice zone during winter. Measurements were carried out from the ship frozen into the pack ice North of 80º N during February to March 2015. Observations at ground level (0.1-2 m) and from the ship's crows nest (30 m) included number concentrations and size spectra of SSA (diameter range 0.3-10 μm) as well as snow particles (diameter range 50-500 μm). During and after blowing snow events significant SSA production was observed. In the aerosol and snow phase sulfate is fractionated with respect to sea water, which confirms sea ice surfaces and salty snow, and not the open ocean, to be the dominant source of airborne SSA. Aerosol shows depletion in bromide with respect to sea water, especially after sunrise, indicating photochemically driven release of bromine. We discuss the SSA source strength from blowing snow in light of environmental conditions (wind speed, atmospheric turbulence, temperature and snow salinity) and recommend improved model parameterisations to estimate regional aerosol production. N-ICE 2015 results are then compared to a similar study carried out previously in the Weddell Sea during the Antarctic winter.

  9. Bromide content of sea-salt aerosol particles collected over the Indian Ocean during INDOEX 1999

    NASA Astrophysics Data System (ADS)

    Gabriel, R.; von Glasow, R.; Sander, R.; Andreae, M. O.; Crutzen, P. J.

    2002-10-01

    Bromide can be depleted from sea-salt aerosol particles in the marine boundary layer (MBL) and converted to reactive gas-phase species like Br, BrO, and HOBr, which affect ozone chemistry. Air pollution can enhance the bromine release from sea-salt aerosols and thus inject additional bromine into the MBL. During the winter monsoon the northern Indian Ocean is strongly affected by air pollution from the Indian subcontinent and Asia. As part of the Indian Ocean Experiment (INDOEX), aerosol particles were sampled with stacked filter units (SFU) on the NCAR Hercules C-130 aircraft during February-March 1999. We determined the vertical and latitudinal distribution of the major inorganic aerosol components (NH4+, Na+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42-) and the Br- content of the coarse aerosol to examine the role of the bromine release on the gas-phase chemistry in the marine boundary layer over the tropical Indian Ocean. The aerosol mass and composition varied significantly with air mass origin and sampling location. In the northern part of the Indian Ocean (5°-15°N, 66°-73°E), high concentrations of pollution-derived inorganic species were found in the marine boundary layer extending from the sea surface to about 1.2 km above sea level. In this layer, the average mass concentration of all aerosol species detected by our technique was comparable to pollution levels observed in industrialized regions. In the Southern Hemisphere (1°-9°S, 66°- 73°E), the aerosol concentrations rapidly declined to remote background levels. A chloride loss from the coarse aerosol particles was observed in parallel to the latitudinal gradient of the non sea salt SO42- burden. In most of the samples, Br- was depleted from the sea-salt aerosols. However, we found an enrichment in bromide in aerosols affected by air masses originating over strong pollution sources in India (Bombay, Calcutta). In these cases the additional pollution-derived Br from organo-halogen additives in petrol

  10. Quantitative Assessment of In-situ Salt Karstification Using Shear Wave Velocity, Dead Sea

    NASA Astrophysics Data System (ADS)

    Ezersky, Michael; Legchenko, Anatoly

    2014-09-01

    The Dead Sea (DS) coastal areas have been dramatically affected by sinkhole formation since around 1990. Such sinkholes along both Israeli and Jordanian shores are linked to karst cavities that form through slow salt dissolution. A quantitative estimate of such in-situ salt karstification would be an important indicator of sinkhole hazard. One of the indications of salt karstification is its increased hydraulic conductivity, caused by the development of dissolution cavities forming conducting channels within the salt layer. We measured the hydraulic conductivity (K) versus shear-wave velocity (Vs) of DS salt in situ for estimating the actual salt karstification in areas of sinkhole development. These parameters were measured with the Magnetic Resonance Sounding (MRS) and Multichannel Analysis of Surface Waves (MASW) methods, respectively. Understanding of the field relationships was augmented by similar inter-relations obtained in the laboratory on samples of DS salt. In-situ salt velocities Vs vary from 750 m/s to over 1650 m/s, while hydraulic conductivity (K) in the same zones varies between about 10- 4 m/s to slightly over 10- 8 m/s. Both field and laboratory K and Vs values fit the exponential function ln(K) = - 0.0045 ∗ Vs - 5.416 with a determination coefficient (R2) of 0.88. A classification based on Vs and K was generated for salt conditions and the corresponding degrees of sinkhole hazard, which was verified in the Mineral Beach sinkhole development area. The mapping of sinkhole sites shows that they form within highly conductive zones with K ≥ 5.5 ∗ 10- 5. It is suggested that this methodology, with some modification, can be used for evaluating the conductive properties of karstified rock and associated sinkhole hazards.

  11. Enrichment of Mineral Dust Storm Particles with Sea Salt Elements - Using bulk and Single Particle Analyses

    NASA Astrophysics Data System (ADS)

    Mamane, Y.; Perrino, C.; Yossef, O.

    2009-12-01

    Mineral aerosol emitted from African and Asian deserts plays an important role in the atmosphere. During their long-range transport, the physical and chemical properties of mineral dust particles change due to heterogeneous reactions with trace gases, coagulation with other particles, and in-cloud processing. These processes affect the optical and hygroscopic properties of dust particles, and in general influencing the physics and chemistry of the atmosphere. Four African and Arabian dust storm episodes affecting the East Mediterranean Coast in the spring of 2006 have been characterized, to determine if atmospheric natural dust particles are enriched with sea salt and anthropogenic pollution. Particle samplers included PM10 and manual dichotomous sampler that collected fine and coarse particles. Three sets of filters were used: Teflon filters for gravimetric, elemental and ionic analyses; Pre-fired Quartz-fiber filters for elemental and organic carbon; and Nuclepore filters for scanning electron microscopy analysis. Computer-controlled scanning electron microscopy (Philips XL 30 ESEM) was used to analyze single particle, for morphology, size and chemistry of selected filter samples. A detailed chemical and microscopical characterization has been performed for the particles collected during dust event days and during clear days. The Saharan and Arabian air masses increased significantly the daily mass concentrations of the coarse and the fine particle fractions. Carbonates, mostly as soil calcites mixed with dolomites, and silicates are the major components of the coarse fraction, followed by sea salt particles. In addition, the levels of anthropogenic heavy metals and sea salt elements registered during the dust episode were considerably higher than levels recorded during clear days. Sea salt elements contain Na and Cl, and smaller amounts of Mg, K, S and Br. Cl ranges from 300 to 5500 ng/m3 and Na from 100 to almost 2400 ng/m3. The Cl to Na ratio on dusty days in

  12. Fission track ages and ages of deposition of deep-sea microtektites.

    PubMed

    Gentner, W; Glass, B P; Storzer, D; Wagner, G A

    1970-04-17

    The Australasian and Ivory Coast deep-sea microtektites have fission track ages of 0.71 and 1.09 million years, respectively. These ages are in good agreement with the ages of deposition of the microtektites determined from paleomagnetic data. Both the fission track ages and ages of deposition of the microtektites agree with the potassium/ argon and fission track ages of tektites from the respective tektite strewn fields. PMID:17809131

  13. Refining the Parameterisation of Sea Salt Aerosol Production from Blowing Snow on Sea Ice Based on Data Collected in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Yang, X.; Frey, M. M.; Levine, J. G.; Brooks, I. M.; Anderson, P. A.; Jones, A. E.; Wolff, E. W.

    2014-12-01

    The hypothesis of blowing snow lifted snow particles, via a subsequent sublimation process, as a significant sea salt aerosol (SSA) source over sea ice has recently been strongly supported by a winter cruise through the Weddell Sea during June-August 2013. The newly collected data, including both physical and chemical components, provide a unique way to test and validate the parameterisation used to date. The observed salinity of surface and blowing snow is very low; on average more than an order in magnitude smaller than column mean value. Here we apply a low salinity of 0.27 PSU (representing an average of the top 10cm of snow plus blowing snow samples) in the p-TOMCAT model to test its effect on sea salt concentrations reaching the Antarctic. The comparison with previous model output (using column mean salinity) shows that SSA concentration in central Antarctica is insensitive to change in snow salinity, due to the compensating effect of increasing fine SSA partitioning upon reducing the salinity. We also investigate the impact of changing the number of SSA particles formed from each snow particle on SSA concentration and size distribution. Applying a ratio of 10 SSA particles per blowing snow particle, rather than one as assumed to date, greatly increases the amount of sub-micrometer SSA reaching central Antarctica. Without applying blowing snow related SSA production in the p-TOMCAT model, the observed elevated SSA in the Weddell Sea could not be reproduced.

  14. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    NASA Astrophysics Data System (ADS)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 μm). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26

  15. Nitric Acid-Sea Salt Reactions: Implications for Nitrogen Deposition to Water Surfaces.

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Sørensen, L. L.

    2000-05-01

    Many previous studies have indicated the importance of nitric acid (HNO3) reactions on sea salt particles for flux divergence of HNO3 in the marine surface layer. The potential importance of this reaction in determining the spatial and temporal patterns of nitrogen dry deposition to marine ecosystems is investigated using models of sea spray generation and particle- and gas-phase dry deposition. Under horizontally homogeneous conditions with near-neutral stability and for wind speeds between 3.5 and 10 m s1, transfer of HNO3 to the particle phase to form sodium nitrate may decrease the deposition velocity of nitrogen by over 50%, leading to greater horizontal transport prior to deposition to the sea surface. Conversely, for wind speeds above 10 m s1, transfer of nitrogen to the particle phase would increase the deposition rate and hence decrease horizontal transport prior to surface removal.

  16. Origin of dimethylsulfide, non-sea-salt sulfate, and methanesulfonic acid in eastern Antarctica

    NASA Astrophysics Data System (ADS)

    Cosme, E.; Hourdin, F.; Genthon, C.; Martinerie, P.

    2005-02-01

    Ignoring the origin of atmospheric chemicals is often a strong limitation to the full interpretation of their measurement. In this article, this question is addressed in the case of the sulfur species in Antarctica, with an original method of retrotransport of tracers. The retrotransport model is derived from the Laboratoire de Météorologie Dynamique Zoom-Tracers (LMD-ZT) atmospheric general circulation model, optimized for polar climate and expanded to simulate atmospheric sulfur chemistry. For two East Antarctic scientific stations (Dumont d'Urville and Vostok) the effects of transport and chemistry and the influence of oceanic, volcanic, and anthropogenic sources on dimethylsulfide (DMS), non-sea-salt (nss) sulfate, and methanesulfonic acid (MSA) concentrations are evaluated in summer and winter. The oceanic source largely dominates, but other sources can episodically be significant. The meridional origin and the age of DMS, MSA, and biogenic nss sulfate are also estimated. The latitudes of origin of MSA and nss sulfate are similar in summer, but they differ markedly in winter. This is a signature of their different chemical production scheme. Also, the interannual variability of the origin of the sulfur species at Vostok is weak compared to that at Dumont d'Urville. Acknowledging that the DMS concentrations in the ocean have no interannual variability in the model, this result suggests unsurprisingly that inland Antarctic stations may be better observation sites to monitor large-scale DMS bioproductivity variability than coastal sites are. The combination of slower chemistry and more intense atmospheric circulation in winter leads to unexpected results, such as a younger DMS in winter than in summer at Vostok.

  17. Biosynthesis and release of pheromonal bile salts in mature male sea lamprey

    PubMed Central

    2013-01-01

    Background In vertebrates, bile salts are primarily synthesized in the liver and secreted into the intestine where they aid in absorption of dietary fats. Small amounts of bile salts that are not reabsorbed into enterohepatic circulation are excreted with waste. In sexually mature male sea lamprey (Petromyzon marinus L.) a bile salt is released in large amounts across gill epithelia into water where it functions as a pheromone. We postulate that the release of this pheromone is associated with a dramatic increase in its biosynthesis and transport to the gills upon sexual maturation. Results We show an 8000-fold increase in transcription of cyp7a1, a three-fold increase in transcription of cyp27a1, and a six-fold increase in transcription of cyp8b1 in the liver of mature male sea lamprey over immature male adults. LC–MS/MS data on tissue-specific distribution and release rates of bile salts from mature males show a high concentration of petromyzonol sulfate (PZS) in the liver and gills of mature males. 3-keto petromyzonol sulfate (3kPZS, known as a male sex pheromone) is the primary compound released from gills, suggesting a conversion of PZS to 3kPZS in the gill epithelium. The PZS to 3kPZS conversion is supported by greater expression of hsd3b7 in gill epithelium. High expression of sult2b1 and sult2a1 in gill epithelia of mature males, and tissue-specific expression of bile salt transporters such as bsep, slc10a1, and slc10a2, suggest additional sulfation and transport of bile salts that are dependent upon maturation state. Conclusions This report presents a rare example where specific genes associated with biosynthesis and release of a sexual pheromone are dramatically upregulated upon sexual maturation in a vertebrate. We provide a well characterized example of a complex mechanism of bile salt biosynthesis and excretion that has likely evolved for an additional function of bile salts as a mating pheromone. PMID:24188124

  18. Salt-influenced structures in the mesozoic-tertiary cover of the southern North Sea, U.K.

    SciTech Connect

    Coward, M.; Stewart, S.

    1996-12-31

    A structural model encompassing the southern North Sea Basin west of the Central Graben has been developed that combines gravity gliding of the postsalt cover with basement tectonics. The basin differs from many salt basins in that it forms a closed system. Section construction and balancing through the cover of the North Sea need to take into account thin-skinned and thick-skinned extensions and contractions. The North Sea salt formed in Permian time in two large oval basins separated by the Mid North Sea High. The shape of these basins reflects variable patterns of thermal subsidence. Subsequent salt tectonics was governed by local graben structures and by regional uplift and subsidence. Rifting initiated during the Triassic and allowed reactive and locally passive diapirs to develop in the post-salt cover. In the southern North Sea, the Dowsing graben system in the cover is offset from the Dowsing fault zone below the salt. This offset in extensional structures probably relates to the salt thickness and to the position of the surface hinge line that controlled the onset of gravity gliding in the postsalt section. Gravity gliding of the cover into the Triassic-Jurassic Sole Pit trough and away from zones of rift flank uplift was associated with Late Jurassic-Early Cretaceous extension in the Central North Sea; gliding caused asymmetric compressional pillows to develop downslope. Gravity spreading of the cover during the Late Cretaceous-early Tertiary was associated with tilting during thermal subsidence of the southern North Sea Basin, enhanced by pulses of tectonic inversion in the southern North Sea basement. The resultant glide tectonics formed new small grabens upslope and compressional pillows downslope. Where the compressional pillows were eroded sufficiently or faulted later, the salt broke through the thinned cover to produce new active and then passive diapirs, which drained the pillows to produce new rim synclines.

  19. Long-term surface elevation changes in German North Sea salt marshes

    NASA Astrophysics Data System (ADS)

    Suchrow, Sigrid; Pohlmann, Nina; Stock, Martin; Jensen, Kai

    2012-02-01

    We analyzed long-term (19-21 years) surface elevation changes of salt marshes along the German mainland North Sea coast in a large and consistent data set (423 plots). Our aim was to determine the influence of 12 predictor variables, e.g. elevation, micro-topography and management data. For each plot, we measured elevation above sea level, once 1988-1990 and again 2009. The calculated surface elevation change per year (target variable SEC) was +0.6 cm yr -1 on average. 85.8% of the plots showed positive SEC values. Although 11 predictors were significantly correlated to SEC, only five driving on different scales were included by the tree fitting algorithm when using regression tree analysis. The resulting tree model with 11 terminal nodes explained 45.7% proportion of the variance in SEC values. Plots tended to high SEC values when a) lying low in relation to mean high tide, b) being located in the northern regions of the study area, and c) lying in drainage ditches. d) Grazing management did account for SEC variance only in northern regions. e) SEC was enhanced on non-grazed plots lying high in relation to mean high tide. We concluded that most of the studied salt marshes may outpace a predicted sea-level rise of about 0.1-0.2 cm yr -1, but barely half of the marsh areas might follow a sea-level rise of 0.6 cm yr -1. Regression tree analysis is a useful approach for studying changes in elevation of salt marshes when considering various variables.

  20. Observation of sea-salt fraction in sub-100 nm diameter particles at Cape Grim

    NASA Astrophysics Data System (ADS)

    Cravigan, Luke T.; Ristovski, Zoran; Modini, Robin L.; Keywood, Melita D.; Gras, John L.

    2015-03-01

    Volatility-hygroscopicity tandem differential mobility analyzer measurements were used to infer the composition of sub-100 nm diameter Southern Ocean marine aerosols at Cape Grim in November and December 2007. This study focuses on a short-lived high sea spray aerosol (SSA) event on 7-8 December with two externally mixed modes in the Hygroscopic Growth Factor (HGF) distributions (90% relative humidity (RH)), one at HGF > 2 and another at HGF~1.5. The particles with HGF > 2 displayed a deliquescent transition at 73-75% RH and were nonvolatile up to 280°C, which identified them as SSA particles with a large inorganic sea-salt fraction. SSA HGFs were 3-13% below those for pure sea-salt particles, indicating an organic volume fraction (OVF) of up to 11-46%. Observed high inorganic fractions in sub-100 nm SSA is contrary to similar, earlier studies. HGFs increased with decreasing particle diameter over the range 16-97 nm, suggesting a decreased OVF, again contrary to earlier studies. SSA comprised up to 69% of the sub-100 nm particle number, corresponding to concentrations of 110-290 cm-3. Air mass back trajectories indicate that SSA particles were produced 1500 km, 20-40 h upwind of Cape Grim. Transmission electron microscopy (TEM) and X-ray spectrometry measurements of sub-100 nm aerosols collected from the same location, and at the same time, displayed a distinct lack of sea salt. Results herein highlight the potential for biases in TEM analysis of the chemical composition of marine aerosols.

  1. Simulating Emission and Chemical Evolution of Coarse Sea-Salt Particles in the Community Multiscale Air Quality (CMAQ) Model

    EPA Science Inventory

    Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-sal...

  2. Reactive uptake of HOCl to laboratory generated sea salt particles and nascent sea-spray aerosol

    NASA Astrophysics Data System (ADS)

    Campbell, N. R.; Ryder, O. S.; Bertram, T. H.

    2013-12-01

    Field observations suggest that the reactive uptake of HOCl on marine aerosol particles is an important source of chlorine radicals, particularly under low NOx conditions. However to date, laboratory measurements disagree on the magnitude of the reactive uptake coefficient for HOCl by a factor of 5 (γ(HOCl) ranges between 0.0004 and 0.0018), and there are no measurements of γ(HOCl) on nascent sea-spray aerosol. Here, we present measurements of the reactive uptake of HOCl to laboratory generated sodium chloride and sea-spray aerosol particles generated in a novel Marine Aerosol Reference Tank (MART), coupled to an entrained aerosol flow reactor and Chemical Ionization Mass Spectrometer (CIMS). Measurements of γ(HOCl) retrieved here are compared against those in the literature, and the role of organic coatings on nascent sea-spray aerosol is explored.

  3. The size dependence of chloride depletion in fine and coarse sea-salt particles

    NASA Astrophysics Data System (ADS)

    Yao, Xiaohong; Fang, Ming; Chan, Chak K.

    The size dependence of the percentage of chloride depletion (%Cl dep) in sea-salt aerosols was investigated using 16 sets of 48-96 h size distribution measurements of atmospheric aerosols, collected from June 2000 to May 2001 in Hong Kong. Chloride and sodium in HK are predominantly from sea-salt aerosols because the prevailing wind is from the sea. In the particles larger than 1.8 μm (coarse particles), the %Cl dep generally decreased with increasing particle size, consistent with the literature. In the particles smaller than 1.8 μm (fine particles), the mode diameter of %Cl dep was associated with the mode diameter of sulfate in the droplet mode. When the sulfate peak appeared at 0.32-0.54 μm, the %Cl dep peaked at 0.54-1.0 μm. Heterogeneous reactions between sea-salt particles and acidic gases are the major routes of the sulfate formation and chloride depletion, leading to a decrease in the %Cl dep with increasing particle size. When the sulfate peak appeared at 0.54-1.0 μm, the maximum %Cl dep appeared at 1.0-1.8 μm and the %Cl dep increased with increasing particle size in the fine mode. Both heterogeneous reactions and in-cloud processes occurred to form sulfate and to deplete chloride. However, heterogeneous reactions, sampling artifacts, and anthropogenic emissions of chloride cannot explain this observed size dependence. Cloud processing including the activation of sea-salt particles with subsequent SO 42- formation, the neutralization by NH 3 and the evaporation of HCl in conjunction with NH 3 during water evaporation from cloud droplets can cause chloride depletion in the droplet mode. The smaller amount of evaporation of NH 3 and HCl from cloud droplets in forming the 0.54-1.0 μm particles than the 1.0-1.8 μm particles can account for the observed size dependence of %Cl dep although direct evidence based on cloud measurements is not available.

  4. Characterization of humic substances in salt marsh soils under sea rush ( Juncus maritimus)

    NASA Astrophysics Data System (ADS)

    Santín, C.; González-Pérez, M.; Otero, X. L.; Vidal-Torrado, P.; Macías, F.; Álvarez, M. Á.

    2008-09-01

    Humic substances (HS) from salt marsh soils were characterized and the relationships among HS composition and some geochemical factors were analysed. For this, three salt marshes with the same vegetation cover ( Juncus maritimus), but with different geochemical characteristics, were selected. The qualitative characterization of the soil humic acids and fulvic acids was carried out by elemental analysis, FTIR spectroscopy, fluorescence spectroscopy and VACP/MAS 13C NMR spectroscopy. HS from salt marsh soils under sea rush ( Juncus maritimus) displayed some shared characteristics such as low degree of humification, low aromatic content and high proportion of labile compounds, mainly polysaccharides and proteins. However, although the three salt marsh soils under study were covered by the same type of vegetation, the HS showed some important differences. HS composition was found to be determined not only by the nature of the original organic material, but also by environmental factors such as soil texture, redox conditions and tidal influence. In general, an increase in the humification process appeared to be related to aerobic conditions and predominance of sand in the mineral fraction of the soil, while the preservation of labile organic compounds may be associated with low redox potential values and fine soil texture.

  5. Sea salt, sulfate, nitrate, chloride in Asian dust particles observed in Japan: results of individual particle analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Daizhou; Yamada, Maromu; Tobo, Yutaka; Ogata, Hiroko; Hara, Kazutaka; Nagatani, Tetsuji; Matsuki, Atsushi; Iwasaka, Yasunobu; Lieke, Kirsten

    2010-05-01

    Atmospheric particles were collected in Japan during Asian dust storm events from 2000 to 2007. Dust particles were analyzed by using electron microscopes and the mixture state of individual dust particles with sea salt, sulfate, nitrate and chloride were investigated. About 60~85% of dust particles were internally mixed with sea salt, 91% or more dust particles contained sulfate, and 27% or less contained nitrate. Besides the coagulation of sea-salt and dust particles, chlorine could deposit onto dust particles through the absorption of chlorine-containing gases when the particles passed through the marine atmosphere between China and Japan. The quantitative estimation revealed that the chlorine deposition on many particles was not negligible compared to sulfur deposition. The preferential formation of chloride in Ca-rich dust particles in cases when the particles contain little or no sulfate was found. Most of the particles were in an amorphous state and nearly spherical even under high vacuum, implying the potential enhancement of dust hygroscopicity. Comparisons of the relative weight ratios of sodium, sulfur and chlorine in mixture particles and in sea salt particles showed that mineral materials could enhance particulate sulfate and nitrate formation and restrain chlorine depletion from the sea salt components in mixture particles. Size distributions of the particles segregated by the mixture degrees of mineral and sea salt in different dust storm events were similar and all distributions showed a diameter range of 1~8 μm with maximum mode around 3 μm. Out of 1~8 μm, dust particles were rarely detected. It is confirmed that the size increase of dust particles had a strong correlation with their sea salt content but was independent from their non-sea-salt sulfur content, suggesting that the growth of dust particles in size during their dispersion in the marine atmosphere was dominated by the combination with sea salt rather than by other processes such as

  6. Deformation above mobile substrates, salt rheology and spatial distribution of salt structures: A 3D seismic study of the Permian southern North Sea

    NASA Astrophysics Data System (ADS)

    Hernandez, Karina; Mitchell, Neil; Huuse, Mads

    2016-04-01

    At ~255 Ma, cycles of evaporation of seawater led to deposition of evaporites including halite (rock salt) in the North Sea Basin. After later burial by denser sediments, the salt beds rose as pillows and diapirs. Assuming mobilization is due to Rayleigh-Taylor gravitational instability of heavy fluid (sediments) overlying light fluid (salts), theory suggests that the spacing between diapirs should be proportional to the original thickness of the salt layer. For example, a description of the theory in Turcotte and Schubert (1982) predicts structure wavelength to be 2.6 times the salt thickness. Previous research has explored mobilization of salt deposits assuming they have uniform rheology. However, this is not justified as halite rheology varies with temperature, grain size and pore brine content. Furthermore, evaporitic sequences contain various minerals besides halite (e.g., anhydrite, gypsum), which have different rheological properties. 3D seismic and well data reveal the internal structure of salt beds. The data have allowed characterization of structure wavelengths and salt thickness, so that the impact of internal composition and other properties on halokinetic behaviour can be assessed.

  7. Subsea salt flows in the Atlantis II Deep and Thetis Deep, Red Sea

    NASA Astrophysics Data System (ADS)

    Feldens, P.; Schmidt, M.; Mitchell, N.; Basaham, A. S.

    2012-04-01

    In the area of today's Red Sea, evaporites were widely deposited during the Miocene. Due to the ongoing rifting and seafloor spreading, the evaporites have lost their lateral constraint and started to move downslope. High sediment temperatures near the Red Sea graben and the weak rheology of halite may also favour evaporite movement. However, the deformation mechanism as well as the velocity of these flows is largely unknown. New high-resolution multibeam and seismic data were recorded in March 2011 (P408-2 cruise) within the framework of the project "The Jeddah Transect", a cooperation between King Abdulaziz University, Saudi-Arabia and GEOMAR, Germany. The data give new insights into evaporite flows in the area of the Atlantis II Deep. This ~400 m deep seafloor depression is located at about 21°N in the central Red Sea graben and is partly filled with hot saline brine (T~68°C, S~270‰). The brine-seawater interface at about 2050 mbsl coincides with the depth of a subseafloor salt layer in the seismic reflection data. The rough seafloor morphology of the Atlantis II Deep area is dominated by a sequence of normal faults showing vertical offsets of several hundred meters. However, SW-NE directed lineaments parallel to the seafloor gradient in the south east and possibly north-west of the deep, with typical heights between 20 and 40 m, widths between 300 and 1000 m and lengths exceeding 10 km in places, are interpreted as surface indications of subsurface evaporite flow. The fronts of some of these flows are well rounded, and their occurrence is limited to areas of low seafloor gradients. Generally, the appearance of evaporite flows in the Atlantis II Deep is comparable to salt flows in the Thetis Deep at ~23°N (Mitchell et al., 2010). Furthermore, deformed hemipelagic layers deposited on top of the Miocene evaporites indicate salt movement 60 km off the central rift axis. A second research cruise is planned in March 2012 (RV Pelagia) to obtain more high

  8. Measurement of Atmospheric Sea Salt Concentration in the Dry Storage Facility of the Spent Nuclear Fuel

    SciTech Connect

    Masumi Wataru; Hisashi Kato; Satoshi Kudo; Naoko Oshima; Koji Wada; Hirofumi Narutaki

    2006-07-01

    Spent nuclear fuel coming from a Japanese nuclear power plant is stored in the interim storage facility before reprocessing. There are two types of the storage methods which are wet and dry type. In Japan, it is anticipated that the dry storage facility will increase compared with the wet type facility. The dry interim storage facility using the metal cask has been operated in Japan. In another dry storage technology, there is a concrete overpack. Especially in USA, a lot of concrete overpacks are used for the dry interim storage. In Japan, for the concrete cask, the codes of the Japan Society of Mechanical Engineers and the governmental technical guidelines are prepared for the realization of the interim storage as well as the code for the metal cask. But the interim storage using the concrete overpack has not been in progress because the evaluation on the stress corrosion cracking (SCC) of the canister is not sufficient. Japanese interim storage facilities would be constructed near the seashore. The metal casks and concrete overpacks are stored in the storage building in Japan. On the other hand, in USA they are stored outside. It is necessary to remove the decay heat of the spent nuclear fuel in the cask from the storage building. Generally, the heat is removed by natural cooling in the dry storage facility. Air including the sea salt particles goes into the dry storage facility. Concerning the concrete overpack, air goes into the cask body and cools the canister. Air goes along the canister surface and is in contact with the surface directly. In this case, the sea salt in the air attaches to the surface and then there is the concern about the occurrence of the SCC. For the concrete overpack, the canister including the spent fuel is sealed by the welding. The loss of sealability caused by the SCC has to be avoided. To evaluate the SCC for the canister, it is necessary to make clear the amount of the sea salt particles coming into the storage building and the

  9. Global Simulations of Radiative Forcing from Sea Salt Injections into Marine Clouds: The Effect of Injection Rate and Particle Size

    NASA Astrophysics Data System (ADS)

    Alterskjaer, K.; Kristjánsson, J.

    2011-12-01

    Sea salt seeding of low level marine clouds is a suggested technique to counteract or slow global warming. The injected sea salt is to act as cloud condensation nuclei (CCN) and through the aerosol indirect effect increase the cloud albedo and therefore the reflection of solar radiation from the earth-atmosphere system. Using the Norwegian Earth System Model (NorESM) we investigate the global radiative forcing achieved through sea salt seeding as a function of both (i) emission rate and (ii) sea salt particle size. The injection rates are uniform and confined over ocean between 30°S and 30°N, and range from 10-9 to 10-11 kg m-2 s-1. The size of the particles ranges from a dry modal radius of 0.022 μm to 0.13 μm, with geometric standard deviations of 1.59. The study includes aerosol indirect effects both in the shortwave and the longwave and investigates the direct radiative effect of the added sea salt particles. Preliminary results show that increasing emissions of the 0.13 μm sea salt mode leads to an aerosol indirect effect of between -3.4 Wm-2 and -0.04 Wm-2, depending on emission rate. The maximum achieved forcing is close to cancelling the positive forcing resulting from a doubling of atmospheric CO2 concentrations (-3.8 Wm-2). Results also show that the direct effect of the sea salt parties is much larger than previously assumed, and the total radiative effect and the cooling potential of this geo-engineering technique may therefore be much greater than what has been assumed earlier. We find that ignoring the direct effect of sea salt may lead to serious errors in determining both the effectiveness of sea salt seeding and possible side effects. The longwave forcing resulting from a change in cloud emissivity with added sea salt is found to be negligible. Results also show that the size of the added sea salt is of crucial importance for the achieved radiative forcing. While adding large sea salt particles leads to a significant negative forcing at the

  10. Heat and salt redistribution within the Mediterranean Sea in the Med-CORDEX model ensemble

    NASA Astrophysics Data System (ADS)

    Llasses, J.; Jordà, G.; Gomis, D.; Adloff, F.; Macías, D.; Harzallah, A.; Arsouze, T.; Akthar, N.; Li, L.; Elizalde, A.; Sannino, G.

    2016-06-01

    Characterizing and understanding the basic functioning of the Mediterranean Sea in terms of heat and salt redistribution within the basin is a crucial issue to predict its evolution. Here we quantify and analyze the heat and salt transfers using a simple box model consisting of four layers in the vertical for each of the two (western and eastern) basins. Namely, we box-average 14 regional simulations of the Med-CORDEX ensemble plus a regional and a global reanalysis, computing for each of them the heat and salt exchanges between layers. First, we analyze in detail the mechanisms behind heat and salt redistribution at different time scales from the outputs of a single simulation (NEMOMED8). We show that in the western basin the transfer between layer 1 (0-150 m) and layer 2 (150-600 m) is upwards for most models both for heat and salt, while in the eastern basin both transfers are downwards. A feature common to both basins is that the transports are smaller in summer than in winter due to the enhanced stratification, which dampen the mixing between layers. From the comparison of the 16 simulations we observe that the spread between models is much larger than the ensemble average for the salt transfer and for the heat transfer between layer 1 and layer 2. At lower layers (below 600 m) there is a set of models showing a good agreement between them, while others are not correlated with any other. The mechanisms behind the ensemble spread are not straightforward. First, to have a coarse resolution prevents the model to correctly represent the heat and salt redistribution in the basin. Second, those models with a very different initial stratification also show a very different redistribution, especially at intermediate and deep layers. Finally, the assimilation of data seems to perturb the heat and salt redistribution. Besides this, the differences among regional models that share similar spatial resolution and initial conditions are induced by more subtle mechanisms

  11. A model for the atmospheric fate of sea salt particles incoastal areas

    NASA Astrophysics Data System (ADS)

    Demoisson, Ambre; Tedeschi, Gilles; Piazzola, Jacques

    2013-04-01

    Aerosol particles affect climate by scattering and absorbing radiation (Charlson et al., 1992), and may affect the heat budget. Among them, the particles generated at the air-sea interface by wave breaking represent a major component of the natural aerosol (Andreae, 1995). Sea-spray aerosols are mechanically produced by the interaction between wind and wave: when the wind speed increases beyond a critical value, waves break to dissipate the excess of energy. This is accompanied by the occurrence of whitecaps (Monahan and O'Muircheartaigh, 1980) and the primary marine aerosol production is directly related to the whitecap fraction. Air entrained into the water breaks up into bubbles, which may be transported to depths of several meters. When the bubbles rise and reach the surface, they burst and produce two kinds of droplets : film drops and jet drops (Blanchard, 1963; Blanchard, 1983; Resch and Afeti, 1991; Resch and Afeti, 1992). Sea-salts dominate atmospheric deposition in maritime regions (Gustafsson and Franzen, 1996; Farrell et al., 1995). However, the fate of marine aerosol particles in the marine atmosphere is still largely unknown. A model for the aerosol transport in coastal areas is then of great interest for a large number of applications among them, climate change and studies on air and water quality. Tedeschi and Piazzola (2011) presented the development of the Marine Aerosol Concentration Model (MACMod), which is a 2D unsteady model dedicated to the atmospheric transport of marine aerosols in the Marine Atmospheric Boundary Layer. However, such a transport model needs to implement an accurate source term for the sea-salt particles. Uncertainties on the sea-salt source function are still large (see Lewis and Schwartz, 2004). In particular, in coastal areas, the sea-spray production through breaking waves depends on both the fetch and the wind speed conditions. In this study, we propose to improve the MACMod model predictions by introducing an accurate

  12. Interannual to decadal climate variability of sea salt aerosols in the coupled climate model CESM1.0

    NASA Astrophysics Data System (ADS)

    Xu, Li; Pierce, David W.; Russell, Lynn M.; Miller, Arthur J.; Somerville, Richard C. J.; Twohy, Cynthia H.; Ghan, Steven J.; Singh, Balwinder; Yoon, Jin-Ho; Rasch, Philip J.

    2015-02-01

    This study examines multiyear climate variability associated with sea salt aerosols and their contribution to the variability of shortwave cloud forcing (SWCF) using a 150 year simulation for preindustrial conditions of the Community Earth System Model version 1.0. The results suggest that changes in sea salt and related cloud and radiative properties on interannual timescales are dominated by the El Niño-Southern Oscillation cycle. Sea salt variability on longer (interdecadal) timescales is associated with low-frequency variability in the Pacific Ocean similar to the Interdecadal Pacific Oscillation but does not show a statistically significant spectral peak. A multivariate regression suggests that sea salt aerosol variability may contribute to SWCF variability in the tropical Pacific, explaining up to 20-30% of the variance in that region. Elsewhere, there is only a small sea salt aerosol influence on SWCF through modifying cloud droplet number and liquid water path that contributes to the change of cloud effective radius and cloud optical depth (and hence cloud albedo), producing a multiyear aerosol-cloud-wind interaction.

  13. Direct radiative effects of sea salt for the Mediterranean region under conditions of low to moderate wind speeds

    NASA Astrophysics Data System (ADS)

    Lundgren, K.; Vogel, B.; Vogel, H.; Kottmeier, Ch.

    2013-02-01

    ABSTRACT This study deals with the direct radiative effect of sea salt on the regional scale, within both the shortwave and longwave ranges. The COSMO-ART model system has been extended and applied for a large part of Europe and adjacent waters within this investigation. For the radiation calculations, we determined the sea salt optical properties based on Mie calculations, giving the optical properties for the three sea salt modes and eight spectral intervals. The simulated sea salt aerosol optical depth is found to show strong dependence on the 10 m wind speed under cloud-free conditions. This relation is best represented by a power law fit and compares well with satellite observations. For clear-sky conditions, the simulated sea salt direct radiative effects on the shortwave and longwave radiative budgets are approximately of the same order of magnitude, but with opposite signs. This causes the net radiative effect to approach zero, which leads to a low impact on the temperature for this area.

  14. Age characteristics in a multidecadal Arctic sea ice simulation

    SciTech Connect

    Hunke, Elizabeth C; Bitz, Cecllia M

    2008-01-01

    Results from adding a tracer for age of sea ice to a sophisticated sea ice model that is widely used for climate studies are presented. The consistent simulation of ice age, dynamics, and thermodynamics in the model shows explicitly that the loss of Arctic perennial ice has accelerated in the past three decades, as has been seen in satellite-derived observations. Our model shows that the September ice age average across the Northern Hemisphere varies from about 5 to 8 years, and the ice is much younger (about 2--3 years) in late winter because of the expansion of first-year ice. We find seasonal ice on average comprises about 5% of the total ice area in September, but as much as 1.34 x 10{sup 6} km{sup 2} survives in some years. Our simulated ice age in the late 1980s and early 1990s declined markedly in agreement with other studies. After this period of decline, the ice age began to recover, but in the final years of the simulation very little young ice remains after the melt season, a strong indication that the age of the pack will again decline in the future as older ice classes fail to be replenished. The Arctic ice pack has fluctuated between older and younger ice types over the past 30 years, while ice area, thickness, and volume all declined over the same period, with an apparent acceleration in the last decade.

  15. Modern Tasman Sea surface reservoir ages from deep-sea black corals

    NASA Astrophysics Data System (ADS)

    Komugabe, Aimée F.; Fallon, Stewart J.; Thresher, Ronald E.; Eggins, Stephen M.

    2014-01-01

    Marine reservoir ages are a key element in calculating and constraining uncertainty in radiocarbon age estimates and are also essential to better understand regional ocean circulation. In this study, we present a new method to reconstruct long-term, high-resolution sea surface reservoir ages based on analysis of the organic skeleton of deep-sea (560 m) black coral (Anthozoa, Antipatharia). Our results confirm that antipatharians are extremely slow growing (typical radial growth rate for a South Pacific specimen around 0.03 mm/yr). Coupled uranium series and radiocarbon measurements were made on black coral collected live from the Norfolk Ridge (north Tasman Sea) to provide the first modern reservoir ages for this region. At the Norfolk Ridge, the average reservoir age between 1790 AD and 1900 AD was ∼330 years. This was followed by a steep decrease over time of about 70 years to 1950 AD (our most modern value). This indicates an increase in surface ocean ventilation of water masses in this region. These results are consistent with observational studies for the early twentieth century, which suggest significant changes in regional circulation of the southwest pacific.

  16. Investigating Primary Marine Aerosol Properties: CCN Activity of Sea Salt and Mixed Inorganic–Organic Particles

    PubMed Central

    2012-01-01

    Sea spray particles ejected as a result of bubbles bursting from artificial seawater containing salt and organic matter in a stainless steel tank were sampled for size distribution, morphology, and cloud condensation nucleus (CCN) activity. Bubbles were generated either by aeration through a diffuser or by water jet impingement on the seawater surface. Three objectives were addressed in this study. First, CCN activities of NaCl and two types of artificial sea salt containing only inorganic components were measured to establish a baseline for further measurements of mixed organic–inorganic particles. Second, the effect of varying bubble residence time in the bulk seawater solution on particle size and CCN activity was investigated and was found to be insignificant for the organic compounds studied. Finally, CCN activities of particles produced from jet impingement were compared with those produced from diffuser aeration. Analyses indicate a considerable amount of organic enrichment in the jet-produced particles relative to the bulk seawater composition when sodium laurate, an organic surfactant, is present in the seawater. In this case, the production of a thick foam layer during impingement may explain the difference in activation and supports hypotheses that particle production from the two methods of generating bubbles is not equal. PMID:22809370

  17. Inventory and protection of salt marshes from risks of sea-level rise at Acadia National Park, Maine

    USGS Publications Warehouse

    Dudley, Robert W.; Nielsen, Martha G.

    2011-01-01

    Recent U.S. Geological Survey (USGS) climate studies in the northeastern United States have shown substantial evidence of climate-related changes during the last 100 years, including earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies related to climate change are being expanded to include investigation of coastal wetlands that might be at risk from sealevel rise. Coastal wetlands, particularly salt marshes, are important ecosystems that provide wildlife nursery and breeding habitat, migratory bird habitat, water quality enhancement, and shoreline erosion control. The USGS is investigating salt marshes in Acadia National Park with the goal of determining which salt marshes may be threatened by sea-level rise and which salt marshes may be able to adapt to sea-level rise by migrating into adjacent low-lying lands.

  18. Salt diapirs in the Dead Sea basin and their relationship to Quaternary extensional tectonics

    USGS Publications Warehouse

    Al-Zoubi, A.; ten Brink, U.S.

    2001-01-01

    Regional extension of a brittle overburden and underlying salt causes differential loading that is thought to initiate the rise of reactive diapirs below and through regions of thin overburden. We present a modern example of a large salt diapir in the Dead Sea pull-apart basin, the Lisan diapir, which we believe was formed during the Quaternary due to basin transtension and subsidence. Using newly released seismic data that are correlated to several deep wells, we determine the size of the diapir to be 13 x 10 km. its maximum depth 7.2 km. and its roof 125 m below the surface. From seismic stratigraphy, we infer that the diapir started rising during the early to middle Pleistocene as this section of the basin underwater rapid subsidence and significant extension of the overburden. During the middle to late Pleistocene, the diapir pierced through the extensionally thinned overburden, as indicated by rim synclines, which attest to rapid salt withdrawal from the surrounding regions. Slight positive topography above the diapir and shallow folded horizons indicate that it is still rising intermittently. The smaller Sedom diapir, exposed along the western bounding fault of the basin is presently rising and forms a 200 m-high ridge. Its initiation is explained by localized E-W extension due monoclinal draping over the edge of a rapidly subsiding basin during the early to middle Pleistocene, and its continued rise by lateral squeezing due to continued rotation of the Amazyahu diagonal fault. ?? 2001 Elsevier Science Ltd. All rights reserved.

  19. Understanding salt dynamics for a restored coastal wetland at the Baltic Sea in Germany

    NASA Astrophysics Data System (ADS)

    Selle, Benny; Gräff, Thomas; Salzmann, Thomas; Oswald, Sascha; Walther, Marc; Miegel, Konrad

    2016-04-01

    Coastal fens like the nature reserve „Hütelmoor und Heiligensee"(north-eastern Germany) are important landscape elements along the southern Baltic coast, which exchange fresh water and brackish water with the Baltic Sea. These exchange processes can be understood as experiments with a natural tracer, which may be used to investigate the hydrologic behaviour of these fen systems. With the establishment of coastal protection measures such as dunes and dikes, the installation of surface drainage and, more recently, also nature conservation measures, the hydrologic regime of these coastal wetlands constantly altered over the last centuries. The rehabilitated wetland „Hütelmoor und Heiligensee" is suitable for an analysis of hydrologic change as it was monitored over the time period since nature conservation measures started in the 1990s. Collected data sets include observation of groundwater levels and electrical conductivities, weather data as well as discharge at the outlet of the drainage catchment. In this study, we identifed processes and quantify process magnitudes that govern the salt balance of the study area including its variability in space and time. We found that - over the period of rehabilitation - salt water entered the catchment with episodic storm surges by wave overtopping of dunes. The intruded brackish water was then diluted, which is a slow process occurring over decades. It is governed by local groundwater recharge from precipitation and the inflow of relatively fresh groundwater from the hinterland. It is concluded that salt inputs from the Baltic Sea provide a natural tracer of hydrological processes, which can be readily monitored via electrical conductivity measurements.

  20. Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

    SciTech Connect

    Roark, E B; Guilderson, T P; Dunbar, R B; Ingram, B L

    2006-01-13

    The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimens as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected sample. Similarly, with a growth rate of < 10 {micro}m y{sup -1} and an age of {approx}2377 years, L. glaberrima at the Makapuu coral bed, is also extremely long lived. In contrast, the shallow-collected A. dichotoma samples yield growth rates ranging from 130 to 1,140 {micro}m y{sup -1}. These results show that Hawaiian deep-sea corals grow more slowly and are older than previously thought.

  1. Characterization of Finnish Building materials under salt frost artificial ageing

    NASA Astrophysics Data System (ADS)

    Luodes, Nike M.; Torppa, Akseli; Pirinen, Heikki; Bellopede, Rossana; Marini, Paola

    2016-04-01

    Under a national project co financed by the Confederation of Finnish Construction Industries RT (CFCI), the Finnish Natural Stone Association and the Geological Survey of Finland (GTK), and thanks to the cooperation with the Polytechnic of Turin a comprehensive number of Finnish natural stones has been tested according to SFS EN standards for national CE marking and according to non standardized methods for research purposes. The aim was to evaluate the effects of combined salt and frost weathering caused by de-icing salts and to research a possible correlation between laboratory's accelerated decay and site weathering. The materials tested (60 stones in total) are mainly silicate rocks showing good resistance to the weathering. Results have been affected in some cases by uncertainties connected to the variation of material quality. Some materials have been from new quarries and variation of their properties has been higher than the effects of artificial weathering. Material sampled from crop presented higher weathering level and the additional artificial weathering has induced small variations. Results have shown that material weathering has been better represented by variation of flexural strength compared to uniaxial compressive strength. The most probable reason has been that small changes of planarity and perpendicularity had greater effects on the compressive strength than variations by weathering. Fifteen representative typologies of natural stones have been tested with non standardized methodologies to study the changes of the material and finding a possible correlation with methods used on site. Schmidt rebound test and Ultra Pulse Velocity (UPV) have been used on site to assess the durability of stone on construction. Materials tested in laboratory have shown less variation between rebounds compared to site tests, this can be because of a more controlled environment and saw cut surface instead of rocky or chiselled ones. Laboratory tests showed an average

  2. Heterogeneous Processes of ClO Radicals on the Sea Salts Surface

    NASA Astrophysics Data System (ADS)

    Morozov, I.; Loukhovitskaya, E.; Vasiliev, E.; Hack, W.

    2009-04-01

    The compositions of atmospheric aerosols vary widely. Interaction of atmospheric gases with aerosols alters the gas phase composition as well as the aerosols surface characteristics. Sea salt aerosols represent an unlimited halogen reservoir. Together with salt deposited on shelf ice they are considered the most likely source of reactive halogens in the Arctic. Heterogeneous reactions on sea salt aerosols or deposits are therefore suspected to be a potential source of gas phase halogen compounds. The heterogeneous reactivity of HOCl on solid KBr at ambient temperature reveal the formation of Br- and Cl- containing reaction products such as BrCl and Cl2. Photolysis of these reaction products with subsequent reaction with ozone lead to the chlorine oxide formation. The issue of ozone depletion within the Arctic boundary layer in springtime represents a relatively new area of uncertainty in atmospheric chemistry. However catalytic destruction, especially through reactions involving active bromine on the surface of aerosol particles, does appear to be involved. There is considerable uncertainty as to the processes by which active halogen is liberated from the organic (e.g. CH3X) and inorganic forms (e.g. sea salt) of the halogen source. This is unsurprising because a quantitative description of stratospheric heterogeneous chemistry is much less developed than the gas-phase chemistry. The reaction between chlorine atoms and ozone generates up to (2-4) 1012 ClO radicals/cm3 in the flow reactor: Cl + O3 → ClO + O2 ClO → Sea Salt (determined γ) Study of the heterogeneous processes of the halogen containing radical was carried out in the temperature range 240 - 370 K and at a total pressure ca. 1-10 mbar using the discharge-flow technique. He was used as the carrier gas. The reactants were detected by two different molecular beam mass spectrometers with electron impact detectors. Uptake coefficient measurements were obtained using an MS 7303 quadrupole mass

  3. Salt diffusion in interstitial waters and halite removal from sediments: Examples from the Red Sea and Illinois basins

    SciTech Connect

    Ranganathan, V. )

    1991-06-01

    Large thicknesses of bedded halite can be removed in subsiding sedimentary basins by verticla diffusion of dissolved salt in interstitial waters over geologic time scales. Calculations show that at least 10 m to 40 m of halite may have dissolved and diffused through the Red Sea sediments overlying the salt beds, since cessation of salt deposition approximatley 5.3 million years ago. The total amount of salt diffused out of the sediment column over geologic time is five to twenty times the amount of salt that currently exists in the porewater column. If upward flow in the past occurred at even small rates, 10{sup {minus}3} m/yr, the amount of halite removed could have been ten times as great, 500 m. Unlike the Red Sea Basin, no halite beds are known in the Illinois Basin in spite of the fact that interstitial waters with as much as 200{per thousand} TDS (approximately 220 g/L) occur. Calculations show that if a halite bed had been deposited at the base of the Illinois Basin in Cambrian time, it would have been completely removed from the stratigraphic record had it initially been less than 60 m to 130 m in thickness. A significant thickness of halite deposited in sedimentary basins may thus be removed during active burial of salt beds, and before exhumation and exposure of the salt beds to shallow meteoric waters.

  4. Age-progressive volcanism in the Tasman and Coral seas

    NASA Astrophysics Data System (ADS)

    Williams, S.; Gans, P. B.; Mortimer, N. N.; Meffre, S.; Seton, M.

    2014-12-01

    The South West Pacific is the site of widespread Cenozoic volcanism, much of which has formed without a clear spatio-temporal pattern. Exceptions to this overall trend are found in the Tasman Sea, where two chains of age-progressive volcanism are present, the Tasmantids and the Lord Howe seamount chain (LHSC). Both of these follow broadly north-south co-linear trends, recording rapid northwards motion of the Australian plate since >24 Ma. The bathymetric expression of the volcanic trails can be traced northwards towards the Coral Sea, which hosts a complex tapestry of poorly sampled plateaux and rises whose relationship to hotspot volcanism remains enigmatic. We present the results of a marine geophysical and dredging survey to the eastern Coral Sea onboard the RV Southern Surveyor in October-November, 2012. We constrain the timing of basin opening in the South Rennell Trough and Santa Cruz Basin to between ~43-28 Ma, using a combination of magnetic anomaly profiles, seafloor fabric from swath bathymetry data, Ar-Ar dating of basalts and paleontological dating of carbonates. The evolution of this spreading system corresponds to the opening of the Solomon Sea further north, where chrons 19-16 have been identified, suggesting the existence of a single > 2,000 km long back-arc basin. Rocks dredged from the northernmost volcanoes of the LHSC, close to the southern end of the South Rennell Trough, are dated at ~27-28 Ma. Geochemically the LHSC lavas are intraplate tholeiites and contrast with older E-MORB-type basalts formed at the ultra-slow spreading South Rennell Trough until ~28 Ma. These are the oldest rocks recovered from the LHSC, and their age confirms predictions from absolute plate motion modeling.

  5. Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

    NASA Astrophysics Data System (ADS)

    Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

    2015-06-01

    Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C14N- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C14N- line scans further show that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces determines their hygroscopic and optical properties. These abundant SSA, whose reactive surfaces absorb inorganic and organic acidic gases in the arctic troposphere, need to be incorporated into atmospheric chemical models.

  6. Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere

    NASA Astrophysics Data System (ADS)

    Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

    2015-10-01

    Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes in physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased, the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces adsorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the Arctic atmosphere, which need to be incorporated into atmospheric chemical models in the Arctic troposphere.

  7. Spectroscopic investigations of organic aerosol and its reaction with halogens, released by sea-salt activation

    NASA Astrophysics Data System (ADS)

    Ofner, J.; Zetzsch, C.

    2009-04-01

    The release of reactive halogen species from sea-salt aerosol offers a class of reactants for heterogeneous reactions of utmost importance. These heterogeneous reactions have been overlooked so far, although they may occur with internal and external mixtures of sea-salt aerosol and organic aerosol or organic matter. Such reactions might constitute sources of gaseous organohalogen compounds or halogenated organic aerosol in the atmospheric boundary layer. Infrared and UV/VIS spectroscopy provide an insight into chemical processes at reactive sites of the organic phase on a molecular level. Model studies of heterogeneous reactions of halogens with different kinds of (secondary) organic aerosols and organic matter were performed using a 700L smog chamber with a solar simulator. The model compounds alpha-pinene, catechol and humic acid have been chosen as precursors/material for the condensed, organic phase of the aerosol. After formation of the secondary organic aerosol or preparation of the organic material and the sea-salt solution the reaction was carried out using molecular chlorine and bromine in the presence of simulated sunlight. Chemical transformation of the organic material was studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) on a ZnSe crystal and diffuse reflectance UV/VIS spectroscopy. An electrostatic precipitator was developed to deposit the aerosol particles on the ATR crystal as a thin film. On the other hand, longpath-FTIR spectroscopy with a 40m White-cell allows us to monitor both the condensed and gas phase of the aerosol in situ in the smog chamber directly. These spectroscopic techniques enable us to characterize different organic aerosol particles and their functional groups at reactive sites on these particles as well as to study aerosol formation and transformation directly. The heterogeneous reaction of reactive halogen species with organic material at atmospheric conditions leads to small reactive

  8. The Resilience and Recovery of Salt Marshes to Landfalling Storms and Sea-Level Rise, New Jersey, USA

    NASA Astrophysics Data System (ADS)

    Horton, B.; Nikitina, D.; Kemp, A.; Vane, C. H.; Engelhart, S. E.; Khan, N. S.

    2014-12-01

    Instrumental and observational records are too short to adequately describe the history of land-falling storms or sea-level rise, especially for extreme and rare events such as Hurricane Sandy. However, the sediment preserved beneath coastal wetlands is an archive of when storms impacted the coast and past changes in sea level, and how long it takes for wetlands recovery from such events. Here, we describe late Holocene sediments beneath the Sea Breeze salt marsh on the New Jersey side of Delaware Bay from more than 200 gouge cores positioned along seven transects. The stratigraphic record documents at least seven depositional sequences consisting of salt-marsh peat and mud couplets that represent dramatic changes in sedimentation regime. There are number of processes that could cause this salt-marsh erosion including lateral migration of tidal creeks, rapid relative sea-level rise, tsunamis, formation and expansion of salt pans, and storms. The abrupt contacts between the salt-marsh peat and overlying intertidal mud suggest that erosion of the peat was followed by rapid infilling of accommodation space. Correlation of erosional surfaces across 2.5 km suggests a common mechanism and we propose that the erosion was caused by hurricanes and/or large winter storms. Further, the changes in salt-marsh sedimentation documented at several sites on the north shore of Delaware Bay were synchronous and broadly correlate with storm over-wash deposits and historical record of hurricane landfalls in New Jersey. We estimated wetland recovery time from hurricane-induced erosion using radiocarbon dates that bracket the erosive event in the sedimentary record. Following erosion and lowering of the marsh surface into the tidal frame a low-marsh ecosystem recolonizes the site, followed by recovery to a high salt-marsh environment. We estimate that this ecological and sedimentary succession can take up to 200 years.

  9. Age, growth rates, and paleoclimate studies of deep sea corals

    USGS Publications Warehouse

    Prouty, Nancy G; Roark, E. Brendan; Andrews, Allen; Robinson, Laura; Hill, Tessa; Sherwood, Owen; Williams, Branwen; Guilderson, Thomas P.; Fallon, Stewart

    2015-01-01

    Deep-water corals are some of the slowest growing, longest-lived skeletal accreting marine organisms. These habitat-forming species support diverse faunal assemblages that include commercially and ecologically important organisms. Therefore, effective management and conservation strategies for deep-sea corals can be informed by precise and accurate age, growth rate, and lifespan characteristics for proper assessment of vulnerability and recovery from perturbations. This is especially true for the small number of commercially valuable, and potentially endangered, species that are part of the black and precious coral fisheries (Tsounis et al. 2010). In addition to evaluating time scales of recovery from disturbance or exploitation, accurate age and growth estimates are essential for understanding the life history and ecology of these habitat-forming corals. Given that longevity is a key factor for population maintenance and fishery sustainability, partly due to limited and complex genetic flow among coral populations separated by great distances, accurate age structure for these deep-sea coral communities is essential for proper, long-term resource management.

  10. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation.

    PubMed

    Yakimov, Michail M; La Cono, Violetta; Slepak, Vladlen Z; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S; Rojo, David; Barbas, Coral; Golyshina, Olga V; Ferrer, Manuel; Golyshin, Peter N; Giuliano, Laura

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [(14)C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life. PMID:24352146

  11. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation

    NASA Astrophysics Data System (ADS)

    Yakimov, Michail M.; La Cono, Violetta; Slepak, Vladlen Z.; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S.; Rojo, David; Barbas, Coral; Golyshina, Olga V.; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

    2013-12-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life.

  12. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation

    PubMed Central

    Yakimov, Michail M.; La Cono, Violetta; Slepak, Vladlen Z.; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S.; Rojo, David; Barbas, Coral; Golyshina, Olga V.; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life. PMID:24352146

  13. Combined effect of glycine and sea salt on aerosol cloud droplet activation predicted by molecular dynamics simulations.

    PubMed

    Sun, Lu; Hede, Thomas; Tu, Yaoquan; Leck, Caroline; Agren, Hans

    2013-10-17

    The present study illustrates the combined effect of organic and inorganic compounds on cloud droplet nucleation and activation processes representative for the marine environment. Amino acids and sea salt are common marine cloud condensation nuclei (CCN) which act as a prerequisite for growth of cloud droplets. The chemical and physical properties of these CCN play a key role for interfacial properties such as surface tension, which is important for the optical properties of clouds and for heterogeneous reactions. However, there is a lack of detailed information and in situ measurements of surface tension of such nanosized droplets. Here we present a study of the combined effect of zwitterionic glycine (ZGLY) and sea salt in nanosized water droplets using molecular dynamics simulations, where particular emphasis is placed on the surface tension for the nanosized droplets. The critical supersaturation is estimated by the Köhler equation. It is found that dissolved sea salt interacts with ZGLY through a water bridge and weakens the hydrogen bonds among ZGLYs, which has a significant effect on both surface tension and water vapor supersaturation. Clusters of glycine mixed with sea salt deliquesce more efficiently and have higher growth factors. PMID:24063576

  14. Chemical processes in sea-salt chloride depletion observed at a Canadian rural coastal site

    NASA Astrophysics Data System (ADS)

    Yao, Xiaohong; Zhang, Leiming

    2012-01-01

    Chloride depletion in sea-salt aerosols was studied using size-segregated inorganic ions data collected at a Canadian rural coastal site during a summer (June 29-July 15, 2002) and a fall campaign (October 25 - November 15, 2002). Three samples collected in the fall campaign had high concentrations of sea-salt and ammoniated sulfate and nitrate aerosols and were used to study the relative importance of different chemical reactions contributing to the depletion. The percentage depletion (Cl -depletion(%)) increased substantially with decreasing particle size (up to 86% for particles in the size range of 1.0-3.1 μm). For particles >6.2 μm, the observed NO 3- was responsible for all the depleted Cl -; but less than a quarter of the depletion was explained by the HCl-released reaction between NaCl and HNO 3; the rest of the depletion was likely due to the non-HCl-released reactions, e.g., between NaCl and N 2O 5. For particles in the size range of 3.1-6.2 μm, the NO 3- was responsible for nearly 80-90% of all the depleted Cl - via HCl-released and/or non-HCl-released reactions; the remaining depletion was likely due to the reactions releasing Cl 2, HOCl, etc. Particles >3.1 μm were mostly neutral acidity while a portion of particles at 1.0-3.1 μm was acidic. SO 42- was only responsible for Cl -depletion(%) in acidic particles at 1.0-3.1 μm and the highest Cl -depletion(%) was observed in acidic particles of this size range.

  15. Effects of aging on mineralocorticoid-induced salt appetite in rats.

    PubMed

    Thunhorst, Robert L; Beltz, Terry G; Johnson, Alan Kim

    2013-12-15

    This work examined the effects of age on salt appetite measured in the form of daily saline (i.e., 0.3 M NaCl) drinking in response to administration of deoxycorticosterone acetate (DOCA; 5 mg/kg body wt) using young (4 mo), "middle-aged" adult (12 mo), and old (30 mo) male Brown Norway rats. Water and sodium intakes, excretions, and balances were determined daily. The salt appetite response was age dependent with "middle-aged" rats ingesting the most saline solution followed in order by young and then old rats. While old rats drank the least saline solution, the amounts of saline ingested still were copious and comprise an unambiguous demonstration of salt appetite in old rats. Middle-aged rats had the highest saline preference ratios of the groups under baseline conditions and throughout testing consistent with an increased avidity for sodium taste. There were age differences in renal handling of water and sodium that were consistent with a renal contribution to the greater saline intakes by middle-aged rats. There was evidence of impaired renal function in old rats, but this did not account for the reduced saline intakes of the oldest rats. PMID:24133100

  16. High temperature reaction between sea salt deposit and (U,Zr)O2 simulated corium debris

    NASA Astrophysics Data System (ADS)

    Takano, Masahide; Nishi, Tsuyoshi

    2013-11-01

    In order to clarify the possible impacts of seawater injection on the chemical and physical state of the corium debris formed in the severe accident at Fukushima Daiichi Nuclear Power Plants, the high temperature reaction between sea salt deposit and (U,Zr)O2 simulated corium debris (sim-debris) was examined in the temperature range from 1088 to 1668 K. A dense layer of calcium and sodium uranate formed on the surface of a sim-debris pellet at 1275 K under airflow, with the thickness of over 50 μm. When the oxygen partial pressure is low, calcium is likely to dissolve into the cubic sim-debris phase to form solid solution (Ca,U,Zr)O2+x. The diffusion depth was 5-6 μm from the surface, subjected to 1275 K for 12 h. The crystalline MgO remains affixed on the surface as the main residue of salt components. A part of it can also dissolve into the sim-debris.

  17. Probiotic properties of Pediococcus strains isolated from jeotgals, salted and fermented Korean sea-food.

    PubMed

    Lee, Kang Wook; Park, Ji Yeong; Sa, Hyun Deok; Jeong, Ji Hee; Jin, Dong Eun; Heo, Ho Jin; Kim, Jeong Hwan

    2014-08-01

    Three Pediococcus pentosaceus strains were isolated from jeotgals, salted and fermented Korean sea-foods, and their probiotic potentials were examined. After 2 h exposure to pH 3.0, P. pentosaceus F66 survived with the survival ratio of 32.6% followed by P. pentosaceus D56 (17.2%) and P. pentosaceus A24 (7.5%). P. pentosaceus F66 also survived better (26.6%) than P. pentosaceus A24 (13.7%) and P. pentosaceus D56 (5.8%) after 2 h exposure to 0.3% bile salts. Three strains grew slowly on MRS broth with 15% NaCl (w/v), reaching the OD600 values of 0.4-0.8 in 36 h. They adhered to Caco-2 cells (10.9-13.9 CFU/cell) with similar degree of adherence of a positive control, Lactobacillus rhamnosus GG (12.8 ± 0.5 CFU/cell). Three strains possess some desirable enzyme activities such as β-galactosidase, α-glucosidase, β-glucosidase, and N-acetyl-β-glucosidase. From these results, P. pentosaceus F66 seems qualified as a probiotic and can be utilized for fermented foods including jeotgals. PMID:24979684

  18. Responses of eastern Chinese coastal salt marshes to sea-level rise combined with vegetative and sedimentary processes.

    PubMed

    Ge, Zhen-Ming; Wang, Heng; Cao, Hao-Bin; Zhao, Bin; Zhou, Xiao; Peltola, Heli; Cui, Li-Fang; Li, Xiu-Zhen; Zhang, Li-Quan

    2016-01-01

    The impacts of sea-level rise (SLR) on coastal ecosystems have attracted worldwide attention in relation to global change. In this study, the salt marsh model for the Yangtze Estuary (SMM-YE, developed in China) and the Sea Level Affecting Marshes Model (SLAMM, developed in the U.S.) were used to simulate the effects of SLR on the coastal salt marshes in eastern China. The changes in the dominant species in the plant community were also considered. Predictions based on the SLAMM indicated a trend of habitat degradation up to 2100; total salt marsh habitat area continued to decline (4-16%) based on the low-level scenario, with greater losses (6-25%) predicted under the high-level scenario. The SMM-YE showed that the salt marshes could be resilient to threats of SLR through the processes of accretion of mudflats, vegetation expansion and sediment trapping by plants. This model predicted that salt marsh areas increased (3-6%) under the low-level scenario. The decrease in the total habitat area with the SMM-YE under the high-level scenario was much lower than the SLAMM prediction. Nevertheless, SLR might negatively affect the salt marsh species that are not adapted to prolonged inundation. An adaptive strategy for responding to changes in sediment resources is necessary in the Yangtze Estuary. PMID:27334452

  19. Responses of eastern Chinese coastal salt marshes to sea-level rise combined with vegetative and sedimentary processes

    PubMed Central

    Ge, Zhen-Ming; Wang, Heng; Cao, Hao-Bin; Zhao, Bin; Zhou, Xiao; Peltola, Heli; Cui, Li-Fang; Li, Xiu-Zhen; Zhang, Li-Quan

    2016-01-01

    The impacts of sea-level rise (SLR) on coastal ecosystems have attracted worldwide attention in relation to global change. In this study, the salt marsh model for the Yangtze Estuary (SMM-YE, developed in China) and the Sea Level Affecting Marshes Model (SLAMM, developed in the U.S.) were used to simulate the effects of SLR on the coastal salt marshes in eastern China. The changes in the dominant species in the plant community were also considered. Predictions based on the SLAMM indicated a trend of habitat degradation up to 2100; total salt marsh habitat area continued to decline (4–16%) based on the low-level scenario, with greater losses (6–25%) predicted under the high-level scenario. The SMM-YE showed that the salt marshes could be resilient to threats of SLR through the processes of accretion of mudflats, vegetation expansion and sediment trapping by plants. This model predicted that salt marsh areas increased (3–6%) under the low-level scenario. The decrease in the total habitat area with the SMM-YE under the high-level scenario was much lower than the SLAMM prediction. Nevertheless, SLR might negatively affect the salt marsh species that are not adapted to prolonged inundation. An adaptive strategy for responding to changes in sediment resources is necessary in the Yangtze Estuary. PMID:27334452

  20. Responses of eastern Chinese coastal salt marshes to sea-level rise combined with vegetative and sedimentary processes

    NASA Astrophysics Data System (ADS)

    Ge, Zhen-Ming; Wang, Heng; Cao, Hao-Bin; Zhao, Bin; Zhou, Xiao; Peltola, Heli; Cui, Li-Fang; Li, Xiu-Zhen; Zhang, Li-Quan

    2016-06-01

    The impacts of sea-level rise (SLR) on coastal ecosystems have attracted worldwide attention in relation to global change. In this study, the salt marsh model for the Yangtze Estuary (SMM-YE, developed in China) and the Sea Level Affecting Marshes Model (SLAMM, developed in the U.S.) were used to simulate the effects of SLR on the coastal salt marshes in eastern China. The changes in the dominant species in the plant community were also considered. Predictions based on the SLAMM indicated a trend of habitat degradation up to 2100; total salt marsh habitat area continued to decline (4–16%) based on the low-level scenario, with greater losses (6–25%) predicted under the high-level scenario. The SMM-YE showed that the salt marshes could be resilient to threats of SLR through the processes of accretion of mudflats, vegetation expansion and sediment trapping by plants. This model predicted that salt marsh areas increased (3–6%) under the low-level scenario. The decrease in the total habitat area with the SMM-YE under the high-level scenario was much lower than the SLAMM prediction. Nevertheless, SLR might negatively affect the salt marsh species that are not adapted to prolonged inundation. An adaptive strategy for responding to changes in sediment resources is necessary in the Yangtze Estuary.

  1. Monitoring environmental controls on salt-marsh foraminifera in Tuckerton, NJ: implications for sea-level research

    NASA Astrophysics Data System (ADS)

    Walker, Jennifer; Khan, Nicole; Shaw, Timothy; Garcia-Artola, Ane; Dura, Tina; Horton, Ben

    2016-04-01

    Salt-marsh foraminifera have been widely used as proxies to reconstruct sea-level trends because their modern distribution is strongly linked with tidal elevation, and they are relatively abundant and have a high preservation potential in intertidal sediments. To determine former sea levels, the relation between contemporary foraminifera and their controlling environmental variables must be determined and the influence of post-depositional changes elucidated. Duration and frequency of tidal exposure, while the dominant control, is not the only environmental variable controlling the distribution of foraminifera. Complex interactions between organisms and their environment factor into foraminifera species distributions and these factors will vary over space and time. Here we present preliminary results of a spatial and temporal ecological study to monitor short-term, seasonal, and interannual variations in salt-marsh foraminifera assemblages along a salinity gradient of an intertidal zone of New Jersey, USA. The temporal nature is beneficial in recording potential lags in response to changes in environmental conditions compared with one-time sampling. Live foraminifera assemblage samples are compared with measured environmental parameters (porewater chemistry, porewater nutrients, tidal inundation, grain size) and experiments (bioturbation, overwash deposit, and infaunal) to determine the controlling environmental variables on foraminifera and how these variables and the foraminifera assemblages change through time. Ultimately, this multi-year monitoring experiment provides a more comprehensive understanding of environmental controls on salt-marsh foraminifera and will provide a background data set of salt-marsh foraminifera to compare with future studies and with sampling after large events such as storms. A greater understanding of salt-marsh foraminifera in their environment will contribute to sea-level reconstructions. Since sea-level records use the distribution

  2. Non-sea-salt sulfate, methanesulfonate, and nitrate aerosol concentrations and size distributions at Cape Grim, Tasmania

    NASA Astrophysics Data System (ADS)

    Andreae, Meinrat O.; Elbert, Wolfgang; Cai, Yong; Andreae, Tracey W.; Gras, John

    1999-09-01

    We collected weekly aerosol samples using high-volume impactors over a period of 20 months (1988-1990) at the Cape Grim baseline station on the northwestern coast of Tasmania, Australia. The samples were analyzed for soluble ionic constituents, including sulfate, methanesulfonate (MS-), ammonium, nitrate, and the major sea-salt ions. The sea-salt component showed only a slight seasonal variation, whereas the non-sea-salt (nss) ions all had pronounced summer maxima. Significant interannual variability was seen between the nss ion concentrations measured during the two summers investigated. Nss sulfate and MS- were present both in the fine and coarse aerosol fractions, in the latter presumably associated with sea-salt particles. During the winter period, there was more nss sulfate in the coarse fraction than in the fine fraction. These observations are consistent with an important role of liquid-phase oxidation in haze and cloud droplets for the production of nss sulfate aerosol. The seasonal behavior of the sulfur and nitrogen species at Cape Grim and their mutual correlations suggest that DMS oxidation is the dominant sulfur source during summer, while nonbiogenic sulfur sources make significant contributions to nss sulfate outside of this season. Correlations of CN and CCN concentrations with nss sulfate, MS-, and wind speed suggest that DMS oxidation and, to a lesser extent, seaspray formation contributes to CN and CCN populations. The contrast between the weak seasonality of the sea-salt component and the pronounced seasonal behavior in both sulfur species and CCN supports the central role of biogenic DMS emissions as precursors of CCN in this region, at least in the biologically productive season.

  3. Massive-scale aircraft observations of giant sea-salt aerosol particle size distributions in atmospheric marine boundary layers

    NASA Astrophysics Data System (ADS)

    Jensen, J. B.

    2015-12-01

    iant sea-salt aerosol particles (dry radius, rd > 0.5 μm) occur nearly everywhere in the marine boundary layer and frequently above. This study presents observations of atmospheric sea-salt size distributions in the range 0.7 < rd < 14 μm based on external impaction of sea-spray aerosol particles onto microscope polycarbonate microscope slides. The slides have very large sample volumes, typically about 250 L over a 10-second sampling period. This provides unprecedented sampling of giant sea-salt particles for flights in marine boundary layer air. The slides were subsequently analyzed in a humidified chamber using dual optical digital microscopy. At a relative humidity of 90% the sea-salt aerosol particles form spherical cap drops. Based on measurement the volume of the spherical cap drop and assuming NaCl composition, the Kohler equation is used to derive the dry salt mass of tens of thousands of individual aerosol particles on each slide. Size distributions are given with a 0.2 μm resolution. The slides were exposed from the NSF/NCAR C-130 research aircraft during the 2008 VOCALS project off the coast of northern Chile and the 2011 ICE-T in the Caribbean. In each deployment, size distributions using hundreds of slides are used to relate fitted log-normal size distributions parameters to wind speed, altitude and other atmospheric conditions. The size distributions provide a unique observational set for initializing cloud models with coarse-mode aerosol particle observations for marine atmospheres.

  4. Deformation within an exposed salt wall: Recumbent folding and extrusion of evaporites in the Dead Sea Basin

    NASA Astrophysics Data System (ADS)

    Alsop, G. I.; Weinberger, R.; Levi, T.; Marco, S.

    2015-01-01

    Despite the enormous global interest in salt tectonics, which is largely driven by its importance to hydrocarbon exploration, direct field-based studies of salt exposed at the Earth's surface are rare. However, Mount Sedom, located at the western side of the Dead Sea Basin, presents one such opportunity for detailed analysis of salt and the associated sedimentary and structural record of its movement. The Sedom salt wall is a 10 km × 1.5 km N-S trending ridge comprising a range of Late Miocene-Pliocene evaporites and clastics, which have penetrated the overlying Pleistocene clastic sequence. The salt wall displays a moderate-steep west dipping western margin and an overturned (west-dipping) eastern flank. The sedimentary record of passive wall growth includes sedimentary breccia horizons that locally truncate underlying beds and are interpreted to reflect sediments having been shed off the crest of the growing salt wall. Structurally, the overturned eastern flank is marked by upturn within the overburden, extending for >300 m from the salt wall. Deformation within the evaporites is characterised by ductile folding and boudinage, while a 200 m thick clastic unit within the salt wall forms a tight recumbent fold traceable for 5 km along strike and associated with a 500 m wide inverted limb. This overturned gently-dipping limb is marked by NE-directed folding and thrusting, sedimentary injections, and a remarkable attenuation of the underlying salt from ∼380 m to <20 m over just 200 m of strike length. The inverted limb is overlain by an undeformed anhydrite, gypsum and clastics caprock, thought to be the residue from a now dissolved salt sheet that extruded over the top of the fold. Expulsion of salt down the regional slope towards the NE, combined with subsequent dissolution of evaporites, may have resulted in local 'pinching shut' of the salt wall, leading to a distinctive hour-glass map pattern. This area also coincides with deposition of a thicker

  5. Mobilization of arsenic, lead, and mercury under conditions of sea water intrusion and road deicing salt application

    NASA Astrophysics Data System (ADS)

    Sun, Hongbing; Alexander, John; Gove, Brita; Koch, Manfred

    2015-09-01

    Water geochemistry data from complexly designed salt-solution injection experiments in the laboratory, coastal aquifers of Bangladesh and Italy, taken from the literature, and two salted watersheds of New Jersey, US were collected and analyzed to study the geochemical mechanisms that mobilize As, Pb, and Hg under varied salting conditions. Overall, increased NaCl-concentrations in aquifers and soil are found to increase the release of Pb and Hg into the water. Reducing environments and possible soil dispersion by hydrated Na+ are found to lead to an increase of As-concentration in water. However, the application of a pure NaCl salt solution in the column injection experiment was found to release less As, Pb, and Hg initially from the soil and delay their concentration increase, when compared to the application of CaCl2 and NaCl mixed salts (at 6:4 weight ratio). The concentration correlation dendrogram statistical analyses of the experimental and field data suggest that the release of As, Hg, and Pb into groundwater and the soil solution depends not only on the salt level and content, but also on the redox condition, dissolved organic matter contents, competitiveness of other ions for exchange sites, and source minerals. With the ongoing over-exploration of coastal aquifers from increased pumping, continued sea-level rise, and increased winter deicing salt applications in salted watersheds of many inland regions, the results of this study will help understand the complex relation between the concentrations of As, Pb, and Hg and increased salt level in a coastal aquifer and in soils of a salted watershed.

  6. Mobilization of arsenic, lead, and mercury under conditions of sea water intrusion and road deicing salt application.

    PubMed

    Sun, Hongbing; Alexander, John; Gove, Brita; Koch, Manfred

    2015-09-01

    Water geochemistry data from complexly designed salt-solution injection experiments in the laboratory, coastal aquifers of Bangladesh and Italy, taken from the literature, and two salted watersheds of New Jersey, US were collected and analyzed to study the geochemical mechanisms that mobilize As, Pb, and Hg under varied salting conditions. Overall, increased NaCl-concentrations in aquifers and soil are found to increase the release of Pb and Hg into the water. Reducing environments and possible soil dispersion by hydrated Na(+) are found to lead to an increase of As-concentration in water. However, the application of a pure NaCl salt solution in the column injection experiment was found to release less As, Pb, and Hg initially from the soil and delay their concentration increase, when compared to the application of CaCl2 and NaCl mixed salts (at 6:4 weight ratio). The concentration correlation dendrogram statistical analyses of the experimental and field data suggest that the release of As, Hg, and Pb into groundwater and the soil solution depends not only on the salt level and content, but also on the redox condition, dissolved organic matter contents, competitiveness of other ions for exchange sites, and source minerals. With the ongoing over-exploration of coastal aquifers from increased pumping, continued sea-level rise, and increased winter deicing salt applications in salted watersheds of many inland regions, the results of this study will help understand the complex relation between the concentrations of As, Pb, and Hg and increased salt level in a coastal aquifer and in soils of a salted watershed. PMID:26210297

  7. Effects of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida

    USGS Publications Warehouse

    Langevin, Christian D.; Zygnerski, Michael

    2013-01-01

    A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise.

  8. Effects of aging on mineralocorticoid-induced salt appetite in rats

    PubMed Central

    Beltz, Terry G.; Johnson, Alan Kim

    2013-01-01

    This work examined the effects of age on salt appetite measured in the form of daily saline (i.e., 0.3 M NaCl) drinking in response to administration of deoxycorticosterone acetate (DOCA; 5 mg/kg body wt) using young (4 mo), “middle-aged” adult (12 mo), and old (30 mo) male Brown Norway rats. Water and sodium intakes, excretions, and balances were determined daily. The salt appetite response was age dependent with “middle-aged” rats ingesting the most saline solution followed in order by young and then old rats. While old rats drank the least saline solution, the amounts of saline ingested still were copious and comprise an unambiguous demonstration of salt appetite in old rats. Middle-aged rats had the highest saline preference ratios of the groups under baseline conditions and throughout testing consistent with an increased avidity for sodium taste. There were age differences in renal handling of water and sodium that were consistent with a renal contribution to the greater saline intakes by middle-aged rats. There was evidence of impaired renal function in old rats, but this did not account for the reduced saline intakes of the oldest rats. PMID:24133100

  9. GNI - A System for the Impaction and Automated Optical Sizing of Giant Aerosol Particles with Emphasis on Sea Salt

    NASA Astrophysics Data System (ADS)

    Jensen, Jorgen

    2013-04-01

    Size distributions of giant aerosol particles (e.g. sea-salt particles, dry radius larger than 0.5 μm) are not well characterized in the atmosphere, yet they contribute greatly to both direct and indirect aerosol effects. Measurements are problematic for these particles because they (i) occur in low concentrations, (ii) have difficulty in passing through air inlets, (iii) there are problems in discriminating between dry and deliquesced particles, (iv) and impaction sampling requires labor intensive methods. In this study, a simple, high-volume impaction system called the Giant Nuclei Impactor (GNI), based on free-stream exposure of polycarbonate slides from aircraft is described, along with an automated optical microscope-based system for analysis of the impacted particles. The impaction slides are analyzed in a humidity-controlled box (typically 90% relative humidity) that allows for deliquescence of sea salt particles. A computer controlled optical microscope with two digital cameras is used to acquire and analyze images of the aerosol particles. Salt particles will form near-spherical cap solution drops at high relative humidity. The salt mass in each giant aerosol particle is then calculated using simple geometry and K ̈ohler theory by assuming a NaCl composition. The system has a sample volume of about 10 L/s at aircraft speeds of 105 m/s. For salt particles, the measurement range is from about 0.7 μm dry radius to tens of micrometers, with a size-bin resolution of 0.2 μm dry radius. The sizing accuracy was tested using glass beads of known size. Characterizing the uncertainties of observational data is critical for applications to atmospheric science studies. A comprehensive uncertainty analysis is performed for the airborne GNI manual impaction and automatic optical microscope system for sizing giant aerosol particles, with particular emphasis on sea-salt particles. The factors included are (i) sizing accuracy, (ii) concentration accuracy, (iii

  10. Ice Age Sea Level Change on a Dynamic Earth

    NASA Astrophysics Data System (ADS)

    Austermann, J.; Mitrovica, J. X.; Latychev, K.; Rovere, A.; Moucha, R.

    2014-12-01

    Changes in global mean sea level (GMSL) are a sensitive indicator of climate variability during the current ice age. Reconstructions are largely based on local sea level records, and the mapping to GMSL is computed from simulations of glacial isostatic adjustment (GIA) on 1-D Earth models. We argue, using two case studies, that resolving important, outstanding issues in ice age paleoclimate requires a more sophisticated consideration of mantle structure and dynamics. First, we consider the coral record from Barbados, which is widely used to constrain global ice volume changes since the Last Glacial Maximum (LGM, ~21 ka). Analyses of the record using 1-D viscoelastic Earth models have estimated a GMSL change since LGM of ~120 m, a value at odds with analyses of other far field records, which range from 130-135 m. We revisit the Barbados case using a GIA model that includes laterally varying Earth structure (Austermann et al., Nature Geo., 2013) and demonstrate that neglecting this structure, in particular the high-viscosity slab in the mantle linked to the subduction of the South American plate, has biased (low) previous estimates of GMSL change since LGM by ~10 m. Our analysis brings the Barbados estimate into accord with studies from other far-field sites. Second, we revisit estimates of GMSL during the mid-Pliocene warm period (MPWP, ~3 Ma), which was characterized by temperatures 2-3°C higher than present. The ice volume deficit during this period is a source of contention, with estimates ranging from 0-40 m GMSL equivalent. We argue that refining estimates of ice volume during MPWP requires a correction for mantle flow induced dynamic topography (DT; Rowley et al., Science, 2013), a signal neglected in previous studies of ice age sea level change. We present estimates of GIA- and DT-corrected elevations of MPWP shorelines from the U.S. east coast, Australia and South Africa in an attempt to reconcile these records with a single GMSL value.

  11. Sediment and vegetation spatial dynamics facing sea-level rise in microtidal salt marshes: Insights from an ecogeomorphic model

    NASA Astrophysics Data System (ADS)

    Belliard, J.-P.; Di Marco, N.; Carniello, L.; Toffolon, M.

    2016-07-01

    Modeling efforts have considerably improved our understanding on the chief processes that govern the evolution of salt marshes under climate change. Yet the spatial dynamic response of salt marshes to sea-level rise that results from the interactions between the tidal landforms of interest and the presence of bio-geomorphic features has not been addressed explicitly. Accordingly, we use a modeling framework that integrates the co-evolution of the marsh platform and the embedded tidal networks to study sea-level rise effects on spatial sediment and vegetation dynamics in microtidal salt marshes considering different ecological scenarios. The analysis unveils mechanisms that drive spatial variations in sedimentation rates in ways that increase marsh resilience to rising sea-levels. In particular, marsh survival is related to the effectiveness of transport of sediments toward the interior marshland. This study hints at additional dynamics related to the modulation of channel cross-sections affecting sediment advection in the channels and subsequent delivery in the inner marsh, which should be definitely considered in the study of marsh adaptability to sea-level rise and posterior management.

  12. Reconciliation of coarse mode sea-salt aerosol particle size measurements and parameterizations at a subtropical ocean receptor site

    NASA Astrophysics Data System (ADS)

    Reid, Jeffrey S.; Brooks, Barbara; Crahan, Katie K.; Hegg, Dean A.; Eck, Thomas F.; O'Neill, Norm; de Leeuw, Gerrit; Reid, Elizabeth A.; Anderson, Kenneth D.

    2006-01-01

    In August/September of 2001, the R/P FLIP and CIRPAS Twin Otter research aircraft were deployed to the eastern coast of Oahu, Hawaii, as part of the Rough Evaporation Duct (RED) experiment. Goals included the study of the air/sea exchange, turbulence, and sea-salt aerosol particle characteristics at the subtropical marine Pacific site. Here we examine coarse mode particle size distributions. Similar to what has been shown for airborne dust, optical particle counters such as the Forward Scattering Spectrometer Probe (FSSP), Classical Scattering Aerosol Spectrometer Probe (CSASP) and the Cloud Aerosol Spectrometer (CAS) within the Cloud Aerosol and Precipitation Spectrometer (CAPS) instrument systematically overestimate particle size, and consequently volume, for sea salt particles. Ground-based aerodynamic particle sizers (APS) and AERONET inversions yield much more reasonable results. A wing pod mounted APS gave mixed results and may not be appropriate for marine boundary layer studies. Relating our findings to previous studies does much to explain the bulk of the differences in the literature and leads us to conclude that the largest uncertainty facing flux and airborne cloud/aerosol interaction studies is likely due to the instrumentation itself. To our knowledge, there does not exist an in situ aircraft system that adequately measures the ambient volume distribution of coarse mode sea salt particles. Most empirically based sea salt flux parameterizations can trace their heritage to a clearly biased measurement technique. The current "state of the art" in this field prevents any true form of clear sky radiative "closure" for clean marine environments.

  13. The effects of salt on rheological properties of asphalt after long-term aging.

    PubMed

    Yu, Xin; Wang, Ying; Luo, Yilin; Yin, Long

    2013-01-01

    Limited studies in recent years have shown that asphalt pavement subject to seawater in coastal regions or deicing salt in cold regions may be seriously damaged after being soaked in saline water for a long time. However, there is limited research into the influence of salt on rheological properties of asphalt after long-term aging. In this study, rheological properties of unmodified and polymer-modified asphalt after long-term aging were tested after being soaked in different concentrations of salt (0.3%~5%) for different durations (1 day~30 days). Orthogonal array based on the Taguchi method was used for experimental design. The frequency sweep tests were performed on the specimens of aged asphalt after being soaked for complex modulus and phase angle master curves and ultimate fatigue temperature. BBR tests were performed for stiffness. The test results indicate that saline water appears to reduce low temperature properties and fatigue resistance properties and improved high temperature properties of aged asphalt, and it also affects the sensitivity of complex modulus and phase angles at low frequencies. PMID:24459450

  14. The Effects of Salt on Rheological Properties of Asphalt after Long-Term Aging

    PubMed Central

    Yu, Xin; Luo, Yilin; Yin, Long

    2013-01-01

    Limited studies in recent years have shown that asphalt pavement subject to seawater in coastal regions or deicing salt in cold regions may be seriously damaged after being soaked in saline water for a long time. However, there is limited research into the influence of salt on rheological properties of asphalt after long-term aging. In this study, rheological properties of unmodified and polymer-modified asphalt after long-term aging were tested after being soaked in different concentrations of salt (0.3%~5%) for different durations (1 day~30 days). Orthogonal array based on the Taguchi method was used for experimental design. The frequency sweep tests were performed on the specimens of aged asphalt after being soaked for complex modulus and phase angle master curves and ultimate fatigue temperature. BBR tests were performed for stiffness. The test results indicate that saline water appears to reduce low temperature properties and fatigue resistance properties and improved high temperature properties of aged asphalt, and it also affects the sensitivity of complex modulus and phase angles at low frequencies. PMID:24459450

  15. An optical model for heat and salt budget estimation for shallow seas

    NASA Astrophysics Data System (ADS)

    Warrior, Hari; Carder, Kendall

    2007-12-01

    The effects of the underwater light field on heat-budget calculations for shallow waters are developed and applied for the region of Bahamas. Most of the general circulation models use a simplified heat budget scheme based on Jerlov water types, and do not account for optical bottom effects. By optical bottom effect, we mean the bottom absorption and reflection of the short-wave radiation, which in turn affects the thermal stratification and heat exchange with the atmosphere. In this paper, this optical bottom effect is added to a 3D turbulence model (a 1D model called GOTM is coupled to a 3D model called POM) and the evolution of the temperature structure studied. We call the coupled model 3DGOTM. This optical bottom effect is found to be important in the areas with clear water, shallow depths and small solar zenith angle. On the basis of the coastal meteorological measurements from Andros Island, we have used this three-dimensional turbulence closure model (3DGOTM) to show the influence of bottom reflection and absorption on the sea surface temperature field. The final temperature of the developed water column depends on water depth and bottom albedo. Effects of varying the bottom albedo were studied by comparing results for coral sand and sea grass bottoms. This has an appreciable contribution to the heat budget and salt budget of the shallow waters in these coastal regions. The salinities of the shallow regions near Andros Island have been found to reach as high as 46 psu by summer. In addition to the thermohaline plumes generated by these bottom effects, this warming process has an impact on the moisture feedbacks into the atmosphere due to evaporation.

  16. Drilling below the salt in the Western Mediterranean Sea : the GOLD-1 (Gulf of Lion Drilling) Project.

    NASA Astrophysics Data System (ADS)

    Rabineau, Marina; Aslanian, Daniel; Gorini, Christian; Alain, Karine; Participants, International

    2010-05-01

    In recent years the Gulf of Lion within the Occidental Mediterranean Sea has become a unique natural laboratory for the study both the evolution and interaction of deep processes (geodynamics, tectonics, subsidence, isostasy) and surficial processes (river behavior, sedimentary fluxes, sea-level changes, climatic impacts). Here, representing a large group of international researchers, we present the main objectives for a deep drilling project at the foot of the continental slope (2400 m water depth) in the Gulf of Lion. This position is the only place in the Gulf of Lion where the sedimentary column is expected to be complete without major erosional hiatuses or time gaps. It is located sufficiently far from the shelf and slope to not have been affected by the extraordinarly erosional event of the Messinian, and at the same time be free from salt-related faulting and diapirism. At this position we have recorded nearly a complete high-resolution history of the last 23 through 30 Ma of Mediterranean history in some 7.7 km of sedimentary archive. From the petroleum exploration perspective the deepest part of the margin reamain underexplored since all existing wells were drilled on the shelf and slope GLP1 & 2 being the deepest one. New interpretations in the region (especially concerning the Messinian event) have considerably changed earlier views of potential hydrocarbon reservoirs. New results expected from deep drilling are numerous: 1) For the substratum: the upper continental crust thins to less than 5 km, and changes laterally to a relatively thin crust with high velocities whose precise nature is still undetermined (Gailler et al., 2009). The aim of the drilling is to reach this crucial information which is essential for the understanding of the evolution of the sedimentary basin (Aslanian et al., 2009). 2) The drilling will allow the dating and characterization of the impact of the initiation and changes in glacioeustatic cyclicity in alpine glaciers and

  17. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin.

    PubMed

    Proksch, Ehrhardt; Nissen, Hans-Peter; Bremgartner, Markus; Urquhart, Colin

    2005-02-01

    Magnesium salts, the prevalent minerals in Dead Sea water, are known to exhibit favorable effects in inflammatory diseases. We examined the efficacy of bathing atopic subjects in a salt rich in magnesium chloride from deep layers of the Dead Sea (Mavena(R) Dermaline Mg(46) Dead Sea salt, Mavena AG, Belp, Switzerland). Volunteers with atopic dry skin submerged one forearm for 15 min in a bath solution containing 5% Dead Sea salt. The second arm was submerged in tap water as control. Before the study and at weeks 1-6, transepidermal water loss (TEWL), skin hydration, skin roughness, and skin redness were determined. We found one subgroup with a normal and one subgroup with an elevated TEWL before the study. Bathing in the Dead Sea salt solution significantly improved skin barrier function compared with the tap water-treated control forearm in the subgroup with elevated basal TEWL. Skin hydration was enhanced on the forearm treated with the Dead Sea salt in each group, which means the treatment moisturized the skin. Skin roughness and redness of the skin as a marker for inflammation were significantly reduced after bathing in the salt solution. This demonstrates that bathing in the salt solution was well tolerated, improved skin barrier function, enhanced stratum corneum hydration, and reduced skin roughness and inflammation. We suggest that the favorable effects of bathing in the Dead Sea salt solution are most likely related to the high magnesium content. Magnesium salts are known to bind water, influence epidermal proliferation and differentiation, and enhance permeability barrier repair. PMID:15689218

  18. Response of salt marsh and mangrove wetlands to changes in atmospheric CO2, climate, and sea-level

    USGS Publications Warehouse

    Mckee, Karen L.; Rogers, Kerrylee; Saintilan, Neil

    2012-01-01

    Coastal salt marsh and mangrove ecosystems are particularly vulnerable to changes in atmospheric CO2 concentrations and associated climate and climate-induced changes. We provide a review of the literature detailing theoretical predictions and observed responses of coastal wetlands to a range of climate change stressors, including CO2, temperature, rainfall, and sea-level rise. This review incorporates a discussion of key processes controlling responses in different settings and thresholds of resilience derived from experimental and observational studies. We specifically consider the potential and observed effects on salt marsh and mangrove vegetation of changes in (1) elevated [CO2] on physiology, growth, and distribution; (2) temperature on distribution and diversity; (3) rainfall and salinity regimes on growth and competitive interactions; and (4) sea level on geomorphological, hydrological, and biological processes.

  19. Gas-phase molecular halogen production from sea-salt particles via interface reactions

    NASA Astrophysics Data System (ADS)

    Jimenez-Aranda, A.; Thomas, J.; Finlayson-Pitts, B. J.; Dabdub, D.

    2005-12-01

    Interface reactions at the surface of sea-salt particles have been suggested as an important source of photolyzable gas-phase halogen species in the troposphere. Such reactions are plausible, given theoretical evidence for ions at interfaces, predicted enhancements of some gases at the air-water interface, and the results of a number of experiments in which interface reactions had to be invoked to explain the data. Because of the contributions of halogen chemistry in determining ozone and other trace species in the troposphere, elucidating the roles of interface and bulk chemistry in generating photolyzable halogen gases is important. A revised version of the model of aerosol, gas and interfacial chemistry (MAGIC 2.0) is used in this work to examine the reactions of chloride and bromide ions with OH and O3. The goal is to understand the factors that determine the relative importance of bulk compared to interface chemistry in the most simple chloride and bromide systems represented by deliquesced aerosols of NaCl or NaBr. Results show the interface process involving Cl- and OH(g) is the main source of Cl2(g). For the analogous oxidation of bromide by OH, gaseous Br2 is formed mainly in the bulk aqueous phase and transferred across the interface. However, the reaction of Br- with O3(g) at the interface is the primary source of Br2(g) under dark conditions.

  20. Mapping the Microstructural Location of Salts and Metals in Sea Ice with X-Ray Micro-Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lieb-Lappen, R.; Leonard, J.; Obbard, R. W.

    2015-12-01

    Sea ice forms a permeable boundary between the ocean and the atmosphere, mediating chemical, physical, and transport processes that can have large impacts on a changing climate. It is a complex media composed of ice, brine, air pockets, and salt precipitates whose fine microstructure is constantly evolving with time and temperature. To gain insight of the processes occurring within the sea ice, it is key to have an understanding of how the different phases interact. Using synchrotron x-ray micro-fluorescence (XRF) at Argonne National Laboratory's Advanced Photon Source (APS), we examined the microstructural location of different salts and metals in Antarctic sea ice. In particular, we sought to determine whether these elements are found solely in brine channels and at grain boundaries or exist ubiquitously throughout the crystal lattice of ice. Further, we also investigated the spatial distribution of each impurity to determine how microstructure may vary within the sea ice column. Although it is well known that salts are expelled from the ice matrix during the freezing process and the bulk of impurities lies in brine inclusions and channels, providing quantitative and visual evidence with high resolution remains an ongoing process. XRF enables us to detect and map the precise microstructural and stratigraphic location of the constituent salts in sea ice. Cores were cut into 0.5 cm-thick slices every ten cm along the length of the core. At APS, a 2 mm x 2 mm region of each sample was scanned by an 18 kV X-ray beam and the resulting fluorescence signal detected using a silicon drift detector. By integrating the detected signal for the respective characteristic energy, we were able to obtain two-dimensional elemental maps with ten micron resolution for bromide, chloride, potassium, calcium, strontium, iron, copper, and zinc. Maps were compared to thin sections obtained under cross-polarizing lenses to identify particular features. We were able to show that salts

  1. Response to Comments on "Reactions at Interfaces as a Source of Sulfate Formation in Sea-Salt Particles"

    SciTech Connect

    Laskin, Alexander; Gaspar, Daniel J.; Wang, Weihong; Hunt, Sherri W.; Cowin, James P.; Colson, Steve D.; Finlayson-Pitts, Barbara J.

    2004-01-30

    Our paper (1) demonstrated that the oxidation of chloride at the interface will be a new source of alkalinity that can modulate the acidification of particles during the day when gaseous OH is present. We proposed that this modulation of the acidity of sea-salt particles could potentially affect the rate of uptake and oxidation of SO2[S(IV)], which is very sensitive to pH.

  2. Biogenic sulphur emissions and inferred non-sea-salt-sulphate cloud condensation nuclei in and around Antarctica

    NASA Astrophysics Data System (ADS)

    O'Dowd, Colin D.; Lowe, Jason A.; Smith, Michael H.; Davison, Brian; Hewitt, C. Nicholas; Harrison, Roy M.

    1997-06-01

    Accumulation mode aerosol properties and biogenic sulphur emissions over the South Atlantic and Antarctic Oceans are examined. Two contrasting air masses, polar and maritime, each possessing distinct aerosol properties, were encountered during the summer months. By examining aerosol volatile properties, polar air masses arriving from the Antarctic continent were shown to consist primarily Of H2SO4 in the accumulation mode size range, with inferred NH+4 to SO=4 molar ratios close to zero. By comparison, air masses of temperate maritime origin were significantly neutralized with molar ratios of ≈1. These results suggest a deficit of ammonia in polar air masses compared with that in maritime air masses. Dimethyl sulphide (DMS) exhibited no correlation with its putative aerosol oxidation products, although spatial coherence in atmospheric concentrations of DMS, methane sulphonic acid (MSA), and non-sea-salt (nss)-sulphate mass was observed. Volatility analysis, used to infer nss-sulphate cloud condensation nuclei (nss-sCCN) active at a supersaturation of ≈0.2%, indicates that nss-sCCN mass and number concentration were best correlated with MSA mass (r≈0.63). Aerosol volatility identified the presence of MSA in submicron non-sea-salt aerosol; however, its contribution to the aerosol mass was small relative to the contribution of sulphuric acid and ammonium bisulphate/sulphate aerosol. The marine sulphur cycle appears strongly coupled to the sea-salt cycle with, typically, 80-90% of nss-sulphate thought to be internally mixed with sea-salt aerosol. During the austral Summer of 1992/1993, a period of strong biological productivity in the Weddell Sea and sub-Antarctic Ocean, particularly during ice-melt, the cruise-average DMS flux of 61 μg m-2 d-1 corresponded to a very modest average nss-sCCN concentration of 21 cm-3. Observed peak values of DMS flux and inferred nss-CCN concentrations during the cruise were 477 μg m-2 d-1 and 64 cm-3, respectively. Events of new

  3. On the isolation of halophilic microorganisms from salt deposits of great geological age

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga; Denner, Ewald

    1993-01-01

    From salt sediments of Triassic or Permian age from various locations in the world halophilic microorganisms were isolated. Molecular characteristics of several of the isolates suggested they belong to the archaebacteria. One group appears to represent novel strains; several properties of one such isolate, strain BIp, are described here. The existence of viable microorganisms in ancient sediment would have great implications with respect to our notions on evolution, the research for life in extraterrestrial environments, and the longterm survival of functional biological structures. Of crucial importance is thus the question if these microorganisms existed in the salt since the time of deposition or invaded at some later date. Some suggestions to address these issues experimentally are discussed.

  4. New evidence for 250 Ma age of halotolerant bacterium from a Permian salt crystal

    NASA Astrophysics Data System (ADS)

    Satterfield, Cindy L.; Lowenstein, Tim K.; Vreeland, Russell H.; Rosenzweig, William D.; Powers, Dennis W.

    2005-04-01

    The purported oldest living organism, the spore-forming bacterium Virgibacillus sp. Permian strain 2 9-3, was recently cultured from a brine inclusion in halite of the 250 Ma Permian Salado Formation. However, the antiquity of Virgibacillus sp. 2 9-3 has been challenged; it has been argued that the halite crystal and the fluid inclusion from which the bacterial spores were extracted may be younger than the Permian Salado salts. Here we report that brine inclusions from the same layer of salt that housed Virgibacillus sp. 2 9-3 are composed of evaporated Late Permian seawater that was trapped in halite cement crystals precipitated syndepositionally from shallow groundwater brines at temperatures of 17 37 °C. These results support the 250 Ma age of the fluid inclusions, and by inference, the long-term survivability of microorganisms such as Virgibacillus sp. 2 9-3.

  5. Biogenic, anthropogenic and sea salt sulfate size-segregated aerosols in the Arctic summer

    NASA Astrophysics Data System (ADS)

    Ghahremaninezhad, Roghayeh; Norman, Ann-Lise; Abbatt, Jonathan P. D.; Levasseur, Maurice; Thomas, Jennie L.

    2016-04-01

    Size-segregated aerosol sulfate concentrations were measured on board the Canadian Coast Guard Ship (CCGS) Amundsen in the Arctic during July 2014. The objective of this study was to utilize the isotopic composition of sulfate to address the contribution of anthropogenic and biogenic sources of aerosols to the growth of the different aerosol size fractions in the Arctic atmosphere. Non-sea-salt sulfate is divided into biogenic and anthropogenic sulfate using stable isotope apportionment techniques. A considerable amount of the average sulfate concentration in the fine aerosols with a diameter < 0.49 µm was from biogenic sources (> 63 %), which is higher than in previous Arctic studies measuring above the ocean during fall (< 15 %) (Rempillo et al., 2011) and total aerosol sulfate at higher latitudes at Alert in summer (> 30 %) (Norman et al., 1999). The anthropogenic sulfate concentration was less than that of biogenic sulfate, with potential sources being long-range transport and, more locally, the Amundsen's emissions. Despite attempts to minimize the influence of ship stack emissions, evidence from larger-sized particles demonstrates a contribution from local pollution. A comparison of δ34S values for SO2 and fine aerosols was used to show that gas-to-particle conversion likely occurred during most sampling periods. δ34S values for SO2 and fine aerosols were similar, suggesting the same source for SO2 and aerosol sulfate, except for two samples with a relatively high anthropogenic fraction in particles < 0.49 µm in diameter (15-17 and 17-19 July). The high biogenic fraction of sulfate fine aerosol and similar isotope ratio values of these particles and SO2 emphasize the role of marine organisms (e.g., phytoplankton, algae, bacteria) in the formation of fine particles above the Arctic Ocean during the productive summer months.

  6. Testing the link between hydrocarbon seepage, sea level stands, and salt diapirism in deepwater Gulf of Mexico

    SciTech Connect

    Aharon, P.

    1996-09-01

    Hydrocarbon seepage in both liquid (crude oil) and gas (principally methane) forms has been amply documented over the past decade from submersible dives on the northern Gulf of Mexico seafloor overlying salt diapirs. These seepage sites are inhabited by a remarkably diverse chemosynthetic fauna and are associated with massive carbonate buildups formed through bacterially-mediated processes of hydrocarbon oxidation coupled with sulfate reduction. This study addresses questions concerning the timing and longevity of seepage from four representative sites in the Green Canyon area (27{degrees}50{prime}N; 91{degrees}30{prime}W) on the basis of radiometric dating assays of massive carbonates that act as time keepers of hydrocarbon seeps. {sup 230}Th dates from GC-140 and GC-184 blocks place the initiation and termination of massive seepage there at 195 {+-} 25 Ka and 13.3 {+-} 2.7 Ka, respectively, and are in agreement with the chronology of the salt dome emplacement at shallow depth during mid- to late-Pleistocene low sea-level stands. The prolific seepage activity to the southeast in GC-185 (Bush Hill) and the {sup 230}Th dates of 3.2 to 1.4 Ka are attributed to a recent episode of subsidence caused by salt withdrawal which created late normal faults. When multiple dates, subsurface imaging of the salt domes by 3-D seismics, and high resolution subsurface chronostratigraphy are available from the same site, a link is apparent between the incidence of low sea level stands, salt diapirism, and enhanced hydrocarbon seepage.

  7. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Foley, S.; Borrmann, S.

    2012-05-01

    The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate - which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ≈0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882±0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2(g) → multiple steps → SOOCl2-. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32- by O3 (αseasalt = 1.0124±0.0017 at 19 °C). Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29% of S(IV) oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways - oxidation by O3 and by Cl catalysis (α34 = 1.0163±0.0018 at 19 °C in pure water or 1.0199±0.0024 at pH = 7.2) - which favour the heavy isotope, and the alkalinity non

  8. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Foley, S.; Borrmann, S.

    2012-01-01

    The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate - which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation, and demonstrated that sulfur isotopes can be effectively used to investigate the relative importance of different oxidation pathways in the marine boundary layer. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ~0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882 ± 0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2 (g) -> -> SO32-. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32- by O3 (αseasalt = 1.0124 ± 0.0017 at 19 °C). Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29 % of S(IV) oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways - oxidation by O3 and by Cl

  9. Inhibition of proliferation of psoriatic and healthy fibroblasts in cell culture by selected Dead-sea salts.

    PubMed

    Levi-Schaffer, F; Shani, J; Politi, Y; Rubinchik, E; Brenner, S

    1996-05-01

    The effect of five selected minerals abundant in the Dead-sea brine was studied on proliferation of fibroblasts grown from psoriatic and healthy skin biopsy specimens in cell culture. The reason for carrying out this study was looking for the mechanism of the antiproliferative effect of selective Dead-sea minerals in improving the psoriatic condition. Psoriatic skin shave biopsy specimens (both from involved and uninvolved areas of the body) as well as healthy skin (obtained from amputated limbs) were incubated in tissue culture, and their outgrowing fibroblasts were used for this study. The number of cells and their cyclic AMP content were used as parameters for cell division and for proving the selective involvement of magnesium salts in the antiproliferative effect. It is shown that the inhibitory effects of magnesium bromide and magnesium chloride on cell growth were significantly stronger than those of their corresponding potassium salts or of sodium chloride. These results were obtained with both psoriatic and healthy skin fibroblasts, indicating that the inhibitory effect of the selected Dead-sea minerals is present in healthy and psoriatic skin cells. PMID:8807676

  10. Effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of European eel, Anguilla anguilla.

    PubMed

    Sørensen, Sune Riis; Butts, Ian Anthony Ernest; Munk, Peter; Tomkiewicz, Jonna

    2016-02-01

    Improper activation and swelling of in vitro produced eggs of European eel, Anguilla anguilla, has been shown to negatively affect embryonic development and hatching. We investigated this phenomenon by examining the effects of salinity and sea salt type on egg dimensions, cell cleavage patterns and egg buoyancy. Egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. Activation salinities between 30-40 practical salinity unit (psu) produced higher quality eggs and generally larger egg diameters. Chorion diameters reached maximal values of 1642 ± 8 μm at 35 psu. A positive relationship was found between egg neutral buoyancy and activation salinity. Nine salt types were investigated as activation and incubation media. Five of these types induced a substantial perivitelline space (PVS), leading to large egg sizes, while the remaining four salt types resulted in smaller eggs. All salt types except NaCl treatments led to high fertilization rates and had no effect on fertilization success as well as egg neutral buoyancies at 7 h post-fertilization. The study points to the importance of considering ionic composition of the media when rearing fish eggs and further studies are encouraged. PMID:25707438

  11. Vulnerability of Rhode Island Salt Marshes to Sea Level Rise and Poor Water Quality

    EPA Science Inventory

    Across the northeastern Unites States, salt marshes are losing ground. Edges are eroding, tidal channel networks are expanding, and new ponds are forming and expanding within salt marshes. This leaves shorelines - and in some cases houses - more vulnerable to nor'easters and tr...

  12. Salt facies and budgets as environmental indicators in the Dead Sea

    NASA Astrophysics Data System (ADS)

    Kiro, Yael; Goldstein, Steven L.; Stein, Mordechai; Garcia-Veigas, Javier; Levy, Elan J.; Lazar, Boaz

    2016-04-01

    Deep drilling in the Dead Sea reveals thick sections of halite that precipitated during the last three interglacials, when lake levels were low. Pore water and halite fluid inclusions show an increase in Mg concentration and a decrease in Na/Cl ratio during precipitation of halite, both during the last interglacial and the beginning of the Holocene. A mass balance based on the thickness of the halite layers and the changes in the chemical composition of the brine has been developed in order to calculate the change in the lake levels. Results indicate a drastic decrease in fresh water input, with the average discharge at 30% and 50% of the modern over thousands of years during the last interglacial and early Holocene, respectively. However, packages of detritus alternating with the halite indicate wetter episodes over intervals of centuries to a few millennia with conditions similar to the present-day, as well as more severe conditions with ~10% of the modern discharge over periods of decades to a few centuries. The different facies of halite in the core are well preserved. The lake level calculation based on the salt budget shows that although the lake level decreased drastically, the lake was always >100 m depth, and the absence of significant halite dissolution supports this conclusion. Thus, the halite reflects deep-water facies. There are two main halite crystal types. Small cumulate crystals that are formed on the lake surface, which alternate with bottom-growth crystals with relatively scarce fluid inclusion bands. The frequency of the crystal alternation varies between seasonal and multi-year changes and reflects the hydrological and limnological regime. The small cumulate crystals require that the lake surface was supersaturated with respect to halite, indicating high evaporation and possibly a thermally stratified water column. The bottom-growth crystals are formed only when it is not disturbed by the "rain" of cumulate crystals, with a lower degree of

  13. Experimental evaluation of atmospheric effects on radiometric measurements using the EREP of Skylab. [Salton Sea and Great Salt Lake

    NASA Technical Reports Server (NTRS)

    Chang, D. T. (Principal Investigator); Isaacs, R. G.

    1975-01-01

    The author has identified the following significant results. Test sites were located near the Great Salt Lake and the Salton Sea. Calculations were performed for a set of atmospheric models corresponding to the test sites, in addition to standard models for summer and winter midlatitude atmospheres with respective integrated water vapor amount of 2.4 g/sq cm and 0.9 g/sq cm. Each atmosphere was found to contain an average amount of continental aerosol. Computations were valid for high solar elevation angles. Atmospheric attenuation quantities were computed in addition to simulated EREP S192 radiances.

  14. Ion Partitioning at the liquid/vapor interface of a multi-component alkali halidesolution: A model for aqueous sea salt aerosols

    SciTech Connect

    Ghosal, Sutapa; Brown, Matthew A.; Bluhm, Hendrik; Krisch, Maria J.; Salmeron, Miquel; Jungwirth, Pavel; Hemminger, John C.

    2008-12-22

    The chemistry of Br species associated with sea salt ice and aerosols has been implicated in the episodes of ozone depletion reported at Arctic sunrise. However, Br{sup -} is only a minor component in sea salt, which has a Br{sup -}/Cl{sup -} molar ratio of {approx}0.0015. Sea salt is a complex mixture of many different species, with NaCl as the primary component. In recent years experimental and theoretical studies have reported enhancement of the large, more polarizable halide ion at the liquid/vapor interface of corresponding aqueous alkali halide solutions. The proposed enhancement is likely to influence the availability of sea salt Br{sup -} for heterogeneous reactions such as those involved in the ozone depletion episodes. We report here ambient pressure x-ray photoelectron spectroscopy studies and molecular dynamics simulations showing direct evidence of Br{sup -} enhancement at the interface of an aqueous NaCl solution doped with bromide. The experiments were carried out on samples with Br{sup -}/Cl{sup -} ratios in the range 0.1% to 10%, the latter being also the ratio for which simulations were carried out. This is the first direct measurement of interfacial enhancement of Br{sup -} in a multi-component solution with particular relevance to sea salt chemistry.

  15. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    NASA Astrophysics Data System (ADS)

    Lee, Yonghoon; Ham, Kyung-Sik; Han, Song-Hee; Yoo, Jonghyun; Jeong, Sungho

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results.

  16. Spatial and temporal variations in the age structure of Arctic sea ice

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2005-01-01

    Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reverse chronology algorithm that tracks ice-covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (10 years old (10+ year age class) were observed during 1989-2003. Since the mid-1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6-10 year) age classes. Survival of the 1994 and 1996-1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid-2000s.

  17. A history of salt.

    PubMed

    Cirillo, M; Capasso, G; Di Leo, V A; De Santo, N G

    1994-01-01

    The medical history of salt begins in ancient times and is closely related to different aspects of human history. Salt may be extracted from sea water, mineral deposits, surface encrustations, saline lakes and brine springs. In many inland areas, wood was used as a fuel source for evaporation of brine and this practice led to major deafforestation in central Europe. Salt played a central role in the economies of many regions, and is often reflected in place names. Salt was also used as a basis for population censuses and taxation, and salt monopolies were practised in many states. Salt was sometimes implicated in the outbreak of conflict, e.g. the French Revolution and the Indian War of Independence. Salt has also been invested with many cultural and religious meanings, from the ancient Egyptians to the Middle Ages. Man's innate appetite for salt may be related to his evolution from predominantly vegetarian anthropoids, and it is noteworthy that those people who live mainly on protein and milk or who drink salty water do not generally salt their food, whereas those who live mainly on vegetables, rice and cereals use much more salt. Medicinal use tended to emphasize the positive aspects of salt, e.g. prevention of putrefaction, reduction of tissue swelling, treatment of diarrhea. Evidence was also available to ancient peoples of its relationship to fertility, particularly in domestic animals. The history of salt thus represents a unique example for studying the impact of a widely used dietary substance on different important aspects of man's life, including medical philosophy. PMID:7847480

  18. Ozonolysis of Unsaturated Phosphocholines on NaCl as a Model for Organics on Sea Salt Particles

    NASA Astrophysics Data System (ADS)

    Karagulian, F.; Lea, A.; Finlayson-Pitts, B.

    2007-12-01

    Sea salt particles, which are a major contributor to the global aerosol burden, may be coated with organic material. A major source of organic material is the decomposition of marine organisms, which have biomembranes that are a mixture of lipids, hydrophobic proteins and carbohydrates. The ozonolysis of 1-oleoyl- 2-palmitoyl-sn-glycero-3-phosphocholine (OPPC) on NaCl as a model for this organic coating on sea salt was followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS). Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and Auger electron spectroscopy were used to confirm the identification of the products. Upon exposure to O3, we observed a stable secondary ozonide (SOZ) as well as carbonyl-containing products. The kinetics of formation of these products and the impact of water vapor and photolysis on them were studied. Water vapor decreased the SOZ yield, and photolysis in the actinic region led to loss of the SOZ and the generation of aldehydes, carboxylic acids and anhydrides. These experiments elucidate the mechanism of formation of secondary ozonides on surfaces in polluted and relatively dry environments, which should be taken into account in the chemistry, photochemistry and toxicity of coastal atmospheres and those in the vicinity of dry, alkaline lakes.

  19. Age and thickness distribution of polynya sea ice in the Laptev Sea determined by satellite SAR imagery and airborne EM

    NASA Astrophysics Data System (ADS)

    Rabenstein, L.; Krumpen, T.; Hendricks, S.; Hoelemann, J.

    2012-04-01

    The importance and annual amount of sea ice volume produced during polyna opening events in the Siberian Laptev Sea is still controversially discussed. So far, published information about sea ice volume production are purely based on indirect thickness measurements of thin ice using remote sensing techniques or on computer simulations of sea ice growth based on reanalysis climate data. We recorded a sea ice thickness transect of approximately 160 km length using helicopter electromagnetics (HEM) in the region of the so called West New Siberian (WNS) Polynya located directly north of the Lena delta in April 2008. In addition, a time series of synthetic aperture radar (SAR) images covering the complete polynya region was analyzed and ice area fragments were tracked from their origin to the moment when we recorded their thickness. Both data sets together, HEM and SAR, provide the opportunity to classify overflown ice areas in terms of age, area and thickness and therefore in terms of volume. From December 2007 to April 2008 approximately 50.000 km2 of sea-ice area was produced in the WNS polynya, which is more than the size of Switzerland. The youngest surveyed sea-ice was 6 days old and had a mean total and a mean level-ice thickness of 0.2 m. The oldest surveyed ice floe had an age of 104 days and a mean total thickness of 2.4 +/- 0.3 m and a mean level ice thickness of 1.8 +/- 0.3 m. The error is based on the HEM instrument accuracy and a lag of snow thickness data. Assuming that ice thickness along the HEM transect was representative for entire overflown ice areas, our calculations result that the produced sea ice area contained a volume of approximately 86 km3. This is about 1.8 % of the Arctic wide ice production between October 2007 and March 2008, as it was published by Kwok et al. 2009 on the basis of ICE-Sat ice thickness data. The combined HEM and SAR study enabled us furthermore to analyze thickness vs. age relations of first year ice floes. Mean thickness

  20. Sea-level responses to sediment transport over the last ice age cycle

    NASA Astrophysics Data System (ADS)

    Ferrier, K.; Mitrovica, J. X.

    2013-12-01

    Sea-level changes over the last ice age cycle were instrumental in steering Earth's topographic evolution. These sea-level variations were driven by changes in surface mass loads, including not only ice and ocean mass variations but also the transfer of rock from eroding mountains to sedimentary deposits. Here we use an extended numerical model of ice age sea level (Dalca et al., 2013) to explore how sediment erosion and deposition affected global sea-level variations over the last ice age cycle. The model takes histories of ice and sediment loads as inputs, and it computes gravitationally self-consistent sea level responses by accounting for the deformational, gravitational, and rotational perturbations in the Earth's viscoelastic form. In these model simulations, we use published estimates of erosion rates, sedimentation rates, and ice sheet variations to constrain sediment and ice loading since the Last Interglacial. We explore sea-level responses to several erosional and depositional scenarios, and in each we quantify the relative contributions of crustal deformation and gravitational perturbation to the computed sea-level change. We also present a case study to illustrate the effects that sediment transfer can have on sea level at the regional scale. In particular, we focus on the region surrounding the Indus River, where fluvial sediment fluxes are among the highest on Earth. Preliminary model results suggest that sediment fluxes from Asia to the ocean are large enough to produce a significant response in sea level along the northeastern coast of the Arabian Sea. Moreover, they suggest that modeled sea-level histories are sensitive to the timing and spatial distribution of sediment erosion and deposition. For instance, sediment deposition along the continental shelf - which may have been the primary site of Indus River sediment deposition during the Holocene - produces a different sea-level response than sediment deposition on the deep-sea Indus Fan, where

  1. Comparison of Radiocarbon Ages for Multiproxy Paleoclimate Reconstruction of the Great Salt Lake, Utah

    NASA Astrophysics Data System (ADS)

    Nielson, K. E.; Bowen, G. J.; Eglinton, T. I.

    2008-12-01

    Multiproxy paleoclimate reconstructions from high sedimentation-rate systems offer promising opportunities to deconvolve multiple aspects climate system response to past forcing. However, the time-equivalence of proxies must be established before such reconstructions can be usefully interpreted. Differences in source ages, transport pathways, and surface residence times for substrates may lead to differences in lag times between proxy formation and deposition, compromising comparative analysis of data from multiple proxies. We used multi-substrate radiocarbon dating to investigate the potential for multi-proxy reconstruction of Holocene changes in the volume of the Great Salt Lake (GSL), Utah, based on the stable isotope composition of organic and inorganic substrates in lake sediment cores. Among potential substrates for this work are normal alkanes of vascular higher plant and algal origin, fossil cysts of lake-dwelling brine shrimp (Artemia), and micritic aragonite. Radiocarbon ages for all organic substrates (alkanes, cysts) sampled at any given core depth are concordant within analytical uncertainty and are similar to ages determined on land-plant debris and filamentous algae isolated from the sediment. Inorganic carbonate, in contrast, is depleted in 14C compare to the organic proxies, giving ages that were apparently 2000 to 3000 years older, likely due to winnowing and re-deposition of carbonate at the core site. These results suggest that the maximum temporal resolution achievable through analysis of mineral substrates is on the order of several millennia. Although the limited precision of the radiocarbon analysis precludes precise determination of the maximum potential resolution of organic-proxy based climate reconstructions, the relatively high sedimentation rates (50--150 cm/kyr) and age-equivalence of the substrates analyzed implies that sub- centennial scale resolution should be achievable throughout much of the Holocene portion of the GSL

  2. Toxicity in lead salt spiked soils to plants, invertebrates and microbial processes: Unraveling effects of acidification, salt stress and ageing reactions.

    PubMed

    Smolders, Erik; Oorts, Koen; Peeters, Sofie; Lanno, Roman; Cheyns, Karlien

    2015-12-01

    The fate and effects of toxic trace metals in soil freshly spiked soluble metal salts do not mimic those of metals in the field. This study was set up to test the magnitude of effects of salinity, acidification, and ageing on toxicity of lead (Pb) to plants, invertebrates and soil microbial processes. Three soils were spiked with Pb2+ salts up to a concentration of 8000 mg Pb/kg and were tested either after spiking, after soil leaching followed by pH correction, or after a 5-year outdoor ageing period with free drainage followed by pH correction. Soil solution ionic strength exceeded 150 mmol/L in soils tested directly after spiking and this decreased partially after leaching and returned back to background values after 5-year outdoor equilibration. Chronic toxicity to two plants, two invertebrates, and three microbial endpoints was consistently found in all spiked soils that were not leached. This toxicity significantly decreased or became absent after 5 years of ageing in 19 of the 20 toxicity tests by a factor 8 (median factor; range: 1.4->50), measured by the factor increase of total soil Pb dose required to induce 10% inhibition. The toxicity of Pb in leached soils was intermediate between the other two treatments. The lowest detectable chronic thresholds (EC10) in aged soils ranged 350-5300 mg Pb/kg. Correlation analysis, including data of Pb2+ speciation in soil solution, suggests that reduced ionic strength rather than acidification or true ageing is the main factor explaining the soil treatment effects after spiking. It is suggested that future toxicity studies should test fine PbO powder as a relevant source for Pb in soils to exclude the confounding salt effects. PMID:26218561

  3. Northeastern Salt Marshes: Elevation Capital and Resilience to Sea Level Rise

    EPA Science Inventory

    Stable tidal salt marshes exist at an elevation that is supra-optimal relative to peak biomass production, which for Spartina alterniflora, and other marsh macrophytes, follows a parabolic distribution as a function of elevation, as a surrogate for inundation frequency. In order...

  4. Cardiovascular Effects of Dietary Salt Intake in Aged Healthy Cats: A 2-Year Prospective Randomized, Blinded, and Controlled Study

    PubMed Central

    Chetboul, Valérie; Reynolds, Brice Stéphane; Trehiou-Sechi, Emilie; Nguyen, Patrick; Concordet, Didier; Sampedrano, Carolina Carlos; Testault, Isabelle; Elliott, Jonathan; Abadie, Jérôme; Biourge, Vincent; Lefebvre, Hervé Pierre

    2014-01-01

    High salt dry expanded diets are commercially available for cats to increase water intake and urine volume, as part of the prevention or treatment of naturally occurring urinary stone formation (calcium oxalates and struvites). However, chronic high salt intake may have potential cardiovascular adverse effects in both humans, especially in aging individuals, and several animal models. The objective of this prospective, randomized, blinded, and controlled study was to assess the long-term cardiovascular effects of high salt intake in healthy aged cats. Twenty healthy neutered cats (10.1±2.4 years) were randomly allocated into 2 matched groups. One group was fed a high salt diet (3.1 g/Mcal sodium, 5.5 g/Mcal chloride) and the other group a control diet of same composition except for salt content (1.0 g/Mcal sodium, 2.2 g/Mcal chloride). Clinical examination, systolic and diastolic arterial blood pressure measurements, standard transthoracic echocardiography and conventional Doppler examinations were repeatedly performed on non-sedated cats by trained observers before and over 24 months after diet implementation. Radial and longitudinal velocities of the left ventricular free wall and the interventricular septum were also assessed in systole and diastole using 2-dimensional color tissue Doppler imaging. Statistics were performed using a general linear model. No significant effect of dietary salt intake was observed on systolic and diastolic arterial blood pressure values. Out of the 33 tested imaging variables, the only one affected by dietary salt intake was the radial early on late diastolic velocity ratio assessed in the endocardium of the left ventricular free wall, statistically lower in the high salt diet group at 12 months only (P = 0.044). In conclusion, in this study involving healthy aged cats, chronic high dietary salt intake was not associated with an increased risk of systemic arterial hypertension and myocardial dysfunction, as observed in some

  5. Ten metre global sea-level change associated with South Atlantic Aptian salt deposition

    NASA Technical Reports Server (NTRS)

    Burke, Kevin; Sengor, A. M. Celal

    1988-01-01

    Catastrophic filling of the kind of subsea-level depression commonly formed during ocean opening and ocean closing is the only mechanism, other than glacial eustacy, capable of rapidly lowering sea level. Aptian evaporites overlying oceanic crust on both sides of the South Atlantic between the Walvis Ridge and the Niger Delta were deposited in such a basin by repeated spilling of ocean water. The final flooding of the South Atlantic north of the Walvis Ridge extracted about 14 x 10 to the 8th cu km of sea water from the world ocean and effected about 10 m of sea-level lowering. It is speculated that the middle Aptian unconformity, which is one of the more prominent world-wide unconformities, is associated with this sea-level drop of about 10 m. A corollary of this interpretation is that if the catastrophic sea-level lowerings during the Mesozoic era had amplitudes substantially greater than 10 m, then a glacial mechanism to explain them would seem inescapable although the stratigraphic record has not yet yielded any evidence of such glaciation.

  6. Effect of sea wave age on scatterometer measurements and wind speed retrieval accuracy

    NASA Astrophysics Data System (ADS)

    Panfilova, Maria; Karaev, Vladimir; Jie, Guo

    2015-04-01

    Radiolocation data is widely used for the wind field retrieval over the sea surface. Wind speed is obtained from the radar cross-section. The backscattered signal contains information about the sea surface but not about the wind vector. This means that at the fixed wind speed the radar backscattering cross-section (RCS) depends on the sea maturity. In the present work the influence of the sea state at RCS and wind speed retrieval accuracy was investigated. The collocated array of ERS scatterometer and sea buoys data was processed. Buoy data were used to determine the wave age and all the dataset was separated into three parts: developing wind waves, fully developed waves and mixed sea. It was shown that error of wind retrieval algorithms for scatterometers (CMOD in this case) depends on the sea state. Wind speed is overestimated for swell-dominant sea and underestimated for developing waves. The direct problem of RCS dependence on the wind vector and sea state was also concidered. The large-scale waves slope variance is a very important parameter that implicitly influences the RCS in case of Bragg scattering and depends on the sea state. The buoy data were used to estimate the slope variance. The algorithm based on artificial neural networks taking into account the slope variance for RCS retrieval was proposed and performed better agreement with the measured RCS than CMOD5. It was shown that RCS increases with the slope variance growth other conditions being equal. Thus wind speed retrieval accuracy can be increased by taking into account sea waves parameters and regional peculiarities. Acknowledgments. This work was supported by Russian Foundation for Basic Research grants 130500852a, 14-05-31517mol-a.

  7. Uncovering a Salt Giant. Deep-Sea Record of Mediterranean Messinian Events (DREAM) multi-phase drilling project

    NASA Astrophysics Data System (ADS)

    Camerlenghi, Angelo; Aoisi, Vanni; Lofi, Johanna; Hübscher, Christian; deLange, Gert; Flecker, Rachel; Garcia-Castellanos, Daniel; Gorini, Christian; Gvirtzman, Zohar; Krijgsman, Wout; Lugli, Stefano; Makowsky, Yizhaq; Manzi, Vinicio; McGenity, Terry; Panieri, Giuliana; Rabineau, Marina; Roveri, Marco; Sierro, Francisco Javier; Waldmann, Nicolas

    2014-05-01

    related to the MSC event. Several proposal ideas also emerged to support the Multi-phase drilling project concept: Salt tectonics and fluids, Deep stratigraphic and crustal drilling in the Gulf of Lion (deriving from the GOLD drilling project), Deep stratigraphic and crustal drilling in the Ionian Sea, Deep Biosphere, Sapropels, and the Red Sea. A second MagellanPlus workshop held in January 2014 in Paris (France), has proceeded a step further towards the drafting of the Multi-phase Drilling Project and a set of pre-proposals for submission to IODP.

  8. Salt Marsh as a Coastal Filter for the Oceans: Changes in Function with Experimental Increases in Nitrogen Loading and Sea-Level Rise

    PubMed Central

    Nelson, Joanna L.; Zavaleta, Erika S.

    2012-01-01

    Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH4NO3)-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication. PMID:22879873

  9. Nutrient enrichment and precipitation changes do not enhance resiliency of salt marshes to sea level rise in the Northeastern U.S.

    EPA Science Inventory

    In the U.S. Northeast, salt marshes are exceptionally vulnerable to the effects of accelerated sea level rise as compensatory mechanisms relying on positive feedbacks between inundation and sediment deposition are insufficient to counter inundation increases in low turbidity tida...

  10. Tensile properties and translaminar fracture toughness of glass fiber reinforced unsaturated polyester resin composites aged in distilled and salt water

    NASA Astrophysics Data System (ADS)

    Sugiman, Gozali, M. Hulaifi; Setyawan, Paryanto Dwi

    2016-03-01

    Glass fiber reinforced polymer has been widely used in chemical industry and transportation due to lightweight and cost effective manufacturing. However due to the ability to absorb water from the environment, the durability issue is of interest for up to days. This paper investigated the water uptake and the effect of absorbed water on the tensile properties and the translaminar fracture toughness of glass fiber reinforced unsaturated polyester composites (GFRP) aged in distilled and salt water up to 30 days at a temperature of 50°C. It has been shown that GFRP absorbed more water in distilled water than in salt water. In distilled water, the tensile strength of GFRP tends to decrease steeply at 7 days and then slightly recovered for further immersion time. In salt water, the tensile strength tends to decrease continually up to 30 days immersion. The translaminar fracture toughness of GFRP aged in both distilled and salt-water shows the similar behavior. The translaminar fracture toughness increases after 7 days immersion and then tends to decrease beyond that immersion time. In the existence of ionics content in salt water, it causes more detrimental effect on the mechanical properties of fiberglass/unsaturated polyester composites compared to that of distilled water.

  11. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    SciTech Connect

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  12. Evaluation of the role of sea salt inputs in the long-term acidification of coastal New England lakes

    SciTech Connect

    Sullivan, T.J.; Driscoll, C.T.; Eilers, J.M.; Landers, D.H. )

    1988-02-01

    Input of neutral salt (NaCl) from sea spray, followed by Na{sup +}-H{sup +} exchange within the soil exchange complex, has been proposed as an important factor in surface water acidification of coastal areas. This hypothesis was tested on a regional basis by comparing the Na:Cl ratio of lake water with that of precipitation for the coastal lakes included in the US Environmental Protection Agency Eastern Lake Survey-I in New England. The precipitation Na:Cl ratio closely approximated that of seawater at monitoring stations located within approximately 20 km of the coast. Few lakes in this coastal region exhibited a Na:Cl ratio less than that observed in precipitation. Those lakes that were acidic (ANC {<=} 0) showed no tendency toward a lowered Na:Cl ratio. Sodium contribution from, rather than retention by, watershed soils was suggested by the data from these lakes. Although episodic acidification of runoff due to NaCl deposition may occur, there is little support for the neutral salt effect being an important long-term acidifying process in Northeastern lakes.

  13. Nonlinear responses of coastal salt marshes to nutrient additions and sea level rise

    EPA Science Inventory

    Increasing nutrients and accelerated sea level rise (SLR) can cause marsh loss in some coastal systems. Responses to nutrients and SLR are complex and vary with soil matrix, marsh elevation, sediment inputs, and hydroperiod. We describe field and greenhouse studies examining sing...

  14. Pre-existing caverns in salt formations could be the major cause of sinkhole hazards along the coast of the Dead Sea

    NASA Astrophysics Data System (ADS)

    Legchenko, A.; Ezersky, M.; Boucher, M.; Camerlynck, C.; Al-Zoubi, A.; Chalikakis, K.

    2008-10-01

    Since 1990 hundreds of sinkholes have appeared along the coast of the Dead Sea. In the literature the rapid development of sinkholes is explained as a result of a drop in the level of the Dead Sea. This model assumes very fast dissolution of large volumes of salt and the creation of new caverns that cause sinkholes in 10 to 20 years. However, the results of our geophysical study do not confirm the fast dissolution assumption. To explain the available field observations, we propose the following model: (1) slow dissolution of salt (much longer than 20 years) with the creation of caverns without development of sinkholes; (2) sinkhole development is triggered by the lowering of the groundwater level because the rocks overlying the salt formation become unsaturated; (3) the time of sinkhole appearance is controlled by the mechanical properties of the rocks that overlie pre-existing caverns.

  15. Absolute age of lunar regolith material from the Sea of Fertility

    NASA Technical Reports Server (NTRS)

    Vinogradov, A. P.; Artemov, Y. M.

    1974-01-01

    By averaging the absolute age of lunar regolith materials from the Sea of Fertility for the fine regolith fraction from the core zone V, an age of 4.65 10 to the 9th power + 0.4 10 to the 9th power years was obtained, employing as the primordial Sr-87/Sr-86 ratio 0.69884 (ADOR). Also close to this age value is the age estimate based on the Pb-207/Pb-206 ratio. Using the value 0.69898 (BABI) as a primordial Sr-87/Sr-86 ratio reduces the calculated age of the fine regolith fraction to 4.25 X 10 to the 9th power years. The fine fraction of lunar regolith from the Sea of Fertility is also characterized by a minimum addition of radiogenic Sr-87, a minimum Rb/Sr ratio, and a maximum K/Rb ratio compared with analogous lunar material from other points.

  16. Importance of coarse-mode nitrate produced via sea salt as atmospheric input to East Asian oceans

    NASA Astrophysics Data System (ADS)

    Itahashi, Syuichi; Hayami, Hiroshi; Uno, Itsushi; Pan, Xiaole; Uematsu, Mitsuo

    2016-05-01

    The atmospheric input of anthropogenic total reactive oxygenated nitrogen (NOy) to ocean regions in East Asia during 2002-2004 was revisited with an updated regional chemical transport model and the latest emissions inventory. The updated model treats both fine- and coarse-mode nitrate (NO3-). Coarse-mode NO3- is produced by the reaction of nitric acid (HNO3) and sea salt particles. The modeling system reproduced the atmospheric concentration and wet deposition amount of NO3- quantitatively compared with observations. The fraction of coarse-mode NO3- was also well captured. NOy deposition amounts over marginal seas and open oceans were 733 and 730 Gg N/yr, which are increases of 1.6- and 2.2-fold, respectively, by including coarse-mode NO3-. Anthropogenic NOx emissions from China were 5377 Gg N/yr, and 3060 Gg N/yr was exported from China; therefore, the NOy deposition amount over ocean regions in East Asia (1463 Gg N/yr) corresponded to almost half (48%) of the export amounts.

  17. The role of sea-salt emissions and heterogeneous chemistry in the air quality of polluted coastal areas

    NASA Astrophysics Data System (ADS)

    Athanasopoulou, E.; Tombrou, M.; Pandis, S. N.; Russell, A. G.

    2008-02-01

    Open-ocean and surf-zone sea-salt aerosol (SSA) emissions algorithms are incorporated in the CAMx aerosol model and applied over an area with an extended Archipelago (Greece), with a fine grid nested over the highly populated Attica peninsula. The maximum indirect impact of SSA on PM10 mass (35%) is located over a marine area with moderate SSA production and elevated shipping emissions (central Aegean Sea) where SSA interacts with anthropogenic nitric acid forming sodium nitrate. SSA increases PM10 levels in the Athens city center up to 27% during stable onshore winds. Under such conditions both open-ocean and surf-zone mechanisms contribute to aerosol production over Attica. A hybrid scheme for gas-to-particle mass transfer is necessary for accurately simulating semi-volatile aerosol components when coarse SSA is included. Dynamically simulating mass transfer to the coarse particles leads to a quadrupling of predicted PM10 nitrate in the Athens city center and up to two orders of magnitude in its coarse mass in comparison to using a bulk equilibrium approach.

  18. The role of sea-salt emissions and heterogeneous chemistry in the air quality of polluted coastal areas

    NASA Astrophysics Data System (ADS)

    Athanasopoulou, E.; Tombrou, M.; Pandis, S. N.; Russell, A. G.

    2008-10-01

    Open-ocean and surf-zone sea-salt aerosol (SSA) emission parameterizations are incorporated in the CAMx aerosol model and applied over an area with an extended Archipelago (Greece), with a fine grid nested over the highly populated Attica peninsula. The maximum indirect impact of SSA on PM10 mass (35%) is located over a marine area with moderate SSA production and elevated shipping emissions (central Aegean Sea) where SSA interacts with anthropogenic nitric acid forming sodium nitrate. SSA increases PM10 levels in the Athens city center up to 25% during stable onshore winds. Under such conditions both open-ocean and surf-zone mechanisms contribute to aerosol production over Attica. A hybrid scheme for gas-to-particle mass transfer is necessary for accurately simulating semi-volatile aerosol components when coarse SSA is included. Dynamically simulating mass transfer to the coarse particles leads to a quadrupling of predicted PM10 nitrate in the Athens city center and up to two orders of magnitude in its coarse mass in comparison to using a bulk equilibrium approach.

  19. Open-system coral ages reveal persistent suborbital sea-level cycles.

    PubMed

    Thompson, William G; Goldstein, Steven L

    2005-04-15

    Sea level is a sensitive index of global climate that has been linked to Earth's orbital variations, with a minimum periodicity of about 21,000 years. Although there is ample evidence for climate oscillations that are too frequent to be explained by orbital forcing, suborbital-frequency sea-level change has been difficult to resolve, primarily because of problems with uranium/thorium coral dating. Here we use a new approach that corrects coral ages for the frequently observed open-system behavior of uranium-series nuclides, substantially improving the resolution of sea-level reconstruction. This curve reveals persistent sea-level oscillations that are too frequent to be explained exclusively by orbital forcing. PMID:15831756

  20. Open-System Coral Ages Reveal Persistent Suborbital Sea-Level Cycles

    NASA Astrophysics Data System (ADS)

    Thompson, William G.; Goldstein, Steven L.

    2005-04-01

    Sea level is a sensitive index of global climate that has been linked to Earth's orbital variations, with a minimum periodicity of about 21,000 years. Although there is ample evidence for climate oscillations that are too frequent to be explained by orbital forcing, suborbital-frequency sea-level change has been difficult to resolve, primarily because of problems with uranium/thorium coral dating. Here we use a new approach that corrects coral ages for the frequently observed open-system behavior of uranium-series nuclides, substantially improving the resolution of sea-level reconstruction. This curve reveals persistent sea-level oscillations that are too frequent to be explained exclusively by orbital forcing.

  1. A model for the atmospheric transport of sea-salt particles in coastal areas

    NASA Astrophysics Data System (ADS)

    Demoisson, A.; Tedeschi, G.; Piazzola, J.

    2013-10-01

    A model for the aerosol transport in the lower atmosphere is of great interest for studies on air and water quality. One of the difficulties of such a model is to provide the accurate source terms. In particular, for maritime environment, the production of particles generated at the air-sea interface by breaking waves largely varies in time and space (Piazzola et al., 2009). More particularly, near the coastal zone, the sea-spray aerosol fluxes depend on the development of the wave field. The present paper proposes some improvement of the model MACMod, published by Tedeschi and Piazzola (2011), which is dedicated to the transport of aerosol particles in the marine atmospheric boundary layer (MABL). Taking benefit of the experimental campaign MIRAMER conducted in the French Mediterranean in 2008, a new sea-spray source function has been introduced in the latter version of the model MACMod. This consists in a revisited version of the whitecap dependant formulation established by Monahan et al. (1986). The simulations were then validated using aerosol size distributions recorded on board the ship “Atalante” for different wind speeds. Error calculations show a good performance of the model since it predicts the aerosol concentration to within a maximum factor of 3 for particle radii between 0.5 to 5 μm.

  2. Relative sea-level change in the central Cyclades (Greece) since the Early Bronze Age

    NASA Astrophysics Data System (ADS)

    Draganits, E.

    2012-04-01

    The Aegean is a focus of important cultural achievements in Europe since the Neolithic period. The resulting abundance of archaeological remains, many of them below sea-level represent an advantageous area for the study of local relative sea-level change. We have carried out detailed mapping of Despotiko Island (SW of Antiparos) and its surrounding. Despotiko is situated almost exactly in the center of the Cyclades (as defined nowadays), more so than Delos, and therefore is very well suited for sea-level studies of the Cyclades. This beneficial location, combined with a spacious and protected bay, additionally may explain its former importance as stepping-stone in the Aegean Sea. The island is uninhabited at present, but Early Bronze Age settlement sites and graveyards as well as a large Archaic sanctuary proof its former importance. The sanctuary is situated on a gently northeast dipping slope in the northeast part of Despotiko, in range of sight of the Órmos Despotiko. Since 1997 large parts of this important sanctuary have been excavated during several excavation campaigns. Tectonically, Despotiko, Antiparos and Paros, belong to the Attic-Cycladic Crystalline of the Central Hellenides, a stack of metamorphic tectonic nappes, mainly comprising variable types of gneiss, schist, marble and amphibolite, and tectonic slices of unmetamorphosed sediments on top, separated by low-angle normal faults from the metamorphic units below. Submerged archaeological structures at the sea bottom of the Órmos Despotiko, a Classical marble inscription from the sanctuary and partly submerged agriculture trenches at the east coast Despotiko, indicate that the relative sea-level in this area was some 3 m lower during the Early Bronze Age and still more than 1 m lower during Classical time. These values of relative sea-level rise indicate a subsidence component additional to the global sea-level rise in the investigated time period. Neglecting possible vertical tectonic movements and

  3. Evaluation of otoliths Salt Creek pupfish (Cyprinodon salinus salinus) for use in analyses of age and growth

    USGS Publications Warehouse

    Dzul, Maria C.; Gaines, D. Bailey; Fischer, Jesse R.; Quist, Michael C.; Dinsmore, Stephen J.

    2012-01-01

    We collected Salt Creek pupfish (Cyprinodon salinus salinus) from Salt Creek, Death Valley, California, in November 2009 and May 2010. The purpose of our study was to determine whether otoliths displayed interpretable marks that might be used for estimating age and growth. Otoliths exhibited alternating bands of opaque and translucent material. Kendall rank correlation between number of bands on otoliths and length of fish were high for two readers (τ = 0.65 and 0.79) and exact agreement between readers was 51%. Otoliths exhibited 0–5 bands, which provided evidence that longevity of Salt Creek pupfish likely is >1 year. Total length of fish collected in spring and autumn differed for fish with one and three bands on otoliths.

  4. Spatial and temporal variations in the age structure of Arctic sea ice

    USGS Publications Warehouse

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2005-01-01

    Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reversechronology algorithm that tracks ice-covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (???5 years) ice in the eastern Arctic. Persistent net losses (-4.2% yr-1) in extent of ice >10 years old (10+ year age class) were observed during 1989-2003. Since the mid-1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6-10 year) age classes. Survival of the 1994 and 1996-1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid-2000s. Copyright 2005 by the American Geophysical Union.

  5. Stable isotopes of a subfossil Tamarix tree from the Dead Sea region, Israel, and their implications for the Intermediate Bronze Age environmental crisis

    NASA Astrophysics Data System (ADS)

    Frumkin, Amos

    2009-05-01

    Trees growing on the Mt. Sedom salt diapir, at the southern Dead Sea shore, were swept by runoff into salt caves and subsequently deposited therein, sheltered from surface weathering. A subfossil Tamarix tree trunk, found in a remote section of Sedom Cave is radiocarbon dated to between ˜ 2265 and 1930 BCE. It was sampled in 109 points across the tree rings for carbon and nitrogen isotopes. The Sedom Tamarix demonstrates a few hundred years of 13C and 15N isotopic enrichment, culminating in extremely high δ 13C and δ 15N values. Calibration using modern Tamarix stable isotopes in various climatic settings in Israel shows direct relationship between isotopic enrichment and climate deterioration, particularly rainfall decrease. The subfossil Tamarix probably reflects an environmental crisis during the Intermediate Bronze Age, which subsequently killed the tree ˜ 1930 BCE. This period coincides with the largest historic fall of the Dead Sea level, as well as the demise of the large regional urban center of the 3rd millennium BCE. The environmental crisis may thus explain the archaeological evidence of a shift from urban to pastoral culture during the Intermediate Bronze Age. This was apparently the most severe long-term historical drought that affected the region in the mid-late Holocene.

  6. Abating corrosion in highway structures due to sea or deicing salts

    NASA Astrophysics Data System (ADS)

    Kessler, Rick J.; Powers, Rodney G.

    1995-05-01

    Corrosion of steel reinforcing bars in concrete bridge structures due to the intrusion of chloride ions from seawater or de-icing salts affects many structures in the nation's highway system. Over the past decade cathodic protection has evolved as a promising technology for arresting corrosion. The development of materials, equipment, and methods for applying cathodic protection is in a dynamic state. Through cooperative efforts with academia, industry, and the engineering community, the Florida Deparment of Transportation has developed several innovative corrosion protection systems which incorporate technologies from a wide variety of specialty areas including telemetry, photovoltaics, polymers, and specialty components developed as part of the national defense program. This paper provides an overview of corrosion and cathodic protection technology and focuses on the potential for adaptation of existing technologies into preservation of highway bridge structures.

  7. Involvement of dietary salt in shaping bacterial communities in European sea bass (Dicentrarchus labrax)

    PubMed Central

    Sun, Haifeng; Jami, Elie; Harpaz, Sheenan; Mizrahi, Itzhak

    2013-01-01

    Bacteria associated with the digestive tract of multicellular organisms have been shown to play a major role in their hosts' functioning. In fish, it has been proposed that food fermentation occurs inside the pyloric ceca, pouch like organs found in their digestive tract. However, this notion remains controversial. Furthermore, changes in pyloric cecal bacterial populations under different diets have yet to be demonstrated in fish. In this study, we explore the changes occurring in the bacterial community residing in the pyloric ceca of carnivorous fish fed different diets, which were shown to induce different growth rates. Our results revealed that different diets do indeed induce distinct bacterial compositions within the pyloric ceca. We found that, when salt was added to a low fish meal diet, the bacterial changes were accompanied by a significant enhancement in weight gain, hinting at a possible involvement of the bacterial community in energy harvest. PMID:23558231

  8. Effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance of aged mice.

    PubMed

    Zhang, Guihua; Shirai, Nobuya; Higuchi, Tomoyuki; Suzuki, Hiramitsu; Shimizu, Eiji

    2007-12-01

    The effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance was investigated in aged mice. Fifty three-week-old male Crlj:CD-1 (ICR) mice were fed one of three experimental diets containing either 6% lard, 6% fish oil, or 6% sea snake lipids for 16 wk. The swimming exercise was carried out in an acrylic plastic tank filled with 25 cm of water maintained at 23(o)C. Swimming times to exhaustion were measured with a load of 2% of their body weights attached to the tails of the mice. The swimming times to exhaustion of the group that were fed the sea snake lipid diet tended to be longer than those of the lard diet group, and were significantly improved compared with the fish oil diet group (p<0.05). The plasma and muscle lactate levels were significantly lower in the sea snake lipid diet group than in the lard and fish oil diet groups (p<0.05). The liver glycogen and plasma glucose levels of the sea snake lipid diet group did not differ markedly from those of the lard diet group (p>0.05), and were significantly higher than those of the fish oil diet group (p<0.05). These results suggest that an intake of sea snake lipids but not the fish oil, which is also rich in n-3 polyunsaturated fatty acids (n-3 PUFAs), is useful for improving the swimming endurance of aged mice by attenuating lactate production and/or enhancing lactate clearance during swimming exercise, and the n-3 PUFAs contained in the sea snake lipids did little or nothing for this improved endurance. PMID:18202534

  9. Quantifying the impact of sub-grid surface wind variability on sea salt and dust emissions in CAM5

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Zhao, Chun; Wan, Hui; Qian, Yun; Easter, Richard C.; Ghan, Steven J.; Sakaguchi, Koichi; Liu, Xiaohong

    2016-02-01

    This paper evaluates the impact of sub-grid variability of surface wind on sea salt and dust emissions in the Community Atmosphere Model version 5 (CAM5). The basic strategy is to calculate emission fluxes multiple times, using different wind speed samples of a Weibull probability distribution derived from model-predicted grid-box mean quantities. In order to derive the Weibull distribution, the sub-grid standard deviation of surface wind speed is estimated by taking into account four mechanisms: turbulence under neutral and stable conditions, dry convective eddies, moist convective eddies over the ocean, and air motions induced by mesoscale systems and fine-scale topography over land. The contributions of turbulence and dry convective eddy are parameterized using schemes from the literature. Wind variabilities caused by moist convective eddies and fine-scale topography are estimated using empirical relationships derived from an operational weather analysis data set at 15 km resolution. The estimated sub-grid standard deviations of surface wind speed agree well with reference results derived from 1 year of global weather analysis at 15 km resolution and from two regional model simulations with 3 km grid spacing.The wind-distribution-based emission calculations are implemented in CAM5. In terms of computational cost, the increase in total simulation time turns out to be less than 3 %. Simulations at 2° resolution indicate that sub-grid wind variability has relatively small impacts (about 7 % increase) on the global annual mean emission of sea salt aerosols, but considerable influence on the emission of dust. Among the considered mechanisms, dry convective eddies and mesoscale flows associated with topography are major causes of dust emission enhancement. With all the four mechanisms included and without additional adjustment of uncertain parameters in the model, the simulated global and annual mean dust emission increase by about 50 % compared to the default model

  10. Age- and sex-specific mortality and population structure in sea otters

    USGS Publications Warehouse

    Bodkin, J.L.; Burdin, A.M.; Ryazanov, D.A.

    2000-01-01

    We used 742 beach-cast carcasses to characterize age- and sex-specific sea otter mortality during the winter of 1990-1991 at Bering Island, Russia. We also examined 363 carcasses recovered after the 1989 grounding of the T/V Exxon Valdez, to characterize age and sex composition in the living western Prince William Sound (WPWS) sea otter population. At Bering Island, mortality was male-biased (81%), and 75% were adults. The WPWS population was female-biased (59%) and most animals were subadult (79% of the males and 45% of the females). In the decade prior to 1990-1991 we found increasing sea otter densities (particularly among males), declining prey resources, and declining weights in adult male sea otters at Bering Island. Our findings suggest the increased mortality at Bering Island in 1990-1991 was a density-dependent population response. We propose male-maintained breeding territories and exclusion of juvenile females by adult females, providing a mechanism for potentially moderating the effects of prey reductions on the female population. Increased adult male mortality at Bearing Island in 1990-1991 likely modified the sex and age class structure there toward that observed in Prince William Sound.

  11. Mediterranean Sea surface radiocarbon reservoir age changes since the last glacial maximum.

    PubMed

    Siani, G; Paterne, M; Michel, E; Sulpizio, R; Sbrana, A; Arnold, M; Haddad, G

    2001-11-30

    Sea surface reservoir ages must be known to establish a common chronological framework for marine, continental, and cryospheric paleoproxies, and are crucial for understanding ocean-continent climatic relationships and the paleoventilation of the ocean. Radiocarbon dates of planktonic foraminifera and tephra contemporaneously deposited over Mediterranean marine and terrestrial regions reveal that the reservoir ages were similar to the modern one (approximately 400 years) during most of the past 18,000 carbon-14 years. However, reservoir ages increased by a factor of 2 at the beginning of the last deglaciation. This is attributed to changes of the North Atlantic thermohaline circulation during the massive ice discharge event Heinrich 1. PMID:11729315

  12. Free-living plathelminthes in sheep-grazed and ungrazed supralittoral salt marshes of the North Sea: Abundance, biomass, and their significance in food chains

    NASA Astrophysics Data System (ADS)

    Armonies, W.

    The supralittoral salt marshes of the North Sea are marked by high halophyte primary productivity. The environmental factors are strongly fluctuating. Despite these features the metazoan meiofaunal abundance is equal to that found in other littoral habitats. On average 1250 marine metazoans are found per 10 cm 2 in ungrazed and 770 per 10 cm 2 in sheep-grazed supralittoral salt marshes. Nematoda dominate in numerical abundance, Oligochaeta in biomass. Plathelminthes account for 15% of marine metazoans in ungrazed and 5% in grazed salt marshes. Total plathelminth abundance increases with halophyte density, whereas the abundance of diatom-feeding Plathelminthes decreases. In ungrazed marshes on average 104 Plathelminthes are found per 10 cm 2, accounting for a biomass of 0.65 g DW·m -2. In sheep-grazed marshes the average abundance is only 32 individuals per 10 cm 2, accounting for a biomass of 0.1 g DW·m -2. Average individual weight is 3.2 μg DW or 2.5 μg AFDW. In grazed salt marshes, 30% of plathelminthes feed on diatoms, 66% are predators, and 4% feed on bacteria (gut analysis). In ungrazed salt marshes only 3% are diatom-feeders, and 90% are predators feeding on Nematoda, Copepoda, Oligochaeta, and smaller Plathelminthes. Presumably plathelminthes are top predators on the salt marsh meiofauna.

  13. Estimating age of sea otters with cementum layers in the first premolar

    USGS Publications Warehouse

    Bodkin, J.L.; Ames, J.A.; Jameson, R.J.; Johnson, A.M.; Matson, G.M.

    1997-01-01

    We assessed sources of variation in the use of tooth cementum layers to determine age by comparing counts in premolar tooth sections to known ages of 20 sea otters (Enhydra lutris). Three readers examined each sample 3 times, and the 3 readings of each sample were averaged by reader to provide the mean estimated age. The mean (SE) of known age sample was 5.2 years (1.0) and the 3 mean estimated ages were 7.0 (1.0), 5.9 (1.1) and, 4.4 (0.8). The proportion of estimates accurate to within +/- 1 year were 0.25, 0.55, and 0.65 and to within +/- 2 years 0.65, 0.80, and 0.70, by reader. The proportions of samples estimated with >3 years error were 0.20, 0.10, and 0.05. Errors as large as 7, 6, and 5 years were made among readers. In few instances did all readers uniformly provide either accurate (error 1 yr) counts. In most cases (0.85), 1 or 2 of the readers provided accurate counts. Coefficients of determination (R2) between known ages and mean estimated ages were 0.81, 0.87, and 0.87, by reader. The results of this study suggest that cementum layers within sea otter premolar teeth likely are deposited annually and can be used for age estimation. However, criteria used in interpreting layers apparently varied by reader, occasionally resulting in large errors, which were not consistent among readers. While large errors were evident for some individual otters, there were no differences between the known and estimated age-class distribution generated by each reader. Until accuracy can be improved, application of this ageing technique should be limited to sample sizes of at least 6-7 individuals within age classes of >/=1 year.

  14. Comparative toxicities of aluminum and zinc from sacrificial anodes or from sulfate salt in sea urchin embryos and sperm.

    PubMed

    Caplat, Christelle; Oral, Rahime; Mahaut, Marie-Laure; Mao, Andrea; Barillier, Daniel; Guida, Marco; Della Rocca, Claudio; Pagano, Giovanni

    2010-09-01

    The toxicity of aluminum or zinc from either sacrificial anodes (SA) or their sulfate salts (SS) was evaluated in sea urchin (Paracentrotus lividus) embryos or sperm exposed to Al(III) or Zn(II) (SA or SS, 0.1-10 microM), scoring developmental defects (DDs), fertilization rate (FR), and mitotic abnormalities. A significant DD increase was observed in SS, but not SA Al(III)- and Zn(II)-exposed embryos vs. controls. Both Al(III) and Zn(II), up to 10 microM, from SA and SS, inhibited mitotic activity and induced mitotic aberrations in exposed embryos. SA-Al(III)-exposed sperm displayed a significant FR increase, unlike Al(III) sulfate overlapping with controls. Both SA-Zn(II) and Zn(II) sulfate sperm exposure resulted in a significant FR increase. The offspring of SA-Al(III)-exposed sperm displayed a significant DD decrease, unlike Al(III) sulfate exposure. Zinc sulfate sperm exposure resulted in a significant increase in offspring DDs, whereas SA-Zn(II) sperm exposure decreased DDs. Together, exposures to SA-dissolved Al(III) or Zn(II) resulted in lesser, if any toxicity, up to hormesis, compared to SS. Studies of metal speciation should elucidate the present results. PMID:20650532

  15. Paleomagnetic inclination errors in sediments cored from a Gulf of Mexico salt dome - An indicator of ancient sea level

    SciTech Connect

    Sager, W.W.; Singleton, S.W. )

    1989-08-01

    A paleomagnetic study of piston-cored sediments was done in conjunction with a high-resolution seismic reflection study of a salt dome on the upper continental slope in the northern Gulf of Mexico. Seismic data showed that late Pleistocene sediment layers are exposed around the bank and tilted up to 8{degree} by the diapiric uplift. Cores were taken on the flanks of the bank to test the use of paleomagnetism in measuring the tectonic tilt of the sediments. After structural corrections, results from six cores agreed with the geocentric axial dipole inclination for the site, but four other cores displayed significantly shallowed inclinations. Moreover, several cores showed linear trends of inclination shallowing, increasing downcore. The anomalous results are from the summit of the bank and suggest a relation to subaerial exposure during a sea-level lowstand. The authors think that the shallow inclinations were caused by compaction, but that the linear trends resulted from rehydration of the sediments after exposure by erosion.

  16. Age composition and antioxidant enzyme activities in blood of Black Sea teleosts.

    PubMed

    Rudneva, Irina I; Skuratovskaya, Ekaterina N; Kuzminova, Natalya S; Kovyrshina, Tatyana B

    2010-03-01

    Age composition and age-related trends of antioxidant enzyme activities superoxide dismutase (SOD), catalase (CAT), peroxidase (PER), glutathione reductase (GR) and glutathione-S-transferase (GST) in the blood of seven Black Sea teleosts (Carangidae, Centracanthidae, Gadidae, Mullidae, Gobiidae and Scorpaenidae) collected in marine coastal area of Sevastopol (Ukraine) were studied. In the catches the animals of 1-2 years of age dominated while in the Scorpaena porcus population the number of relatively elder individuals belonging to classes of 3-4 years was the highest. The trends of antioxidant enzyme activities in blood were not uniform. Three types of age-dependent responses were indicated in fish blood: 1. enzymatic activity did not change with age; 2. enzymatic activity decreased with age and 3. enzyme activity increased with age or varied unclearly. The interspecies differences of age-related enzymatic activities associated with the specificity of fish biology and ecology were indicated. Despite no clear evidence of age-related differences between fish species belonging to different ecological groups both benthic forms exhibited similar age-dependent trends of SOD and PER. The correlations between blood antioxidant enzyme activities in fish belonging to suprabenthic and benthic/pelagic groups demonstrated the intermediate values as compared to the benthic and pelagic forms. The results suggest the importance of age trends for biomarkers in fish monitoring studies. PMID:19897051

  17. Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine

    USGS Publications Warehouse

    Nielsen, Martha G.; Dudley, Robert W.

    2013-01-01

    Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median

  18. TOF-SIMS Analysis of Sea Salt Particles: Imaging and Depth Profiling in the Discovery of an Unrecognized Mechanism for pH Buffering

    SciTech Connect

    Gaspar, Dan J.; Laskin, Alexander; Wang, Weihong; Hunt, Sherri W.; Finlayson-Pitts, Barbara J.

    2004-06-15

    As part of a broader effort at understanding the chemistry of sea salt particles, we have performed time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis of individual sea salt particles deposited on a transmission electron microscopy (TEM) grid. Environmental scanning electron microscopy (ESEM) and TOF-SIMS analysis have, in conjunction with OH exposure studies, led to the discovery of an unrecognized buffering mechanism in the uptake and oxidation of SO2 in sea salt particles in the marine boundary layer. This chemistry may resolve several discrepancies in the atmospheric chemistry literature. Several challenges during the acquisition and interpretation of both imaging and depth profiling data on specific particles on the TEM grid identified by the ESEM were overcome. A description of the analysis challenges and the solutions ultimately developed to them is presented here, along with an account of how the TOF-SIMS data were incorporated into the overall research effort. Several issues unique to the analysis of high aspect ratio particles are addressed.[1

  19. TOF-SIMS Analysis of Sea Salt Particles: Imaging and Depth Profiling in the Discovery of an Unrecogized Mechanism for pH Buffering

    SciTech Connect

    Gaspar, Dan J.; Laskin, Alexander; Wang, Weihong; Hunt, Sherri W.; Finlayson-Pitts, Barbara J.

    2004-06-15

    As part of a broader effort at understanding the chemistry of sea salt particles, we have performed time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis of individual sea salt particles deposited on a transmission electron microscopy (TEM) grid. Environmental scanning electron microscopy (ESEM) and TOF-SIMS analysis have, in conjunction with OH exposure studies, led to the discovery of an unrecognised buffering mechanism in the uptake and oxidation of SO2 in sea salt particles in the marine boundary layer. This chemistry may resolve several discrepancies in the atmospheric chemistry literature. Several challenges during the acquisition and interpretation of both imaging and depth profiling data on specific particles on the TEM grid identified by the ESEM were overcome. A description of the analysis challenges and the solutions ultimately developed to them is presented here, along with an account of how the TOF-SIMS data were incorporated into the overall research effort. Several issues unique to the analysis of high aspect ratio particles are addressed.[1

  20. The little ice age and medieval warm period in the Sargasso Sea

    SciTech Connect

    Keigwin, L.D.

    1996-11-29

    Sea surface temperature (SST), salinity, and flux of terrigenous material oscillated on millennial time scales in the Pleistocene North Atlantic, but there are few records of Holocene variability. Because of high rates of sediment accumulation, Holocene oscillations are well documented in the northern Sargasso Sea. Results from a radiocarbondated box core show that SST was {approximately} 1{degree}C cooler than today {approximately} 400 years ago (the Little Ice Age) and 1700 years ago, and {approximately} 1{degree}C warmer than today 1000 years ago (the Medieval Warm Period). Thus, at least some of the warming since the Little Ice Age appears to be part of a natural oscillation. 39 refs., 4 figs., 1 tab.

  1. Dual-band infrared imaging applications: Locating buried minefields, mapping sea ice, and inspecting aging aircraft

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.; Perkins, D.E.

    1992-09-01

    We discuss the use of dual-band infrared (DBIR) imaging for three quantitative NDE applications: location buried surrogate mines, mapping sea ice thicknesses and inspecting subsurface flaws in aging aircraft parts. Our system of DBIR imaging offers a unique combination of thermal resolution, detectability, and interpretability. Pioneered at Lawrence Livermore Laboratory, it resolves 0.2 {degrees}C differences in surface temperatures needed to identify buried mine sites and distinguish them from surface features. It produces both surface temperature and emissivity-ratio images of sea ice, needed to accurately map ice thicknesses (e.g., by first removing clutter due to snow and surface roughness effects). The DBIR imaging technique depicts subsurface flaws in composite patches and lap joints of aircraft, thus providing a needed tool for aging aircraft inspections.

  2. Initial insights into the age and origin of the Kubuqi sand sea of northern China

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoping; Forman, Steven; Hu, Fangen; Zhang, Deguo; Liu, Ziting; Li, Hongwei

    2016-04-01

    The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km2) sand sea with a present annual precipitation of 200-480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. - A.D. 220) and the Tang (A.D. 608 - 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka.

  3. Carbon distributions in Spartina alterniflora dominated salt marshes in Galveston, Texas: The role of elevation, relative sea level history, and land cover conversions

    NASA Astrophysics Data System (ADS)

    Kulawardhana, R. W.; Feagin, R. A.; Popescu, S. C.

    2014-12-01

    Coastal wetlands, including salt marshes, are considered to be large carbon sinks. Yet, there is little knowledge about how the terrain and land cover of these environments are related to carbon distribution. An understanding of the spatial and temporal patterns of carbon held in both the biomass and soil, and the factors that influence its distribution, will be necessary to allow coastal managers to initiate and verify "Blue Carbon" projects. In this study, we attempt to understand: 1) the temporal changes in salt marsh distributions as affected by marsh submergence, vertical accretion and land cover conversions; 2) patterns of soil carbon across different depths of the soil profile; and 3) to evaluate how changes in relative water level governs the spatial and temporal variability of salt marsh carbon storage ability. Our results indicate that over the study period (1954 to present) a considerable portion of salt marsh extents were submerged, while at the higher terrains these salt marshes indicated a landward shift in response to the sea level rise. Soil carbon measured in the soil profile, revealed a gradual depletion of soil carbon with depth. However, both the soil bulk density and the percent carbon indicated an abrupt and significant change at a depth of 15cm (p=0.05), which we interpreted as distinct of two different environments. As evidenced by historical aerial imagery (1954, 1969), the first (15-30 cm depth) coincided with an unvegetated salt flat at the sample locations, which were then overlain by lower bulk density and higher carbon Spartina alterniflora low marsh (0-15 cm depth) that migrated upslope in response to rapid relative sea level rise. However, within each of these two environments separately, carbon distribution followed a unique pattern with respect to elevation. Our results further point to two different processes, each acting at a different time scale (daily tides versus relative sea level rise), and each results in distinct spatial

  4. Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Jimenez-Guerrero, P.; Jorba, O.; Pay, M. T.; Montavez, J. P.; Jerez, S.; Gomez-Navarro, J. J.; Baldasano, J. M.

    2010-12-01

    A number of attempts have been made to incorporate sea-salt aerosols (SSA) source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution in a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the surface wind speed cubed and particle size. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around -0.003 and -1.2 μg m-3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA vary strongly across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m-3) and CMAQ in the Gulf of Lion (9 μg m-3). The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes implemented. Dry deposition essentially follows the surface drag stress patterns, meanwhile wet

  5. Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Jiménez-Guerrero, P.; Jorba, O.; Pay, M. T.; Montávez, J. P.; Jerez, S.; Gómez-Navarro, J. J.; Baldasano, J. M.

    2011-05-01

    A number of attempts have been made to incorporate sea-salt aerosol (SSA) source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution for a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the particle size and the surface wind speed raised to the power 3.41. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around -0.002 and -1.2 μg m-3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA strongly vary across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m-3) and CMAQ in the Gulf of Lion (9 μg m-3). The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes implemented. Dry deposition essentially follows the surface drag stress patterns

  6. N(2)O(5) reaction on submicron sea salt aerosol: kinetics, products, and the effect of surface active organics.

    PubMed

    Thornton, Joel A; Abbatt, Jonathan P D

    2005-11-10

    The reaction of N(2)O(5) on sea salt aerosol is a sink for atmospheric nitrogen oxides and a source of the Cl radical. We present room-temperature measurements of the N(2)O(5) loss rate on submicron artificial seawater (ASW) aerosol, performed with an entrained aerosol flow tube coupled to a chemical ionization mass spectrometer, as a function of aerosol phase (aqueous or partially crystalline), liquid water content, and size. We also present an analysis of the product growth kinetics showing that ClNO(2) is produced at a rate equal to N(2)O(5) loss, with an estimated lower limit yield of 50% at 50% relative humidity (RH). The reaction probability for N(2)O(5), gamma(N(2)(O)(5)), depends strongly on the particle phase, being 0.005 +/- 0.004 on partially crystalline ASW aerosol at 30% RH and 0.03 +/- 0.008 on aqueous ASW aerosol at 65% RH. At 50% RH, N(2)O(5) loss is relatively insensitive to particle size for radii greater than 100 nm, and gamma(N(2)(O)(5)) displays a statistically insignificant increase from 0.022 to approximately 0.03 for aqueous ASW aerosol over the RH range of 43-70%. We find that the presence of millimolar levels of hexanoic acid in the aerosol bulk decreases the gamma(N(2)(O)(5)) at 70% RH by a factor of 3-4 from approximately 0.025 to 0.008 +/- 0.004. This reduction is likely due to the partitioning of hexanoic acid to the gas-aerosol interface at a surface coverage that we estimate to be equivalent to a monolayer. This result is the first evidence that a monolayer coating of aqueous organic surfactant can slow the reactive uptake of atmospheric trace gases to aerosol. PMID:16838918

  7. Large spatial variations in coastal 14C reservoir age - a case study from the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Lougheed, B. C.; Filipsson, H. L.; Snowball, I.

    2013-05-01

    Coastal locations are highly influenced by input from freshwater river runoff, including sources of terrestrial carbon, which can be expected to modify the 14C reservoir age, or R (t), associated with marine water. In this Baltic Sea case study, pre-bomb museum collection mollusc shells of known calendar age, from 30 locations across a strategic salinity transect of the Baltic Sea, were analysed for 14C, δ13C and δ18O. R (t) was calculated for all 30 locations. Seven locations, of which six are within close proximity of the coast, were found to have relatively higher R (t) values, indicative of hard-water effects. Whenever possible, the Macoma genus of mollusc was selected from the museum collections, in order to exclude species specific reservoir age effects as much as possible. When the Macoma samples are exclusively considered, and samples from hard-water locations excluded, a statistically significant correlation between Macoma R (t) and average salinity is found, indicating a two end-member linear mixing model between 14Cmarine and 14Crunoff. A map of Baltic Sea Macoma aragonite R (t) for the late 19th and early 20th centuries is produced. Such a map can provide an estimate for contemporary Baltic Sea Macoma R (t), although one must exercise caution when applying such estimates back in time or to 14C dates obtained from different sample material. A statistically significant correlation is found between δ18Oaragonite and Macoma R (t), suggesting that δ18Oaragonite can be used to estimate Macoma palaeo-R (t), due to the δ18Oaragonite signal being dominated by the salinity gradient of the Baltic Sea. A slightly increased correlation can be expected when δ18Oaragonite is corrected for temperature fractionation effects. The results of this Baltic Sea case study, which show that R (t) is affected by hydrographic conditions and local carbon inputs, have important consequences for other coastal and estuarine locations, where R (t) is also likely to significantly

  8. On the Isolation of Halophilic Microorganisms from Salt Deposits of Great Geological Age

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga; Denner, Ewald; Orans, Robin (Editor)

    1993-01-01

    From salt sediments of Triassic or Permian ace from various locations in the world halophilic microorganisms were isolated. Molecular characteristics of several of the isolates suggested they belong to the archaebacteriae. One group appears to represent novel strains; several properties or one such isolate, strain BIp, are described here. The existence of viable microorganisms in ancient sediments would have great implications with respect to our notions on evolution, the search for life in extraterrestrial environments and the long- term survival of functional biological structures. Of crucial importance is thus the question if these microorganisms existed in the salt since the time of deposition or invaded at some later date. Some suggestions to address these issues experimentally are discussed.

  9. Influence of Sea Water Aging on the Mechanical Behaviour of Acrylic Matrix Composites

    NASA Astrophysics Data System (ADS)

    Davies, P.; Le Gac, P.-Y.; Le Gall, M.

    2016-07-01

    A new matrix resin was recently introduced for composite materials, based on acrylic resin chemistry allowing standard room temperature infusion techniques to be used to produce recyclable thermoplastic composites. This is a significant advance, particularly for more environmentally-friendly production of large marine structures such as boats. However, for such applications it is essential to demonstrate that composites produced with these resins resist sea water exposure in service. This paper presents results from a wet aging study of unreinforced acrylic and glass and carbon fibre reinforced acrylic composites. It is shown that the acrylic matrix resin is very stable in seawater, showing lower property losses after seawater aging than those of a commonly-used epoxy matrix resin. Carbon fibre reinforced acrylic also shows good property retention after aging, while reductions in glass fibre reinforced composite strengths suggest that specific glass fibre sizing may be required for optimum durability.

  10. Age-related Declines in Thirst and Salt Appetite Responses in Male Fischer 344 x Brown Norway Rats

    PubMed Central

    Thunhorst, Robert L.; Beltz, Terry; Johnson, Alan Kim

    2014-01-01

    The F344xBN strain is the first generational cross between Fischer 344 (F344) and Brown Norway (BN) rats. The F344xBN strain is widely used in aging studies as it is regarded as a model of “healthy” aging (Sprott, 1991). In the present work, male F344xBN rats aged 4 mo (young, n = 6) and 20 mo (old, n = 9) received a series of experimental challenges to body fluid homeostasis to determine their thirst and salt appetite responses. Corresponding urinary responses were measured in some of the studies. Following sodium depletion, old rats ingested less saline solution (0.3 M NaCl) than young rats on a body weight basis, but both ages drank enough saline solution to completely repair the accrued sodium deficits. Following intracellular dehydration, old rats drank less water than young rats, again on a body weight basis, and were less able than young rats to drink amounts of water proportionate to the osmotic challenge. Compared with young rats, old rats drank less of both water and saline solution after combined food and fluid restriction, and also were refractory to the stimulatory effects of low doses of captopril on water drinking and sodium ingestion. Age differences in urinary water and sodium excretion could not account for the age differences in accumulated water and sodium balances. These results extend observations of diminished behavioral responses of aging animals to the F344xBN rat strain and support the idea that impairments in behavior contribute more to the waning ability of aging animals to respond to body fluid challenges than do declines in kidney function. In addition, the results suggest that behavioral defense of sodium homeostasis is less diminished with age in the F344xBN strain compared to other strains so far studied. PMID:24952266

  11. Implications of IODP Expedition 349 Age Results for the Spreading History of the South China Sea

    NASA Astrophysics Data System (ADS)

    Briais, Anne

    2016-04-01

    The International Ocean Discovery Program (IODP) Expedition 349 in the South China Sea drilled three sites (U1431, U1433, and U1434) into the basaltic crustal basement near the fossil spreading center in the East and Southwest Subbasins. These results provided age constraints on the termination of seafloor spreading in the South China Sea (SCS) basin. Shipboard biostratigraphic analysis of microfossils from the sediment immediately above or between flows in the basaltic basement indicates early Miocene ages: 16.7-17.6 Ma for Site U1431 in the East Subbasin, ~18-21 Ma for Site U1433 in the Southwest Subbasin. Since Expedition 349, Ar/Ar dating of basalt samples from these two sites have confirmed these ages in the east, and have provided an age of 17 Ma in the Southwest. The similarity in crustal age between sites suggests that the last stages of spreading have been coeaval in both the East and Southwest Subbasins, forming a single mid-ocean ridge system with a series of transform faults and discontinuities between the two subbasins. Expedition 349 also drilled Site U1435 on a bathymetric high along the northwestern continent-ocean boundary. Onboard core description, biostratigraphy and magnetostratigraphy revealed that sediment at this site shows a sharp discontinuity at about 33 Ma, interpreted to represent the breakup unconformity and date the beginning of seafloor spreading in the East Subbasin. The results of IODP Exp. 349, as well as results from deep-towed magnetic surveys, thus imply that oceanic seafloor spreading in the SCS, from 33 to ~16-18 Ma, is coeval with a large part of the left-lateral motion along the Ailao Shan-Red River Fault Zone (dated 34 to 17 Ma). This episode of the extension of the South China Sea basin is therefore more likely driven by the extrusion of the Indochina tectonic block resulting from the collision of India with Eurasia than by the subduction of a proto-South China Sea to the south.

  12. Growth rate and age distribution of deep-sea black corals in the Gulf of Mexico

    USGS Publications Warehouse

    Prouty, N.G.; Roark, E.B.; Buster, N.A.; Ross, S.W.

    2011-01-01

    Black corals (order Antipatharia) are important long-lived, habitat-forming, sessile, benthic suspension feeders that are found in all oceans and are usually found in water depths greater than 30 m. Deep-water black corals are some of the slowest-growing, longest-lived deep-sea corals known. Previous age dating of a limited number of black coral samples in the Gulf of Mexico focused on extrapolated ages and growth rates based on skeletal 210Pb dating. Our results greatly expand the age and growth rate data of black corals from the Gulf of Mexico. Radiocarbon analysis of the oldest Leiopathes sp. specimen from the upper De Soto Slope at 300 m water depth indicates that these animals have been growing continuously for at least the last 2 millennia, with growth rates ranging from 8 to 22 µm yr–1. Visual growth ring counts based on scanning electron microscopy images were in good agreement with the 14C-derived ages, suggestive of annual ring formation. The presence of bomb-derived 14C in the outermost samples confirms sinking particulate organic matter as the dominant carbon source and suggests a link between the deep-sea and surface ocean. There was a high degree of reproducibility found between multiple discs cut from the base of each specimen, as well as within duplicate subsamples. Robust 14C-derived chronologies and known surface ocean 14C reservoir age constraints in the Gulf of Mexico provided reliable calendar ages with future application to the development of proxy records.

  13. Salt tectonics, a controlling factor on the development of the Marseilles and Grand-Rhone sedimentary ridges, Gulf of Lions, western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    dos Reis, Antonio Tadeu; Gorini, Christian; Mauffret, Alain; Weibull, Wiktor

    2004-02-01

    The Marseilles (also called Marseilles/Planier) and Grand Rhone sedimentary ridges, offshore the Gulf of Lions, western Mediterranean Sea, are generated by sediment spillover funnelled by the Marseilles and Grand-Rhone canyons, respectively. We show that the Marseilles and Grand-Rhone canyon directions are tectonically conditioned by Plio-Quaternary salt-induced sea-floor relief. Overburden extension in the area created an assemblage of listric faults running parallel to the strike of the continental margin. This salt-induced topography resulted in accentuated fault scarps impacting the sea-floor morphology and forcing submarine valleys to deflect to the east. Gravity-induced extension equally influenced the morphological pattern of the valley overbanking deposits. Sediment spillover occurred on both flanks of the canyons, but because active faulting generated space accommodation for overflow deposits, it inhibited the development of typical levee morphology along the canyons' left flanks. To cite this article: A.T. dos Reis, C. R. Geoscience 336 (2004).

  14. Large spatial variations in coastal 14C reservoir age - a case study from the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Lougheed, B. C.; Filipsson, H. L.; Snowball, I.

    2013-02-01

    Coastal locations are highly influenced by input from freshwater river runoff, including sources of terrestrial carbon, which can be expected to modify the 14C reservoir age, or R(t), associated with marine water. In this Baltic Sea case study, pre-bomb museum collection mollusc shells of known calendar age, from 30 locations across a strategic salinity transect of the Baltic Sea, were analysed for 14C, δ13C and δ18O. R(t) was calculated for all 30 locations. Seven locations, of which six are within close proximity of the coast, were found to have relatively higher R(t) values, indicative of hard-water effects. δ13Caragonite values were found to be indicative of hard-water influence only for certain locations, suggesting the possibility of different sources of old carbon in different locations. Whenever possible, the Macoma genus of mollusc was selected from the museum collections, in order to exclude species specific reservoir age effects as much as possible. When the Macoma samples are exclusively considered, and samples from hard-water locations excluded, a statistically significant correlation between Macoma R(t) and average salinity is found, indicating a two end-member linear mixing model between 14Cmarine and 14Crunoff. A map of Baltic Sea Macoma aragonite R(t) for the late 19th and early 20th centuries is produced. Such a map can provide an estimate for contemporary Baltic Sea Macoma R(t), although one must exercise caution when applying such estimates back in time or to 14C dates obtained from different sample material. A statistically significant correlation is also found between δ18Oaragonite and Macoma R(t), suggesting that δ18Oaragonite can be used to estimate Macoma palaeo-R(t). The results of this Baltic Sea case study, which show that R(t) is affected by hydrographic conditions and local carbon inputs, have important consequences for other coastal and estuarine locations, where R(t) is also likely to significantly vary on spatial and temporal

  15. Year-round records of sea salt, gaseous, and particulate inorganic bromine in the atmospheric boundary layer at coastal (Dumont d'Urville) and central (Concordia) East Antarctic sites

    NASA Astrophysics Data System (ADS)

    Legrand, Michel; Yang, Xin; Preunkert, Susanne; Theys, Nicolas

    2016-01-01

    Multiple year-round records of bulk and size-segregated compositions of aerosol were obtained at the coastal Dumont d'Urville (DDU) and inland Concordia sites located in East Antarctica. They document the sea-salt aerosol load and composition including, for the first time in Antarctica, the bromide depletion of sea-salt aerosol relative to sodium with respect to seawater. In parallel, measurements of bromide trapped in mist chambers and denuder tubes were done to investigate the concentrations of gaseous inorganic bromine species. These data are compared to simulations done with an off-line chemistry transport model, coupled with a full tropospheric bromine chemistry scheme and a process-based sea-salt production module that includes both sea-ice-sourced and open-ocean-sourced aerosol emissions. Observed and simulated sea-salt concentrations sometime differ by up to a factor of 2 to 3, particularly at DDU possibly due to local wind pattern. In spite of these discrepancies, both at coastal and inland Antarctica, the dominance of sea-ice-related processes with respect to open ocean emissions for the sea-salt aerosol load in winter is confirmed. For summer, observations and simulations point out sea salt as the main source of gaseous inorganic bromine species. Investigations of bromide in snow pit samples do not support the importance of snowpack bromine emissions over the Antarctic Plateau. To evaluate the overall importance of the bromine chemistry over East Antarctica, BrO simulations were also discussed with respect data derived from GOME-2 satellite observations over Antarctica.

  16. Simple approximations for estimating quickly the motion and timing of salt diapir rise, overhang development, and associated thermal anomalies using present-day observations: Case history from the Gulf of Mexico and Danish North Sea

    SciTech Connect

    Lerche, I. ); Thomsen, R.O. )

    1993-09-01

    Estimates of the upward motion of salt, due solely to buoyancy forces, through deposited and depositing sedimentary cover can be split into several parts: the critical thickness of sedimentary cover necessary to cause an underlying salt to become buoyant; the critical thickness of sedimentary cover necessary for a salt diapir to reach the sediment mudline in the absence of an impeding pressure of competent sediments opposing salt rise and in the absence of significant overpressure (both differential impedance and differential overpressure will slow the rise of the salt to the mudline); the effective speed of motion of the salt through the nonimpeding sediments during the salt's buoyant-ascent phase; current observed salt-top depth below mudline versus nonimpeded predicted salt-top depth leading to (a) minimum estimate of mechanical strength of competent resistive layers, and (b) an approximate estimate of buoyancy pressure of salt attempting to penetrate the resistive cover layer; uplift estimate of the overlying competent sediments because of the buoyancy pressure, in relation to observed uplift, leading to an estimate of salt-diapir rise speed since reaching the impeding formation; timing estimates of [open quotes]mushroom cap[close quotes] development of salt since emplacement of the resistive overlying layer and an estimate of the lateral competence of sedimentary beds ahead of the mushroom-salt sheet cap as a consequence of the observed mushroom extent; an estimate of evolving thermal anomalies around the dynamic salt/sediment system as a consequence of high-salt thermal conductivity. Such simple rough estimation methods are important in assessing the local and regional factors influencing the dynamic, thermal, and hydrocarbon retention factors in basinal sediments influenced by salt. Examples from the Gulf of Mexico and the Danish North Sea illustrate how to use both seismic and/or downhole data to perform the simple estimates.

  17. Determination of the age distribution of sea ice from Lagrangian observations of ice motion

    SciTech Connect

    Kwok, R.; Cunningham, G.F.; Rothrock, D.A.; Stern, H.L.

    1995-03-01

    A procedure for monitoring the local age distribution of the Arctic sea ice cover is presented. The age distribution specifies the area covered by ice in different age classes. In the authors` approach, a regular array of grid points is defined initially on the first image of a long time series, and an ice tracker finds the positions of those points in all subsequent images of the series. These Lagrangian points mark the corners of a set of cells that move and deform with the ice cover. The area of each cell changes with each new image or time step. A positive change indicates that ice in a new age class was formed in the cell. A negative change is assumed to have ridged the youngest ice in the cell, reducing its area. The ice in each cell ages as it progresses through the time series. The area of multiyear ice in each cell is computed using an ice classification algorithm. Any area that is not accounted for by the young ice or multiyear ice is assigned to a category of older first-year ice. They thus have a fine age resolution in the young end of the age distribution, and coarse resolution for older ice. The age distribution of the young ice can be converted to a thickness distribution using a simple empirical relation between accumulated freezing-degree days and ice thickness, or using a more complicated thermodynamic model. They describe a general scheme for implementing this procedure for the Arctic Ocean from fall freeze-up until the onset of melt in the spring. The concept is illustrated with a time series of five ERS-1 SAR images spanning a period of 12 days. Such a scheme could be implemented with RADARSAT SAR imagery to provide basin-wide ice age and thickness information.

  18. Effects of a rainstorm high in sea-salts on labile inorganic aluminium in drainage from the acidified catchments of Lake Terjevann, southernmost Norway

    NASA Astrophysics Data System (ADS)

    Andersen, D. O.; Seip, H. M.

    1999-10-01

    The acidification of many streams and lakes that has occurred in southern Norway during several decades is to a large extent caused by acid deposition. However, in coastal areas deposition events with high loading of sea-salts may result in increased acidity and aluminium concentration in the discharge. Since such episodes are difficult to predict and usually of short duration, the aluminium chemistry during such episodes has so far not been evaluated in detail. In January 1993, during monitoring of streams in the Lake Terjevann catchment, the area was exposed to an extraordinary high sea-salt loading. The Cl - concentration in the stream water more than doubled (reaching about 900 μeq/l), the labile inorganic aluminium (Al i) concentration almost quadrupled (reaching about 33 and 18 μM in the two streams), and the relative increase in the Al 3+ concentration was even higher. It took 3-4 months until the Al i concentration and almost a year until the Cl - concentration returned to pre-event levels. Simple equilibria with minerals such as gibbsite, jurbanite, kaolinite/halloysite or imogolite do not control aluminium concentration in the discharge from these catchments. Retention of Na + more than compensated for the desorption of Al 3+. The results strongly indicate that cation exchange in the organic soil layers was essential in controlling the aluminium chemistry in the stream waters especially during high flow. Similar, but less pronounced, effects of the sea-salt episode were seen at the Birkenes catchment about 37 km inland from Lake Terjevann.

  19. Importance of biogeomorphic and spatial properties in assessing a tidal salt marsh vulnerability to sea-level rise

    USGS Publications Warehouse

    Thorne, Karen M.; Elliott-Fisk, Deborah L.; Wylie, Glenn D.; Perry, William M.; Takekawa, John Y.

    2014-01-01

    We evaluated the biogeomorphic processes of a large (309 ha) tidal salt marsh and examined factors that influence its ability to keep pace with relative sea-level rise (SLR). Detailed elevation data from 1995 and 2008 were compared with digital elevation models (DEMs) to assess marsh surface elevation change during this time. Overall, 37 % (113 ha) of the marsh increased in elevation at a rate that exceeded SLR, whereas 63 % (196 ha) of the area did not keep pace with SLR. Of the total area, 55 % (169 ha) subsided during the study period, but subsidence varied spatially across the marsh surface. To determine which biogeomorphic and spatial factors contributed to measured elevation change, we collected soil cores and determined percent and origin of organic matter (OM), particle size, bulk density (BD), and distance to nearest bay edge, levee, and channel. We then used Akaike Information Criterion (AICc) model selection to assess those variables most important to determine measured elevation change. Soil stable isotope compositions were evaluated to assess the source of the OM. The samples had limited percent OM by weight (-3, indicating that the soils had high mineral content with a relatively low proportion of pore space. The most parsimonious model with the highest AICc weight (0.53) included distance from bay's edge (i.e., lower intertidal) and distance from levee (i.e., upper intertidal). Close proximity to sediment source was the greatest factor in determining whether an area increased in elevation, whereas areas near landward levees experienced subsidence. Our study indicated that the ability of a marsh to keep pace with SLR varied across the surface, and assessing changes in elevation over time provides an alternative method to long-term accretion monitoring. SLR models that do not consider spatial variability of biogeomorphic and accretion processes may not correctly forecast marsh drowning rates, which may be especially true in modified and urbanized

  20. A spatial age-structured model for describing sea lamprey (Petromyzon marinus) population dynamics

    USGS Publications Warehouse

    Robinson, Jason M.; Wilberg, Michael J.; Adams, Jean V.; Jones, Michael L.

    2013-01-01

    The control of invasive sea lampreys (Petromyzon marinus) presents large scale management challenges in the Laurentian Great Lakes. No modeling approach has been developed that describes spatial dynamics of lamprey populations. We developed and validated a spatial and age-structured model and applied it to a sea lamprey population in a large river in the Great Lakes basin. We considered 75 discrete spatial areas, included a stock-recruitment function, spatial recruitment patterns, natural mortality, chemical treatment mortality, and larval metamorphosis. Recruitment was variable, and an upstream shift in recruitment location was observed over time. From 1993–2011 recruitment, larval abundance, and the abundance of metamorphosing individuals decreased by 80, 84, and 86%, respectively. The model successfully identified areas of high larval abundance and showed that areas of low larval density contribute significantly to the population. Estimated treatment mortality was less than expected but had a large population-level impact. The results and general approach of this work have applications for sea lamprey control throughout the Great Lakes and for the restoration and conservation of native lamprey species globally.

  1. Salt: a sacred substance.

    PubMed

    De Santo, N G; Bisaccia, C; De Santo, R M; De Santo, L S; Petrelli, L; Gallo, L; Cirillo, M; Capasso, G

    1997-11-01

    Salt is the last relic of the ocean where life was born. Its presence has influenced the whole gamut of history and its name is linked to hundred of geographical locations. Its importance for nutrition is supported by the discovery of Aeneolithic salt cellars. Salt cellars and pyramids of salt have been included in paintings and other works of art. In Japan where salt was and still is obtained from the sea, a salt culture has developed that can be traced in the rituals of everyday life, including meal preparation, sports, and Shinto ceremonies. PMID:9350697

  2. Controls on the age of vascular plant biomarkers in Black Sea sediments

    NASA Astrophysics Data System (ADS)

    Kusch, Stephanie; Rethemeyer, Janet; Schefuß, Enno; Mollenhauer, Gesine

    2010-12-01

    Transfer of organic carbon (OC) from the terrestrial to the oceanic carbon pool is largely driven by riverine and aeolian transport. Before transport, however, terrigenous organic matter can be retained in intermediate terrestrial reservoirs such as soils. Using compound-specific radiocarbon analysis of terrigenous biomarkers their average terrestrial residence time can be evaluated. Here we show compound-specific radiocarbon ( 14C) ages of terrigenous biomarkers and bulk 14C ages accompanied by geochemical proxy data from core top samples collected along transects in front of several river mouths in the Black Sea. 14C ages of long chain n-alkanes, long chain n-fatty acids and total organic carbon (TOC) are highest in front of the river mouths, correlating well with BIT (branched and isoprenoid tetraether) indices, which indicates contribution of pre-aged, soil-derived terrigenous organic matter. The radiocarbon ages decrease further offshore towards locations where organic matter is dominated by marine production and aeolian input potentially contributes terrigenous organic matter. Average terrestrial residence times of vascular plant biomarkers deduced from n-C 29+31 alkanes and n-C 28+30 fatty acids ages from stations directly in front of the river mouths range from 900 ± 70 years to 4400 ± 170 years. These average residence times correlate with size and topography in climatically similar catchments, whereas the climatic regime appears to control continental carbon turnover times in morphologically similar drainage areas of the Black Sea catchment. Along-transect data imply petrogenic contribution of n-C 29+31 alkanes and input via different terrigenous biomarker transport modes, i.e., riverine and aeolian, resulting in aged biomarkers at offshore core locations. Because n-C 29+31 alkanes show contributions from petrogenic sources, n-C 28+30 fatty acids likely provide better estimates of average terrestrial residence times of vascular plant biomarkers

  3. Improved age constraints for the retreat of the Irish Sea Ice Stream

    NASA Astrophysics Data System (ADS)

    Smedley, Rachel; Chiverrell, Richard; Duller, Geoff; Scourse, James; Small, David; Fabel, Derek; Burke, Matthew; Clarke, Chris; McCarroll, Danny; McCarron, Stephen; O'Cofaigh, Colm; Roberts, David

    2016-04-01

    BRITICE-CHRONO is a large (> 45 researchers) consortium project working to provide an extensive geochronological dataset constraining the rate of retreat of a number of ice streams of the British-Irish Ice Sheet following the Last Glacial Maximum. When complete, the large empirical dataset produced by BRITICE-CHRONO will be integrated into model simulations to better understand the behaviour of the British-Irish Ice Sheet in response to past climate change, and provide an analogue for contemporary ice sheets. A major feature of the British-Irish Ice Sheet was the dynamic Irish Sea Ice Stream, which drained a large proportion of the ice sheet and extended to the proposed southern limit of glaciation upon the Isles of Scilly (Scourse, 1991). This study will focus on a large suite of terrestrial samples that were collected along a transect of the Irish Sea basin, covering the line of ice retreat from the Isles of Scilly (50°N) in the south, to the Isle of Man (54°N) in the north; a distance of 500 km. Ages are determined for both the eastern and western margins of the Irish Sea using single-grain luminescence dating (39 samples) and terrestrial cosmogenic nuclide dating (10 samples). A Bayesian sequence model is then used in combination with the prior information determined for deglaciation to integrate the geochronological datasets, and assess retreat rates for the Irish Sea Ice Stream. Scourse, J.D., 1991. Late Pleistocene stratigraphy and palaeobotany of the Isles of Scilly. Philosophical Transactions of the Royal Society of London B334, 405 - 448.

  4. On the age of the Mangyshlakian deposits of the northern Caspian Sea

    NASA Astrophysics Data System (ADS)

    Bezrodnykh, Yuri P.; Sorokin, Valentin M.

    2016-03-01

    The distribution, sedimentology, and age of early Holocene Mangyshlakian deposits beneath the northern Caspian Sea are studied. Analyses and interpretations derive from high-resolution sub-bottom profiling, lithological analysis of core sections and boreholes, biostratigraphic analysis of mollusc shells, and radiocarbon dating. We show that the Mangyshlakian deposits overlie Upper Pleistocene Khvalynian deposits, filling valleys and depressions that formed during lower water levels, similar to present lacustrine water bodies (ilmeni) of the Volga Delta. Transgressive marine Holocene Neo-Caspian sediments that are filling facies overlie the Mangyshlakian deposits. The deposits are composed of both organogenous and terrigenous materials. The flora and fauna in the sediment indicate deposition into freshwater, differing from marine biota in the underlying and overlying sediments. Eighteen radiocarbon ages indicate that the Mangyshlakian deposits accumulated between 9 and 12 ka.

  5. Ar-Ar Age Distributions of Glacially Derived Hornblende Grains in the Eastern Weddell Sea

    NASA Astrophysics Data System (ADS)

    Dahlhauser, E. M.; Pierce, E. L.; Hemming, S. R.; Williams, T.; Steponaitis, E. A.; Brachfeld, S. A.

    2010-12-01

    How the East Antarctic Ice Sheet has responded to past changes in climate is an important question in paleo- and future-climate research. Subglacial water is increasingly recognized as a major weakness that allows the destabilization of glaciers, and thus an important avenue of provenance research around Antarctica is to characterize the composition of glaciogenic detritus on the perimeter of Antarctica downstream from large subglacial lakes. For this study we use the Ar-Ar method to date detrital hornblendes from thirteen marine sediment cores from the Eastern Weddell Sea and off the coast of Dronning Maud Land. This area could be an important iceberg source in some climate conditions due to its proximity to the Recovery Subglacial Basin (Bell et al., 2007, Nature), a potential weak spot in the ice sheet. Research conducted by Roy et al., (2007, Chemical Geology) and Williams et al., (2010, EPSL) demonstrates that Ar-Ar of glacially derived detrital hornblende grains from marine sediments can be used: 1) to characterize Antarctica’s subglacial geology and 2) as a sedimentary provenance tool to study Antarctic Ice Sheet dynamics. The purpose of this project is to learn more about the subglacial geology around the Eastern Weddell Sea by characterizing the composition of ice rafted detritus (IRD). The relatively high closure temperature of Ar-Ar in hornblende (~500°C) allows this system to record the last major tectonothermal event to effect a body of Antarctic rock such as orogenic metamorphism or, often, initial crystallization from magma. The detrial hornblende ages are consistent with limited on-land ages showing dominant populations of 400-600 Ma, 900-1100 Ma, and 2800-3200 Ma. These ages correspond to the Pan-African, Grenville, and Humboldt orogenies respectively. Comparison of the Ar-Ar ages and the core sites’ proximities to the ice streams and ice divides allows us to determine the likely source areas. The ~500 Ma population to corresponds to the

  6. The role of elevation, relative sea-level history and vegetation transition in determining carbon distribution in Spartina alterniflora dominated salt marshes

    NASA Astrophysics Data System (ADS)

    Kulawardhana, Ranjani W.; Feagin, Rusty A.; Popescu, Sorin C.; Boutton, Thomas W.; Yeager, Kevin M.; Bianchi, Thomas S.

    2015-03-01

    Spartina alterniflora salt marshes are among the most productive ecosystems on earth, and represent a substantial global carbon sink. Understanding the spatial heterogeneity in the distribution of both above- and below-ground carbon in these wetland ecosystems is especially important considering their potential in carbon sequestration projects, as well as for conservation efforts in the context of a changing climate and rising sea-level. Through the use of extensive field sampling and remote sensing data (Light Detection and Ranging - LiDAR, and aerial images), we sought to map and explain how vegetation biomass and soil carbon are related to elevation and relative sea-level change in a S. alterniflora dominated salt marsh on Galveston Island, Texas. The specific objectives of this study were to: 1) understand the relationship between elevation and the distribution of salt marsh vegetation percent cover, plant height, plant density, above-and below-ground biomass, and carbon, and 2) evaluate the temporal changes in relative sea-level history, vegetation transitions, and resulting changes in the patterns of soil carbon distribution. Our results indicated a clear zonation of terrain and vegetation characteristics (i.e., height, cover and biomass). In the soil profile, carbon concentrations and bulk densities showed significant and abrupt change at a depth of ∼10-15 cm. This apparent transition in the soil characteristics coincided temporally with a transformation of the land cover, as driven by a rapid increase in relative sea-level around this time at the sample locations. The amounts of soil carbon stored in recently established S. alterniflora intertidal marshes were significantly lower than those that have remained in situ for a longer period of time. Thus, in order to quantify and predict carbon in coastal wetlands, and also to understand the heterogeneity in the spatial distribution of carbon stocks, it is essential to understand not only the elevation, the

  7. Effects of age, colony, and sex on mercury concentrations in California sea lions

    USGS Publications Warehouse

    McHuron, Elizibeth A; Peterson, Sarah H.; Ackerman, Josh; Melin, Sharon R.; Harris, Jeffrey D.; Costa, Daniel P.

    2016-01-01

    We measured total mercury (THg) concentrations in California sea lions (Zalophus californianus) and examined how concentrations varied with age class, colony, and sex. Because Hg exposure is primarily via diet, we used nitrogen (δ 15N) and carbon (δ 13C) stable isotopes to determine if intraspecific differences in THg concentrations could be explained by feeding ecology. Blood and hair were collected from 21 adult females and 57 juveniles from three colonies in central and southern California (San Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged from 0.01 to 0.31 μg g−1 wet weight (ww) in blood and 0.74 to 21.00 μg g−1 dry weight (dw) in hair. Adult females had greater mean THg concentrations than juveniles in blood (0.15 vs. 0.03 μg−1 ww) and hair (10.10 vs. 3.25 μg−1 dw). Age class differences in THg concentrations did not appear to be driven by trophic level or habitat type because there were no differences in δ 15N or δ 13C values between adults and juveniles. Total Hg concentrations in adult females were 54 % (blood) and 24 % (hair) greater in females from San Miguel than females from San Nicolas Island, which may have been because sea lions from the two islands foraged in different areas. For juveniles, we detected some differences in THg concentrations with colony and sex, although these were likely due to sampling effects and not ecological differences. Overall, THg concentrations in California sea lions were within the range documented for other marine mammals and were generally below toxicity benchmarks for fish-eating wildlife.

  8. Effects of Age, Colony, and Sex on Mercury Concentrations in California Sea Lions.

    PubMed

    McHuron, Elizabeth A; Peterson, Sarah H; Ackerman, Joshua T; Melin, Sharon R; Harris, Jeffrey D; Costa, Daniel P

    2016-01-01

    We measured total mercury (THg) concentrations in California sea lions (Zalophus californianus) and examined how concentrations varied with age class, colony, and sex. Because Hg exposure is primarily via diet, we used nitrogen (δ (15)N) and carbon (δ (13)C) stable isotopes to determine if intraspecific differences in THg concentrations could be explained by feeding ecology. Blood and hair were collected from 21 adult females and 57 juveniles from three colonies in central and southern California (San Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged from 0.01 to 0.31 μg g(-1) wet weight (ww) in blood and 0.74 to 21.00 μg g(-1) dry weight (dw) in hair. Adult females had greater mean THg concentrations than juveniles in blood (0.15 vs. 0.03 μg(-1) ww) and hair (10.10 vs. 3.25 μg(-1) dw). Age class differences in THg concentrations did not appear to be driven by trophic level or habitat type because there were no differences in δ (15)N or δ (13)C values between adults and juveniles. Total Hg concentrations in adult females were 54 % (blood) and 24 % (hair) greater in females from San Miguel than females from San Nicolas Island, which may have been because sea lions from the two islands foraged in different areas. For juveniles, we detected some differences in THg concentrations with colony and sex, although these were likely due to sampling effects and not ecological differences. Overall, THg concentrations in California sea lions were within the range documented for other marine mammals and were generally below toxicity benchmarks for fish-eating wildlife. PMID:26259982

  9. Estimating daily salt intake based on 24 h urinary sodium excretion in adults aged 18–69 years in Shandong, China

    PubMed Central

    Zhang, Ji-yu; Yan, Liu-xia; Tang, Jun-li; Ma, Ji-xiang; Guo, Xiao-lei; Zhao, Wen-hua; Zhang, Xiao-fei; Li, Jian-hong; Chu, Jie; Bi, Zhen-qiang

    2014-01-01

    Objective 24 h urinary sodium extretion was used to estimate the daily salt intake of shandong residents aged from 18 to 69 years in China. Setting 20 selected counties/districts in Shandong stratified by geographic region (Eastern, Central Southern and North Western) and residence type (urban vs rural). Participants Among 2184 randomly selected adults, 2061 provided usable 24 h urine samples. Urine volume <500 mL or male creatinine <3.81 (female creatinine <4.57) are not included in the analysis. Results The mean sodium level excreted over 24 h was 237.61 mmol (95% CI 224.77 to 250.44) mmol. Overall, the estimated mean salt intake was 13.90 g/day (95% CI 13.15 to 14.65). The mean salt intake among rural residents was higher than that among urban residents (14.00 vs 13.68 g; p<0.01). Salt intake in men was higher than that in women (14.40 vs 13.37 g; p<0.01). Approximately 96% of the survey participants had a dietary salt intake of ≥6 g/day. Conclusions The salt intake in Shandong is alarmingly higher than the current recommended amount (6 g/day). Thus, effective interventions to reduce salt intake levels to combat the increasing burden of non-communicable diseases need to be developed and implemented. PMID:25037642

  10. Microplastic Pollution in Table Salts from China.

    PubMed

    Yang, Dongqi; Shi, Huahong; Li, Lan; Li, Jiana; Jabeen, Khalida; Kolandhasamy, Prabhu

    2015-11-17

    Microplastics have been found in seas all over the world. We hypothesize that sea salts might contain microplastics, because they are directly supplied by seawater. To test our hypothesis, we collected 15 brands of sea salts, lake salts, and rock/well salts from supermarkets throughout China. The microplastics content was 550-681 particles/kg in sea salts, 43-364 particles/kg in lake salts, and 7-204 particles/kg in rock/well salts. In sea salts, fragments and fibers were the prevalent types of particles compared with pellets and sheets. Microplastics measuring less than 200 μm represented the majority of the particles, accounting for 55% of the total microplastics, and the most common microplastics were polyethylene terephthalate, followed by polyethylene and cellophane in sea salts. The abundance of microplastics in sea salts was significantly higher than that in lake salts and rock/well salts. This result indicates that sea products, such as sea salts, are contaminated by microplastics. To the best of our knowledge, this is the first report on microplastic pollution in abiotic sea products. PMID:26486565

  11. Thorium-230 ages of corals and duration of the last interglacial sea-level high stand on Oahu, Hawaii

    SciTech Connect

    Szabo, B.J.; Ludwig, K.R.; Muhs, D.R.; Simmons, K.R.

    1994-10-07

    Thorium-230 ages of emergent marine deposits on Oahu, Hawaii, have a uniform distribution of ages from {approximately}114,000 to {approximately}131,000 years, indicating a duration for the last interglacial sea-level high stand of {approximately}17,000 years, in contrast to a duration of {approximately}8000 years inferred from the orbitally tuned marine oxygen isotope record. Sea level on Oahu rose to {>=}1 to 2 meters higher than present by 131,000 years ago or {approximately}6000 years earlier than inferred from the marine record. Although the latter record suggests a shift back to glacial conditions beginning at {approximately}119,000 years ago, the Oahu coral ages indicate a near present sea level until {approximately}114,000 years ago.

  12. Phenotypic plasticity in age at first reproduction of female northern sea otters (Enhydra lutris kenyoni)

    USGS Publications Warehouse

    Von Biela, V.R.; Gill, V.A.; Bodkin, J.L.; Burns, Jennifer M.

    2009-01-01

    Life-history theory predicts that within a species, reproduction and survival rates will differ among populations that differ in resource availability or predation rates through phenotypic plasticity. When populations are near carrying capacity (K) or when they are declining due to reduced prey resources, the average age at 1st reproduction (average AFR) is predicted to be older than in populations below K. Differences between the trajectories of northern sea otter (Enhydra lutris kenyoni) populations in Alaska provides an opportunity to examine phenotypic plasticity. Using premolar teeth or reproductive tracts, we estimated average AFR from demographically distinct populations of sea otters in Alaska. We obtained samples from 2 populations near K, Prince William Sound (PWS) and the Aleutian Archipelago (archived samples), and from 2populations below K, the Kodiak Archipelago and Sitka. The average AFR was lower in populations below K (3.60 years ??0.16 SD)compared to those near K (4.21 ?? 0.13 years, P <0.001), and differed among all populations, with the Aleutian population possessing the oldest average AFR (4.29 ?? 0.09 years) followed by PWS (4.05 ?? 0.24 years), Sitka (3.80 ?? 0.21 years), and Kodiak (3.19 ?? 0.37 years). The difference in average AFR among populations supports life-history theory and provides evidence of phenotypic plasticity in sea otters. Our findings highlight the value of using average AFR as a tool for monitoring mammalian populations. ?? 2009 American Society of Mammalogists.

  13. Salinization forced anoxia in the Sea of Aral, the Dead Sea and the Urmia Lake: a temporal feature of the salt lakes development under the Global Change?

    NASA Astrophysics Data System (ADS)

    Yakushev, Evgeniy; Ghaffari, Peygham; Zavialov, Petr; Kurbaniyazov, Abilgazi

    2016-04-01

    The Sea of Aral is undergone a process of its volume decrease and salinization started about 30 years ago. In the remained now lake in the former deepest part of the Sea the salinity increased from about 8 PSU in 1990 to 120 PSU in the surface layer, and 240 PSU in the bottom layer in 2015. On top of an increase of salinity, there was formed a sulfidic zone in the bottom layer, that was separated from the upper layer by an extremely strong halocline (more than 50 PSU in 100 cm). The reason of this halocline might be an influx of the heavy high salinity water formed in summer in the shallower part of the Aral Sea to the bottom layer of the deeper part of the Sea through a strait between them. The similar processes could take place in the Urmia Lake, where salinity increased from 120 PSU in 2000 to about 350-400 PSU in 2015. This lake also consists from a shallow and deep parts connected by a channel in the dam, and where there was also reported anoxia. And finally, the Dead Sea demonstrates a further development happened after the shallower Southern part of the Sea was totally evaporated. After 1993 the vertical mixing started to occur down to the bottom layer, and the lake regime changed from meromictic to monomictic, that resulted in aeration of the bottom layer. In this work we compare interannual changes of the main salinity components in the 3 water bodies and analyze results of the vertical chemical structure of the Sea of Aral studied in 2015.

  14. Centuries of Human-Driven Change in Salt Marsh Ecosystems

    NASA Astrophysics Data System (ADS)

    Gedan, K. Bromberg; Silliman, B. R.; Bertness, M. D.

    2009-01-01

    Salt marshes are among the most abundant, fertile, and accessible coastal habitats on earth, and they provide more ecosystem services to coastal populations than any other environment. Since the Middle Ages, humans have manipulated salt marshes at a grand scale, altering species composition, distribution, and ecosystem function. Here, we review historic and contemporary human activities in marsh ecosystems—exploitation of plant products; conversion to farmland, salt works, and urban land; introduction of non-native species; alteration of coastal hydrology; and metal and nutrient pollution. Unexpectedly, diverse types of impacts can have a similar consequence, turning salt marsh food webs upside down, dramatically increasing top down control. Of the various impacts, invasive species, runaway consumer effects, and sea level rise represent the greatest threats to salt marsh ecosystems. We conclude that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management.

  15. Centuries of human-driven change in salt marsh ecosystems.

    PubMed

    Gedan, K Bromberg; Silliman, B R; Bertness, M D

    2009-01-01

    Salt marshes are among the most abundant, fertile, and accessible coastal habitats on earth, and they provide more ecosystem services to coastal populations than any other environment. Since the Middle Ages, humans have manipulated salt marshes at a grand scale, altering species composition, distribution, and ecosystem function. Here, we review historic and contemporary human activities in marsh ecosystems--exploitation of plant products; conversion to farmland, salt works, and urban land; introduction of non-native species; alteration of coastal hydrology; and metal and nutrient pollution. Unexpectedly, diverse types of impacts can have a similar consequence, turning salt marsh food webs upside down, dramatically increasing top down control. Of the various impacts, invasive species, runaway consumer effects, and sea level rise represent the greatest threats to salt marsh ecosystems. We conclude that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management. PMID:21141032

  16. Senile plaques and cerebral amyloid angiopathy in an aged California sea lion (Zalophus californianus).

    PubMed

    Takahashi, Erika; Kuribayashi, Hiroyuki; Chambers, James Kenn; Imamura, Emi; Une, Yumi

    2014-09-01

    Senile plaques (SPs) and cerebral amyloid angiopathy (CAA) consisting of β-amyloid (Aβ) are major features in the brain of Alzheimer's disease (AD) patients and elderly humans and animals. In this study, we report the finding of SPs and CAA in an aged sea lion (30 years), which is the first demonstration of AD-related pathological changes in a marine animal. Histologically, SPs were observed at the cerebral cortex, most frequently at the frontal lobe, with two morphologically different types: the small round type and the large granular type. Only the small round SPs were positive for Congo red staining. The SPs were equally immunoreactive to Aβ40 and Aβ42 and were mainly composed of Aβ with an N-terminal pyroglutamate residue at position 3. Amyloid depositions at vessel walls were noted at the meninges and within the parenchyma. Interestingly, double immunofluorescence staining for Aβ40 and Aβ42 showed that the two subtypes were deposited segmentally in different parts of the vessel walls. The lesions observed in the sea lion suggest that Aβ deposition is widely present in various animal species, including marine mammals; however, the peculiar deposits similar to cotton wool plaques and the specific pattern of CAA are characteristic features of this animal. PMID:24779910

  17. CONTRIBUTION FROM DEICING SALT TO CHEMICAL COMPOSITION OF SALT SUPPLYED TO AREA UNDER THE BRIDGES

    NASA Astrophysics Data System (ADS)

    Takebe, Masamichi; Ohya, Makoto; Hirose, Nozomu; Ochibe, Keishi; Aso, Toshihiko

    Salt is known to accelerate the corrosion of weathering steel bridges. The origin of salt around girders is valuable information in terms of the maintenance for anti-corrosion of steel bridges. Salt around girders generally originates from sea-salt and deicing salt. Since salt of both origin increases in winter, contribution of deicing salt is hard to be estimated only from fluctuation of total abundance of salt around the bridge. In this study, abundance of Mg2+ as well as that of Cl- in salt sampled under bridges is analyzed. As a result, this study revealed that the supply of deicing salt declines Mg2+/Cl- ratio of salt on the girder. In addition, examination of Mg2+/Cl- ratio of salt sampled under the examined bridge near sea revealed that the fluctuation of quantity of air-born salt under the bridge is ascribed to the fluctuation of supply of sea salt.

  18. Evolution of salt diapir and karst morphology during the last glacial cycle: Effects of sea-level oscillation, diapir and regional uplift, and erosion (Persian Gulf, Iran)

    NASA Astrophysics Data System (ADS)

    Bruthans, Jiří; Filippi, Michal; Zare, Mohammad; Churáčková, Zdenka; Asadi, Naser; Fuchs, Markus; Adamovič, Jiří

    2010-09-01

    Marine, fluvial and cave sediments, and karst phenomena were studied and dated by 14C, U-series, and OSL methods to determine the evolution of the Namakdan diapir and the world's longest salt cave (3N Cave) during the Holocene and the Last Glacial. Sea-level oscillations, the uplift rate of the diapir and its surroundings, and erosion are the main factors influencing the diapir morphology. Although the diapir uplift rate has been constant for the last 50 kyr (˜ 4 mm/yr at a distance 600 m from the diapir edge), the uplift rate decreases with the distance from the diapir center. Drag-induced host rock deformation extends for ˜ 300 m from the outside edge of the diapir, and host rocks in this zone have an uplift rate of 0.4-0.6 mm/yr, which is 2-3 times greater than the regional uplift rate. Based on known sea-level oscillations, radiometric dating, and geological evidence, the Namakdan diapir was repeatedly flooded by sea water between 130 and 80 kyr BP. Submarine residuum composed mainly of gypsum and dolomite formed cap rock on the diapir. After ˜ 80 kyr BP, surficial drainage network and karst development started. Blind valleys and their corresponding cave systems evolved continuously for ˜ 20-30 kyr. Between 9 and 6 cal kyr BP the rate of sea-level rise exceeded the Namakdan diapir uplift rate by the factor of 3. As a consequence upward incision of cave streams (paragenetic trend) occurred, and blind valleys near the seashore were filled with gravels. Cave passages now accessible on the Namakdan and Hormoz diapirs started to form 3-6 cal kyr BP when sea level stabilized and downward stream incision began. Older cave levels are still preserved but are filled with sediments and salt precipitates. A comparison of the Namakdan diapir evolution with data from the Hormoz and Larak diapirs shows that the evolution of diapir morphology is strongly affected by the differences in uplift rates and geological settings. The general scheme of the evolution of the Namakdan

  19. 40Ar-39Ar Age Constraints on Volcanism and Tectonism in the Terror Rift of the Ross Sea, Antarctica

    USGS Publications Warehouse

    2007-01-01

    Volcanic sills and dikes inferred from seismic reflection profiles and geophysical studies of the Ross Sea are thought to be related to the rift basins in the region, and their emplacement to be coeval with extension. However, lack of precise geochronology in the Terror Rift of the Ross Sea region has left these inferred relationships poorly constrained and has hindered neotectonic studies, because of the large temporal gaps between seismic reflectors of known ages. New 40Ar/39Ar geochronology presented here for submarine volcanic rocks provides better age constraints for neotectonic interpretations within the Terror Rift. Several samples from seamounts yielded young ages between 156 ± 21 and 122 ± 26 Ka. These ages support interpretations that extension within the Terror Rift was active at least through the Pleistocene. Three evenly spaced samples from the lowermost 100 m of Franklin Island range in age from 3.28 ± 0.04 to 3.73 ± 0.05 Ma. These age determinations demonstrate that construction of a small volcanic edifice such as Franklin Island took at least several hundred thousand years, and therefore that much larger ones in the Erebus Volcanic Province are likely to have taken considerably longer than previously inferred. This warrants caution in applying a limited number of age determinations to define the absolute ages of events in the Ross Sea region

  20. Age-specific reproduction in female sea otters (Enhydra lutris) from south-central Alaska: analysis of reproductive tracts

    USGS Publications Warehouse

    Bodkin, J.; Mulcahy, D.; Lensink, C.

    1993-01-01

    We estimated age at sexual maturity and age-specific reproductive rates by examining carcasses and reproductive tracts from 177 female sea otters (Enhydra lutris). Carcasses were recovered from south-central Alaska, Primarily from western Prince William Sound, as a result of the T/V Exxon Valdez oit spill in 1989. We found 65% of our sample to be sexually mature. Sexual maturity was first attained at age 2. The proportion of sexually mature animals increased from 30% at age 2 to 100% at age 5. Annual reproductive rates increased from 22% at age 2 to 78% at age 5 and remained relatively stable (75-88%) through to age 15. the sex ratio (female:male) of 49 fetal sea otters was 18:37 and differed significantly from parity. Females younger than 8 tended to produce more female fetuses, while older mothers did not. Our estimates of the reproductive characteristics of female sea otters obtained by examination of reproductive tracts wre similiar to those reported in the literature based on in situ observations of marked individuals.

  1. Distribution, stocks, and age structure of the invader Mya arenaria before and after mass mortalities in the Black Sea

    NASA Astrophysics Data System (ADS)

    Ivanov, D. A.

    2013-05-01

    The distribution, stocks, and age structure of the invader soft-shell clam Mya arenaria populations before and after the mass mortalities in the northwestern Black Sea have been studied from 1967 to 1987. At the prolonged influence of mortalities from 1973 to 1985, the number of age classes decreased from six in the period before the mortalities to three in 1985. The restoration of the stocks of Mya arenaria and the possibility of fishing these mollusks after the improvement of the ecological state in this part of the sea are predicted.

  2. Sea salt irradiation experiments relevant to the surface conditions of ocean worlds such as Europa and Enceladus

    NASA Astrophysics Data System (ADS)

    Hand, Kevin P.; Carlson, Robert W.

    2015-11-01

    We have conducted a set of laboratory experiments to measure changes in NaCl, KCl, MgCl2, and mixtures of these salts, as a function of exposure to the temperature, pressure, and radiation conditions relevant to ice covered ocean worlds in our solar system. Reagent grade salts were placed onto a diffuse aluminum target at the end of a cryostat coldfinger and loaded into an ultra-high vacuum chamber. The samples were then cooled to 100 K and the chamber pumped down to ~10-8 Torr, achieving conditions comparable to the surface of several moons of the outer solar system. Samples were subsequently irradiated with 10 keV electrons at an average current of 1 µA.We examined a range of conditions for NaCl including pure salts grains (~300 µm diameter), salt grains with water ice deposited on top, and evaporites. For the evaporites saturated salt water was loaded onto the cryostat target, the chamber closed, and then slowly pumped down to remove the water, leaving behind a salt evaporate for irradiation.The electron bombardment resulted in the trapping of electrons in halogen vacancies, yielding the the F- and M- color centers. After irraditiation we observed yellow-brown discoloration in NaCl. KCl was observed to turn a distinct violet. In NaCl these centers have strong absorptions at 450 nm and 720 nm, respectively, providing a highly diagnostic signature of otherwise transparent alkali halides, making it possible to remotely characterize and quantify the composition and salinity of ocean worlds.

  3. Constraints on the ages of mineralization and deformation in the Oquirrh Mountains, Salt Lake Co. , Utah

    SciTech Connect

    Presnell, R.D. ); Wilson, P.N.; Kroko, C.T.; Parry, W.T. )

    1993-04-01

    The Oquirrh Mountains are the easternmost range in the Basin and Range Province and have experienced several deformational events due to compressional and extensional tectonism. The Oquirrh Mountains contain two major mining districts: Bingham and Mercur. The Bingham porphry copper deposit has been dated at [approximately]39 Ma. The porphyry system contains mineralized NE trending faults which are cut by unmineralized NW trending faults. These two fault sets record two periods of Cenozoic extension in the Oquirrh Mountains: late Eocene and Miocene to recent. The Carlin-type Barneys Canyon gold deposit occurs 7.2 km northeast of the Bingham system on the northern flank of the Copperton anticline. Ages of illite-rich bedding plane gouges formed during growth of the Copperton anticline are late Jurassic. Alteration at Barneys Canyon includes decalcification, weak silicification, and argillization. Argillization consists of illite and kaolinite. The dated illite-rich gouges are gold bearing, have hydrothermal textures and are within the illite-rich argillic alteration zone associated with the orebody. The Carlin-type Mercur gold deposits occur on the east hinge of the Ophir anticline in the southern Oquirrh Mountains. K/Ar ages of illite veins and clay-sized separates range from 122 to 189 Ma and average 160 Ma. Vein attitudes are consistent with formation during growth of the Ophir anticline. Mineralization at Mercur is controlled by high-angle ENE and NNW faults which may have formed during growth of the Ophir anticline. These data suggest that compressional deformation and alteration/mineralization in the Mercur district and at Barneys Canyon are Late Jurassic in age.

  4. Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

    DOEpatents

    Maroni, Victor A.; von Winbush, Samuel

    1988-01-01

    A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

  5. Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

    DOEpatents

    Maroni, V.A.; von Winbush, S.

    1987-05-01

    A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

  6. Growth rates and ages of deep-sea corals impacted by the Deepwater Horizon oil spill

    USGS Publications Warehouse

    Prouty, Nancy G.; Fisher, Charles R.; Demopoulos, Amanda W. J.; Druffel, Ellen R. M.

    2016-01-01

    The impact of the April 2010 Deepwater Horizon (DWH) spill on deep-sea coral communities in the Gulf of Mexico (GoM) is still under investigation, as is the potential for these communities to recover. Impacts from the spill include observation of corals covered with flocculent material, with bare skeleton, excessive mucous production, sloughing tissue, and subsequent colonization of damaged areas by hydrozoans. Information on growth rates and life spans of deep-sea corals is important for understanding the vulnerability of these ecosystems to both natural and anthropogenic perturbations, as well as the likely duration of any observed adverse impacts. We report radiocarbon ages and radial and linear growth rates based on octocorals (Paramuricea spp. and Chrysogorgia sp.) collected in 2010 and 2011 from areas of the DWH impact. The oldest coral radiocarbon ages were measured on specimens collected 11 km to the SW of the oil spill from the Mississippi Canyon (MC) 344 site: 599 and 55 cal yr BP, suggesting continuous life spans of over 600 years for Paramuricea biscaya, the dominant coral species in the region. Calculated radial growth rates, between 0.34 μm yr−1 and 14.20 μm yr−1, are consistent with previously reported proteinaceous corals from the GoM. Anomalously low radiocarbon (Δ14C) values for soft tissue from some corals indicate that these corals were feeding on particulate organic carbon derived from an admixture of modern surface carbon and a low 14C carbon source. Results from this work indicate fossil carbon could contribute 5–10% to the coral soft tissue Δ14C signal within the area of the spill impact. The influence of a low 14C carbon source (e.g., petro-carbon) on the particulate organic carbon pool was observed at all sites within 30 km of the spill site, with the exception of MC118, which may have been outside of the dominant northeast-southwest zone of impact. The quantitatively assessed extreme longevity and slow growth rates documented

  7. Studies of sulfur biogeochemistry, microbiology and paleontology in three anoxic environments: The Black Sea, a salt marsh mat, and an Ordovician black shale

    SciTech Connect

    Muramoto, J.A.

    1992-01-01

    The author studied the biogeochemistry, microbial ecology and paleontology of three anoxic environments. In the Black Sea, three studies dealt with the role of particle fluxes in sulfur cycling and microbial ecology. In the water column, iron sulfides form at the oxic-anoxic interface from dissolved sulfide left after chemical oxidation, based on sulfur isotopes; formation in deep water is minimal and iron-limited. Sinking organic aggregates transport iron sulfides to the bottom. Sedimentary sulfides may originate from sulfide fluxes and record intensity of chemical vs. microbial oxidation at the oxic-anoxic interface. Sulfate reduction rates from modelled diagenesis of organic carbon fluxes agree with other measured rates. A box model summarizes sulfur cycling between water column and sediments. An algal sulfur compound, dimethylsulfoniopropionate (DMSP), precursor to dimethylsulfide (DMS), was measured in deep-sea particle fluxes. DMSP levels in particle fluxes vary seasonally and between oceans. Though DMSP is only 0.005% of organic carbon fluxes, its removal to the deep sea by fluxes may lessen sea-air DMS fluxes. A DMSP-DMS cycle for ocean and sediments is proposed. A third study compared bacteria biomass and morphology in particle fluxes and water column, using TEM and epifluorescence microscopy. Some bacteria had intracellular structures indicating autotrophy. Concentrations in particle fluxes were high compared to sediment bacteria populations elsewhere, but bacterial carbon is a tiny fraction of total organic carbon. In contrast, phototrophic bacteria dominated a microbial mat in a salt marsh where sulfate reduction is important. Cyanobacteria, purple and green sulfur bacteria species were strongly depth-zoned, and cell sizes decreased as depth increased. Also investigated was spatiotemporal change in a fossil lingulid brachiopod from a suboxic facies, using gradient analyses of benthic invertebrate and planktonic graptolite assemblages.

  8. What is the Age and Origin of the Spherule Bearing Layer in some Ross Sea Cores?

    NASA Astrophysics Data System (ADS)

    Yeh, C.; Abbott, D. H.; Anders, M. H.; Breger, D.

    2012-12-01

    L.P. Khyranina (1985) was the first to suggest that there were two structures present on the Antarctic continental shelf beneath the Ross Sea. One was the ~100 km Bowers impact crater candidate. However, there was no solid evidence that proved an extraterrestrial impact produced the Bowers structure. Debate has ensued for decades on whether the Bowers structure was an impact crater. Now we have come close to finding an answer. We used core samples taken near the crater and sieved into four size fractions (>250,>125,>63,>38 μm). Impact ejecta candidates were then picked from cores ELT 32-08, ELT 32-03, ELT 32-43, ELT 32-06, DSDP 273, DSDP 274, and NPB 95-01 39KC and were analyzed for chemical composition and physical features. All but DSDP site 274 contain pure SiO2 glasses that resemble tektites. We also found candidates for flow textured impact glass and shocked quartz. This led us to conclude that the origin of the spherule-bearing layer was from an impact. With the use of dated core NBP 95-01 39KC, we have constrained the age to lie between 7,305±80 BP and 11,150±95 BP (corrected radiocarbon ages) (Cunningham et al., 1999).

  9. Deciphering the Role of Climate and Sea-Level Changes on Observed Decadal-Scale Variability in Salt-Marsh Sedimentation.

    NASA Astrophysics Data System (ADS)

    Kolker, A. S.; Goodbred, S. L.; Cochran, J. K.; Beck, A.; Kroboth, T.

    2004-12-01

    We are investigating the controls that climate and local oceanography exert on sedimentation patterns in 4 salt marsh-estuary complexes around Long Island, New York, USA. These systems encompass a variety of physical settings, including a range of tidal conditions, wave fetches, and human influences, but are all located within one climatic regime. Within these settings, we hypothesize that sedimentation patterns in limited-fetch, mesotidal salt marshes are influenced most strongly by sea-level changes, as the system is largely steady-state under high-energy conditions and sedimentation should track the longer-term sea-level transgression. Conversely, sedimentation in microtidal systems with large fetch should better track atmospheric forcings, because marsh-surface accretion largely occurs during episodic wind and storm events. To test this hypothesis, accretion rates (cm/yr) were determined by applying a constant-flux model to profiles of excess 210Pb, which reveals temporal variation in sedimentation. Additionally, we examined the rate of mineral sediment deposition (g/cm2/yr) and rate of organic matter accumulation (g/cm2/yr). These measures yielded a chronology of sedimentation patterns ~100 years long with a temporal resolution of 2-5 years, sufficient for resolving decadal-scale oscillations. Our proxies for sea-level change come from a variety of tide gauges; including the gauge at Battery Park, NYC which covers much of the past century, as well as local tide gauges with records spanning several decades. Proxies used for atmospheric forcings include mean annual winds for the past 50 years, storm histories and Hurrel's index of the North Atlantic Oscillation, which extends for over a century. Initial results reveal clear decadal-scale variability in marsh accretion, with variations ranging 2-3 fold about the long-term mean. These oscillations are very similar in timing and magnitude to those observed for the climate proxies and sea-level records. However

  10. Laboratory studies of the sensitivity of tropospheric ozone to the chemistry of sea salt aerosol. Final report, September 15, 1993--September 14, 1994

    SciTech Connect

    Finlayson-Pitts, B.J.

    1994-11-15

    Ozone plays a critical role in both the chemistry and radiation balance of the troposphere. Understanding the factors controlling tropospheric ozone levels is critical to our understanding of a variety of issues in global chemistry and climate change. Chlorine atoms have the potential to contribute significantly to the ozone balance in the free troposphere. They can react directly with ozone or alternately, with organics and may actually lead to the formation of ozone in the presence of sufficient NO. Reactions of alkali halides in sea salt particles are a potential source of atomic chlorine, hence reactions of these alkali halides, especially those producing precursors to atomic chlorine, are of great interest. Finally, the mechanisms, intermediates and products of the Cl-biogenic reactions are unknown; these could serve as unique markers of chlorine atom chemistry in the troposphere, and hence are important to define.

  11. A Rapid Radiocarbon Method for Age Surveys of Southern Ocean Deep-sea Corals

    NASA Astrophysics Data System (ADS)

    Burke, A.; Robinson, L. F.; Gerlach, D. S.; Jenkins, W. J.; McNichol, A. P.

    2008-12-01

    Deep-sea corals provide a unique archive of past ocean radiocarbon because they are sessile and can be dated independently using U-series nuclides. One difficulty, however, is that using current techniques it is impractical to date large numbers of corals in order to determine which specimens have the appropriate ages for radiocarbon reconstructions. Here we present results from a quick method of making graphite for radiocarbon dating that reduces the amount of sample preparation time, thus allowing us to date a greater number of corals. In addition, these rapid age surveys provide important information on coral age populations, allowing us to examine coral distributions through time. The corals used in this study come from a sample set of about 6,000 specimens of Flabellum, Balanophyllia and Desmophyllum spp. collected from the Drake Passage area (50S -70S, 120 m-1700 m depth). Replicate samples from a single coral yielded a standard deviation of 81 years (n=9). Variations in sample mass (3 to 85 mg) have no clear effect on the Fm and furthermore, a simple cleaning using methanol yields the same results as a more involved cleaning procedure that includes an oxidizing solution and perchloric acid rinse. To improve the efficiency of the method, we assumed a delta13C = 0 per mil. This assumption is likely our largest source of uncertainty, resulting in offsets of up to 200 radiocarbon years over a reasonable range of delta13C. This level of uncertainty is sufficiently low to allow distinction between corals from different time periods over the past 35 ky (e.g. Last Glacial Maximum, Younger Dryas, etc.). To date, we have found corals from Burdwood Bank dating from the modern to the Younger Dryas and corals from the Drake Passage dating from the modern to Heinrich Event 1, which will be used in future paleo-climatic reconstructions in this important part of the ocean.

  12. Iodine Status of Women of Reproductive Age in Sierra Leone and Its Association with Household Coverage with Adequately Iodized Salt

    PubMed Central

    Rohner, Fabian; Wirth, James P.; Woodruff, Bradley A.; Chiwile, Faraja; Yankson, Hannah; Sesay, Fatmata; Koroma, Aminata S.; Petry, Nicolai; Pyne-Bailey, Solade; Dominguez, Elisa; Kupka, Roland; Hodges, Mary H.; de Onis, Mercedes

    2016-01-01

    Salt iodization programs are a public health success in tackling iodine deficiency. Yet, a large proportion of the world’s population remains at risk for iodine deficiency. In a nationally representative cross-sectional survey in Sierra Leone, household salt samples and women’s urine samples were quantitatively analyzed for iodine content. Salt was collected from 1123 households, and urine samples from 817 non-pregnant and 154 pregnant women. Household coverage with adequately iodized salt (≥15 mg/kg iodine) was 80.7%. The median urinary iodine concentration (UIC) of pregnant women was 175.8 µg/L and of non-pregnant women 190.8 µg/L. Women living in households with adequately iodized salt had higher median UIC (for pregnant women: 180.6 µg/L vs. 100.8 µg/L, respectively, p < 0.05; and for non-pregnant women: 211.3 µg/L vs. 97.8 µg/L, p < 0.001). Differences in UIC by residence, region, household wealth, and women’s education were much smaller in women living in households with adequately iodized salt than in households without. Despite the high household coverage of iodized salt in Sierra Leone, it is important to reach the 20% of households not consuming adequately iodized salt. Salt iodization has the potential for increasing equity in iodine status even with the persistence of other risk factors for deficiency. PMID:26848685

  13. Iodine Status of Women of Reproductive Age in Sierra Leone and Its Association with Household Coverage with Adequately Iodized Salt.

    PubMed

    Rohner, Fabian; Wirth, James P; Woodruff, Bradley A; Chiwile, Faraja; Yankson, Hannah; Sesay, Fatmata; Koroma, Aminata S; Petry, Nicolai; Pyne-Bailey, Solade; Dominguez, Elisa; Kupka, Roland; Hodges, Mary H; de Onis, Mercedes

    2016-02-01

    Salt iodization programs are a public health success in tackling iodine deficiency. Yet, a large proportion of the world's population remains at risk for iodine deficiency. In a nationally representative cross-sectional survey in Sierra Leone, household salt samples and women's urine samples were quantitatively analyzed for iodine content. Salt was collected from 1123 households, and urine samples from 817 non-pregnant and 154 pregnant women. Household coverage with adequately iodized salt (≥15 mg/kg iodine) was 80.7%. The median urinary iodine concentration (UIC) of pregnant women was 175.8 µg/L and of non-pregnant women 190.8 µg/L. Women living in households with adequately iodized salt had higher median UIC (for pregnant women: 180.6 µg/L vs. 100.8 µg/L, respectively, p < 0.05; and for non-pregnant women: 211.3 µg/L vs. 97.8 µg/L, p < 0.001). Differences in UIC by residence, region, household wealth, and women's education were much smaller in women living in households with adequately iodized salt than in households without. Despite the high household coverage of iodized salt in Sierra Leone, it is important to reach the 20% of households not consuming adequately iodized salt. Salt iodization has the potential for increasing equity in iodine status even with the persistence of other risk factors for deficiency. PMID:26848685

  14. Variations in the size distribution of non-sea-salt sulfate aerosol in the marine boundary layer at Barbados: Impact of African dust

    NASA Astrophysics Data System (ADS)

    Li-Jones, X.; Prospero, J. M.

    1998-01-01

    Four African mineral dust episodes occurred during a program of daily aerosol measurements at Barbados (13°15'N, 59°30'W) in April 1994. Non-sea-salt sulfate (nss SO4=) and dust were highly correlated (r2 = 0.93) and ranged from 0.5 to 4.2 μg m-3 and 0.9 to 257 μg m-3, respectively. Day-to-day variations in the size distributions of mineral dust and sea salt were relatively small. However, the coarse-particle (aerodynamic diameter > 1 μm) fraction (CPF) of nss SO4= varied substantially, from 21% to 73%. The highest CPF SO4= values were associated with dust events; the lowest CPF was associated with the air mass from the central North Atlantic when the dust concentration was lowest, 0.9 μg m-3. We suggest that large CPF SO4= values are a consequence of SO2 in European pollutants that heterogeneously react with the suspended dust over North Africa. Nonetheless, the association of pollutants and dust does not always result in a large CPF; low CPF values suggest that SO2 may have been oxidized to SO4= prior to mixing with dust-laden air. On those days when dust and pollution concentrations were low, the dominant source of nss SO4= was ascribed to oceanic dimethylsulfide (DMS) and the CPF remained close to 20%. Because such large variations can occur in the particle size distribution of nss SO4= in association with dust events, the role of mineral dust on nss SO4= size must be taken into account when estimating the impact of nss SO4= on radiation transfer in the atmosphere.

  15. Age and dynamics of the Namib Sand Sea: A review of chronological evidence and possible landscape development models

    NASA Astrophysics Data System (ADS)

    Stone, A. E. C.

    2013-06-01

    The Namib Sand Sea constitutes a major physiographic feature of the Namib Desert on the west of Namibia, covering a 50-160 km wide region of the coast between Lüderitz and Walvis Bay. It is widely considered to be one of the oldest desert regions, with a Tertiary-aged fossil desert underlying the modern sand sea. The sand sea has been well studied, benefiting from the presence of the Gobabeb Training and Research Centre during the past 50 years. Whilst much is understood about its sediments and geomorphology, it is only recently that new chronological information, using cosmogenic-nuclide burial dating and optically stimulated luminescence dating have offered new insights, and this calls for an updated review of the age and landscape development of the sand sea. This assessment of the geomorphological and Quaternary dynamics of the region is complemented by developments in the description and analysis of sediment composition. New age control from cosmogenic dating indicates that the sand sea is in excess of a million years old. Initial data from luminescence dating yields depositional ages for dune sediments from three broad areas of the sand sea that include MIS 5, later in the Pleistocene around the Last Glacial Maximum and the Holocene, although it is not expected that these will be the only, or discrete age groupings. Detailed dating and application of ground penetrating radar in the far northern reaches reveals extensive dune migration and deposition during the Holocene. It is important to stress that the upper limit of luminescence dating here is about ˜200 ka (depending on the environmental dose rate of the site) and that migration and reworking of dunes resets the luminescence signal (so what is recorded is(are) the last phase(s) of preserved sediment accumulation). Whilst there are three potential sources of material for the Namib Sand Sea (reworked Tsondab Sandstone (TSS), material from the Great Escarpment derived by rivers and water and wind

  16. Agricultural fingerprints in salt-marsh sediments and adaptation to sea-level rise in the eastern Cantabrian coast (N. Spain)

    NASA Astrophysics Data System (ADS)

    García-Artola, Ane; Cearreta, Alejandro; Irabien, María Jesús; Leorri, Eduardo; Sanchez-Cabeza, Joan-Albert; Corbett, D. Reide

    2016-03-01

    A multi-proxy approach based on benthic foraminifera, sand content, short-lived radioisotope activities, heavy metal concentrations and aerial photography was developed to characterise the process of human disturbance on the intensely impacted eastern Cantabrian coast (N. Spain) over the last two centuries. Analysis of two 50 cm long sediment cores from different saltmarshes in the Santoña estuary and their comparison with previous results in nearby coastal areas defines criteria to identify records of agricultural activities in salt-marsh sediments. Agricultural occupation of saltmarshes and the later regeneration was recognised based on foraminifera and sand content. Saltmarshes in the eastern Cantabrian coast are expected to adapt to ongoing sea-level rise based on the high sedimentation rates (14-18 mm yr-1) observed during the regeneration process of previously reclaimed areas. These findings can potentially be useful in other temperate saltmarshes with abundant sediment input, as a cost-effective adaptation measure to counteract the effects of sea-level rise.

  17. Sea level reconstructions and non-marine sedimentation at the Triassic-Jurassic boundary: southwestern margin of the Neotethys in the Salt Range, Pakistan

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Wagreich, Michael

    2016-04-01

    The environmental changes during the Triassic-Jurassic boundary interval and the associated mass extinction event are still strongly debated. Sea-level reconstruction records during this interval reveal an end-Triassic global regression event. Erosion and karstification at the top of Triassic sediments, and Lower Jurassic fluvial channels with reworked Triassic clasts indicate widespread regression in the European basins. Laterite at the top of the Triassic, and quartzose conglomerates/sandstones at the base of the Jurassic indicate a fluvial/terrestrial onset in Iran and Afghanistan. Abrupt emergence, erosion and facies dislocation, from the Triassic dolomites (Kingriali Formation) to Lower Jurassic fluvial/continental quartzose conglomerates/pebbly sandstones (Datta Formation) occur in the Tethyan Salt Range of Pakistan. Sedimentological analyses indicate marine regression and emergence under tropical-subtropical conditions (Greenhouse conditions) and negates the possibility of glacial influence in this region. Field evidences indicate the presence of an undulatory surface at the base of the Jurassic and a high (Sargodha High) is present south of the Salt Range Thrust, the southern boundary of the basin. Furthermore, geophysical data (mostly seismic sections) in different parts of the basin display normal faults in the basement. These features are interpreted as horst and graben structures at the Triassic-Jurassic boundary in the Kohat-Potwar Plateau. The Lower Jurassic Datta Formation appears to have been deposited in an overall graben fill settings. Similar normal faults and graben fill geometries are observed on seismic sections in Tanzania, Mozambique, Madagascar and other regions of the southeastern margin of the African Plate and are related to the Karoo rift system. To summarize, the basement normal faults and the graben fill features at the Triassic-Jurassic boundary in the Kohat-Potwar Plateau can be correlated to similar features common in the Karoo

  18. Effects of the North Atlantic Oscillation and wind waves on salt marsh dynamics in the Danish Wadden Sea: a quantitative model as proof of concept

    NASA Astrophysics Data System (ADS)

    Kim, Daehyun; Grant, William E.; Cairns, David M.; Bartholdy, Jesper

    2013-08-01

    Long-term eustatic sea-level variation has been recognized as a primary factor affecting the hydrological and geomorphic dynamics of salt marshes. However, recent studies suggest that wind waves influenced by atmospheric oscillations also may play an important role in many coastal areas. Although this notion has been conceptually introduced for the Wadden Sea, no modeling attempts have been made yet. As a proof of concept, this study developed a simulation model using the commercially available STELLA® software, based on long-term data on water level and sedimentation collected at a back-barrier marsh on the Skallingen peninsula in Denmark. In the model, the frequency (number year-1) of wind-driven extreme high water level (HWL) events (>130 cm Danish Ordnance Zero) was simulated in terms of the North Atlantic Oscillation (NAO) index. Then, surface accretion (cm year-1) and submergence duration (h year-1) were simulated for the period 1933-2007. The model showed good performances: simulated rates of surface accretion and simulated durations of submergence decreased from 1950 to 1980, the point at which the NAO shifted from its negative to its positive phase, and increased thereafter. Despite continuous increases in surface elevation, increases in simulated submergence duration were apparently due to wind-driven HWL events, which generally increased in frequency after 1980. These findings for the Danish Wadden Sea add to the growing body of evidence that the role of atmospheric oscillations—e.g., the NAO—as drivers of wind-generated water level variations merits more attention in assessing the impact of climate change on coastal marshes.

  19. Stability of salt in the Permian salt basin of Kansas, Oklahoma, Texas and New Mexico, with a section on dissolved salts in surface water

    USGS Publications Warehouse

    Bachman, George Odell; Johnson, Ross Byron

    1973-01-01

    The Permian salt basin in the Western Interior of the United States is defined as that region comprising a series of sedimentary basins in which halite and associated salts accumulated during Permian time. The region includes the western parts of Kansas, Oklahoma, and Texas, and eastern parts of Colorado and New Mexico. Following a long period of general tectonic stability throughout the region during most of early Paleozoic time, there was much tectonic activity in the area of the Permian salt basin during Late Pennsylvanian and Early Permian time just before bedded salt was deposited. The Early Permian tectonism was followed by stabilization of the basins in which the salt was deposited. These salt basins were neither contemporaneous nor continuous throughout the region, so that many salt beds are also discontinuous. In general, beds in the northern part of the basin (Kansas and northern Oklahoma) are older and the salt is progressively younger towards the south. Since Permian time the Permian salt basin has been relatively stable tectonically. Regionally, the area of the salt basin has been tilted and warped, has undergone periods of erosion, and has been subject to a major incursion of the sea; but deep-seated faults or igneous intrusions that postdate Permian salt are rare. In areas of the salt basin where salt is near the surface, such as southeastern New Mexico and central Kansas, there are no indications of younger deep-seated faulting and only a few isolated igneous intrusives of post-Permian age. On the other hand, subsidence or collapse of the land surface resulting from dissolution has been commonplace in the Permian salt basin. Some dissolution of salt deposits has probably been taking place ever since deposition of the salt more than 230 million years ago. Nevertheless, the subsurface dissolution fronts of the thick bedded-salt deposits of the Permian basin have retreated at a very slow average rate during that 230 million years. The preservation of

  20. The age of illite cement growth, Village Fields area, Southern North Sea: Evidence from K-Ar ages and [sup 18]O/[sup 16]O ratios

    SciTech Connect

    Robinson, A.G.; Coleman, M.L.; Gluyas, J.G. )

    1993-01-01

    In this paper we describe K-Ar radiometric ages and oxygen isotope ratio measurements of illite cements from eolian sandstone samples of the Permian lower Leman Sandstone Formation (Rotliegen-des Group). The samples come from a large (about 100 [times] 100 km) part of the Southern North Sea basin (Village Fields area) and from a range of burial depths (2.8-3.4 km subsea bed). Mean illite ages in the gas fields of Ravenspuran North (164 Ma [+-] 20.1 [2[sigma

  1. Maintenance of somatic tissue regeneration with age in short- and long-lived species of sea urchins.

    PubMed

    Bodnar, Andrea G; Coffman, James A

    2016-08-01

    Aging in many animals is characterized by a failure to maintain tissue homeostasis and the loss of regenerative capacity. In this study, the ability to maintain tissue homeostasis and regenerative potential was investigated in sea urchins, a novel model to study longevity and negligible senescence. Sea urchins grow indeterminately, regenerate damaged appendages and reproduce throughout their lifespan and yet different species are reported to have very different life expectancies (ranging from 4 to more than 100 years). Quantitative analyses of cell proliferation and apoptosis indicated a low level of cell turnover in tissues of young and old sea urchins of species with different lifespans (Lytechinus variegatus, Strongylocentrotus purpuratus and Mesocentrotus franciscanus). The ability to regenerate damaged tissue was maintained with age as assessed by the regrowth of amputated spines and tube feet (motor and sensory appendages). Expression of genes involved in cell proliferation (pcna), telomere maintenance (tert) and multipotency (seawi and vasa) was maintained with age in somatic tissues. Immunolocalization of the Vasa protein to areas of the tube feet, spines, radial nerve, esophagus and a sub-population of circulating coelomocytes suggests the presence of multipotent cells that may play a role in normal tissue homeostasis and the regenerative potential of external appendages. The results indicate that regenerative potential was maintained with age regardless of lifespan, contrary to the expectation that shorter lived species would invest less in maintenance and repair. PMID:27095483

  2. Age and Sex Composition of Seals Killed by Polar Bears in the Eastern Beaufort Sea

    PubMed Central

    Pilfold, Nicholas W.; Derocher, Andrew E.; Stirling, Ian; Richardson, Evan; Andriashek, Dennis

    2012-01-01

    Background Polar bears (Ursus maritimus) of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n = 650) and hunting attempts on ringed seal (Pusa hispida) lairs (n = 1396) observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985–2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. Principal Findings Polar bears primarily preyed on ringed seals (90.2%) while bearded seals (Erignathus barbatus) only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344) of the ringed seals killed, while their pups comprised 38.4% (132/344). Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344) of the ringed seal kills. The proportion of ringed seal pups was highest between 2007–2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥21 years (60/121), and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n = 78). The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r2 = 0.30, P = 0.04), but was not correlated with the number of adult kills (P = 0.37). Conclusions/Significance Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender. PMID:22829949

  3. Depositional features and source and reservoir rocks of Tertiary age in northern part of South China Sea

    SciTech Connect

    Wang, S.

    1986-07-01

    The northern part of the South China Sea covers an area of about 400,000 km/sup 2/. Tertiary deposits more than 10,000 m in thickness are widely distributed there. The area has sedimentary rocks more than 1000 m thick covers more than 300,000 km/sup 2/. Five sedimentary basins have been established in this area: Beibu Bay, Yinggehai, Southeastern Qiong, Pearl River Mouth, and Southwestern Taiwann basins. The primary source and reservoir rocks for oil and gas prospects are of Tertiary age. Tertiary rocks underwent three stages of development, each forming a specific sedimentation system: (1) a system of fluviolacustrine deposits in rift depressions from the Paleocene to early Oligocene; (2) a system of semiclosed-sea deposits from the late Oligocene to early Miocene; and (3) a system of deltaic open-sea deposits from the middle Miocene to Pliocene. These three sedimentation systems resulted in three suites of source rocks, three suites of reservoir rocks, and three groups of independent oil pools, complete with source, reservoir, and cap rocks. The three suites of source rocks are as follows: (1) the Eocene Liushagang Formation in the Beibu Bay basin, which is believed to be the best source rock discovered in the area; (2) the Oligocene Zhuhai Formation in the Pearl River Mouth basin; and (3) the lower Miocene series in the Pearl River Mouth basin. The Eocene formation is probably the principal source rock of regional scale in the northern part of the South China Sea. The three suites of reservoir rocks are as follows: (1) the fluviolacustrine sandstone bodies in the Liushagang Formation; (2) the fluviolacustrine sand bodies and shallow-sea sandstone bodies in the Zhuhai Formation and Lingshu Formation; (3) the deltaic, littoral, and shallow-sea sand bodies and bioherms of Neogene age, with the middle Miocene sandstone reservoirs having the best physical properties.

  4. Geochemistry and petrology of surface samples, six boreholes and brines from the Salton Sea geothermal field: A natural analog of a nuclear waste repository in salt: Report No. 3

    SciTech Connect

    Not Available

    1987-05-01

    Cuttings from six wells in the Salton Sea geothermal field, and rocks at outcrop that are correlative in age with those encountered at depth in the wells were analyzed in detail. Mineralogy, petrography, x-ray diffraction, electron microprobe, instrumental neutron activation analysis, fission track radiography, oxygen and stable carbon isotopic, uranium-thorium series disequilibrium, and fluid inclusion analyses are reported. Where fluids were being produced from wells, brine chemistry as well as stable isotope and uranium-thorium series analyses are reported. Particular attention has been paid to defining zones of fluid-rock interaction in which analyses of coexisting geothermal reservoir brine and hydrothermally altered sediments could be acquired. A wide span of temperatures, from surficial to greater than 300/degree/C, and salinities ranging from relatively dilute ground waters up to brines of 25 wt% total dissolved solids, span a range of environments that might be encountered in a waste repository in salt. Progressive hydrothermal alteration, mineral formation and element mobility are documented in the data presented. 52 refs., 25 figs., 49 tabs.

  5. Uranium-series ages of fossil corals from Mallorca, Spain: The "Neotyrrhenian" high stand of the Mediterranean Sea revisited

    USGS Publications Warehouse

    Muhs, Daniel R.; Simmons, Kathleen R.; Porat, Naomi

    2015-01-01

    We analyzed corals from the Neotyrrhenian beds on Mallorca, which gave U-series ages from ~ 126 ka to ~ 118 ka. These ages are consistent with previously published amino acid data that show that the Neotyrrhenian and Eutyrrhenian deposits are not significantly different in age. A fossil molluscan fauna from the Neotyrrhenian deposits on Mallorca has a warm-water paleozoogeographic aspect, with nine southward-ranging species and four extralimital southern species. When compared with sea surface temperatures obtained from planktonic foraminifera and alkenones from ODP core 977 in the nearby Alboran Sea, the only time period that shows comparable warmth is MIS 5.5/5e, consistent with the U-series ages of corals from the Neotyrrhenian deposits. We propose that the Neotyrrhenian deposits are a beachrock facies of the same age as the Eutyrrhenian deposits. This interpretation is consistent with the differences in physical sedimentology of the two deposits, explains the U-series and amino acid data indicating the same age, is consistent with the very slight elevation difference of the Neotyrrhenian and Eutyrrhenian beds, and explains the similar, though not identical paleozoogeographic aspects of their fossil faunas.

  6. Halorubrum chaoviator sp. nov., a haloarchaeon isolated from sea salt in Baja California, Mexico, Western Australia and Naxos, Greece.

    PubMed

    Mancinelli, Rocco L; Landheim, Ragnhild; Sánchez-Porro, Cristina; Dornmayr-Pfaffenhuemer, Marion; Gruber, Claudia; Legat, Andrea; Ventosa, Antonio; Radax, Christian; Ihara, Kunio; White, Melisa R; Stan-Lotter, Helga

    2009-08-01

    Three halophilic isolates, strains Halo-G*T, AUS-1 and Naxos II, were compared. Halo-G* was isolated from an evaporitic salt crystal from Baja California, Mexico, whereas AUS-1 and Naxos II were isolated from salt pools in Western Australia and the Greek island of Naxos, respectively. Halo-G*T had been exposed previously to conditions of outer space and survived 2 weeks on the Biopan facility. Chemotaxonomic and molecular comparisons suggested high similarity between the three strains. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the strains clustered with Halorubrum species, showing sequence similarities of 99.2-97.1%. The DNA-DNA hybridization values of strain Halo-G*T and strains AUS-1 and Naxos II are 73 and 75%, respectively, indicating that they constitute a single species. The DNA relatedness between strain Halo-G*T and the type strains of 13 closely related species of the genus Halorubrum ranged from 39 to 2%, suggesting that the three isolates constitute a different genospecies. The G+C content of the DNA of the three strains was 65.5-66.5 mol%. All three strains contained C20C20 derivatives of diethers of phosphatidylglycerol, phosphatidylglyceromethylphosphate and phosphatidylglycerolsulfate, together with a sulfated glycolipid. On the basis of these results, a novel species that includes the three strains is proposed, with the name Halorubrum chaoviator sp. nov. The type strain is strain Halo-G*T (=DSM 19316T=NCIMB 14426T=ATCC BAA-1602T). PMID:19567575

  7. Halorubrum chaoviator sp. nov., a haloarchaeon isolated from sea salt in Baja California, Mexico, Western Australia and Naxos, Greece

    PubMed Central

    Mancinelli, Rocco L.; Landheim, Ragnhild; Sanchez-Porro, Cristina; Dornmayr-Pfaffenhuemer, Marion; Gruber, Claudia; Legat, Andrea; Ventosa, Antonio; Radax, Christian; Ihara, Kunio; White, Melisa R.; Stan-Lotter, Helga

    2011-01-01

    Three halophilic isolates, strains Halo-G*T, AUS-1 and Naxos II, were compared. Halo-G* was isolated from an evaporitic salt crystal from Baja California, Mexico, whereas AUS-1 and Naxos II were isolated from salt pools in Western Australia and the Greek island of Naxos, respectively. Halo-G*T had been exposed previously to conditions of outer space and survived 2 weeks on the Biopan facility. Chemotaxonomic and molecular comparisons suggested high similarity between the three strains. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the strains clustered with Halorubrum species, showing sequence similarities of 99.2–97.1 %. The DNA–DNA hybridization values of strain Halo-G*T and strains AUS-1 and Naxos II are 73 and 75 %, respectively, indicating that they constitute a single species. The DNA relatedness between strain Halo-G*T and the type strains of 13 closely related species of the genus Halorubrum ranged from 39 to 2 %, suggesting that the three isolates constitute a different genospecies. The G+C content of the DNA of the three strains was 65.5–66.5 mol%. All three strains contained C20C20 derivatives of diethers of phosphatidylglycerol, phosphatidylglyceromethylphosphate and phosphatidylglycerolsulfate, together with a sulfated glycolipid. On the basis of these results, a novel species that includes the three strains is proposed, with the name Halorubrum chaoviator sp. nov. The type strain is strain Halo-G*T (=DSM 19316T =NCIMB 14426T =ATCC BAA-1602T). PMID:19567575

  8. Structure of the invertebrate fauna in salt marshes of the Wadden Sea coast of Schleswig-Holstein influenced by sheep-grazing

    NASA Astrophysics Data System (ADS)

    Meyer, H.; Fock, H.; Haase, A.; Reinke, H. D.; Tulowitzki, I.

    1995-03-01

    Results of investigations on the influence of five different sheep grazing intensities on the invertebrate fauna of two mainland salt marsh sites of the German Wadden Sea coast are presented for the years 1990 and 1991. The investigation of the invertebrate fauna has been carried out since 1989 in the Puccinellia maritima zone, and the Festuca-Puccinellia as well as the Festuca-Armeria zones, with trapping transects arranged along an inundation gradient. Apart from specific biotic effects, grazing causes changes in environmental characteristics. Effects on microclimate comprise higher ranges of variance in soil-surface temperature on grazed sites. Decreasing food resources caused by grazing bring disadvantages to herbivores, the major part of the invertebrate fauna, due to merotope destruction (e. g. inflorescences of Aster tripolium) and the decline of host plant stands (e. g. A. tripolium, Plantago ssp.). Flower visitors and pollen feeding species that depend on A. tripolium have become extinct. Increasing food resources, caused by grazing, lead to higher population densities of a few specialized grass-feeding and surface-grazing invertebrates (e. g. Mayetiola ssp., Psammotettix putoni, Bledius tricornis). Soil characteristics in the lower salt marsh have not been altered significantly by grazing; hence, the direct effect of grazing and trampling leads to a decrease in population density of many species such as Assiminea grayana, Orchestia gammarellus and collembolans. The biomass and abundance of detritivores and many herbivores increased from 1990 to 1991 on the totally grazed fields, whereas predators diminished in numbers at the same time. A descriptive model is presented, involving grazing, winter temperature, and precipitation as basic factors.

  9. Live (Rose-bengal stained) foraminifera from deep-sea anoxic salt brine in the Eastern Mediterranean: toward understanding limit of life for single-celled eukaryotes (foraminifera)

    NASA Astrophysics Data System (ADS)

    Kitazato, H.; Ohkawara, N.; Iwasaki, A.; Nomaki, H.; Akoumianaki, I.; Tokuyama, H.

    2012-04-01

    What is a limit of life for the eukaryotes? Eukaryotes are thought to adapt and evolve under oxic environmental conditions. Recently, there are many exceptions for this hypothesis, as many eukaryotes including metazoan groups are found in anoxic environmental conditions. We found many rose-bengal stained foraminifera from a deep-hypersaline anoxic basin (DHAB) in the eastern Mediterranean. During KH06-04 cruise, we conducted oceanographic research at Medée Lake, the largest DHAB, that is located 100km southwest of Crete Island in the eastern Mediterranean. The lake situates at 2920m in water depth. Depth of saline water is 120m in maximum. Both water and sediment samplings were carried out both with Niskin bottles and multiple corer attached to camera watching sampling system at three sites, inside of the lake (CS), the edge of the lake (OMS) and the normal deep-sea floor (RS). Temperature, salinity, and dissolved oxygen concentrations at central saline lake are 15.27 oC, 328PSU, and 0.0 ml/L, respectively. Strong smell of hydrogen sulfide was detected from the lake sediment. Subsamples were conducted for multiple core samples using 3 subcores(φ 2.9cm) from each core tube (φ 8.2cm). Sediment samples were fixed with 4% formalin Rose Bengal solution on board. In laboratory, samples were washed with 32μm sieve. Rose Bengal stained specimens were picked under binocular stereomicroscope (Zeiss Stemi SV11) for surface 0.5cm layer, and identified with inverted microscope (Nikon ECLIPSE TE300). In total, 26 species belonging to 9 genera were identified from three sites. Six species belonging to two genera were identified in the center of the salt brine. Only a few species are common among three sites, even though the numbers of common species were 10 between OMS and RS sites. In DHAB, spherical organic-walled species, such as allogromiid and psammosphaerid, are dominant. In contrast, tube-like chitinous foraminifera, such as Resigella, Conicotheca and Nodellum, are

  10. Pirates, Pirates over the Salt, Salt Sea.

    ERIC Educational Resources Information Center

    Nikola-Lisa, W.

    1993-01-01

    Focuses on the changing role of females in the picture-book pirate fantasies produced over the last two decades. Critiques these picture books from a feminist perspective. Summarizes and discusses numerous pirate picture books. (HB)

  11. Socio-economic, demographic, lifestyle and health characteristics associated with consumption of fatty-sweetened and fatty-salted foods in middle-aged French adults.

    PubMed

    Méjean, Caroline; Macouillard, Pauline; Castetbon, Katia; Kesse-Guyot, Emmanuelle; Hercberg, Serge

    2011-03-01

    Few studies have specifically focused on characteristics associated with consumption of combined fatty-salted and fatty-sweetened foods, whereas their identification could be useful for defining effective public health measures. The aim of the present study was to investigate the association between demographic, socio-economic, lifestyle and health characteristics and consumption of these types of food in a general sample of French adults. Dietary intake was assessed using a minimum of six 24 h dietary records collected over a 2-year period in 6240 subjects aged 35-60 years who participated in the Supplémentation en VItamines Minéraux et AntioXydants cohort study. Associations of individual characteristics with high and intermediate consumption of fatty-sweetened and fatty-salted foods were assessed using multivariate polytomic logistic regression models. Risk of moderate or high consumption of fatty-salted foods decreased with increasing age. Current smokers, drinkers, individuals with overweight and with hypertension were more likely to consume moderate or high amounts of such foods. Risk of moderate or high consumption of fatty-sweetened foods decreased with increasing age. Women, individuals living as a couple, moderate drinkers and persons with low or medium physical activity level were more likely to consume moderate or high amounts of such foods. Lower educated subjects, current smokers, heavy drinkers and individuals with severe hypertriacylglycerolaemia were less likely to have moderate or high consumption. Consumption of fatty-sweetened and fatty-salted foods varied according to demographic, lifestyle and health characteristics. Common unhealthy behaviours such as smoking, low physical activity and alcohol drinking, associated with high consumption of these food groups, may help to effectively target public health efforts. PMID:20946706

  12. From pre-salt sources to post-salt traps: A specific petroleum system in Congo coastal basin

    SciTech Connect

    Vernet, R.

    1995-08-01

    The Bas Congo basin extends from Gabon to Angola and is a prolific oil province where both pre-salt and post salt sources and reservoirs have been found. In the northern part of the basin referred to as the Congo coastal basin, the proven petroleum system is more specific: mature source rocks are found only in pre-salt series whereas by contrast 99 % proven hydrocarbon reserves am located in post-salt traps. Such a system is controlled by the following factors: Source rocks are mostly organic rich shales deposited in a restricted environment developed in a rift prior to the Atlantic Ocean opening; Migration from pre-salt sources to post-salt traps is finalized by local discontinuities of the regional salt layer acting otherwise as a tight seal; Post-salt reservoirs are either carbonates or sands desposited in the evolutive shelf margin developped during Upper Cretaceous; Geometric traps are linked to salt tectonics (mostly turtle-shaped structures); Regional shaly seals are related to transgressive shales best developped during high rise sea level time interval. Stratigraphically, the age of hydrocarbon fields trends are younger and younger from West to East: lower Albian in Nkossa, Upper Albian and lower Cenomanian in Likouala, Yanga, Sendji, Upper Cenomanian in Tchibouela, Turonian in Tchendo, Turanian and Senonian in Emeraude.

  13. Marine Creatures and the Sea in Bronze Age Greece: Ambiguities of Meaning

    NASA Astrophysics Data System (ADS)

    Berg, Ina

    2013-06-01

    Like most cultures, prehistoric Greek communities had an ambiguous relationship with the sea and the creatures that inhabit it. Positive and negative associations always co-existed, though the particular manifestations changed over time. By drawing together evidence of consumption of marine animals, seafaring, fishing, and iconography, this article unites disparate strands of evidence in an attempt to illuminate the relationship prehistoric Greeks had with marine creatures and the sea. Based on the marked reduction in seafood consumption after the Mesolithic and the use of marine creatures in funerary iconography in the post-palatial period, it becomes apparent that the sea—then as now—is an inherently ambiguous medium that captures both positive and negative emotions. On the one hand, the sea and the animals residing in it are strongly associated with death. On the other hand, the sea's positive dimensions, such as fertility and rebirth, are expressed in conspicuous marine consumption events.

  14. Direct Observations of Heat and Salt Entrainment Fluxes Across the Base of the Ocean Mixing Layer Under Marginal Ice Conditions in the Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Gallaher, S.; Stanton, T. P.; Shaw, W. J.

    2014-12-01

    Measurements of turbulent fluxes of heat and salt across the base of the upper ocean mixed layer in summer marginal ice zone conditions in the Beaufort Sea were made using two eddy-correlation flux sensors with a vertical separation of 6m mounted on a depth-controlled frame. A third flux sensor measured fluxes 2m below the ice. A 16 element thermistor string measured finescale thermal gradients while a high resolution ADCP measured current profiles every 20cm across the frame to resolve finescale shear. Every hour the frame was profiled between 2m and 60m depth then re-positioned to span the base of the active mixing layer, determined primarily from the density profile, allowing the surface mixed layer entrainment fluxes to be determined. A range of wind conditions allowed mixed layer entrainment fluxes to be compared with several bulk entrainment formulations based on surface friction velocity values and the density jump across the base of the surface mixing layer.

  15. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    NASA Astrophysics Data System (ADS)

    Vet, Robert; Artz, Richard S.; Carou, Silvina; Shaw, Mike; Ro, Chul-Un; Aas, Wenche; Baker, Alex; Bowersox, Van C.; Dentener, Frank; Galy-Lacaux, Corinne; Hou, Amy; Pienaar, Jacobus J.; Gillett, Robert; Forti, M. Cristina; Gromov, Sergey; Hara, Hiroshi; Khodzher, Tamara; Mahowald, Natalie M.; Nickovic, Slobodan; Rao, P. S. P.; Reid, Neville W.

    2014-08-01

    A global assessment of precipitation chemistry and deposition has been carried out under the direction of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Scientific Advisory Group for Precipitation Chemistry (SAG-PC). The assessment addressed three questions: (1) what do measurements and model estimates of precipitation chemistry and wet, dry and total deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity, and phosphorus show globally and regionally? (2) has the wet deposition of major ions changed since 2000 (and, where information and data are available, since 1990) and (3) what are the major gaps and uncertainties in our knowledge? To that end, regionally-representative measurements for two 3-year-averaging periods, 2000-2002 and 2005-2007, were compiled worldwide. Data from the 2000-2002 averaging period were combined with 2001 ensemble-mean modeling results from 21 global chemical transport models produced in Phase 1 of the Coordinated Model Studies Activities of the Task Force on Hemispheric Transport of Air Pollution (TF HTAP). The measurement data and modeling results were used to generate global and regional maps of major ion concentrations in precipitation and deposition. A major product of the assessment is a database of quality assured ion concentration and wet deposition data gathered from regional and national monitoring networks. The database is available for download from the World Data Centre for Precipitation Chemistry (http://wdcpc.org/)

  16. Remote-sensing-based analysis of landscape change in the desiccated seabed of the Aral Sea--a potential tool for assessing the hazard degree of dust and salt storms.

    PubMed

    Löw, F; Navratil, P; Kotte, K; Schöler, H F; Bubenzer, O

    2013-10-01

    With the recession of the Aral Sea in Central Asia, once the world's fourth largest lake, a huge new saline desert emerged which is nowadays called the Aralkum. Saline soils in the Aralkum are a major source for dust and salt storms in the region. The aim of this study was to analyze the spatio-temporal land cover change dynamics in the Aralkum and discuss potential implications for the recent and future dust and salt storm activity in the region. MODIS satellite time series were classified from 2000-2008 and change of land cover was quantified. The Aral Sea desiccation accelerated between 2004 and 2008. The area of sandy surfaces and salt soils, which bear the greatest dust and salt storm generation potential increased by more than 36 %. In parts of the Aralkum desalinization of soils was found to take place within 4-8 years. The implication of the ongoing regression of the Aral Sea is that the expansion of saline surfaces will continue. Knowing the spatio-temporal dynamics of both the location and the surface characteristics of the source areas for dust and salt storms allows drawing conclusions about the potential hazard degree of the dust load. The remote-sensing-based land cover assessment presented in this study could be coupled with existing knowledge on the location of source areas for an early estimation of trends in shifting dust composition. Opportunities, limits, and requirements of satellite-based land cover classification and change detection in the Aralkum are discussed. PMID:23564411

  17. The influence of fish age, salt level, and Mtgase addition on the quality of gels prepared from unwashed mince of farmed meagre (Argyrosomus regius).

    PubMed

    Cardoso, Carlos; Ribeiro, Bernardo; Mendes, Rogério

    2014-06-01

    The potential of using the unwashed mince of farmed meagre as raw material for the preparation of heat-induced gel products was assessed taking into account the effect of age (small size <1 kg meagre vs commercial size > 2kg meagre), lower salt levels (1.0%, w/w, vs 2.5%, w/w), and microbial transglutaminase (MTGase) incorporation (0.0%, w/w, vs 0.5%, w/w). Heat-induced gel products from > 2 kg fish were of superior quality. Salt reduction from 2.5% to 1.0% (w/w) was detrimental for textural quality, particularly, of gels prepared from >2 kg meagre mince. MTGase addition improved texture. Moreover, MTGase incorporation led to a greater importance of non-covalent hydrophobic bonding. PMID:23751542

  18. Hematology and plasma biochemistry analytes in five age groups of immature, captive-reared loggerhead sea turtles (Caretta caretta).

    PubMed

    Rousselet, Estelle; Stacy, Nicole I; LaVictoire, Kara; Higgins, Benjamin M; Tocidlowski, Maryanne E; Flanagan, Joseph P; Godard-Codding, Céline A J

    2013-12-01

    Abstract: Blood samples of 85 immature, apparently healthy, captive-reared loggerhead sea turtles (Caretta caretta) were analyzed for 13 hematologic variables and total solids of 5 age groups (8, 20, 32, 44, and 56 mo old) and for 20 plasma biochemical analytes of 4 age groups (20 to 56 mo old). Each individual turtle was sampled under similar conditions during a blood collection period of 3 days. Hematologic analytes included packed cell volume, white blood cell (WBC) counts, WBC estimates, and leukocyte differentials. Biochemical analysis included albumin, alanine aminotransferase, alkaline phosphatase, amylase, aspartate aminotransferase, blood urea nitrogen, calcium, chloride, cholesterol, creatine kinase, creatinine, gamma glutamyltransferase, globulins, glucose, phosphorous, potassium, sodium, total bilirubin, total protein, total solids, and uric acid. In due consideration of small sample size in all five age groups, the results of hematologic and biochemical analysis were used to determine ranges for these analytes and to compare values among consecutive age groups. Several significant differences in some hematologic and biochemical variables were identified and need to be considered in the interpretation of blood work of immature, growing sea turtles in human care. PMID:24450044

  19. Variability of the northeast Atlantic sea surface Δ 14C and marine reservoir age and the North Atlantic Oscillation (NAO)

    NASA Astrophysics Data System (ADS)

    Tisnérat-Laborde, Nadine; Paterne, Martine; Métivier, Bernard; Arnold, Maurice; Yiou, Pascal; Blamart, Dominique; Raynaud, Stéphane

    2010-09-01

    We compiled new 14C analyses of mollusc shells (bivalves and gastropods) of known age from the collection of the Muséum National d'Histoire Naturelle de Paris and previously published data to investigate changes in the sea surface Δ 14C and reservoir age in the northeast Atlantic sector (NEA) between 1823 and 1952 AD. The mollusc shells are mainly located off the Atlantic margin between 45°N and 60°N downstream of the North Atlantic Current (NAC). We show that the temporal variability of the NEA Δ 14C is independent of the mollusc species, depth habitat, diet and latitudinal distribution. The quasi-null difference between mollusc Δ 14C and the marine model indicate that the mollusc Δ 14C reflects the Δ 14C values of open marine conditions. Between 1823 and 1850 AD, the pre-anthropogenic mean of Δ 14C is -45 ± 5‰, corresponding to a reservoir age of 380 ± 60 years and a Δ R value of -7 ± 50 years, in agreement with previous estimates. The Δ 14C values show a significant long-term decrease of ˜12‰ from 1823 to 1952 AD attributed to changes in 14C production between 1823 and 1900 AD and the Suess effect between 1900 and 1952 AD. Between 1885 and 1950 AD, Δ 14C fluctuations of ˜10‰ up to 18‰ occurred in the northeast Atlantic, corresponding to reservoir age variations of ˜90 years up to 170 years. These fluctuations are very similar to changes of Δ 14C in the southern Norwegian Sea. Spectral analyses of the NEA Δ 14C exhibit quasi-periodic cycles of about 7.4 years, almost equivalent to the quasi-periodic cycles of the winter index of the North Atlantic Oscillation (NAO) with a period around 6.5 years. We find that changes of NEA Δ 14C cannot be attributed to changes in river runoff or the precipitation/evaporation budget. The Δ 14C lows (or high reservoir ages) correspond to the more intense phase of the winter NAO, with a time lag of ˜1-3 years. Such a time lag may reflect the eastward transit time of upstream changes originating in the

  20. Age-structured modeling reveals long-term declines in the natality of western Steller sea lions.

    PubMed

    Holmes, E E; Fritz, L W; York, A E; Sweeney, K

    2007-12-01

    Since the mid-1970s, the western Steller sea lion (Eumetopias jubatus), inhabiting Alaskan waters from Prince William Sound west through the Aleutian Islands, has declined by over 80%. Changing oceanographic conditions, competition from fishing operations, direct human-related mortality, and predators have been suggested as factors driving the decline, but the indirect and interactive nature of their effects on sea lions have made it difficult to attribute changes in abundance to specific factors. In part, this is because only changes in abundance, not changes in vital rates, are known. To determine how vital rates of the western Steller sea lion have changed during its 28-year decline, we first estimated the changes in Steller sea lion age structure using measurements of animals in aerial photographs taken during population surveys since 1985 in the central Gulf of Alaska (CGOA). We then fit an age-structured model with temporally varying vital rates to the age-structure data and to total population and pup counts. The model fits indicate that birth rate in the CGOA steadily declined from 1976 to 2004. Over the same period, survivorship first dropped severely in the early 1980s, when the population collapsed, and then survivorship steadily recovered. The best-fitting model indicates that in 2004, the birth rate in the central Gulf of Alaska was 36% lower than in the 1970s, while adult and juvenile survivorship were close to or slightly above 1970s levels. These predictions and other model predictions concerning population structure match independent field data from mark-recapture studies and photometric analyses. The dominant eigenvalue for the estimated 2004 Leslie matrix is 1.0014, indicating a stable population. The stability, however, depends on very high adult survival, and the shift in vital rates results in a population that is more sensitive to changes in adult survivorship. Although our modeling analysis focused exclusively on the central Gulf of Alaska

  1. Age, Growth, Reproduction and Feeding of the Spurdog ( Squalus acanthias Linnaeus, 1758) in the South-eastern Black Sea

    NASA Astrophysics Data System (ADS)

    Avsar, D.

    2001-02-01

    Life-history parameters and diet of spurdog ( Squalus acanthias) sampled from the SE Black Sea were studied. Spurdog from age classes I to XIV were identified, with a dominance of age class VIII for both sexes. The length-weight relationship was W=0·0040*L 2·95and the mean annual growth rates in length and weight were 7·2 cm and 540·1 g, respectively. The estimated von Bertalanffy growth parameters were: W ∞=12021 (g), L ∞=157 (cm), K=0·12 (year -1) and t 0=-1·30 (year). The size at first maturity was 82 cm for males and 88 cm for females. Mean biennial fecundity was also found to be 8 pups/female. The relationships between fecundity-length, fecundity-weight and fecundity-age were found to be: F=-17·0842+0·2369*L (R=0·93), F=0·3780+0·0018*W (R=0·89) and F =-0·7859+1·1609*A (R=0·94) respectively. The spurdog can be considered an opportunistic feeder. Their natural diet was composed mainly of teleost fishes, followed by Crustaceans, Nematodes and Actinarians (=sea anemones). Whiting ( Merlangius merlangus euxinus) was the predominant prey item among their fish prey. Demersal teleosts formed the majority of the diet, and there was no difference ( P>0·05) among the food items of immature, maturing and mature individuals of both sexes.

  2. Age-specific vibrissae growth rates: a tool for determining the timing of ecologically important events in Steller sea lions

    USGS Publications Warehouse

    Rea, L.D.; Christ, A.M.; Hayden, A.B.; Stegall, V.K.; Farley, S.D.; Stricker, Craig A.; Mellish, J.E.; Maniscalco, J.M.; Waite, J.N.; Burkanov, V.N.; Pitcher, K.W.

    2015-01-01

    Steller sea lions (SSL; Eumetopias jubatus) grow their vibrissae continually, providing a multiyear record suitable for ecological and physiological studies based on stable isotopes. An accurate age-specific vibrissae growth rate is essential for registering a chronology along the length of the record, and for interpreting the timing of ecologically important events. We utilized four methods to estimate the growth rate of vibrissae in fetal, rookery pup, young-of-the-year (YOY), yearling, subadult, and adult SSL. The majority of vibrissae were collected from SSL live-captured in Alaska and Russia between 2000 and 2013 (n = 1,115), however, vibrissae were also collected from six adult SSL found dead on haul-outs and rookeries during field excursions to increase the sample size of this underrepresented age group. Growth rates of vibrissae were generally slower in adult (0.44 ± 0.15 cm/mo) and subadult (0.61 ± 0.10 cm/mo) SSL than in YOY (0.87 ± 0.28 cm/mo) and fetal (0.73 ± 0.05 cm/mo) animals, but there was high individual variability in these growth rates within each age group. Some variability in vibrissae growth rates was attributed to the somatic growth rate of YOY sea lions between capture events (P = 0.014, r2 = 0.206, n = 29).

  3. Habitat management affects soil chemistry and allochthonous organic inputs mediating microbial structure and exo-enzyme activity in Wadden Sea salt-marsh soils

    NASA Astrophysics Data System (ADS)

    Mueller, Peter; Granse, Dirk; Thi Do, Hai; Weingartner, Magdalena; Nolte, Stefanie; Hoth, Stefan; Jensen, Kai

    2016-04-01

    The Wadden Sea (WS) region is Europe's largest wetland and home to approximately 20% of its salt marsh area. Mainland salt marshes of the WS are anthropogenically influenced systems and have traditionally been used for livestock grazing in wide parts. After foundation of WS National Parks in the late 1980s and early 1990s, artificial drainage has been abandoned; however, livestock grazing is still common in many areas of the National Parks and is under ongoing discussion as a habitat-management practice. While studies so far focused on effects of livestock grazing on biodiversity, little is known about how biogeochemical processes, element cycling, and particularly carbon sequestration are affected. Here, we present data from a recent field study focusing on grazing effects on soil properties, microbial exo-enzyme activity, microbial abundance and structure. Exo-enzyme activity was studied conducting digestive enzyme assays for various enzymes involved in C- and N cycling. Microbial abundance and structure was assessed measuring specific gene abundance of fungi and bacteria using quantitative PCR. Soil compaction induced by grazing led to higher bulk density and decreases in soil redox (∆ >100 mV). Soil pH was significantly lower in grazed parts. Further, the proportion of allochthonous organic matter (marine input) was significantly smaller in grazed vs. ungrazed sites, likely caused by a higher sediment trapping capacity of the taller vegetation in the ungrazed sites. Grazing induced changes in bulk density, pH and redox resulted in reduced activity of enzymes involved in microbial C acquisition; however, there was no grazing effect on enzymes involved in N acquisition. While changes in pH, bulk density or redox did not affect microbial abundance and structure, the relative amount of marine organic matter significantly reduced the relative abundance of fungi (F:B ratio). We conclude that livestock grazing directly affects microbial exo-enzyme activity, thus

  4. Validating Annual Growth Bands of Deep-Sea Black Corals and Calculating Ocean Reservoir Ages in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Roark, E. B.; Mohon, M. L.; Prouty, N.; Guillemette, R. N.; Fallon, S.; Ross, S. W.

    2015-12-01

    Deep-sea black corals (Leiopathes sp.) are long-lived (up to 4,000 yrs old), and grow in a tree-like fashion depositing growth rings in their skeleton. Scanning electron microscopy at 900x magnification was used to image thin sections and identify peaks in iodine intensity using energy dispersive x-ray spectroscopy in three specimens from the Gulf of Mexico. Age determination by counting visual growth bands and iodine peaks were compared to both radiocarbon and U/Th-derived ages. The first specimen (GOM-JSL04-4734-BC1) has an iodine peak count age of 695 ±70, and growth band age of 785 ± 80 which compare quite well to the radiocarbon age of 670 ±40 years and a U/Th age of 780 ±16 years. There was similar agreement between the radiocarbon ages (1399 ±30 and 670 ±35 years) and the iodine peak count ages (1240 ±125 and 715±70 years) for the remaining two specimens with growth rates ranging from 11 ±3 to 16 ±2 µm yr-1 for all 3 specimens. Using the independent (iodine derived) age models in conjunction with the radiocarbon data, a high resolution ocean reservoir age record was developed for the last 600 years. Reservoir ages varied from 120 to 550 14C years on decadal to centennial time scales. The modern reservoir age in the GOM is 235 ±11 14C years. The preferred explanation for the variability found in these reservoir ages is related to changes in the strength of the Yucatan Current. This novel approach combines the identification of growth bands captured in high-resolution SEM in combination with synchronous peaks in skeleton iodine composition and is the first to validate that both can be used as annual chronometers. Using the independent iodine age models in conjunction with the radiocarbon records, ocean reservoir age records can be developed for the last ~500 to 1000 years.

  5. Little Ice Age climate and oceanic conditions of the Ross Sea, Antarctica from a coastal ice core record

    NASA Astrophysics Data System (ADS)

    Rhodes, R. H.; Bertler, N. A. N.; Baker, J. A.; Steen-Larsen, H. C.; Sneed, S. B.; Morgenstern, U.; Johnsen, S. J.

    2012-07-01

    Increasing paleoclimatic evidence suggests that the Little Ice Age (LIA) was a global climate change event. Understanding the forcings and associated climate system feedbacks of the LIA is made difficult by the scarcity of Southern Hemisphere paleoclimate records. We use a new glaciochemical record of a coastal ice core from Mt. Erebus Saddle, Antarctica, to reconstruct atmospheric and oceanic conditions in the Ross Sea sector of Antarctica over the past five centuries. The LIA is identified in stable isotope (δD) and lithophile element records, which respectively demonstrate that the region experienced 1.6 ± 1.4 °C cooler average temperatures prior to 1850 AD than during the last 150 yr and strong (>57 m s-1) prevailing katabatic winds between 1500 and 1800 AD. Al and Ti concentration increases of an order of magnitude (>120 ppb Al) are linked to enhanced aeolian transport of complex silicate minerals and represent the strongest katabatic wind events of the LIA. These events are associated with three 12-30 yr intervals of cooler temperatures at ca. 1690 AD, 1770 AD and 1840 AD. Furthermore, ice core concentrations of the biogenic sulphur species MS- suggest that biological productivity in the Ross Sea polynya was ~80% higher prior to 1875 AD than at any subsequent time. We propose that cooler Antarctic temperatures promoted stronger katabatic winds across the Ross Ice Shelf, resulting in an enlarged Ross Sea polynya during the LIA.

  6. Quaternary sea level high-stand deposits of the southeast U.S. Atlantic Coastal Plain: Age, distribution, and implications.

    NASA Astrophysics Data System (ADS)

    Poirier, R. K.; Cronin, T. M.; Ghaleb, B.; Portell, R.; Hillaire-Marcel, C.; Wehmiller, J. F.; Thompson, W. G.; Oches, E. A.; Willard, D. A.; Katz, M. E.

    2015-12-01

    Emerged Quaternary paleo-shorelines and marine deposits provide a more direct way to reconstruct and analyze sea-level variability than methods using oxygen isotope analyses of deep ocean benthic foraminifera. New Uranium-series dates on fossil corals (primarily Astrangia spp. and Septastrea spp.) combined with previously published dates have allowed us to constrain the age, elevation, and geographical distribution of marine sediments deposited in the United States Atlantic Coastal Plain (ACP) from Virginia to Florida during periods of past high relative sea level (SL). We present new dates from deposits (VA/NC: Tabb/Norfolk, Nassawadox, & Omar Formations; SC: Wando, Socastee, & Canepatch Formations; FL: Anastasia, Ft. Thompson, & Bermont Formations) representing interglacial high-stands during Marine Isotope Stages (MIS) 5, 7, 9, and 11. In addition, we incorporate stratigraphic, marine micropaleontologic, and palynologic records with our SL chronology to reconstruct a more complete history of middle-to-late Pleistocene interglacial climates of the ACP. Ultimately, these results will test modeled sea-level fingerprint studies based on various melting scenarios of the Greenland and/or Antarctic ice sheets.

  7. An estimation of ship-plume SO2 lifetimes as a function of mixing ratios of hydroxyl radicals and pH of sea-salt particles

    NASA Astrophysics Data System (ADS)

    Kim, H.; Kim, Y.; Song, C. H.

    2010-12-01

    The ship-plume equivalent lifetimes of SO2 (τeqSO2) were estimated for the ITCT 2K2 (Intercontinental Transport and Chemical Transformation 2002) ship plume experiment using the ship-plume photochemical/dynamic model developed in this study. Ship-plume modeling analysis revealed two main factors affecting τeqSO2: (i) the mixing ratios of in-plume hydroxyl radicals (OH) and (ii) pH of sea-salt particles (pHss). The former is governed primarily by stability conditions of the marine boundary layer (MBL) when the ship NOx emission rate is fixed. The latter determines if the heterogeneous oxidation of dissolved SO2 occurs via reaction with hydrogen peroxide (H2O2, when pHss<6.5) or with ozone (O3, when pHss>6.5). According to the multiple ship-plume photochemical/dynamic model simulations, the estimated τeqSO2 over the entire ship plumes ranged from 13.03 to 17.28 hrs under the neutral (D) to stable (F) MBL conditions, when the pHss was assumed to be <6.5. These values are clearly shorter than the background SO2 lifetime (τbSO2) of 23.2 hrs. τeqSO2 was estimated to be 0.77-3.59 hrs when the pHss was pHss > 6.5 despite the massive acid production inside the ship plumes (rather unlikely case).

  8. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    NASA Astrophysics Data System (ADS)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  9. Alterations to Tidal Marsh Carbon Cycling and Greenhouse Gas Exchange in Response to Sea-Level and Salt-Water Intrusion (Invited)

    NASA Astrophysics Data System (ADS)

    Weston, N. B.

    2013-12-01

    Tidal marshes are highly productive ecosystems with the potential to sequester large amounts of carbon. However, tidal wetlands may be sources of the powerful greenhouse gases (GHGs) methane (CH4) and nitrous oxide (N2O), which are produced via microbial metabolic processes. As global climate changes it is increasingly important to understand the factors that control ecosystem productivity, GHG fluxes, and potential feedbacks between global change factors, C cycling, and marsh resilience to sea-level rise (SLR). Field measurements were undertaken to quantify rates of GHG (CO2 and CH4) exchange rates, plant biomass, microbial sulfate reduction and methanogenesis rates, and soil biogeochemistry at three tidal wetland sites along the salinity gradient in the Delaware River Estuary over four years. Despite similar plant productivity between marsh types, differences in microbial processes largely determined the GHG source/sink status of the wetland types. Mesohaline salt-marshes consistently sequestered C (~300 g C m-2 yr-1), and due to negligible CH4 release, were also a GHG sink (~1350 g CO2-eq m-2 yr-1). In contrast, the TFM sequestered C (~350 g C m-2 yr-1) but because of appreciable release of CH4 from freshwater wetland soils was GHG neutral. The oligohaline marsh site experienced significant seasonal salt-water intrusion (SWI) in the late summer during the four year study period, resulting in major alterations to marsh C cycling. The oligohaline marsh did not sequester C (loss of ~45 g C m-2 yr-1) in part due to surprisingly high rates of CH4 release (190 g CH4 m-2 yr-1). The oligohaline marsh undergoing SWI was therefore a significant source of GHG to the atmosphere (~4000 g CO2-eq m-2 yr-1). These results indicate that SWI alters C cycling and GHG exchange in marsh systems, and may accelerate the decomposition of organic matter limiting the ability of marshes to accrete material and keep pace with SLR. The impacts of SWI on TFM soil C cycling were further

  10. Year-round records of bulk and size-segregated aerosol composition and HCl and HNO3 levels in the Dumont d'Urville (coastal Antarctica) atmosphere: Implications for sea-salt aerosol fractionation in the winter and summer

    NASA Astrophysics Data System (ADS)

    Jourdain, Bruno; Legrand, Michel

    2002-11-01

    Year-round composition of bulk and size-segregated aerosol was examined at a coastal Antarctic site (Dumont d'Urville). Sea-salt particles display a summer depletion of chloride relative to sodium, which reaches ˜10%. The mass chloride loss is maximum on 1- to 3-μm-diameter particles, nitrate being often the anion causing the chloride loss. The summer SO42-/Na+ ratio exceeds the seawater value on submicron particles due to biogenic sulfate and on coarse particles due to ornithogenic (guano-enriched soils) sulfate and to heterogeneous uptake of SO2 (or H2SO4). HCl levels range from 47 ± 28 ng m-3 in the winter to 130 ± 110 ng m-3 in the summer, being close to the mass chloride loss of sea-salt aerosols. In the winter, sea-salt particles exhibit Cl-/Na+ and SO42-/Na+ mass ratios of 1.9 ± 0.1 and 0.13 ± 0.04, respectively. Resulting from precipitation of mirabilite during freezing of seawater, this sulfate-depletion-relative sodium takes place from May to October. From March to April, warmer temperatures and/or smaller sea ice extent offshore the site limit the phenomenon. A range of 14-50 ng m-3 of submicron sulfate is found, confirming the existence of nssSO42- in the winter at a coastal Antarctic site, highest values being found in the winters of 1992-1994 due to the Pinatubo volcanic input. Apart from these three winters, nssSO42- levels range between 15 and 30 ng m-3, but its origin is still unclear (quasi-continuous SO2 emissions from the Mount Erebus volcano or local wintertime dimethyl sulfide [DMS] oxidation, in addition to long-range transported by-product of DMS oxidation).

  11. Effect of Post-thermal shock on Prolonged Sea Water aged GFRP Composite

    NASA Astrophysics Data System (ADS)

    Chakraverty, A. P.; Mohanty, U. K.; Mishra, S. C.; Biswal, B. B.

    2016-02-01

    The present investigation is an attempt of evaluating the suitability of glass fibre reinforced polymer composites to thermal shock treatments of various lengths of time subject to pre-immersion in sea water for 1 year. Mechanical properties like inter laminar shear strength (ILSS), stress at rupture, strain at rupture and modulus values are recorded by adopting 3-point bend test method. Mechanical properties show a general decreasing trend at higher durations of up and down-thermal shock exposure irrespective of showing initial nonequilibrium zig-zag trend. Glass Transition temperature (Tg) with respect to optimum durations of thermal shock treatment show considerable variation for the sample with minimum sea water immersion period. SEM fractographs of the thermally shocked specimens revealed the mode of failures like fibre pull out, fibre/matrix debonding, cusp formation indicating polymer crazing, matrix cracking, fibre breaking etc.

  12. Age Specific Survival Rates of Steller Sea Lions at Rookeries with Divergent Population Trends in the Russian Far East

    PubMed Central

    Altukhov, Alexey V.; Andrews, Russel D.; Calkins, Donald G.; Gelatt, Thomas S.; Gurarie, Eliezer D.; Loughlin, Thomas R.; Mamaev, Evgeny G.; Nikulin, Victor S.; Permyakov, Peter A.; Ryazanov, Sergey D.; Vertyankin, Vladimir V.; Burkanov, Vladimir N.

    2015-01-01

    After a dramatic population decline, Steller sea lions have begun to recover throughout most of their range. However, Steller sea lions in the Western Aleutians and Commander Islands are continuing to decline. Comparing survival rates between regions with different population trends may provide insights into the factors driving the dynamics, but published data on vital rates have been extremely scarce, especially in regions where the populations are still declining. Fortunately, an unprecedented dataset of marked Steller sea lions at rookeries in the Russian Far East is available, allowing us to determine age and sex specific survival in sea lions up to 22 years old. We focused on survival rates in three areas in the Russian range with differing population trends: the Commander Islands (Medny Island rookery), Eastern Kamchatka (Kozlov Cape rookery) and the Kuril Islands (four rookeries). Survival rates differed between these three regions, though not necessarily as predicted by population trends. Pup survival was higher where the populations were declining (Medny Island) or not recovering (Kozlov Cape) than in all Kuril Island rookeries. The lowest adult (> 3 years old) female survival was found on Medny Island and this may be responsible for the continued population decline there. However, the highest adult survival was found at Kozlov Cape, not in the Kuril Islands where the population is increasing, so we suggest that differences in birth rates might be an important driver of these divergent population trends. High pup survival on the Commander Islands and Kamchatka Coast may be a consequence of less frequent (e.g. biennial) reproduction there, which may permit females that skip birth years to invest more in their offspring, leading to higher pup survival, but this hypothesis awaits measurement of birth rates in these areas. PMID:26016772

  13. Spatial variability in the abundance, composition, and age of organic matter in surficial sediments of the East China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Ying; Eglinton, Timothy; Yang, Liyang; Deng, Bing; Montluçon, Daniel; Zhang, Jing

    2013-12-01

    the sources and fate of organic matter (OM) sequestered in continental margin sediments is of importance because the mode and efficiency of OM burial impact the carbon cycle and the regulation of atmospheric CO2 over long time scales. We carried out molecular (lignin-derived phenols from CuO oxidation), elemental, isotopic (δ13C, Δ14C), and sedimentological (grain size and mineral surface area) analyses in order to examine spatial variability in the abundance, source, age of surface sediments of the East China Sea. Higher terrigenous organic matter values were found in the main accumulating areas of fluvial sediments, including the Changjiang (Yangtze) Estuary and Zhejiang-Fujian coastal zone. Isotopic and biomarker data suggest that the sedimentary OM in the inner shelf region was dominated by aged (Δ14C = -423 ± 42‰) but relatively lignin-rich OM (Λ = 0.94 ± 0.57 mg/100 mg OC) associated with fine-grained sediments, suggesting important contributions from soils. In contrast, samples from the outer shelf, while of similar age (Δ14 C = -450 ± 99‰), are lignin poor (Λ = 0.25 ± 0.14 mg/100 mg OC) and associated with coarse-grained material. Regional variation of lignin phenols and OM ages indicates that OM content is fundamentally controlled by hydrodynamic sorting (especially, sediment redistribution and winnowing) and in situ primary production. Selective sorption of acid to aldehyde in clay fraction also modified the ratios of lignin phenols. The burial of lignin in East China Sea is estimated to be relatively efficient, possibly as a consequence of terrigenous OM recalcitrance and/or relatively high sedimentation rates in the Changjiang Estuary and the adjacent Zhejing-Fujian mud belt.

  14. IODP Expedition 325: Great Barrier Reefs Reveals Past Sea-Level, Climate and Environmental Changes Since the Last Ice Age

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Webster, J. M.; Cotterill, C.; Braga, J. C.; Jovane, L.; Mills, H.; Morgan, S.; Suzuki, A.; IODP Expedition 325 Scientists, the

    2011-09-01

    The timing and courses of deglaciations are key components in understanding the global climate system. Cyclic changes in global climate have occurred, with growth and decay of high latitude ice sheets, for the last two million years. It is believed that these fluctuations are mainly controlled by periodic changes to incoming solar radiation due to the changes in Earth's orbit around the sun. However, not all climate variations can be explained by this process, and there is the growing awareness of the important role of internal climate feedback mechanisms. Understanding the nature of these feedbacks with regard to the timing of abrupt global sea-level and climate changes is of prime importance. The tropical ocean is one of the major components of the feedback system, and hence reconstructions of temporal variations in sea-surface conditions will greatly improve our understanding of the climate system. The Integrated Ocean Drilling Program (IODP) Expedition 325 drilled 34 holes across 17 sites in the Great Barrier Reef, Australia to recover fossil coral reef deposits. The main aim of the expedition was to understand the environmental changes that occurred during the last ice age and subsequent deglaciation, and more specifically (1) establish the course of sea-level change, (2) reconstruct the oceanographic conditions, and (3) determine the response of the reef to these changes. We recovered coral reef deposits from water depths down to 126 m that ranged in age from 9,000 years to older than 30,000 years ago. Given that the interval of the dated materials covers several paleoclimatologically important events, including the Last Glacial Maximum, we expect that ongoing scientific analyses will fulfill the objectives of the expedition. doi:10.2204/iodp.sd.12.04.2011

  15. Direct ageing of Thunnus thynnus from the eastern Atlantic Ocean and western Mediterranean Sea using dorsal fin spines.

    PubMed

    Luque, P L; Rodriguez-Marin, E; Landa, J; Ruiz, M; Quelle, P; Macias, D; Ortiz De Urbina, J M

    2014-06-01

    This study deals with important methodology issues that affect age estimates of eastern Atlantic bluefin tuna Thunnus thynnus using dorsal fin spines. Nearly 3800 spine sections were used from fish caught in the north-east Atlantic Ocean and western Mediterranean Sea over a 21 year period. Edge type and marginal increment analyses indicated a yearly periodicity of annulus formation with the translucent bands (50% of occurrence) appearing from October to May. Nucleus vascularization seriously affected specimens older than 6 years, with the disappearance of 40-50% of the presumed annuli by that age. An alternate sectioning location was a clear improvement and this finding is an important contribution to the methodology of using this structure for ageing the full-length range of eastern T. thynnus. Finally, there were no significant differences between the coefficients of von Bertalanffy growth model estimated from mean length at age data (L∞  = 327.4; k = 0.097; t0  = -0.838) and those estimated from the growth curves accepted for the eastern and western T. thynnus management units. PMID:24890407

  16. Age and growth of chub mackerel ( Xcomber japonicus) in the East China and Yellow Seas using sectioned otolith samples

    NASA Astrophysics Data System (ADS)

    Li, Gang; Chen, Xinjun; Feng, Bo

    2008-11-01

    Although chub mackerel ( Scomber japonicus) is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion ( AIC), the von Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.

  17. Modelling of tsunami generated by the giant Late Bronze Age eruption of Thera, South Aegean Sea, Greece

    NASA Astrophysics Data System (ADS)

    Novikova, T.; Papadopoulos, G. A.; McCoy, F. W.

    2011-08-01

    Tsunami generated by the Late Bronze Age (LBA) eruption of Thera were simulated using synthetic tide records produced for selected nearshore (˜20 m depths) sites of northern Crete, the Cyclades Islands, SW Turkey and Sicily. Inundation distances inland were also calculated along northern Crete. Modelling was performed by incorporating fully non-linear Boussinesq wave theory with two tsunamigenic mechanisms. The first involved the entry of pyroclastic flows into the sea, assuming a thick (55 m; 30 km3) flow entering the sea along the south coast of Thera in three different directions all directed towards northern Crete, then a thin pyroclastic flow (1 m; 1.2 km3) entering the sea along the north coast of Thera directed towards the Cyclades Islands. Flows were modelled as a solid block that slowly decelerates along a horizontal surface. The second mechanism assumed caldera collapse, of 19 km3 and 34 km3 modelled as a dynamic landslide producing rapid vertical displacements. Calculated nearshore wave amplitudes varied from a few metres to 28 m along northern Crete from pyroclastic flows, and up to 19 m from caldera collapse (34 km3 volume). Inundation distances on Crete were 250-450 m. Waves produced by pyroclastic flows were highly focused, however, as a function of sea entry direction. Smaller volume pyroclastic flows produced nearshore wave amplitudes up to 4 m in the Cyclades islands north of Thera. Wave amplitudes in the Cyclades from smaller volume caldera collapse (19 km3) were up to 24 m, whereas in SW Turkey were as low as 2.1 and 0.8 m (Didim and Fethye where LBA tsunami deposits have been found). Wave amplitudes for the larger volume caldera collapse (34 km3) were generally 2.5-3 times larger than those generated by the smaller volume collapse (19 km3). These results provide estimates for understanding possible consequences of tsunami impact in LBA coastal zones, thus providing criteria at archaeological sites for detecting inundation damage, as well as

  18. On the instability and evolutionary age of deep-sea chemosynthetic communities

    NASA Astrophysics Data System (ADS)

    Vrijenhoek, Robert C.

    2013-08-01

    Though not directly dependent on photosynthesis, deep-sea chemosynthetic communities have not been sheltered from catastrophic changes affecting Earth's photic zone. Instead, the constituent animals may be particularly vulnerable to large climatic changes that have historically affected ocean temperatures and circulation patterns. Chemosynthetic animals occupy narrow redox zones, mostly at hydrothermal vents, hydrocarbon seeps, or sites of organic deposition where subsurface fluids laden with reduced gases (e.g., sulfides, methane, hydrogen) meet oxygenated seawater. Dependence on chemolithoautotrophic bacteria as primary producers may render these deep-sea communities particularly susceptible to climatic changes that alter the breadth of the oxic/anoxic interface. The fossil record clearly reveals major transitions of chemosynthetic faunas during the middle to late Mesozoic, failing to support prior hypotheses that these environments harbor an extraordinary number of ancient relics and living fossils. The molecular phylogenetic analyses summarized herein support Cenozoic (<65 Myr old) radiations for most of the dominant invertebrate taxa now occupying these habitats. Although stem ancestors for many of the mollusks, annelids and crustaceans found at vents and seeps survived the Cretaceous/Tertiary (K/T) extinction event, their contemporary crown taxa radiated mostly after the Paleocene/Eocene thermal maximum (PETM), which led to a widespread anoxic/dysoxic event in the world's deep-ocean basins.

  19. Age-dependent zonation of the periwinkle Littorina littorea (L.) in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Saier, Bettina

    2000-12-01

    On sedimentary tidal flats near the island of Sylt (German Bight, North Sea) abundance and size distribution of periwinkles, Littorina littorea L., were studied in low intertidal and in shallow and deep subtidal mussel beds ( Mytilus edulis L.). In low intertidal mussel beds, surveys revealed that high densities (1,369±571 m-2) of juvenile snails (≤13 mm) were positively correlated with strong barnacle epigrowth ( Semibalanus balanoides L. and Balanus crenatus Bruguière) on mussels. A subsequent field experiment showed that recruitment of L. littorea was restricted to the intertidal zone. Abundances of periwinkles (213±114 m-2) and barnacles abruptly decreased in the adjacent shallow subtidal zone, which served as a habitat for older snails (>13 mm). L. littorea was completely absent from disjunct deep (5 m) subtidal mussel beds. Snail abundance varied seasonally with maxima of >4,000 m-2 in low intertidal mussel beds in October and minima in July, just before the onset of new recruitment. I suggest that the presence of cracks and crevices among the dense barnacle overgrowth in intertidal mussel beds favoured recruitment and survival of juvenile snails. Larger (older) specimens are assumed to actively migrate to the less favourable adjacent subtidal. Therefore, intertidal mussel beds are considered as nurseries for the population of L. littorea in the Wadden Sea.

  20. High precision thorium-230 ages of corals and the timing of sea level fluctuations in the late Quaternary

    SciTech Connect

    Edwards, R.L.

    1988-01-01

    Mass spectrometric techniques for the measurement of {sup 230}Th and {sup 234}U have been developed. These techniques have made it possible to reduce the analytical errors in {sup 230}Th dating of corals using very small samples (10{sup 7} to 10{sup 10} atoms). The time range over which useful data on corals can now be obtained ranges from 15 to 500,000 years. For young corals, this approach may be preferable to {sup 14}C dating. The precision with which the age of a coral can not be determined makes it possible to determine the timing of sea level fluctuations in the late Quaternary. Analyses of a number of corals that grew during the last interglacial period yield ages of 122 to 130 ky. The ages coincide with or slightly postdate the summer solar insolation high at 65{degree}N latitude, which occurred 128 ky ago. This supports the idea that changes in Pleistocene climate can be the result of orbital forcing. Coral ages may allow us to resolve the ages of individual coseismic uplift events and thereby date prehistoric earthquakes. This possibility has been examined at two localities, northwest Santo Island and north Malekula Island, Vanuatu. The {sup 230}Th growth dates of the surfaces of adjacent emerged coral heads, collected from the same elevation on northwest Santo Island, were, within analytical error, identical (A.D. 1866 {plus minus} 4 and A.D. 1864 {plus minus} 4). This indicates that the corals died at the same time and is consistent with the idea that they were killed by coseismic uplift. Similar adjacent coral heads on north Malekula Island yielded {sup 230}Th growth dates of A.D. 1729 {plus minus} 3 and A.D. 1718 {plus minus} 5. The ages are similar but analytically distinguishable. The difference may be due to erosion of the outer, younger, portion of the latter coral head.

  1. DEVELOPING INDICATORS OF SALT MARSH HEALTH

    EPA Science Inventory

    We relate plant zonation in salt marshes to key ecosystem services such as erosion control and wildlife habitat. Ten salt marshes in Narragansett Bay, with similar geological bedrock and sea exchange, were identified to examine plant zonation. Sub-watersheds adjacent to the salt ...

  2. Hygroscopic properties of NaCl and NaNO3 mixture particles as reacted inorganic sea-salt aerosol surrogates

    NASA Astrophysics Data System (ADS)

    Gupta, D.; Kim, H.; Park, G.; Li, X.; Eom, H.-J.; Ro, C.-U.

    2015-03-01

    NaCl in fresh sea-salt aerosol (SSA) particles can partially or fully react with atmospheric NOx/HNO3, so internally mixed NaCl and NaNO3 aerosol particles can co-exist over a wide range of mixing ratios. Laboratory-generated, micrometer-sized NaCl and NaNO3 mixture particles at 10 mixing ratios (mole fractions of NaCl (XNaCl) = 0.1 to 0.9) were examined systematically to observe their hygroscopic behavior, derive experimental phase diagrams for deliquescence and efflorescence, and understand the efflorescence mechanism. During the humidifying process, aerosol particles with the eutonic composition (XNaCl = 0.38) showed only one phase transition at their mutual deliquescence relative humidity (MDRH) of 67.9 (±0.5)% On the other hand, particles with other mixing ratios showed two distinct deliquescence transitions; i.e., the eutonic component dissolved at MDRH, and the remainder in the solid phase dissolved completely at their DRHs depending on the mixing ratios, resulting in a phase diagram composed of four different phases, as predicted thermodynamically. During the dehydration process, NaCl-rich particles (XNaCl > 0.38) showed a two stage efflorescence transition: the first stage was purely driven by the homogeneous nucleation of NaCl and the second stage at the mutual efflorescence RH (MERH) of the eutonic components, with values in the range of 30.0-35.5%. Interestingly, aerosol particles with the eutonic composition (XNaCl = 0.38) also showed two-stage efflorescence, with NaCl crystallizing first followed by heterogeneous nucleation of the remaining NaNO3 on the NaCl seeds. NaNO3-rich particles (XNaCl ≤ 0.3) underwent single-stage efflorescence transitions at ERHs progressively lower than the MERH because of the homogeneous nucleation of NaCl and the almost simultaneous heterogeneous nucleation of NaNO3 on the NaCl seeds. SEM/EDX elemental mapping indicated that the effloresced NaCl-NaNO3 particles at all mixing ratios were composed of a homogeneously

  3. Mid-Holocene stabilization of the Karakum and Kyzylkum sand seas, central Asia - evidence from OSL ages

    NASA Astrophysics Data System (ADS)

    Maman, Shimrit; Tsoar, Haim; Blumberg, Dan G.; Porat, Naomi

    2013-04-01

    Sand seas (ergs) are large areas of deserts covered by wind-swept sand with varying degrees of vegetation cover. The Kyzylkum and Karakum ergs have accumulated in the Turan basin, northwest of the Hindu Kush range, and span from south Turkmenistan to the Syrdarya River in Kazakhstan. These ergs are dissected by the Amudarya River; To the north lies the Kyzylkum (red sands) and to the south the Karakum (black sands). This area is understudied, and little information has been published regarding the sands stabilization processes and deposition ages. This research focuses on identifying and mapping the ergs of Central Asia and analyzing the climate factors that set the dunes into motion and that stabilized them. A variety of spaceborne imagery with varying spectral and spatial resolutions was used. These images provide the basis for mapping sand distribution, dune forms, and vegetation cover. Wilson (1973) defined these ergs as active based on precipitation. Our results show that they are mostly stabilized, with an estimated area of ~260,000 sq. Km for Kara-Kum , and ~195,500 sq. Km for the Kyzyl-Kum . Meteorological analysis of wind and precipitation data indicate a low wind energy environment (DP<200) and sufficient rainfall (>100 mm) to which is essential for vegetation cover. We present the first optically stimulated luminescence (OSL) ages from the upper meter of 14 exposed sections from both ergs. The age of the sand samples was determined as ~Mid-Holocene by OSL, which provides an insight into past climate characteristics. These ages indicate extensive sand and dune stabilization during the Mid-Holocene. GIS analysis was performed in parallel with field work to validate and verify the results. The OSL ages, coupled with a compilation of regional palaeoclimatic data, corroborate and reinforce the previously proposed Mid-Holocene Liavliakan phase, known to reflect a warmer, wetter, less windy climate than persists today and that resulted in dune stabilization

  4. Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks

    NASA Astrophysics Data System (ADS)

    Miller, Gifford H.; Geirsdóttir, Áslaug; Zhong, Yafang; Larsen, Darren J.; Otto-Bliesner, Bette L.; Holland, Marika M.; Bailey, David A.; Refsnider, Kurt A.; Lehman, Scott J.; Southon, John R.; Anderson, Chance; Björnsson, Helgi; Thordarson, Thorvaldur

    2012-01-01

    Northern Hemisphere summer temperatures over the past 8000 years have been paced by the slow decrease in summer insolation resulting from the precession of the equinoxes. However, the causes of superposed century-scale cold summer anomalies, of which the Little Ice Age (LIA) is the most extreme, remain debated, largely because the natural forcings are either weak or, in the case of volcanism, short lived. Here we present precisely dated records of ice-cap growth from Arctic Canada and Iceland showing that LIA summer cold and ice growth began abruptly between 1275 and 1300 AD, followed by a substantial intensification 1430-1455 AD. Intervals of sudden ice growth coincide with two of the most volcanically perturbed half centuries of the past millennium. A transient climate model simulation shows that explosive volcanism produces abrupt summer cooling at these times, and that cold summers can be maintained by sea-ice/ocean feedbacks long after volcanic aerosols are removed. Our results suggest that the onset of the LIA can be linked to an unusual 50-year-long episode with four large sulfur-rich explosive eruptions, each with global sulfate loading >60 Tg. The persistence of cold summers is best explained by consequent sea-ice/ocean feedbacks during a hemispheric summer insolation minimum; large changes in solar irradiance are not required.

  5. Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns.

    PubMed

    Monson, D H; Doak, D F; Ballachey, B E; Johnson, A; Bodkin, J L

    2000-06-01

    We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spill on annual survival increased rather than dissipated for older animals. Otters born after the 1989 spill were affected less than those alive in March 1989, but do show continuing negative effects through 1998. Population-wide effects of the spill appear to have slowly dissipated through time, due largely to the loss of cohorts alive during the spill. Our results demonstrate that the difficult-to-detect long-term impacts of environmental disasters may still be highly significant and can be rigorously analyzed by using a combination of population data, modeling techniques, and statistical analyses. PMID:10823920

  6. Age, growth and reproduction of the sand smelt Atherina boyeri Risso, 1810 in the Gomishan wetland - southeast Caspian Sea

    NASA Astrophysics Data System (ADS)

    Patimar, Rahman; Yousefi, Morteza; Hosieni, Seyyed Morteza

    2009-03-01

    A total of 2256 specimens of Atherina boyeri caught in Gomishan wetland (a marsh lagoon located at the southeast Caspian Sea) during spawning season from February to August 2007 were examined for life-history attributes. The population has a 4-year life cycle. Length-weight relationship was estimated as W = 0.0053TL 3.0181 for males and W = 0.0050TL 3.063 for females, being allometrically positive for both sexes. The von Bertalanffy growth function fitted to back-calculated size at age data was: Lt = 155.17[1 - exp - 0.28( t + 0.738)] and Lt = 162.77[1 - exp - 0.27( t + 0.727)] for males and females respectively. The sex ratio was 1:1.30 in favor of females. The reproductive season, evaluated from GSI, extended from March to July, with a peak in March. The average absolute and relative fecundities were 2976 eggs and 874 eggs g -1 of body weight respectively. The diameter of oocytes ranged from 0.03 to 0.20 mm with a mean value of 0.68. The life-history patterns of A. boyeri in the population under study imply that the population of this species in the southeast Caspian Sea differs markedly from those of other localities of its range distribution. The differences were thought to be due to differences in geographical locations.

  7. Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns

    USGS Publications Warehouse

    Monson, D.H.; Doak, D.F.; Ballachey, B.E.; Johnson, Aaron H.; Bodkin, J.L.

    2000-01-01

    We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spill on annual survival increased rather than dissipated for older animals. Otters born after the 1989 spill were affected less than those alive in March 1989, but do show continuing negative effects through 1998. Population-wide effects of the spill appear to have slowly dissipated through time, due largely to the loss of cohorts alive during the spill. Our results demonstrate that the difficult-to-detect long- term impacts of environmental disasters may still be highly significant and can be rigorously analyzed by using a combination of population data, modeling techniques, and statistical analyses.

  8. Deep-sea scleractinian coral age and depth distributions in the northwest Atlantic for the last 225,000 years

    USGS Publications Warehouse

    Robinson, L.F.; Adkins, J.F.; Scheirer, D.S.; Fernandez, D.P.; Gagnon, A.; Waller, R.G.

    2007-01-01

    Deep-sea corals have grown for over 200,000 yrs on the New England Seamounts in the northwest Atlantic, and this paper describes their distribution both with respect to depth and time. Many thousands of fossil scleractinian corals were collected on a series of cruises from 2003-2005; by contrast, live ones were scarce. On these seamounts, the depth distribution of fossil Desmophyllum dianthus (Esper, 1794) is markedly different to that of the colonial scleractinian corals, extending 750 m deeper in the water column to a distinct cut-off at 2500 m. This cut-off is likely to be controlled by the maximum depth of a notch-shaped feature in the seamount morphology. The ages of D. dianthus corals as determined by U-series measurements range from modern to older than 200,000 yrs. The age distribution is not constant over time, and most corals have ages from the last glacial period. Within the glacial period, increases in coral population density at Muir and Manning Seamounts coincided with times at which large-scale ocean circulation changes have been documented in the deep North Atlantic. Ocean circulation changes have an effect on coral distributions, but the cause of the link is not known. ?? 2007 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.

  9. Maastrichtian-aged lithostratigraphic patterns in the European tethys: Implications for sea level change and end-Cretaceous extinction patterns

    SciTech Connect

    Ward, P.; Macleod, K.G. . Dept. of Geological Sciences)

    1992-01-01

    Thirteen Maastrichtian-aged stratigraphic sections from a variety of sites spanning the ancient Tethys ocean in Western and Eastern Europe and Northern Africa have been measured in this study. The similarity in lithologies between even geographically separated localities allows refined lithostratigraphic correlation; individual members first defined from Bay of Biscay sections can now be recognized through all sections. The sections are found in the Bay of Biscay and Basque region of France and Spain (Sopelana, Zumaya, Hendaye, Bidart, Tercis, Pamplona;) southern Spain (Caravaca, Agost); northern Africa (El Kef); and Eastern Europe (Georgia). All of the sections are dominated by limestones in the Lower Maastrichtian, and marls or limestone-marl rhythmites in the Upper Maastrichtian. A conspicuous, massive limestone, usually 10 to 15 m thick, is found in all sections at the top of the Lower Maastrichtian; it is invariably overlain by a thicker unit composed entirely of marl. The thick limestone contains the last body fossils of the genus Inoceramus, and occurs just beneath the first occurrence of foraminifera diagnostic of the Abathomphalus mayaroensis Zone of Late Maastrichtian age. The dramatic shift in lithology lies at or just beneath the boundary between the Lower and Upper Maastrichtian, and may have been caused by one of the most rapid and profound sea level changes of the Cretaceous Period. The sea-level change may be a causal factor in the mid-Maastrichtian extinction which affected the Inoceramidae and other mollusks, such as the rudistid bivalves and ammonites, and certainly is one of the dominant factors in forming the sequence of lithologies found in the Maastrichtian Stage of Tethys.

  10. Depositional environment, foraminifer content and ESR ages of Quaternary Gediz Delta Sediments (Eastern Aegean Sea, İzmir-Western Turkey)

    NASA Astrophysics Data System (ADS)

    Gökçe Benli, Ekin; Aydın, Hülya; İşintek, İsmail; Engin, Birol; Şengöçmen, Berna

    2016-04-01

    Sediments and fossil content of Gediz Delta (Eastern Aegean Sea - İzmir) were examined based on the drilling core samples of the YSK-C and SK-246 drilling. W-SW part of the Delta is represented by continental delta sediments up to 6 meters and shallow marine detritic sediments up to 35 meters in the YSK-C drilling. Continental part consists of an soiled, graveled, muddy and sandy sediment in terms of rich organic substance. As for marine part, it consists of bioclast, muddy, fine graveled sand and by repetition of pebble, sand and bioclast bearing mud layers. Bioclasts comprise of bivalvia, echinoid, ostracod, gastropod, foramifer and bryozoa fragments. Benthic foraminiferal fauna determinated in the marine levels are represented by 55 bethic, 2 planktonic species. These foraminifers and bioclasts reflect that the W-SW part of the delta, has been occured in marine conditions between 8-31m deep. E-NE part of the delta is generally represented by continental sediments up to 43.5m in SK-246 drilling. In addition, it includes marine levels in 18-19 m, 23-24 m and 36-37,5 m intervals. Continental sediments of E-NE part is generally represented by calcareous and sandy mud rocks which mostly includes ash, tuff, and pebble derived from Neogene volcanic rocks. As for marine levels, it is composed of calcareous mud stones and calcareous clay stones including very thin gastropod, bivalvia and ostracod in 18- 19 and 36-37.5 meters whereas it is represented by sandy mud stones including a great deal of bentic foraminifer, bivalvia, bryozoa, echinoid, gastropod in 23-24 metres. Thus show that E-NE part of the delta is usually in continental condition but it is occasionally covered by sea. In aging studies of YSK-C core done by ESR method, age of 8-9 m interval is determined to be 11. 376 ± 0,067 Ka; however ages of 10-11m and 24-25 m intervals are revealed to be 16.466 ± 0,016 Ka and 15.344 ± 0,021 Ka respectively; finally age of 25-26 m interval is found to be 19.995 ± 0

  11. Formation of the Gulf of Mexico Salt Basin

    NASA Astrophysics Data System (ADS)

    Norton, I. O.; Van Avendonk, H. J.; Christeson, G. L.; Eddy, D. R.

    2014-12-01

    Recently acquired seismic refraction data in the northern Gulf of Mexico (GOM) have provided new insights into the basin's crustal structure. We use the four refraction profiles to build regional-scale crustal sections across the GOM, and then use these profiles as the basis for basin modeling of crustal subsidence through time. Basin modeling includes flexural backstripping of the sediment load and correction for thermal subsidence, with the aim of calculating the shape of the basin at the time (Callovian) of salt deposition. The age of salt deposition relative to rifting events is debated, with opinions ranging from salt being synrift to entirely postrift. We suggest that salt was deposited near the end of rifting, close to the time of initiation of sea floor spreading. This interpretation is based partly on reconstructing possible water depths at the start of salt deposition, using the backstripping method. If water depths were too deep, i.e. sea floor spreading already established, salt thickness based on isostatic balance would be far too large. If water depths were too shallow, i.e. little crustal thinning, salt thickness would be too thin. We can compare the outcome of this analysis with the distribution of evaporites in the Gulf of Mexico basin, which may have formed a 4 km thick layer in some areas, though these salt deposits have subsequently been remobilized. Crustal structure from the refraction data shows crustal thicknesses of 8-15 km under the salt basin. The seismic velocity structure of the thinned crust suggests that at least some of the basement was formed by magmatic intrusions. If we correct for the inferred stretching of the continental margin and thermal subsidence, we obtain a plausible depth for the margin at Callovian time. Velocity structure from the refraction data plus observations of SDRs in the eastern GOM are consistent with the margins of the GOM having a significant synrift volcanic component. We suggest that this volcanic

  12. Radiocarbon Ages from Two Submerged Strandline Features in the Western Gulf of Maine and a Sea-Level Curve for the Northeastern Massachusetts Coastal Region

    USGS Publications Warehouse

    Oldale, R.N.; Colman, Steven M.; Jones, Glenn A.

    1993-01-01

    New radiocarbon dates provide ages for two submerged strandline features on the Massachusetts inner shelf. These ages provide limited control on a relative sea-level (RSL) curve for the late Wisconsinan and Holocene. The curve indicates a late Wisconsinan high stand of RSL of +33 m about 14,000 yr ago and a very short-lived relative low stand of about -43 m at about 12,000 yr ago followed by a rise to present sea level. Rapid changes of RSL around 12,000 yr ago may be related to changes in global glacial meltwater discharge and eustatic sea-level change shown by dated corals off Barbados. Variations in the magnitude and timing of RSL change from south to north along the coast of the western Gulf of Maine are due to greater crustal depression and later deglaciation to the north.

  13. Increase in penguin populations during the Little Ice Age in the Ross Sea, Antarctica

    PubMed Central

    Hu, Qi-Hou; Sun, Li-Guang; Xie, Zhou-Qing; Emslie, Steven D.; Liu, Xiao-Dong

    2013-01-01

    Penguins are an important seabird species in Antarctica and are sensitive to climate and environmental changes. Previous studies indicated that penguin populations increased when the climate became warmer and decreased when it became colder in the maritime Antarctic. Here we determined organic markers in a sediment profile collected at Cape Bird, Ross Island, high Antarctic, and reconstructed the history of Adélie penguin colonies at this location over the past 700 years. The region transformed from a seal to a penguin habitat when the Little Ice Age (LIA; 1500–1800 AD) began. Penguins then became the dominant species. Penguin populations were the highest during ca. 1490 to 1670 AD, a cold period, which is contrary to previous results in other regions much farther north. Different responses to climate change may occur at low latitudes and high latitudes in the Antarctic, even if for same species. PMID:23969993

  14. The radiocarbon age of calcite dissolving at the sea floor: Estimates from pore water data

    SciTech Connect

    Martin, W.R.; McNichol, A.P.; McCorkle, D.C.

    2000-04-01

    The authors measured the radiocarbon content and stable isotopic composition of pore water and bottom water {Sigma}CO{sub 2}, sedimentary organic carbon, and CaCO{sub 3} at two sites on the Ceara Rise, one underlying bottom water that is supersaturated with respect to calcite (Site B), the other underlying under saturated bottom water (Site G). The results were combined with pore water O{sub 2}, {Sigma}CO{sub 2}, and Ca{sup 2+} profiles (Martin and Sayles, 1996) to estimate the radiocarbon content of the CaCO{sub 3} that is dissolving in the sediment mixed layer. At Site G, the CaCO{sub 3} that is dissolving in the upper 2 cm of the sediments is clearly younger (richer in {sup 14}C) than the bulk sedimentary CaCO{sub 3}, indicating that nonhomogeneous CaCO{sub 3} dissolution occurs there. The case for nonhomogeneous dissolution is much weaker at the site underlying supersaturated bottom water. The results indicate that nonhomogeneous dissolution occurs in sediments underlying under saturated bottom water, that the dissolution is rapid relative to the rate of homogenization of the CaCO{sub 3} in the mixed layer by bioturbation, and that the dissolution rate of CaCO{sub 3} decreases as it ages in the sediment mixed layer. The results support the hypothesis, based on solid phase analyses, that the preferential dissolution of young (i.e., radiocarbon-rich) CaCO{sub 3} leads to a pattern of increasing radiocarbon age of mixed-layer CaCO{sub 3} as the degree of under saturation of bottom water increases (Keir, 1984; Broecker et al., 1991).

  15. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  16. The Impact of Gravitationally Self-Consistent Ice Age Sea-Level Variations on the Evolution of the Antarctic Ice Sheet (Invited)

    NASA Astrophysics Data System (ADS)

    Gomez, N. A.; Pollard, D.; Mitrovica, J. X.

    2013-12-01

    We couple a three-dimensional ice sheet-shelf model to a gravitationally self-consistent global sea-level model in order to investigate the ice age stability of the Antarctic Ice Sheet. The coupled model incorporates deformational and gravitational perturbations to a viscoelastic, rotating Earth and it captures the complex spatiotemporal geometry of post-glacial sea-level change, including at the grounding lines of marine-based ice. We apply the coupled model to simulate the evolution of the Antarctic Ice Sheet over the last 40,000 years, focusing in particular on ice distributions and sea levels from the Last Glacial Maximum to present. The results demonstrate, in support of our earlier work based on simplified, one-dimensional ice-sheet models, that the sea-level feedback has a significant stabilizing influence on marine ice-sheets, acting to slow down grounding-line migration relative to ice sheet model simulations that do not include the sea-level coupling. We also explore the sensitivity of the results to adopted Earth and ice model parameters and compare our model predictions to relative sea level (RSL) histories and GPS-derived present-day uplift rates at sites around the periphery of Antarctica. We find that the coupled model yields improved fits to uplift rates. The model also yields fits to the RSL observations that are comparable to those reported in recent, uncoupled simulations in which the viscoelastic Earth model was varied to obtain a best fit.

  17. Uranium-Series Ages of Marine Terrace Corals from the Pacific Coast of North America and Implications for Last-Interglacial Sea Level History

    USGS Publications Warehouse

    Muhs, D.R.; Kennedy, G.L.; Rockwell, T.K.

    1994-01-01

    Few of the marine terraces along the Pacific coast of North America have been dated using uranium-series techniques. Ten terrace sequences from southern Oregon to southern Baja California Sur have yielded fossil corals in quantities suitable for U-series dating by alpha spectrometry. U-series-dated terraces representing the ???80,000 yr sea-level high stand are identified in five areas (Bandon, Oregon; Point Arena, San Nicolas Island, and Point Loma, California; and Punta Banda, Baja California); terraces representing the ???125,000 yr sea-level high stand are identified in eight areas (Cayucos, San Luis Obispo Bay, San Nicolas Island, San Clemente Island, and Point Loma, California; Punta Bands and Isla Guadalupe, Baja California; and Cabo Pulmo, Baja California Sur). On San Nicolas Island, Point Loma, and Punta Bands, both the ???80,000 and the ???125,000 yr terraces are dated. Terraces that may represent the ???105,000 sea-level high stand are rarely preserved and none has yielded corals for U-series dating. Similarity of coral ages from midlatitude, erosional marine terraces with coral ages from emergent, constructional reefs on tropical coastlines suggests a common forcing mechanism, namely glacioeustatically controlled fluctuations in sea level superimposed on steady tectonic uplift. The low marine terrace dated at ???125,000 yr on Isla Guadalupe, Baja California, presumed to be tectonically stable, supports evidence from other localities for a +6-m sea level at that time. Data from the Pacific Coast and a compilation of data from other coasts indicate that sea levels at ???80,000 and ???105,000 yr may have been closer to present sea level (within a few meters) than previous studies have suggested.

  18. Himalaya evolution at Paleogene-Neogene boundary unraveled by zircon age spectrum from Arabian Sea Sediments

    NASA Astrophysics Data System (ADS)

    Feng, Han; Lu, Huayu; Zhang, Hanzhi

    2016-04-01

    Although virtually all the intensive orogenic activities of Himalaya occurred in Neogene, the tectonic evolution of this high mountain range in Paleogene is poorly understood. Investigations of tectonic change pattern at Paleogene-Neogene boundary are important to better understand the interaction between mountain building and climate evolution. Here we present new U-Pb ages of zircon grains from Indus Fan sediments to constrain the orogenic history of Himalaya at Paleogene-Neogene boundary. 11 samples between late Oligocene and early Miocene from ODP 117 cores are dated by the zircon U-Pb technique. We calculate relative contributions of potential sources by counting zircon grains for each sample, and the quantized results indicate Himalaya contributed sediments to the coring site, and an extremely high input from Great and Tethyan Himalaya during late Oligocene-early Miocene. Four samples in Pleistocene are also dated for comparison, which indicates that high proportion of Lesser Himalaya has contributed to the sediment in Pleistocene. Our results suggest that the high contribution of Great and Tethyan Himalaya at Paleogene-Neogene boundary might correlate with the beginning of activity of MCT and extension of STD with leucogranite intrusion along Himalaya, which give rise to the extensive Great Himalaya exhumation. Our study demonstrates that zircon U-Pb dating technique is a good tool to reconstruct erosional history of mountain building on a tectonic timescale. Key words: ODP, Himalaya, Indus Fan, zircon U-Pb dating, Paleogene-Neogene boundary

  19. Benthic assemblages on artificial reefs in the northwestern Adriatic Sea: does structure type and age matter?

    PubMed

    Ponti, Massimo; Fava, Federica; Perlini, Rossella Angela; Giovanardi, Otello; Abbiati, Marco

    2015-03-01

    The use of artificial reefs is on the rise worldwide. While their fish aggregating effects are well known, the epibenthic assemblages have been poorly investigated. Two types of artificial reefs (pyramids of concrete slabs and bundles of concrete tubes) have been deployed out of the Po River Delta in 2006 and 2010. The epibenthic assemblages were investigated in 2009 and 2012. Benthic assemblages on both structure typologies were dominated by species tolerating high sedimentation rates. Dissimilarities were found among assemblages with different ages, and, in less extend, between reef typologies. Colonisation by Mytilus galloprovincialis and other major space occupiers did not follow a clear succession pattern and was not affected by reef typology. Species colonisation was likely driven by variability in environmental conditions and recruitment processes rather than by reef typology. This study suggests that environmental features of the deployment sites should be carefully considered in planning and designing artificial reefs, especially in eutrophic and turbid coastal waters, exposed to high river loads. PMID:25569857

  20. The relationship between the age and depth of the oceanic crust in the central South China Sea

    NASA Astrophysics Data System (ADS)

    Peng, Yi-Jui; Hsu, Shu-Kun; Chiao, Ling-Yun

    2016-04-01

    South China Sea (SCS) is the largest marginal basin in the western Pacific. The onset of seafloor spreading in the central part of the SCS was suggested at 32 Ma. After a ridge jump around 25 Ma, the southwestern sub-basin started to open. The spreading of the entire basin ended at ~16 Ma, then a phase of post-magmatic seamount formation occurred (eg., Taylor and Hayes, 1983; Briais et al.,1993; Barckhausen et al., 2014). In this study, we want to find the relationship between the age and depth of the oceanic crust in the central SCS. We will also study a fracture zone trending NW-SE near to Manila trench and to understand how did the fracture zone affect the development of the SCS. We have analyzed five reflection seismic profiles collected by R/V Ocean Researcher 1 during the cruise ORI-1115. We have correlated the age of seismic strata in the central SCS by comparing to the seismic phase of profile MCS1115-7 that has crossed the IODP drilling site U1431. To understand the characteristics of the fracture zone, we have also applied the analytic signal and Euler deconvolution methods to the gravity and magnetic anomalies related to the fracture zone. We suggest that the fraction zone was formed in order to accommodate the spreading in the east sub-basin. However, this fracture zone is somewhat curved concave southwestward. According to the collision-extrusion model of Tapponnier et al. (1982), the formation of Indochina is followed with the constitution of Ailao Shan-Red River Shear Zone. We suppose that the formation of the fracture zone in this study is similar to the Ailao Shan-Red River Shear Zone. The fan-shaped crustal fabric is distinct in the younger portions of the oceanic basin. Both Ailao Shan-Red River Shear Zone and the fracture zone in northeastern SCS may share the same rotation pole. Furthermore, we have tried to find a relationship between oceanic crust depth and age in this area. The preliminary result shows that the relationship between depth and

  1. Cloud Condensation Nuclei and Chemical Composition of size-resolved particles in a Brazilian megacity: Effect of NPF event, biomass burning and sea salt from remote regions on the CCN properties

    NASA Astrophysics Data System (ADS)

    Souto-Oliveira, Carlos; de Fátima Andrade, Maria; Kumar, Prashant; Lopes, Fabio; Babinski, Marly; Landulfo, Eduado; Vara-Vela, Angel

    2016-04-01

    Atmospheric aerosol particles are an important source of cloud condensation nuclei (CCN). Their microphysics and chemical composition can directly affect development of clouds and precipitation process1,2. Only a few studies in Latin American have reported the impact of urban aerosol on the formation of CCN and their contribution to global climate change3. In this study, we simultaneously measured size distributed particle number concentration (PNC), CCN, black carbon (BC) and elemental concentrations (EC) in aerosol samples from São Paulo city. The PNC was measured by DMPS (model 3936) operated with a DMA (model 3080) and CPC (TSI, model 3010). The CCN was measuredby a single-column continuous-flow stream-wise thermal gradient CCN chamber (DMT CCNC-100). The BC and EC were determined in polycarbonate filter collected by Cascade Impactor (MOUDI-MSP), using a smoke stain reflectometer and an ED-XRF (EDX 700; Shimadzu), respectively. During the study period, which was August to September 2014, four events of new particle formation (NPF), characterizing secondary process of aerosol formation were noted. The total PNC varied between 1106 and 29168 cm‑3, while CCN presented concentrations of 206 to 12761 cm‑3for SS=1.0%. The PNC showed different concentrations during diurnal and nocturnal periods with average of 16392±7811 cm‑3 and 6874±3444cm‑3, respectively. The activated ratio (CCN/CN) presented diurnal and nocturnal values of 0.19±0.10 and 0.41±0.18, while apparent activation diameter (Dact,a) was estimated to be 110±29 and 71±28 nm (SS=0.6%), respectively. Combining EC and BC results with air mass trajectory analysis (Lidar aerosol profiles and Hysplit air trajectories), apportionment events were identified for sea salt and biomass burning from coastal and continental regions, respectively. The nocturnal AR and Dact,apresented values of 0.46±0.11 and 49±15 nm (SS=0.6%) for sea salt events as opposed to 0.33±0.14 and 64±30 nm (SS=0.6%) during

  2. Extreme Dead Sea drying event during the last interglacial from the ICDP Dead Sea Deep Drill Core

    NASA Astrophysics Data System (ADS)

    Goldstein, S.; Stein, M.; Ben-Avraham, Z.; Agnon, A.; Ariztegui, D.; Brauer, A.; Haug, G.; Ito, E.; Kitagawa, H.; Torfstein, A.; Yasuda, Y.

    2012-04-01

    The ICDP funded Dead Sea Deep Drilling Project (DSDDP) recovered the longest and most complete paleo-environmental record in the Middle East, drilling holes in a deep and a shallow site extending to ~450 meters. The Dead Sea expands during the glacials and contracts during interglacials, and the sediments are an archive of the evolving climatic conditions. During glacials the sediments comprise intervals of marl (aragonite, gypsum and detritus) and during interglacials they are salts and marls. We estimate that the deep site core spans ~200 kyr (to early MIS 7). A dramatic discovery is a ~40 cm interval of rounded pebbles at ~235 m below the lake floor, the only clean pebbly unit in the entire core. It appears to be a beach layer, near the deepest part of the Dead Sea, lying above ~35 meters of mainly salt. If it is a beach layer, it implies an almost complete dry-down of the paleo-Dead Sea. The pebble layer lies within the last interglacial interval. Our initial attempt to estimate the age of the possible dry down shows an intriguing correlation between the salt-mud stratigraphy of the Dead Sea core and the oxygen isotope record of Soreq Cave, whereby excursions to light oxygen in the speleothems correspond to periods of salt deposition. Through this comparison, we estimate that the dry down occurred during MIS 5e. The occurrence of ~35 meters of mainly salt along with the pebble layer demonstrates a severe dry interval during MIS 5. This observation has implications for the Middle East today, where the Dead Sea level is dropping as all the countries in the area use the runoff. GCM models indicate a more arid future in the region. The core shows that the runoff nearly stopped during a past warm period without human intervention.

  3. Manufacture of reduced-sodium Cheddar-style cheese with mineral salt replacers.

    PubMed

    Grummer, J; Karalus, M; Zhang, K; Vickers, Z; Schoenfuss, T C

    2012-06-01

    The use of mineral salt replacers to reduce the sodium content in cheese has been investigated as a method to maintain both the salty flavor and the preservative effects of salt. The majority of studies of sodium reduction have used mineral salt replacers at levels too low to produce equal water activity (a(w)) in the finished cheese compared with the full-sodium control. Higher a(w) can result in differences in cheese quality due to differences in the effective salt-to-moisture ratio. This creates differences in biochemical and microbial reactions during aging. We hypothesized that by targeting replacer concentrations to produce the same a(w) as full sodium cheese, changes in cheese quality would be minimized. Stirred-curd Cheddar-style cheese was manufactured and curd was salted with NaCl or naturally reduced sodium sea salt. Reduced-sodium cheeses were created by blends of NaCl or sea salt with KCl, modified KCl, MgCl₂, or CaCl₂ before pressing. Sodium levels in reduced-sodium cheeses ranged from 298 to 388 mg of sodium/100g, whereas the control full-sodium cheese had 665 mg/100g. At 1 wk of age, a(w) of reduced-sodium cheeses were not significantly different from control, which had an a(w) of 0.96. The pH values of all reduced-sodium cheeses, excluding the treatment that combined sea salt and MgCl₂, were lower than those of full-sodium cheese, indicating that the starter culture was possibly less inhibited at the salting step by the replacers than by NaCl. Instrumental hardness values of the treatments with sea salt were higher than in cheeses containing NaCl, with the exception of the NaCl/CaCl₂ treatment, which was the hardest. Treatments with MgCl₂ and modified KCl were generally less hard than other treatments. In-hand and first-bite firmness values correlated with the instrumental texture profile analysis results. Both CaCl₂ and MgCl₂ produced considerable off-flavors in the cheese (bitter, metallic, unclean, and soapy), as measured by

  4. Bubble bursting as an aerosol generation mechanism during an oil spill in the deep-sea environment: molecular dynamics simulations of oil alkanes and dispersants in atmospheric air/salt water interfaces.

    PubMed

    Liyana-Arachchi, Thilanga P; Zhang, Zenghui; Ehrenhauser, Franz S; Avij, Paria; Valsaraj, Kalliat T; Hung, Francisco R

    2014-01-01

    Potential of mean force (PMF) calculations and molecular dynamics (MD) simulations were performed to investigate the properties of oil n-alkanes [i.e., n-pentadecane (C15), n-icosane (C20) and n-triacontane (C30)], as well as several surfactant species [i.e., the standard anionic surfactant sodium dodecyl sulfate (SDS), and three model dispersants similar to the Tween and Span species present in Corexit 9500A] at air/salt water interfaces. This study was motivated by the 2010 Deepwater Horizon (DWH) oil spill, and our simulation results show that, from the thermodynamic point of view, the n-alkanes and the model dispersants have a strong preference to remain at the air/salt water interface, as indicated by the presence of deep free energy minima at these interfaces. The free energy minimum of these n-alkanes becomes deeper as their chain length increases, and as the concentration of surfactant species at the interface increases. The n-alkanes tend to adopt a flat orientation and form aggregates at the bare air/salt water interface. When this interface is coated with surfactants, the n-alkanes tend to adopt more tilted orientations with respect to the vector normal to the interface. These simulation results are consistent with the experimental findings reported in the accompanying paper [Ehrenhauser et al., Environ. Sci.: Processes Impacts 2013, in press, (DOI: 10.1039/c3em00390f)]. The fact that these long-chain n-alkanes show a strong thermodynamic preference to remain at the air/salt water interfaces, especially if these interfaces are coated with surfactants, makes these species very likely to adsorb at the surface of bubbles or droplets and be ejected to the atmosphere by sea surface processes such as whitecaps (breaking waves) and bubble bursting. Finally, the experimental finding that more oil hydrocarbons are ejected when Corexit 9500A is present in the system is consistent with the deeper free energy minima observed for the n-alkanes at the air/salt water

  5. Salt appetite in the elderly.

    PubMed

    Hendi, Khadeja; Leshem, Micah

    2014-11-28

    The present study investigated whether salt appetite in the elderly is impaired similar to thirst because of the commonality of their physiological substrates and whether alterations in salt appetite are related to mood. Elderly (65-85 years, n 30) and middle-aged (45-58 years, n 30) men and women were compared in two test sessions. Thirst, psychophysical ratings of taste solutions, dietary Na and energy intakes, seasoning with salt and sugar, number of salty and sweet snacks consumed, preferred amounts of salt in soup and sugar in tea, and an overall measure of salt appetite and its relationship with mood, nocturia and sleep were measured. Elderly participants were found to be less thirsty and respond less to thirst. In contrast, no impairment of salt appetite was found in them, and although they had a reduced dietary Na intake, it dissipated when corrected for their reduced dietary energy intake. Diet composition and Na intake were found to be similar in middle-aged and elderly participants, despite the lesser intake in elderly participants. There were no age-related differences in the intensity of taste or hedonic profile of Na, in salting habits, in tests of salting soup, or number of salty snacks consumed. No relationship of any measure of salt appetite with mood measured by the Positive and Negative Affect Schedule, frequency of nocturia, or sleep duration was observed. The age-related impairment of the physiology of mineralofluid regulation, while compromising thirst and fluid intake, spares salt appetite, suggesting that salt appetite in humans is not regulated physiologically. Intact salt appetite in the elderly might be utilised judiciously to prevent hyponatraemia, increase thirst and improve appetite. PMID:25287294

  6. Using an independent geochronology based on palaeomagnetic secular variation (PSV) and atmospheric Pb deposition to date Baltic Sea sediments and infer 14C reservoir age

    NASA Astrophysics Data System (ADS)

    Lougheed, Bryan C.; Snowball, Ian; Moros, Matthias; Kabel, Karoline; Muscheler, Raimund; Virtasalo, Joonas J.; Wacker, Lukas

    2012-05-01

    Dating of sediment cores from the Baltic Sea has proven to be difficult due to uncertainties surrounding the 14C reservoir age and a scarcity of macrofossils suitable for dating. Here we present the results of multiple dating methods carried out on cores in the Gotland Deep area of the Baltic Sea. Particular emphasis is placed on the Littorina stage (8 ka ago to the present) of the Baltic Sea and possible changes in the 14C reservoir age of our dated samples. Three geochronological methods are used. Firstly, palaeomagnetic secular variations (PSV) are reconstructed, whereby ages are transferred to PSV features through comparison with varved lake sediment based PSV records. Secondly, lead (Pb) content and stable isotope analysis are used to identify past peaks in anthropogenic atmospheric Pb pollution. Lastly, 14C determinations were carried out on benthic foraminifera (Elphidium spec.) samples from the brackish Littorina stage of the Baltic Sea. Determinations carried out on smaller samples (as low as 4 μg C) employed an experimental, state-of-the-art method involving the direct measurement of CO2 from samples by a gas ion source without the need for a graphitisation step - the first time this method has been performed on foraminifera in an applied study. The PSV chronology, based on the uppermost Littorina stage sediments, produced ten age constraints between 6.29 and 1.29 cal ka BP, and the Pb depositional analysis produced two age constraints associated with the Medieval pollution peak. Analysis of PSV data shows that adequate directional data can be derived from both the present Littorina saline phase muds and Baltic Ice Lake stage varved glacial sediments. Ferrimagnetic iron sulphides, most likely authigenic greigite (Fe3S4), present in the intermediate Ancylus Lake freshwater stage sediments acquire a gyroremanent magnetisation during static alternating field (AF) demagnetisation, preventing the identification of a primary natural remanent magnetisation for

  7. Volatile-Rich Mineral Phases in the Hawaiian Lithosphere: Phlogopites and Carbonates in 0-age Garnet Pyroxenite Xenoliths From Salt Lake Crater, (Oahu, Hawaii).

    NASA Astrophysics Data System (ADS)

    Bizimis, M.; Sen, G.; Salters, V. J.

    2003-12-01

    We present the first detailed Hf, Nd, Sr isotope and trace and major element investigation on clinopyroxene (cpx), garnet, phlogopite and carbonate mineral separates from garnet pyroxenite xenoliths from the Salt Lake crater, Oahu, Hawaii. These xenoliths are brought to the surface by the post-erosional lavas that mark the last stage of the evolution of a Hawaiian volcano. Previous studies have suggested that these pyroxenites are either high pressure cumulates associated with the Honolulu volcanics (HV) post erosional lavas, or MORB-related cumulates at a 80-100 Ma paleo ridge. In both Nd-Hf and Nd-Sr isotope spaces all cpx and garnet data are within the range of the HV and other Hawaiian post-erosional lavas. The Lu-Hf and Sm-Nd isotope systematics of the cpx - garnet pairs give essentially 0 ages, providing the first direct evidence that these garnet pyroxenites are indeed 0-age high pressure cumulates from melts isotopically similar to the HVs. Some 0-age pyroxenites also contain veins with volatile-rich mineral assemblages (phlogopite, carbonates and associated glass pockets), that have infiltrated and reacted with the cpx-garnet matrix. These phlogopites have identical 143Nd/144Nd ratios as the cpx (0.51303) but significantly more radiogenic 87Sr/86Sr (0.7032 - 0.7033 in cpx, 0.70365 - 0.70385 in phlogopites, carbonates and glass). These minerals have higher 87Sr/86Sr (for a given 143Nd/144Nd) than MORBs or HVs and fall at the extension of the horizontal displacement of the post shield and post erosional Hawaiian lavas from the Pacific MORB field in Nd-Sr isotope space. Isotopically then, these volatile phases are more similar to the post-erosional lavas than the shield (Koolau) tholeites, providing new evidence for the involvement of volatiles in the generation of the post-erosional volcanism. The association of these volatile-rich phases with garnet pyroxenites and their absence in the more shallow, spinel peridotites points to a deep (i.e. non

  8. About Weichselian Ice-Marginal Positions South of the Baltic Sea - Stratigraphy and Critical Discussion of Age Estimates

    NASA Astrophysics Data System (ADS)

    Boese, Margot; Hardt, Jacob

    2015-04-01

    In the classical research area of glacial morphology south of the Baltic Sea, the supposed main ice-marginal positions of the Weichselian glaciation have been documented on various maps. The lines in the maps suggest a similar timing of the ice margin along these hypothetical lines and represent a traditional morphostratigraphical approach. Nevertheless, more recent research resulting in stratigraphical interpretations of the related sediments give controversial results about the connectivity of ice-marginal features in the landscape. In addition, the development of new dating techniques reveals more diversified ice dynamics of the Scandinavian ice sheet as well as a time transgressiveness of the formation of major end moraine belts. On the other hand, age estimates generated by various methods don't give an unambiguous pattern of ice advances and retreat phases. The interpretation of geochronological data is a highly sensitive challenge in respect to the methods themselves and in respect to landscape processes induced by Late Glacial climatic phases, the relief, and by human impact during the Holocene. The Pomeranian ice margin will be taken as an example for the diverse interpretations of data obtained by Surface Exposure Dating, Optically Stimulated Luminescence, and Radiocarbon data. The dating methods require material of different origin, such as boulders at the surface, fine grained sediment, and organic material. All methods have been applied for dating the same ice marginal position. The remaining question is to which extent the reactions of the ice margins of the Scandinavian Ice Sheet can be brought into accordance with the general climatic record of long term climate archives or whether local weather conditions linked to changes in the atmospheric flow pattern influenced small scale ice advances or retreat along the fringe of the Scandinavian Ice Sheet.

  9. Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349

    NASA Astrophysics Data System (ADS)

    Li, Chun-Feng; Xu, Xing; Lin, Jian; Sun, Zhen; Zhu, Jian; Yao, Yongjian; Zhao, Xixi; Liu, Qingsong; Kulhanek, Denise K.; Wang, Jian; Song, Taoran; Zhao, Junfeng; Qiu, Ning; Guan, Yongxian; Zhou, Zhiyuan; Williams, Trevor; Bao, Rui; Briais, Anne; Brown, Elizabeth A.; Chen, Yifeng; Clift, Peter D.; Colwell, Frederick S.; Dadd, Kelsie A.; Ding, Weiwei; Almeida, Iván. Hernández; Huang, Xiao-Long; Hyun, Sangmin; Jiang, Tao; Koppers, Anthony A. P.; Li, Qianyu; Liu, Chuanlian; Liu, Zhifei; Nagai, Renata H.; Peleo-Alampay, Alyssa; Su, Xin; Tejada, Maria Luisa G.; Trinh, Hai Son; Yeh, Yi-Ching; Zhang, Chuanlun; Zhang, Fan; Zhang, Guo-Liang

    2014-12-01

    analyses of deep tow magnetic anomalies and International Ocean Discovery Program Expedition 349 cores show that initial seafloor spreading started around 33 Ma in the northeastern South China Sea (SCS), but varied slightly by 1-2 Myr along the northern continent-ocean boundary (COB). A southward ridge jump of ˜20 km occurred around 23.6 Ma in the East Subbasin; this timing also slightly varied along the ridge and was coeval to the onset of seafloor spreading in the Southwest Subbasin, which propagated for about 400 km southwestward from ˜23.6 to ˜21.5 Ma. The terminal age of seafloor spreading is ˜15 Ma in the East Subbasin and ˜16 Ma in the Southwest Subbasin. The full spreading rate in the East Subbasin varied largely from ˜20 to ˜80 km/Myr, but mostly decreased with time except for the period between ˜26.0 Ma and the ridge jump (˜23.6 Ma), within which the rate was the fastest at ˜70 km/Myr on average. The spreading rates are not correlated, in most cases, to magnetic anomaly amplitudes that reflect basement magnetization contrasts. Shipboard magnetic measurements reveal at least one magnetic reversal in the top 100 m of basaltic layers, in addition to large vertical intensity variations. These complexities are caused by late-stage lava flows that are magnetized in a different polarity from the primary basaltic layer emplaced during the main phase of crustal accretion. Deep tow magnetic modeling also reveals this smearing in basement magnetizations by incorporating a contamination coefficient of 0.5, which partly alleviates the problem of assuming a magnetic blocking model of constant thickness and uniform magnetization. The primary contribution to magnetic anomalies of the SCS is not in the top 100 m of the igneous basement.

  10. Uranium-series ages of corals, sea level history, and palaeozoogeography, Canary Islands, Spain: an exploratory study for two Quaternary interglacial periods

    USGS Publications Warehouse

    Muhs, Daniel R.; Meco, Joaquín; Simmons, Kathleen R.

    2014-01-01

    We present the first U-series ages of corals from emergent marine deposits on the Canary Islands. Deposits at + 20 m are 481 ± 39 ka, possibly correlative to marine isotope stage (or MIS) 11, while those at + 12 and + 8 m are 120.5 ± 0.8 ka and 130.2 ± 0.8 ka, respectively, correlative to MIS 5.5. The age, elevations, and uplift rates derived from MIS 5.5 deposits on the Canary Islands allow calculations of hypothetical palaeo-sea levels during the MIS 11 high sea stand. Estimates indicate that the MIS 11 high sea stand likely was at least + 9 m (relative to present sea level) and could have been as high as + 24 m. The most conservative estimates of palaeo-sea level during MIS 11 would require an ice mass loss equivalent to all of the modern Greenland and West Antarctic ice sheets; the more extreme estimates would require additional ice mass loss from the East Antarctic ice sheet. Extralimital southern species of mollusks, found in both MIS 11 and MIS 5.5 deposits on the Canary Islands, imply warmer-than-modern sea surface temperatures during at least a part of MIS 11 and much warmer sea surface temperatures during at least a part of MIS 5.5. Both MIS 11 and MIS 5.5 marine deposits on the Canary Islands contain extralimital northern species of mollusks as well, indicating cooler-than-present waters at times during these interglacial periods. We hypothesize that the co-occurrence of extralimital southern and northern species of marine invertebrates in the fossil record of the Canary Islands reflects its geographic location with respect to major synoptic-scale controls on climate and ocean currents. Previous interglacials may have been characterized by early, insolation-forced warming, along with northward migration of the intertropical convergence zone (ITCZ), accompanied by weakened trade winds and diminished upwelling. This allowed the arrival of extralimital southern taxa from the tropical Senegalese faunal province. During later parts of the MIS 11 and 5

  11. Age depth model construction of the upper section of ICDP Dead Sea Deep Drilling Project based on the high-resolution 14C dating

    NASA Astrophysics Data System (ADS)

    Kitagawa, H.; Nakamura, T.; Neugebauer, I.; Schwab, M. J.; Brauer, A.; Goldstein, S. L.; Stein, M.

    2014-12-01

    To reconstruct environmental, climatic and tectonic histories of the Levant, a deep drilling has been accomplished in the northern basin of the Dead Sea during the fall winter of 2010-2011 by the Dead Sea Deep Drilling Project (DSDDP) in the framework of the ICDP program. The sediment cores from site 5017-1 (water depth of ~300 m) recorded the paleoenvironmental and paleohydrological changes in the Dead Sea and the Levant during the last two glacial-interglacial cycles (Neugebauer et al., QSR in press). To provide precise timing of sedimentological - limnological events in the lake and its watershed, and more critically the relative timing of these events, radiocarbon dating of >70 well-preserved terrestrial plants and some carbonate deposits from the upper 150 m long section of the sediment core were performed. Based on the high-resolution radiocarbon dating, a statistical age-depth model was constructed with assumptions on the deposition condition and the radiocarbon age offset of carbonate samples. We discuss the practicality and the limitation of the age-depth model toward interpreting the high-resolution records of environmental, climatic and tectonic events recorded in the long sediment cores from site 5017-1.

  12. Aging.

    PubMed

    Park, Dong Choon; Yeo, Seung Geun

    2013-09-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  13. Aging

    PubMed Central

    Park, Dong Choon

    2013-01-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  14. Quantifying Sea Ice Advection Through Key "Gates" in the Arctic Using the Sea Ice Motion and Age Data Products at the University of Colorado, Boulder With Applications to Studying Changes in the Arctic Ice Pack.

    NASA Astrophysics Data System (ADS)

    Tooth, M.; Tschudi, M. A.

    2015-12-01

    The past several decades have seen an alarming decline in sea ice extent, and a trend toward thinner, first-year ice throughout the Arctic. This younger ice has a lower probability of surviving the next melt season, and features different surface properties than multi-year ice floes typically possess. Through the combination of satellite passive microwave observations and buoy data, the motion and age of the ice pack in the Arctic are tracked and analyzed using datasets produced at the University of Colorado, Boulder that are archived at the National Snow and Ice Data Center. The ice motion product is produced daily from 1978 to the present, and the weekly age data span from 1985 onward. Using these products, the advection of first-year and multi-year ice is tracked through several key ice "gates" throughout the Arctic on relatively short time scales. Understanding the "sinks" that sea ice travels to and melts in will provide a more complete picture of the underlying causes in the decline in sea ice extent and volume in the Arctic. Through tracking the trajectory and locations of ice parcels in our ice motion product, we can also use other co-located data products to assess the impact of radiative and other climate component forcing on the Arctic ice pack.

  15. Variability of 14C reservoir age and air-sea flux of CO2 in the Peru-Chile upwelling region during the past 12,000 years

    NASA Astrophysics Data System (ADS)

    Carré, Matthieu; Jackson, Donald; Maldonado, Antonio; Chase, Brian M.; Sachs, Julian P.

    2016-01-01

    The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air-sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air-sea carbon flux in this region.

  16. Loss of ‘Blue Carbon’ from Coastal Salt Marshes Following Habitat Disturbance

    PubMed Central

    Macreadie, Peter I.; Hughes, A. Randall; Kimbro, David L.

    2013-01-01

    Increased recognition of the global importance of salt marshes as ‘blue carbon’ (C) sinks has led to concern that salt marshes could release large amounts of stored C into the atmosphere (as CO2) if they continue undergoing disturbance, thereby accelerating climate change. Empirical evidence of C release following salt marsh habitat loss due to disturbance is rare, yet such information is essential for inclusion of salt marshes in greenhouse gas emission reduction and offset schemes. Here we investigated the stability of salt marsh (Spartinaalterniflora) sediment C levels following seagrass (Thallasiatestudinum) wrack accumulation; a form of disturbance common throughout the world that removes large areas of plant biomass in salt marshes. At our study site (St Joseph Bay, Florida, USA), we recorded 296 patches (7.5 ± 2.3 m2 mean area ± SE) of vegetation loss (aged 3-12 months) in a salt marsh meadow the size of a soccer field (7 275 m2). Within these disturbed patches, levels of organic C in the subsurface zone (1-5 cm depth) were ~30% lower than the surrounding undisturbed meadow. Subsequent analyses showed that the decline in subsurface C levels in disturbed patches was due to loss of below-ground plant (salt marsh) biomass, which otherwise forms the main component of the long-term ‘refractory’ C stock. We conclude that disturbance to salt marsh habitat due to wrack accumulation can cause significant release of below-ground C; which could shift salt marshes from C sinks to C sources, depending on the intensity and scale of disturbance. This mechanism of C release is likely to increase in the future due to sea level rise; which could increase wrack production due to increasing storminess, and will facilitate delivery of wrack into salt marsh zones due to higher and more frequent inundation. PMID:23861964

  17. Common Era Sea-Level Change

    NASA Astrophysics Data System (ADS)

    Horton, B.; Kemp, A.; Kopp, R. E., III

    2014-12-01

    The Atlantic coast of North America provides a sedimentary record of Common Era sea levels with the resolution to identify the mechanisms that cause spatial variability in sea-level rise. This coast has a small tidal range, improving the precision of sea-level reconstructions. Coastal subsidence (from glacial isostatic adjustment, GIA) creates accommodation space that is filled by salt-marsh peat and preserves accurate and precise sea-level indicators and abundant material for radiocarbon dating. In addition, the western North Atlantic Ocean is sensitive to spatial variability in sea-level change, because of static equilibrium effects from melting of the Greenland Ice Sheet, ocean circulation and wind-driven variability in the Gulf Stream and GIA induced land-level change from ongoing collapse of Laurentide forbuldge. We reveal three distinct patters in sea-level during the Common Era along the North American Atlantic coast, likely linked to wind-driven changes in the Gulf Stream: (1) Florida, sea level is essentially flat, with the record dominated by long-term geological processes; (2) North Carolina, sea level falls to a minimum near the beginning of the second millennium, climbing to an early Little Ice Age maximum in the fifteenth century, and then declining through most of the nineteenth century; and (3) New Jersey, a sea-level maximum around 900 CE, a sea-level minimum around 1500 CE, and a long-term sea-level rise through the second half of the second millennium. We combine the salt-marsh data from North American Atlantic coast with tide-gauge records and lower resolution proxies from the northern and southern hemispheres. We apply a noisy-input Gaussian process spatio-temporal modeling framework, which identifies a long-term falling global mean sea-level (GMSL), interrupted in the middle of the 19th century by an acceleration yielding a 20th century rate of rise extremely likely (probability P = 0:95) faster than any previous century in the Common Era.

  18. Sea level pressure variability in the Amundsen Sea region inferred from a West Antarctic glaciochemical record

    NASA Astrophysics Data System (ADS)

    Kreutz, K. J.; Mayewski, P. A.; Pittalwala, I. I.; Meeker, L. D.; Twickler, M. S.; Whitlow, S. I.

    2000-02-01

    Using European Center for Medium-Range Weather Forecasts (ECMWF) numerical operational analyses, sea ice extent records, and station pressure data, we investigate the influence of sea level pressure variability in the Amundsen Sea region on a West Antarctic (Siple Dome) glaciochemical record. Empirical orthogonal function analysis of the high-resolution Siple Dome multivariate ice core chemical time series record (SDEOF1) documents lower tropospheric transport of sea-salt aerosols to the site. During 1985-1994 the SDEOF1 record of high (low) aerosol transport corresponds to anomalously low (high) sea level pressure (SLP) in the Amundsen Sea region. Spatial correlation patterns between ECMWF monthly SLP fields and the annual SDEOF1 record suggest that a majority of sea-salt aerosol is transported to Siple Dome during spring (September, October, and November). Analysis of zonal and meridional wind fields supports the SLP/SDEOF1 correlation and suggests the SDEOF1 record is sensitive to changes in regional circulation strength. No relationship is found between sea ice extent and the SDEOF1 record for the period 1973-1994. To investigate the SDEOF1 record prior to ECMWF coverage, a spring transpolar index (STPI) is created, using normalized SLP records from the New Zealand and South America/Antarctic Peninsula sectors, and is significantly correlated (at least 95% c.l.) with the SDEOF1 record on an annual (r = 0.32, p < 0.001) and interannual (3 years; r = 0.51, p < 0.001) basis. Dominant periodicities (3.3 and 7.1 years) in the annual SDEOF1 record (1890-1994 A.D.) suggest that a portion of the recorded interannual variability may be related tropical/extratropical ENSO teleconnections. Changes in the periodic structure of the full (850-1994 A.D.) Siple Dome record suggests a shift in SLP forcing during the Little Ice Age (˜1400-1900 A.D.) interval.

  19. Community solar salt production in Goa, India

    PubMed Central

    2012-01-01

    Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa’s riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans. Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1–2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested. Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced. The aim of this review is to describe salt farming in Goa’s history, importance of salt production as a community activity, traditional method of salt production and the

  20. Community solar salt production in Goa, India.

    PubMed

    Mani, Kabilan; Salgaonkar, Bhakti B; Das, Deepthi; Bragança, Judith M

    2012-01-01

    Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa's riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans.Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1-2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested.Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced.The aim of this review is to describe salt farming in Goa's history, importance of salt production as a community activity, traditional method of salt production and the biota

  1. Liking, salt taste perception and use of table salt when consuming reduced-salt chicken stews in light of South Africa's new salt regulations.

    PubMed

    De Kock, H L; Zandstra, E H; Sayed, N; Wentzel-Viljoen, E

    2016-01-01

    This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products. PMID:26415915

  2. Age distributions of sea otters found dead in Prince William Sound, Alaska, following the Exxon Valdez oil spill. Marine mammal study 6-15. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Monson, D.H.; Ballachey, B.

    1995-06-01

    Age distribution of sea otters (Enhydra lutris) found dead on beaches in western Prince William Sound Alaska, from 1976 to 1984, were compared to those of sea otters found dead from 1989 to 1993, following the Exxon Valdez oil spill. The age distribution of sea otters recovered in western Prince William Sound prior to the spill was bimodal and composed of primarily young and old animals. The high proportion of prime-age otters recovered immediately following the spill indicates significant losses occurred within a segment of the population which normally experiences very low mortality. The high proportion of prime-age otters recovered in 1990-1991 may be evidence of a prolonged, spill-related effect on the western Prince William Sound sea otter population.

  3. Relative sea-level response to Little Ice Age ice mass change in south central Alaska: Reconciling model predictions and geological evidence

    NASA Astrophysics Data System (ADS)

    Barlow, Natasha L. M.; Shennan, Ian; Long, Antony J.

    2012-01-01

    Integration of geological data and glacio-isostatic adjustment (GIA) modelling shows that it is possible to decouple complex mechanisms of relative sea-level (RSL) change in a tectonically active glacial environment. We model a simplest solution in which RSL changes in upper Cook Inlet, Alaska, are a combination of the interplay of tectonic and isostatic processes driven by the unique rheology of this tectonically active location. We calculate interseismic uplift during latter part of the penultimate earthquake cycle to vary from 0.3 to 0.7 mm/yr. Diatom based reconstructions of RSL from tidal marsh sediment sequences coupled with detailed age models, from AD 1400 to the AD 1964 great earthquake, show deviations from a purely tectonically driven model of regional RSL. Glacial isostatic modelling, constrained by GPS data, predicts up to 70 cm sea-level change due to mountain glacier mass balance changes during the Little Ice Age. Misfits between the GIA model predictions and RSL reconstructions in the 19th and 20th century highlight that the tidal marshes of upper Cook Inlet potentially record a hemispheric-wide acceleration in sea level and that other more complex Earth process combinations may contribute to regional RSL change.

  4. Accretion of a New England (U.S.A.) salt marsh in response to inlet migration, storms, and sea-level rise

    USGS Publications Warehouse

    Roman, C.T.; Peck, J.A.; Allen, J.R.; King, J.W.; Appleby, P.G.

    1997-01-01

    Sediment accumulation rates were determined at several sites throughout Nauset Marsh (Massachusetts, U.S.A.), a back-barrier lagoonal system, using feldspar marker horizons to evaluate short-term rates (1 to 2 year scales) and radiometric techniques to estimate rates over longer time scales (137Cs, 210Pb, 14C). The barrier spit fronting the Spartima-dominated study site has a complex geomorphic history of inlet migration and overwash events. This study evaluates sediment accumulation rates in relation to inlet migration, storm events and sea-level rise. The marker horizon technique displayed strong temporal and spatial variability in response to storm events and proximity to the inlet. Sediment accumulation rates of up to 24 mm year-1 were recorded in the immediate vicinity of the inlet during a period that included several major coastal storms, while feldspar sites remote from the inlet had substantially lower rates (trace accumulation to 2.2 mm year-1). During storm-free periods, accumulation rates did not exceed 6.7 mm year-1, but remained quite variable among sites. Based on 137Cs (3.8 to 4.5 mm year-1) and 210Pb (2.6 to 4.2 mm year-1) radiometric techniques, integrating sediment accumulation over decadal time scales, the marsh appeared to be keeping pace with the relative rate of sea-level rise from 1921 to 1993 of 2.4 mm year-1. At one site, the 210Pb-based sedimentation rate and rate of relative sea-level rise were nearly similar and peat rhizome analysis revealed that Distichlis spicata recently replaced this once S. patens site, suggesting that this portion of Nauset Marsh may be getting wetter, thus representing an initial response to wetland submergence. Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea-level rise.

  5. Age-specific reproduction in female sea otters (`enhydra lutris`) from southcentral Alaska: Analysis of reproductive tracts. Marine mammal study 6-4. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Bodkin, J.L.; Mulcahy, D.M.; Lensink, C.J.

    1996-06-01

    We estimated age of sexual maturity and age-specific reproductive rates by examining carcasses and reproductive tracts from 177 female sea otters (Enhydra lutris). Carcasses were recovered from southcentral Alaska, primarily western Prince William Sound, following the T/V Exxon Valdez oil spill in 1989. Our estimates of the reproductive characteristics of female sea otters obtained by examination of reproductive tracts were similar to those in the literature based on in situ observations of marked individuals.

  6. Recent Trends in Bird Abundance on Rhode Island Salt Marshes

    EPA Science Inventory

    Salt marsh habitat is under pressure from development on the landward side, and sea level rise from the seaward side. The resulting loss of habitat is potentially disastrous for salt marsh dependent species. To assess the population status of three species of salt marsh dependent...

  7. North Atlantic sea-level variability during the last millennium

    NASA Astrophysics Data System (ADS)

    Gehrels, Roland; Long, Antony; Saher, Margot; Barlow, Natasha; Blaauw, Maarten; Haigh, Ivan; Woodworth, Philip

    2014-05-01

    Climate modelling studies have demonstrated that spatial and temporal sea-level variability observed in North Atlantic tide-gauge records is controlled by a complex array of processes, including ice-ocean mass exchange, freshwater forcing, steric changes, changes in wind fields, and variations in the speed of the Gulf Stream. Longer records of sea-level change, also covering the pre-industrial period, are important as a 'natural' and long-term baseline against which to test model performance and to place recent and future sea-level changes and ice-sheet change into a long-term context. Such records can only be reliably and continuously reconstructed from proxy methods. Salt marshes are capable of recording decimetre-scale sea-level variations with high precision and accuracy. In this paper we present four new high-resolution proxy records of (sub-) decadal sea-level variability reconstructed from salt-marsh sediments in Iceland, Nova Scotia, Maine and Connecticut that span the past 400 to 900 years. Our records, based on more than 100 new radiocarbon analyses, Pb-210 and Cs-137 measurements as well as other biological and geochemical age markers, together with hundreds of new microfossil observations from contemporary and fossil salt marshes, capture not only the rapid 20th century sea-level rise, but also small-scale (decimetre, multi-decadal) sea-level fluctuations during preceding centuries. We show that in Iceland three periods of rapid sea-level rise are synchronous with the three largest positive shifts of the reconstructed North Atlantic Oscillation (NAO) index. Along the North American east coast we compare our data with salt-marsh records from New Jersey, North Carolina and Florida and observe a trend of increased pre-industrial sea-level variability from south to north (Florida to Nova Scotia). Mass changes and freshwater forcing cannot explain this pattern. Based on comparisons with instrumental sea-level data and modelling studies we hypothesise that

  8. Salt Marshes as Monitors of Late Holocene Outlet Glacier Retreat

    NASA Astrophysics Data System (ADS)

    Wake, L. M.; Woodroffe, S.; Long, A. J.; Milne, G. A.

    2014-12-01

    New proxy sea-level records extracted from salt marshes in the vicinity of Jakobshavn Isbrae (Pakitsoq; 69.51°N, 50.74°W) and at previous sites in central western Greenland (Sisimiut; 66.47°N, 53.61°W and Aasiaat; 68.69°N, 52.88°W) are analyzed with respect to their ability to act as proximal tide gauges detecting mass balance changes in nearby outlet glaciers associated with the transition from the Little Ice Age ("LIA", 1400-1850AD) to the Industrial Period (>1850AD). Data at Pakitsoq demonstrate that sea-level rose at a rate of 3.5 ±1.7 mm/yr prior to 1850AD and slowed to 0.3 ±0.6mm/yr thereafter, producing a slowdown in sea level of 3.2 ± 1.8 mm/yr. A similar slowdown, occurring at 1600AD, is observed at Aasiaat and Sisimiut. We interpret these observed changes using a glacial isostatic adjustment model of sea-level change truncated at degree and order 4096, with an aim to determine if the sea-level data can be used to place constraints on changes in Jakobshavn Isbrae and/or Kangiata Nunaata Sermia (Nuuk fjord) during this period. Modelled sea level at Pakitsoq is insensitive to the location of thickening (thinning) associated with grounding line advance (retreat) and the rate of advance and retreat but is sensitive to the change point in time between periods of growth associated with LIA expansion (sea level rise) and the onset of 19th century recession (sea level fall) of Jakobshavn Isbrae. We conclude that the change in sea-level rate observed at Pakitsoq circa 1850AD marks the onset of post LIA retreat of this outlet glacier. Conversely, the modelled sea-level response to the retreat of Kangiata Nunaata Sermia from its LIA maximum at ca. 1761AD is below the detection threshold of the salt marsh record at Sisimiut.

  9. Accretion of a New England (U.S.A.) salt march in response to inlet migration, storms, and sea-level rise

    USGS Publications Warehouse

    Roman, C.T.; Peck, J.A.; Allen, J.R.; King, J.W.; Appleby, P.G.

    1997-01-01

    Sediment accumulation rates were determined at several sites throughout Nauset Marsh (Massachusetts, U.S.A.), a back-barrier lagoonal system, using feldspar marker horizons to evaluate short-term rates (1 to 2 year scales) and radiometric techniques to estimate rates over longer time scales (137Cs, 210Pb, 14C). The barrier spit fronting the Spartina-dominated study site has a complex geomorphic history of inlet migration and over-wash events. This study evaluates sediment accumulation rates in relation to inlet migration, storm events, and sea-level rise. The marker horizon technique displayed strong temporal and spatial variability in response to storm events and proximity to the inlet. Sediment accumulation rates of up to 24 mm year -1 were recorded in the immediate vicinity of the inlet during a period that included several major coastal storms, while feldspar sites remote from the inlet had substantially lower rates (trace accumulation to 2.2 mm year -1). During storm-free periods, accumulation rates did not exceed 6.7 mm year -1, but remained quite variable among sites. Based on 137Cs (3.8 to 4.5 mm year -1) and 210Pb (2.6 to 4.2 mm year -1) radiometric techniques, integrating sediment accumulation over decadal time scales, the marsh appeared to be keeping pace with the relative rate of sealevel rise from 1921 to 1993 of 2.4 mm year -1. At one site, the 210Pb-based sedimentation rate and rate of relative sea-level rise were nearly similar and peat rhizome analysis revealed that Distichlis spicata recently replaced this once S.patens site, suggesting that this portion of Nauset Marsh may be getting wetter, thus representing an initial response to wetland submergence. Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea

  10. Use of stable isotopes, tritium, soluble salts, and redox-sensitive elements to distinguish ground water from irrigation water in the Salton Sea basin

    USGS Publications Warehouse

    Schroeder, Roy A.; Setmire, James G.; Densmore, Jill N.

    1991-01-01

    Evaporative concentration of irrigation water diverted from the Colorado River to the Salton Sea basin for several decades has produced an overlying system (that includes drainwater and surface waters) whose composition is highly variable and differs from that of the shallow regional ground water beneath it. The role of hydrologic and geochemical processes in causing these differences (and the variability) is inferred from analyses of selected isotopes (3H, D, 18O, 15N, 34S) and elements (As, B, Br, Cl, Fe, N, Se). Selected element-to-Cl ratios establish the relative importance and location of the various processes. Isotopes of H O are used in estimating the relative contribution of leakage from an unlined canal and regional ground water to a nearby spring.

  11. A search for scale in sea-level studies

    USGS Publications Warehouse

    Larsen, C.E.; Clark, I.

    2006-01-01

    Many researchers assume a proportional relationship among the atmospheric CO2 concentration, temperature, and sea level. Thus, the rate of sea-level rise should increase in concert with the documented exponential increase in CO2. Although sea surface temperature has increased in places over the past century and short-term sea level rose abruptly during the 1990s, it is difficult to demonstrate a proportional relationship using existing geologic or historic records. Tide gauge records in the United States cover too short a time interval to verify acceleration in the rate of sea-level rise, although multicentury tide gauge and staff records from the Netherlands and Sweden suggest a mid-19th-century acceleration in sea-level rise. Reconstructions of sea-level changes for the past 1000 years derived using benthic foraminifer data from salt marshes along the East Coast of the United States suggest an increased rate of relative sea-level rise beginning in the 1600s. Geologic records of relative sea-level rise for the past 6000 years are available for several sites along the US East Coast from 14C-dated basal peat below salt marshes and estuarine sediments. When these three scales of sea-level variation are integrated, adjusted for postglacial isostatic movement, and replotted, the range of variation in sea level suggested by basal peat ages is within ??1 meter of the long-term trend. The reconstruction from Long Island Sound data shows a linear rise in sea level beginning in the mid-1600s at a rate consistent with the historic record of mean high water. Long-term tide gauge records from Europe and North America show similar trends since the mid-19th century. There is no clear proportional exponential increase in the rate of sea-level rise. If proportionality exists among sea level, atmospheric CO2, and temperature, there may be a significant time lag before an anthropogenic increase in the rate of sea-level rise occurs.

  12. Ageing of native cellulose fibres under archaeological conditions: textiles from the Dead Sea region studied using synchrotron X-ray microdiffraction

    NASA Astrophysics Data System (ADS)

    Müller, M.; Murphy, B.; Burghammer, M.; Riekel, C.; Pantos, E.; Gunneweg, J.

    2007-12-01

    Archaeological cellulose textile fibres (linen and cotton) from caves in the Dead Sea region were investigated using synchrotron X-ray microdiffraction. The degradation of the up to 2100 year old fibres was found to depend on the climatic conditions at the place of storage. The size and the lattice parameters of the cellulose nanocrystals (microfibrils) in the fibres change upon degradation; these parameters are shown to be strongly correlated, leading to a microscopic description of the degradation process in terms of molecular disorder. Artificial ageing does not seem to reproduce the effects observed here for the first time on archaeological cellulose fibres.

  13. Vertical distribution and source identification of polycyclic aromatic hydrocarbons (PAHs) in southwest of the Caspian Sea: most petrogenic events during the late Little Ice Age.

    PubMed

    Varnosfaderany, Mohammad Nemati; Bakhtiari, Alireza Riyahi; Gu, Zhaoyan; Chu, Guoqiang

    2014-10-15

    In this study, 75 samples of two (210)Pb-dated cores from the southwest of the Caspian Sea were analysed for 30 compounds of polycyclic aromatic hydrocarbons (PAHs). The TPAH29 flux of the last six centuries ranged from 16.3 to 177.3 and 22.3 to 426.2 ng cm(-2)y(-1) in the Rezvanshahr and Anzali core sediments, respectively. Prior to 1840, four distinct maxima in PAH fluxes (61-426.2 ng cm(-2)y(-1)) with a low weathered petrogenic pattern were found in each of the core sediments. Simultaneity of distinct peaks of PAH fluxes before 1840 and Caspian Sea level high-stands during the Little Ice Age (LIA), revealed the high importance of this phenomenon in washing and transport of land-based oil pollution into the Caspian Sea. An overall increase in some diagnostic ratios (Flu/202, IP/276 and BaA/228), especially after 1940, indicated increase of pyrogenic PAHs as a result of industrial development in the catchment area. PMID:25131419

  14. Feeding ecology of age-0 walleye pollock (Gadus chalcogrammus) and Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Strasburger, Wesley W.; Hillgruber, Nicola; Pinchuk, Alexei I.; Mueter, Franz J.

    2014-11-01

    Walleye pollock (Gadus chalcogrammus) and Pacific cod (Gadus macrocephalus) are of particular economic and ecological importance in the southeastern Bering Sea. The spatial and temporal overlap of early life stages of both species may explain their strongly correlated recruitment trends. Pelagic larvae and juveniles were collected during four research cruises in May, July and September of 2008, an exceptionally cold year, and their stomach contents were examined. Feeding success and diet composition of walleye pollock and Pacific cod were consistently different in spring, summer, and fall. Pacific cod larvae and juveniles always consumed larger and progressively fewer prey items per stomach than walleye pollock; this difference was particularly pronounced in the fall. Our data suggest that co-occurring early life stages of walleye pollock and Pacific cod were dividing prey resources rather than competing for them, at least during the exceptionally cold conditions in 2008 in the southeastern Bering Sea.

  15. Age of overwash and rate of relative sea-level rise inferred from detrital heads and microatolls of medieval corals at Anegada, British Virgin Islands

    NASA Astrophysics Data System (ADS)

    Jennifer, W.; Feuillet, N.; Robert, H.; Brian, A.; Ten Brink, U. S.; Deschamps, P.; Tuttle, M. P.; Wei, Y.; Fuentes, Z.

    2012-12-01

    Coral boulders deposited on Anegada, an island 120 km south of the Puerto Rico Trench, record overwash dated to AD 1200-1450 and relative sea-level changes that preceded it. Composed largely of Pleistocene limestone, Anegada is less than 8 m above sea level and is fringed on the north and east by a coral reef where Atlantic Ocean waves break. The lowest parts of the island were washed over from the north in AD 1650-1800, as judged from landforms and deposits reported previously (doi:10.1007/s11069-010-9622-6). The coral boulders indicate overwash of higher elevation and earlier age. The boulders were apparently torn from the adjacent reef by a tsunami of nearby origin, as inferred in companion abstracts on geology and modeling. We found the corals scattered in five areas inland from the north shore. Two of the areas show solitary coral heads 1500 m from the reef. The boulders are more numerous in the three other areas, where they are up to 500-700 m from the reef and up to 4 m above sea level. Some were transported over beach ridges or through breaches cut into them. Others are hundreds of meters inland from a modern storm berm. Most rest on the Pleistocene limestone. Many are overturned. Most are broken but few are whole. The largest measured diameter is 2 m and the greatest measured height is 1 m. Most of the boulders are of the brain coral Diploria strigosa, but smaller Porites asteroides and Montastrea annularis are also present. Some of the D. strigosa retain the rounded shape typical of living heads and are dimpled with holes perhaps left by feather-duster worms. The preservation of these features suggests that many of the boulders came ashore alive. We avoided dating a head that shows field evidence for death before transport; an erosional surface cuts across its youngest growth bands and is covered with the remains of encrusting marine organisms. Among the 18 coral boulders dated, 13 form a young group with ages in the range 890±25 to 1020±25 14C yr BP

  16. Phosphate salts

    MedlinePlus

    ... taken by mouth or used as enemas. Indigestion. Aluminum phosphate and calcium phosphate are FDA-permitted ingredients ... Phosphate salts containing sodium, potassium, aluminum, or calcium are LIKELY SAFE for most people when taken by mouth short-term, when sodium phosphate is inserted into the ...

  17. Origin and permeability of deep ocean salts

    NASA Astrophysics Data System (ADS)

    Hovland, M.; Rueslåtten, H.

    2009-04-01

    Large, buried salt bodies occur in numerous offshore rift-related sedimentary basins, worldwide. For most practical purposes, the conventional evaporite (solar evaporation of seawater) theory is adequate for explaining these occurrences. However, a new model for their formation has now been published (Hovland et al., 2006; 2007, 2008). This model relies on the properties of supercritical water, a fluid which does not dissolve salt (within specific temperature and pressure ranges). The model predicts that some of the large volumes of salt occurring underground in the Red Sea and also in the Mediterranean Sea, formed by forced hydrothermal circulation of seawater down to depths where it became superctical (i.e., temperatures above 405°C, and pressures above 300 bars). Thus, salt precipitated under-ground and filled up cracks and crevices and also formed massive accumulations, which partly flowed upwards as dense, hot brines, precipitating more solid salts upon cooling. In addition, Holness and Lewis (1997) have shown experimentally that salt bodies subjected to high pressures and elevated temperatures, acquire a permeability comparable to sand. This is because the crystalline structure of salt (halite) attains dihedral angles between salt crystals less than 60° at higher temperatures and pressures, allowing water to form continuous strings around all salt crystals. This allows hot dense brines to migrate through the salt. Thus, the salt may act as conduits for flow of brines and salt slurries from previously accumulated salt in the subsurface. If these brines reach the sea floor, they can also form brine-pools and layered salt bodies on the sea floor. An IODP Pre-proposal (No. 741-pre) is now actively promoting drilling some targets in order of checking out this new theory against the conventional evaporite model. It is hoped that European scientists will take up this question and actively promote drilling into salt bodies, for example in the Red Sea (The

  18. Constraining the dynamic response of subcontinental lithospheric mantle to rifting using Re-Os model ages in the Western Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Doherty, C.; Class, C.; Goldstein, S. L.; Shirey, S. B.; Martin, A. P.; Cooper, A. F.; Berg, J. H.; Gamble, J. A.

    2012-12-01

    In order to understand the dynamic response of the subcontinental lithospheric mantle (SCLM) to rifting, it is important to be able to distinguish the geochemical signatures of SCLM vs. asthenosphere. Recent work demonstrates that unradiogenic Os isotope ratios can indicate old depletion events in the convecting upper mantle (e.g. Rudnick & Walker, 2009), and allow us to make these distinctions. Thus, if SCLM can be traced across a rifted margin, its fate during rifting can be established. The Western Ross Sea provides favorable conditions to test the dynamic response of SCLM to rifting. Re-Os measurements from 8 locations extending from the rift shoulder to 200 km into the rift basin reveal 187Os/188Os ranging from 0.1056 at Foster Crater on the shoulder, to 0.1265 on Ross Island within the rift. While individual sample model ages vary widely throughout the margin, 'aluminochron' ages (Reisberg & Lorand, 1995) reveal a narrower range of lithospheric stabilization ages. Franklin Island and Sulfur Cones show a range of Re-depletion ages (603-1522 Ma and 436-1497 Ma) but aluminochrons yield Paleoproterozoic stabilization ages of 1680 Ma and 1789 Ma, respectively. These ages coincide with U-Pb zircon ages from Transantarctic Mountain (TAM) crustal rocks, in support of SCLM stabilization at the time of crust formation along the central TAM. The Paleoproterozoic stabilization age recorded at Franklin Island is especially significant, since it lies 200km off of the rift shoulder. The similar ages beneath the rift shoulder and within the rift suggests stretched SCLM reaches into the rift and thus precludes replacement by asthenospheric mantle. The persistence of thinned Paleoproterozoic SCLM into the rifted zone in WARS suggests that it represents a 'type I' margin of Huismans and Beaumont (2011), which is characterized by crustal breakup before loss of lithospheric mantle. The Archean Re-depletion age of 3.2 Ga observed on the rift shoulder suggests that cratonic

  19. Expression of c-type lysozyme gene in sea cucumber (Apostichopus japonicus) is highly regulated and time dependent after salt stress.

    PubMed

    Tian, Yi; Liang, Xue-Wang; Chang, Ya-Qing; Song, Jian

    2015-02-01

    Lysozymes have been confirmed to possess varieties of functions in a range of organisms. In the present study, we cloned and sequenced c-type lysozyme cDNAs, constructed the recombinant protein over-expression of c-type lysozyme and analyzed the expression of transcription level in various tissues. The c-type lysozyme cDNA contained an open reading frame of 759 bp encoding a polypeptide of 252 amino acids. The molecular weight of the deduced amino acid of AjcLYZ is 26.7 kDa with an estimated pI of 4.66. Multiple sequence alignments revealed that AjcLYZ had two highly conserved active sites (Glu147 and Asp159) and eight typical Cys residues. The tertiary structure and modeled AjcLYZ showed structural similarity to Meretrix lusoria LYZ. The results of mRNA transcripts showed that the highest expression was found in the tube foot, followed by the muscle, body wall, and coelomic fluid. In contrast, the intestine, tentacle and respiratory tree exhibited very low expression levels. Under salinity stress, significant down-regulation of AjcLYZ was observed in response to salinity stress in the intestine and coelomic fluid. Significant up-regulation and down-regulation of AjcLYZ were observed in response to salinity stress in body wall and respiratory tree. The purified recombinant protein was analyzed by SDS-PAGE and a single band with a molecular mass of 45.09 kDa, which was in agreement with the theoretical size (26.7 kDa for AjcLYZ and 18.39 kDa Trx-His-S tags) of the recombinant protein. Radial diffusion assay was employed to determine the antimicrobial spectrum of recombinant AjcLYZ against three Gram-positive and Gram-negative bacteria, and three sea cucumber pathogenic Vibrio species. From the radius of the antimicrobial zone, it was found that recombinant AjcLYZ harbored remarkable in vitro inhibitive effect on tested Gram-positive bacteria, while lytic activity against Gram-negative bacteria was relatively weak. The results will provide new clues about the

  20. The impact of salt tectonics on supra-salt (Lago Mare?) deposits and on the structural evolution of the Cyprus-Eratosthenes collision zone

    NASA Astrophysics Data System (ADS)

    Reiche, Sönke; Hübscher, Christian; Ehrhardt, Axel

    2015-04-01

    Averagely 1.5 km thick Messinian evaporites laterally continue from the Levant Basin, easternmost Mediterranean Sea, into the collision zone between Cyprus and Eratosthenes Seamount where incipient continent-continent-collision is believed to occur. In this study, the impact of Messinian evaporites on the structural evolution of the collision zone is investigated for the first time based on a comprehensive set of seismic reflection profiles. Results show that the collision zone may be subdivided into an eastern and a western domain. In the eastern part, bordered by Eratosthenes Seamount and the Hecataeus Rise, compressionally thickened autochthonous salt is observed. Sub- and supra-salt deposits within this area appear to be in the stage of active accretion. Further west, between Cyprus and Eratosthenes Seamount strongly deformed allochthonous salt has evidently started to advance across sediments of post-Messinian age. In this domain, previously active sediment accretion at the Cyprus margin has now become inactive and shortening is largely accommodated at the leading edge of the allochthonous salt sheet. Such observations bear important implications for the structural interrelation between salt tectonics and the evolution of a young collision zone. On top of highly deformed mobile Messinian evaporites, up to 700 m thick late Messinian supra-salt deposits are mapped within the western part of the Cyprus - Eratosthenes collision zone. Their uppermost 200 m were drilled in the course of ODP Leg 160 (Site 968) and interpreted as Lago Mare sediments, deposited during the final stage of the Messinian Salinity Crisis (Robertson, 1998). These sediments occupy small sub-basins flanked by salt diapirs, indicating a salt-tectonic control on late Messinian sediment deposition. Distribution of these sediments may have further been controlled by sea-level, inferred from rapid eastward thinning and pinchout of Messinian supra-salt deposits towards the Levant Basin

  1. Stone Age settlement and Holocene water level changes of the Baltic Sea in the Torvajoe Basin area, Narva-Luga Klint Bay, NE Estonia

    NASA Astrophysics Data System (ADS)

    Raig, Hanna; Rosentau, Alar; Muru, Merle; Risberg, Jan

    2014-05-01

    The Tõrvajõe basin is located in NE Estonia in the southern part of the Narva-Luga Klint Bay, that is characterized by slow post-glacial isostatic uplift (about 0-1mm/yr) and slowly undulating low topography. Post-glacial changes of the water-level of the Baltic Sea have at times flooded the area, and at times, it has emerged as terrestrial land. In addition to a complex geological development, the surroundings of the Tõrvajõe basin are interesting from the archaeological point of view because of abundant archaeological findings in the area, of which the oldest (c 8.1 cal ka BP) from the Mesolithic period and the majority, indicating very intense habitation (c 7.1-5.5 cal ka BP), from the Neolithic period. Development of the Tőrvajőe basin area during the period of Stone Age settlement (c 8.1-5.5 cal. ka BP) is studied with multiple geological and archaeological proxies. Sediments are described by lithostratigraphical methods, loss-on-ignition. AMS radiocarbon dates are used to date events and create an age-depth model. Environment is described by pollen analyses and water environment by siliceous microfossil analyses. Palaeogeographical reconstructions for time slices of interest are created to illustrate Stone Age settlement pattern and changes of the coastline and landscape over time. The aim of this interdisciplinary study is to investigate and associate palaeoenvironmental conditions and water-level changes with Stone Age settlement pattern in the Tőrvajőe area. Results show four developmental stages in the post-glacial history of the basin: Ancylus Lake lagoon, mire, lagoon during the Litorina Sea and mire. During the Ancylus Lake transgression at about 10.8-10.2 cal. ka BP a spit started to form north of the basin and a lagoon evolved behind it. Following the Ancylus Lake regression river activity and formation of palaeosoil and fen peat took place. Due to the Litorina Sea transgression, that was initially slower but accelerated around 7.8-7.6 cal ka

  2. Extreme drying event in the Dead Sea basin during MIS5 from the ICDP Dead Sea Deep Drill Core

    NASA Astrophysics Data System (ADS)

    Goldstein, S. L.; Stein, M.; Ben-Avraham, Z.; Agnon, A.; Ariztegui, D.; Brauer, A.; Haug, G. H.; Ito, E.; Kitagawa, H.; Torfstein, A.; Yasuda, Y.; The Icdp-Dsddp Scientific Party

    2011-12-01

    The ICDP funded Dead Sea Deep Drilling Project (DSDDP) recovered the longest and most complete paleo-environmental record in the Middle East, drilling holes of ~450 and ~350 meters in length in deep (~300 m below the lake level) and shallow sites (~3 mbll) respectively. The Dead Sea expands during the glacials and contracts during interglacials, and the sediments comprise a geological archive of the evolving environmental conditions (e.g. rains, floods, dust-storms, droughts). Dead Sea sediments include inorganic aragonite, allowing for dating by U-series (e.g. Haase-Schramm et al. GCA 2004). The deep site cores were opened and described in June 2011. The cores are composed mainly of alternating intervals of marl (aragonite, gypsum and detritus) during glacials, and salts and marls during interglacials. From this stratigraphy we estimate that the deep site core spans ~200 kyr (to the boundary of MIS 6 and 7). A dramatic discovery is a ~40 cm thick interval of partly rounded pebbles at ~235 m below the lake floor. This is the only clean pebbly unit in the entire core. It appears to be a beach layer, near the deepest part of the Dead Sea, lying above ~35 meters of mainly salt. If it is a beach layer, it implies an almost complete dry-down of the paleo-Dead Sea. The pebble layer lies within the last interglacial interval. Our initial attempt to more precisely estimate the age of the possible dry down shows an intriguing correlation between the salt-mud stratigraphy of the Dead Sea core and the oxygen isotope record of Soreq Cave, whereby excursions to light oxygen in the speleothems correspond to periods of salt deposition. Through this comparison, we estimate that the possible dry down occurred during MIS 5e. The occurrence of ~35 meters of mainly salt along with the pebble layer demonstrates a severe dry interval during MIS 5. This observation has implications for the Middle East today, where the Dead Sea level is dropping as all the countries in the area use the

  3. Iatrogenic salt poisoning in captive sandhill cranes

    USGS Publications Warehouse

    Franson, J.C.; Sileo, L.; Fleming, W.J.

    1981-01-01

    Salt poisoning developed in captive sandhill cranes (Grus canadensis) when sea salt was added to normal drinking water to produce a sodium chloride concentration of 1%. Two of 18 cranes died and 2 were euthanatized when moribund. Muscle weakness, paresis, dyspnea, and depression were observed. Brain and serum sodium, serum uric acid,:and plasma osmolality values were abnormally high. Lesions were those of visceral gout, renal tubular necrosis, nephrosis, and skeletal muscle.necrosis.

  4. Inference on energetics of deep-sea fish that cannot be aged: The case of the hagfish

    NASA Astrophysics Data System (ADS)

    van der Meer, Jaap; Kooijman, Sebastiaan (Bas) A. L. M.

    2014-11-01

    Dynamic Energy Budget (DEB) theory is used to estimate maximum growth rates and age at maturity for two hagfish species, the Atlantic hagfish Myxine glutinosa and the Pacific hagfish Eptatretus stoutii. Neither direct measurements on growth nor aging methods are available for these species. Only limited information on, for example, length and mass at birth and at puberty, and on oxygen consumption versus mass is available. For the Atlantic hagfish, but not for the Pacific hagfish, estimated growth rates are much higher and estimated age at maturity is much lower than previously thought, which may have implications for fisheries management. Yet, whether or not these results are due to erroneous oxygen consumption measurements remains to be seen.

  5. Determining an age for the Inararo Tuff eruption of Mt. Pinatubo, based on correlation with a distal ash layer in core MD97-2142, South China Sea

    USGS Publications Warehouse

    Ku, Y.-P.; Chen, C.-H.; Newhall, C.G.; Song, S.-R.; Yang, T.F.; Iizuka, Y.; McGeehin, J.

    2008-01-01

    The largest known eruption of Mt. Pinatubo in the late Quaternary was the Inararo Tuff Formation (ITF) eruption, roughly estimated as five times larger than the 1991 eruption. The precise age of the ITF eruption has been uncertain. Here, a correlative of the ITF eruption, Layer D, is identified in marine sediments, and an age obtained. Tephras were identified in core MD97-2142 of Leg II of the IMAGES III cruise in northern offshore of Palawan, southeastern South China Sea (12??41.33???N, 119??27.90???E). On the basis of the geochemical and isotopic fingerprints, Layer D can be correlated with the ITF eruption of the modern Pinatubo-eruption sequence. By means of the MD97-2142 SPECMAP chronology, Layer D was dated at around 81??2 ka. This estimated age of the ITF eruption and tephra Layer D coincides with an anomalously high SO4-2 spike occurring within the 5 millennia from 79 to 84 ka in the GISP2 ice core record. ?? 2007.

  6. Rb-Sr age and content of potassium, rubidium strontium, barium, and rare earths in surface material from the Sea of Fertility

    NASA Technical Reports Server (NTRS)

    Allegre, C. J.; Birck, J. L.; Loubet, M.; Provost, A.

    1974-01-01

    The Luna 16 automatic station returned from the Sea of Fertility a 35 cm long column of lunar surface material. 1 g of the Luna 16 lunar surface material, taken at a depth of 22 cm, consists of fine material: surface material and fine fragments of rocks from 1 to 4 mm in diameter. Analyses made on 17 mg of the fine lunar surface material are presented. The results obtained for the Luna 16 surface material are plotted on the diagram of the isotopic evolution of strontium and show that this surface material is most depleted of radiogenic Sr-87 of all the known lunar surface materials and that the point characterizing Lunar 16 lies somewhat to the right of the line corresponding to an age of 4.6 billion years.

  7. Studying the driving forces of landscape change in the surroundings of the Late Bronze Age harbor town Halla Sultan Tekke, Cyprus.

    NASA Astrophysics Data System (ADS)

    Heyvaert, V.; Kaniewski, D.; Sintubin, M.; Szkornik, K.; Verstraeten, G.; Walstra, J.

    2012-04-01

    A complex of salt lakes, fringing the Mediterranean Sea between Larnaca and Cape Kiti, marks the Larnaca coastal plain in Eastern Cyprus. The ancient city of Hala Sultan Tekke is situated directly to the west of the main salt lake, and has been abandoned at the end of the Late Bronze Age (LBA; ~1200 BC). Several hypotheses circulate with respect to the LBA societal collapse in the Eastern Mediterranean: from the invasion by the 'sea people', climate change to an earthquake or even a tsunami catastrophe. Nearby the archaeological site, the salt lake is protected from the Mediterranean Sea by a Pleistocene sandstone barrier.A second middle to late Holocene ridge separates the salt lakes completely from the Mediterranean Sea. Three faults, trending nearly perpendicular to the present-day coastline, are identified near the salt lakes. Human-environmental interactions that may have led to the abandonment of the ancient city of Hala Sultan Tekke are investigated by studying the sedimentary record of the Larnaca salt lakes in great detail. Hand-operated augering took place in the main salt lake as well as in the southernmost lake (Menoui beach). A detailed lithological facies analysis and preliminary microfossil and pollen analysis were carried out. The sedimentary sequence is subdivided into Pliocene bedrock, open marine (rich in Posidonia Oceanica), lagoon, salt lake and coastal ridge deposits. It is suggested that during the Early Holocene the Larnaca Bay was open, but protected; its floor being built up behind a sublittoral Posidonia meadow. Close to the Hala Sultan Tekke site, the succession reflects a confined marine embayment protected by the Pleistocene barrier. This embayment gradually evolved into lagoon, coastal marsh and finally into an enclosed salt lake due to the development of a Middle to Late Holocene coastal ridge along the present-day shoreline. From the 16th century, the lake became an important site for salt extraction.

  8. Insights from heavy minerals and zircon U-Pb ages into the middle Miocene-Pliocene provenance evolution of the Yinggehai Basin, northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Cao, Licheng; Xie, Xinong; Wang, Zhenfeng; Li, Xushen; Zhang, Yingzhao; Zhang, Daojun; Sun, Hui

    2015-08-01

    The well-preserved Cenozoic sedimentary record in the Yinggehai Basin, South China Sea, is suitable to explore the tectonic and climatic evolution of SE Asia. Red River, a large-scale fluvial system in this region, was previously regarded as the major sediment source for the basin. Here we combine heavy mineral analysis and detrital zircon U-Pb dating to shed new light on the middle Miocene-Pliocene provenance evolution at a basin scale. The results clearly reveal potential source areas additional to the Red River. Sediments have been delivered to the proximal areas from Hainan Island, as indicated by the high zircon content and the Yanshanian U-Pb ages in the southern segment of the Yingdong Slope. A provenance from Central Vietnam is explicitly discerned in the upper Miocene of the Central Depression, where sediments are characterized by few metamorphic heavy minerals and the U-Pb age pattern peaking at around 250 Ma and 440 Ma. Coeval large-scale relative sea-level fall and rapid exhumation along the Vietnamese margin together may have facilitated this long-distance sediment transport. Provenance of sediments from the Red River seems to change over time. Song Lo River, on the north side of the main stream, probably flowed from the NE and carried Neoproterozoic-early Paleozoic zircons to the Yinggehai Basin during the middle Miocene. Since the late Miocene, rocks along the Red River Fault Zone have become the dominant source. Subsequently, widespread metamorphic minerals in the Central Depression of the Yinggehai Basin, combined with the strong river incision and high offshore sedimentation rates, indicate an increased sediment supply from the Red River in the Pliocene.

  9. Extending the Instrumental Record of Sea-Level Change: A 1300-Year Sea-Level Record From Eastern Connecticut

    NASA Astrophysics Data System (ADS)

    Donnelly, J. P.; Cleary, P.

    2002-12-01

    The instrumental record of sea-level change in the northeastern United States extends back to the early 20th century and at New York City (NYC) extends back to 1856. These tide gauge records indicate that sea level has risen at a rate of 2.5 to 4 mm/year over the last 100-150 years. Geologic evidence of sea-level change in the region over the last 2,000 years indicates rates of sea-level rise of about 1 mm/year or less. The discordance between the instrumental and geologic records is frequently cited as potentially providing evidence that anthropogenic warming of the climate system has resulted in an increase in the rate of sea-level rise. In order to begin to test the hypothesis that acceleration in the rate of sea-level rise has occurred in the last 150 years due to anthropogenic climate warming, accurate and precise information on the timing of the apparent acceleration in sea-level rise are needed. Here we construct a high-resolution relative sea-level record for the past 1350 years by dating basal salt marsh peat samples above a glacial erratic in a western Connecticut salt marsh. Preservation of marsh vegetation remains in the sediment record that has a narrow vertical habitat range at the upper end of the tidal range provides information on past sea levels. { \\it Spartina patens} (marsh hay) and { \\it Juncus gerardi} (black rush) dominate both the modern marsh and their remains are the major constituent of the marsh sediments and occur in the modern marsh between mean high water (MHW) and mean highest high water. We use the elevation distribution of modern plant communities to estimate the relationship of sediment samples to paleo-mean high water. The chronology is based on 15 radiocarbon ages, supplemented by age estimates derived from the horizons of industrial Pb pollution and pollen indicative of European land clearance. Thirteen of the radiocarbon ages and the Pb and pollen data come from samples taken along a contact between marsh peat and a glacial

  10. Postmortem aging and freezing and thawing storage enhance ability of early deboned chicken pectoralis major muscle to hold added salt water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of postdeboning aging and frozen storage on water-holding capacity (WHC) of chicken breast pectoralis major muscle were investigated. Broiler breast muscle was removed from carcasses either early postmortem (2 h) or later postmortem (24 h). Treatments included: no postdeboning aging; 1-...

  11. Strontium-isotope stratigraphy of Upper Cretaceous rudist bivalves: Biozones, evolutionary patterns and sea-level change calibrated to numerical ages

    NASA Astrophysics Data System (ADS)

    Steuber, Thomas; Schlüter, Malte

    2012-08-01

    Numerical ages derived from strontium-isotope stratigraphy of 81 Late Turonian-Maastrichtian rudist localities from the Caribbean to Oman are used to establish stratigraphical ranges of readily identifiable taxa of rudist bivalves (Hippuritida). Based on these ranges, seven biozones for the Turonian-Maastrichtian of the central-eastern Mediterranean Tethys, and three biozones for the mid-Campanian-Maastrichtian of the Arabian Plate are established. Most of these are interval zones, each based on the first stratigraphical appearance of the nominal taxon. Micro-evolutionary patterns such as phyletic size increase have been demonstrated for some of the nominal species, as well as a trend of stratigraphical range expansion from the Turonian to the Maastrichtian. Implications of the geochronology of Late Cretaceous carbonate platforms for the biostratigraphy of other benthic fossils are briefly discussed. Three significant gaps in the stratigraphical distribution of rudist localities in the lower, middle, and uppermost Campanian, respectively, correlate with other records of sea-level change, indicating that they correspond to major eustatic sea-level falls. Only a limited number of rudist taxa is evaluated here, but the early and latest Campanian sea-level falls correspond to faunal turnover and extinction of characteristic associations of Late Cretaceous Hippuritida. The final extinction of the Hippuritida at the Cretaceous/Paleogene boundary is evaluated based on the available numerical ages of eighteen Late Maastrichtian localities. Eighteen genera are recorded at the six youngest localities, which thus have a species richness similar to older Late Cretaceous localities. While the ultimate cause for extinction of the Hippuritida must be evaluated on time scales beyond the resolution of strontium-isotope stratigraphy, the data set evaluated provides some insight into the pattern of their demise, which is considered to be the result of a high degree of endemism

  12. Sedimentation dynamics about salt features

    SciTech Connect

    Lowrie, A.; Blake, D.W.

    1985-02-01

    Detailed side-scan sonar and gridded bathymetric surveys on continental margins reveal the existence of numerous submarine canyons. Recently published compilations of current velocities in submarine canyons indicate that alternating and undirectionaly flows often exceed 20-30 cm/sec with peak velocities ranging from 70 to 100 cm/sec. Current meters attached to the ocean floor have been lost at current velocities of 190 cm/sec. Such velocities are ample to transport sand-size sediments. The results of DSDP Leg 96 show the existence of massive sands and gravels on the Louisiana slope, deposited during the last glacial advance. Thus, present physical oceanographic data may be an analog to conditions during glacially induced lowered sea levels. Salt ridges and domes underlie much of the Louisiana slope, determining morphology. Submarine canyons lace the slope. Given a prograding shelf, the net sediment transport routes will be down the submarine canyons. Sediment deposition patterns around the salt ridges and domes include parallel-bedded foredrifts on the upslope side, lee drifts on the downslope side, and moats along the lateral flanks of the salt features. Major differences exist between the sedimentation patterns around a ridge and a dome. The size and shape of the flow pattern will determine whether there can be a flow over the salt feature with a resulting turbulent wave that may influence sedimentation. Sedimentation patterns about salt features on the present slope should be applicable to similar paleoenvironments.

  13. Re-Os systematics of the lithospheric mantle beneath the Western Ross Sea area, Antarctica: depletion ages and dynamic response during rifting

    NASA Astrophysics Data System (ADS)

    Doherty, C.; Class, C.; Goldstein, S. L.; Shirey, S. B.; Martin, A. P.; Cooper, A. F.; Berg, J. H.; Gamble, J. A.

    2013-12-01

    The West Antarctic Rift System (WARS) is situated between the East Antarctic craton and Marie Byrd Land. Seismic studies on the structure of the lithosphere beneath the WARS reveal thinned lithosphere [1] with crustal thickness ranging from 16 to 22 km in the Ross Sea basin [2,3] that is underlain by a low velocity zone at 80-200 km [4]. However, seismic studies alone provide little information on the age of the lithospheric mantle or its fate during rifting and the formation of the WARS. Geochemical studies on lithosphere surrounding Archean cratons have demonstrated the persistence of off-craton Proterozoic lithosphere and potentially Archean lithosphere (e.g. southeast Australia and southern Africa) [5,6], and suggest that it is possible to constrain the age and structure of the lithosphere in the WARS. Os isotope ratios can be used to date the melt depletion events in the asthenosphere that are considered to be equivalent to the stabilization age of the lithospheric mantle [7]. Here we present the first Re-Os isotope measurements on mantle xenoliths from 5.0 to <1.0 Ma-old volcanic rocks collected in a transection from the rift shoulder and into the rift basin in the Western Ross Sea area of the WARS, and suggest that these data can be used to examine the dynamic response of the lithosphere to rifting. For example, ancient Re-depletion ages across this margin could indicate thinning of the lithospheric mantle during continental extension and dynamic extension of the lithospheric mantle beneath the rift basin. In contrast, younger ages might suggest a more complex history or possibly the replacement by asthenosphere as a result of lithospheric delamination during rifting. Our 187Os/188Os isotope ratios show a large range throughout the rifted margin (0.1051 at Foster Crater to 0.1265 on Ross Island), yet define individual melt depletion trends at 7 locations across the rift. Alumachron model ages derived from 187Os/188Os vs. Al2O3 wt% depletion trends reveal

  14. 3.5-D model of sediment age and grain size for the Northern Gulf of Aqaba-Elat (Red Sea) using submarine cores

    NASA Astrophysics Data System (ADS)

    Kanari, Mor; Ben-Avraham, Zvi; Tibor, Gideon; Goodman Tchernov, Beverly N.; Bookman, Revital; Taha, Nimer; Marco, Shmuel

    2016-04-01

    The Northern Gulf of Aqaba-Elat (NGAE) is the northeast extension of the Red Sea, located at the southernmost part of the Dead Sea Fault, at the transition zone between the deep en-echelon submarine basins of the Red Sea and the shallow continental basins of the Arava Valley (Israel and Jordan). We aim to characterize the top sedimentary cover across the NGAE in order to check the effect of tectonics on the sedimentary column, using high resolution grain size data and radiocarbon dating of core sediments. We analyzed 11 piston cores and 9 short cores: high resolution grain-size and radiocarbon age determinations were used to compile a 3.5-D (3.5 dimensional) model of age-depth-grain size for the top 3-5 meters of the NGAE. Two general trends of the grain size spatial distribution are observed: grains are coarsest at the NE corner of the NGAE (Aqaba coastline) and grow finer with the distance to the west on the shelf and with the distance from shore to the south. Long- and short-term accumulation rates were compiled for the entire NGAE, demonstrating a distinct E-W trend on the shelf and a NNE-SSW trend in the deep basin. The 3.5-D age-depth-grain size model conforms to- and validates the tectonic structure of the shelf detailed by previous authors. We suggest that the impact of tectonic structure of the shelf is highly significant in terms of spatial variations across the shelf, both in age of the sediment and its grain size characteristics. The temporal-spatial distribution of the grain size in the deep basin of the NGAE reveals a correlation between sediment age, dominant grain size and active tectonics: fine-grain, old sediment in the margins (Late Pleistocene, as old as >40 ka on the west margin; Early Holocene, as old as 7.5 ka, on the east margin), and Late Pleistocene sediment farther south from the dominant active diagonal fault which underlies the Elat Canyon. Young coarse sediment is present in the middle of the basin, where most of the active sediment

  15. New determinations of 40Ar/39Ar isotopic ages and flow volumes for Cenozoic volcanism in the Terror Rift, Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Rilling, S.; Mukasa, S.; Wilson, T.; Lawver, L.; Hall, C.

    2009-12-01

    This study provides new determinations of 40Ar/39Ar isotopic ages and flow volumes for submarine and subaerial Neogene volcanism developed within the Terror Rift, Ross Sea, Antarctica, the youngest segment of the West Antarctic Rift System. The study is based on the first dredged samples from seven seamounts north of Ross Island, as well as new data from Franklin and Beaufort Islands. The sampled foidite and basanitic lavas range in age from Quaternary (90 ± 66 ka) on a small seamount ˜10 km north of Franklin Island to 6.80 ± 0.05 Ma on Beaufort Island. These ages are consistent with ages of volcanism in both the Melbourne and Erebus Volcanic Provinces and significantly expand the documented area of Neogene magmatism in Victoria Land. There is no geographic progression of volcanism through time, but volcanism was voluminous in the Pliocene and particularly widespread during the Pleistocene. Two of the dredges sampled edifices comprised of less than 0.2 km3 of volcanic materials. The largest seamount in the study area has 58.8 km3 of volcanic material and represents growth over a period of several thousand years. Estimated minimum eruption rates range from 2 × 10-4 km3 y-1 to 2 × 10-3 km3 y-1, consistent with rates proposed for other rift systems and nearby Mt. Erebus. Recent estimates of extension magnitude for the Terror Rift correspond to minimal decompression of only 0.10 to 0.22 GPa and therefore limited melt output of a typical peridotite source.

  16. Slip rate determination along the Southern Dead Sea fault: optically stimulated luminescence, 10Be cosmogenic radionuclide, and 14C ages brought face to face

    NASA Astrophysics Data System (ADS)

    Le Beon, Maryline; Jaiswal, Manoj; Kunz, Alexander; Al-Qaryouti, Mahmoud; Burr, George; Klinger, Yann; Moumani, Khaled; Chen, Yue-Gau; Abdelghafoor, Mohammed; Suppe, John

    2014-05-01

    Active tectonics studies are often limited by difficulties in accurately and precisely dating Late Quaternary alluvial deposits that commonly lack organic matter or date beyond the 14C dating limit. This is illustrated at a site called Fidan, in arid southern Jordan, where a series of alluvial fans are laterally offset by the southern Dead Sea fault. Geodetic, geomorphic and geologic studies converge to a fault slip rate of 5 ± 2 mm/a. Yet, Late Pleistocene slip rate at Fidan cover a wide range due to the dispersion of 10Be cosmogenic radionuclide (CRN) ages. The maximum slip rate since ~100 ka is up to a value of 11 mm/a, possibly suggesting significant variations in fault activity with time. In order to reduce the uncertainty on the Late Pleistocene slip rate and draw further conclusions regarding the fault seismic behavior, we implement complementary dating using optically stimulated luminescence (OSL) techniques on both quartz and K-feldspar minerals and using 14C when possible. OSL measurements include a newly developed technique called post-infra-red infra-red stimulated luminescence at 290°C (pIR290). We extensively sampled surface levels F2 and F4, digging ~50-cm deep pits into the geomorphic surfaces. Annual dose rates were determined in the laboratory from both geochemical analysis of the sediment and gamma-ray spectrometry. Due to sediment heterogeneity, we consider gamma-ray spectrometry as more reliable because it is based on a larger volume of sediment. Quartz OSL ages and preliminary pIR290 results on K-feldspars give consistent Early Holocene ages of 9-14 ka for F2, also in agreement with a 14C age of 13 ka from a landsnail shell. 10Be CRN exposure ages on F2 were significantly older, with 37 ± 4 ka, probably due to inheritance. On F4, 10Be CRN exposure ages showed a scattered distribution, from ~50 ka to ~120 ka, with most samples comprised in the mean interval of 87 ± 26 ka. Quartz OSL ages from 5 locations on F4 are comprised between 32 ± 3

  17. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    PubMed Central

    Pade, Nadin; Hagemann, Martin

    2014-01-01

    The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants. PMID:25551682

  18. Geoarchaeological research on Bronze Age settlement mounds in the Kolkheti lowlands at the Black Sea coast of Georgia

    NASA Astrophysics Data System (ADS)

    Laermanns, Hannes; Heisterkamp, Arne; Kirkitadze, Giorgi; Elashvili, Mikheil; Verheul, Jan; Kelterbaum, Daniel; Helmut, Brückner

    2016-04-01

    0.0.1 Situated between the Rivers Enguri in the north and Khobistsqali in the south, more than 20 settlement mounds (local name Dikhagudzuba), identified by field survey and remote sensing techniques, give evidence of a densely populated landscape in the coastal lowlands of eastern Georgia during the Bronze Age. While the existing chronology of these mounds is based on ceramic evidence obtained during a previous archaeological research, only limited information is available on their internal architecture and their palaeoenvironmental context, and the chronology of the different layers is as yet lacking. 0.0.2 Within the framework of a geoarchaeological research project, we carried out eleven vibracores on and in direct vicinity of three of the most prominent mounds, situated close to the villages of Orulu and Ergeta. Based on these sediment cores, our study aims at (i) establishing a chronostratigraphical framework for the settlements based on radiocarbon dating; (ii) reconstructing possible phases and gaps of occupation; and (iii) identifying the environmental conditions during the time of their existence. Geochemical and sedimentological analyses were carried out to decipher element contents (XRF), granulometry, and organic contents (LOI, C/N) of sediment samples, supporting the interpretation of the mounds' stratigraphical evolution and related human occupation. The three investigated settlement mounds are similar in dimension and stratigraphy, and different settlement layers could be identified in each of them. The 14C age estimates indicate that their formation occurred during the second half of the 3rd and the first half of the 2nd millennium BC, thus confirming the archaeological interpretation of their Bronze Age origin. Based on the granulometric and geochemical data, palaeoenvironmental conditions in the vicinity of the settlements were dominated by fluvial processes.

  19. Age-related changes in thirst, salt appetite, and arterial blood pressure in response to aldosterone-dexamethasone combination in rats

    PubMed Central

    Xue, Baojian; Beltz, Terry G.; Johnson, Alan Kim

    2015-01-01

    This work examined the effects of age on daily water and sodium ingestion and cardiovascular responses to chronic administration of the mineralocorticoid, aldosterone (ALDO) either alone or together with the glucocorticoid, dexamethasone (DEX). Young (4 mo), adult (12 mo), and aged (30 mo) male Brown Norway rats were prepared for continuous telemetry recording of blood pressure (BP) and heart rate (HR). Baseline water and sodium (i.e., 0.3 M NaCl) intake, BP, and HR were established for 10 days. Then ALDO (60 μg/day sc) was infused alone, or together with DEX (2.5 or 20 μg/day sc), for another 10 days. Compared with baseline levels, ALDO stimulated comparable increases in daily saline intake at all ages. ALDO together with the higher dose of DEX (i.e., ALDO/DEX20) increased daily saline intake more than did ALDO, but less so in aged rats. Infusion of ALDO/DEX20 increased mean arterial pressure (MAP), and decreased HR, more than did infusion of ALDO. The changes in MAP in response to both treatments depended on age. For all ages, MAP and saline intake increased simultaneously during ALDO, while MAP always increased before saline intake did during ALDO/DEX20. Contrary to our predictions, MAP did not increase more in old rats in response to either treatment. We speculate that age-related declines in cardiovascular responses to glucocorticoids contributed to the attenuated increases in sodium intake in response to glucocorticoids that were observed in older animals. PMID:25833938

  20. Grains of Salt. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    Joly, Dominique

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume provides information on the origin and uses of salt, both in the ancient world and today. Topics are: (1) relationship of salt to the human body; (2) collection methods; (3) uses for human life;…

  1. Impacts of Multiple Stressors on Southern New England Salt Marshes

    EPA Science Inventory

    In the Northeastern U.S., salt marsh area is in decline. Low sediment supply combined with regionally high rates of sea level rise mean that future salt marsh survival depends primarily on biomass production and organic matter accumulation, which are impacted by high nutrient lo...

  2. Investigation Of North Anatolian Fault In The Sea Of Marmara: Fault Geometry, The Cumulative Extension, Age Modeling In Çinarcik Basin Using Multi Channel Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Atgın, Orhan; Çifçi, Günay; Soelien, Christopher; Seeber, Leonardo; Steckler, Michael; Shillington, Donna; Kurt, Hülya; Dondurur, Derman; Okay, Seda; Gürçay, Savaş; Sarıtaş, Hakan; Mert Küçük, H.; Barın, Burcu

    2013-04-01

    Marmara Sea is a limelight area for investigations due to its tectonic structure and remarkable seismic activity of North Anatolian Fault Zone (NAFZ). As NAFZ separates into 3 branches in the Marmara Sea, it has a complicated tectonic structure which gives rise to debates among researchers. Çınarcık Basin, which is close to Istanbul and very important for its tectonic activity is studied in this thesis. Two different multichannel seismic reflection data were used in this thesis. First data were acquired in 2008 in the frame of TAMAM (Turkish American Multichannel Project) and second data were in 2010 in the frame of TAMAM-2 (PirMarmara) onboard R/V K.Piri Reis. Also high resolution multibeam data were used which is provided by French Marine Institute IFREMER. In the scope of TAMAM project total 3000 km high resolution multi channel data were collected. 3000 km of multichannel seismic reflection profiles were collected in 2008 and 2010 using 72, 111, and 240 channels of streamer with a 6.25 m group interval. The generator-injector airgun was fired every 12.5 or 18.75 m and the resulting MCS data has 10-230 Hz frequency band. In this study, a detailed fault map of the basin is created and the fault on the southern slope of the basin which is interpreted by many researchers in many publications was investigated. And there is no evidence that such a fault exists on the southern part of the basin. With the multichannel seismic reflection data seismic stratigrafic interpretations of the basin deposits were done. The yearly cumulative north-south extension of the basin was calculated by making some calculations on the most active part of the faulting in the basin. In addition, the tilt angles of parallel tilted sediments were calculated and correlated with global sea level changes to calculate ages of the deposits in the basin. Keywords: NAFZ, multi channel seismic reflection, Çınarcık Basin

  3. Ecology of Great Salt Pond, Block Island

    EPA Science Inventory

    Great Salt Pond is an island of estuarine water on Block Island, which sits in the middle of the Northwest Atlantic Continental Shelf. When the last continental glaciers retreated, they left a high spot on a terminal moraine. The rising sea from melting glaciers formed two island...

  4. Postmortem aging can significantly enhance water-holding capacity of broiler pectoralis major muscle measured by the salt-induced swelling/centrifuge method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-holding capacity (WHC) is one of the most important functional properties of fresh meat and can be significantly affected by postmortem muscle changes. Two experiments were carried out to evaluate the effects of postmortem aging on WHC of broiler pectoralis (p.) major muscle indicated with % s...

  5. Potential for Carbon Sequestration in Transplanted Salt Marshes

    NASA Astrophysics Data System (ADS)

    O'Brien, C.; Davis, J.; Currin, C.

    2014-12-01

    The photosynthetic uptake of atmospheric carbon dioxide (CO2) by tidal salt marshes results in the long-term storage of carbon in the sediment. In recent decades, pressures such as land-use change and sea level rise have significantly reduced the global extent of salt marshes and increased the need for restoration projects. Restored salt marshes have been shown to provide many of the same ecological and economic benefits as natural marshes, including fish habitat, pollution filtration, and shoreline stabilization. Given the high carbon sequestration capacity of tidal marshes, carbon storage is likely an additional benefit of restoration; however, the degree to which restored marshes achieve equivalency with natural marshes in terms of carbon burial has not been well-defined. In this study, annual carbon sequestration rates in transplanted marshes were estimated and belowground carbon stocks were compared in transplanted versus natural marshes. Sediment cores were collected from five transplanted Spartina alterniflora marshes of known age (12-38 years old) in the Newport River Estuary, NC and from two natural marshes of unknown age. Organic matter content was estimated using the loss on ignition method and carbon content was estimated based on previously established relationships. In transplanted marshes, the rate of carbon sequestration in the top 30 cm decreased with marsh age and ranged from 76.70 g C/m2/yr (38 year old marsh) to 212.83 g C/m2/yr (12 year old marsh). The natural marshes contained significantly larger carbon stocks in the top 30 cm (4534.61 - 7790.18 g C m-2) than the transplanted marshes (1822.97 - 3798.62 g C m-2). However, the annual sequestration rates in the transplanted marshes are similar to those observed by others in natural marshes, and therefore it is likely that over time restored marshes are capable of accreting belowground carbon stocks equivalent to those found in natural marshes.

  6. Mediterranean sea level variations.

    NASA Astrophysics Data System (ADS)

    Vigo, I.; Sánchez Reales, J. M.; García, D.; Chao, B. F.

    2009-04-01

    In this work we report an updated study of the sea level variations for the Mediterranean sea for the period from October 1992 to January 2008. The study addresses two mayor issues: (i)The analysis of the spatial and temporal variability of sea surface height (SSH) from radar altimetry measurements (from TOPEX/Poseidon (T/P) + Jason-1, etc.). We use EOF analysis to explain most of its interannual variation, and how the different basins interact. (ii) The analysis of dynamics and balance of water mass transport for the whole period. We estimate the steric SSH by combining the steric SSH estimated from temperature and salt profiles simulated by the ECCO model with time-variable gravity (TVG) data (from GRACE) for the Mediterranean Sea. The estimated steric SSH together with the SSH obtained from altimetry allow for a more realistic estimation of the water mass variations in the Mediterranean for the whole period.

  7. A Pan African age for the HP-HT granulite gneisses of Zabargad island: implications for the early stages of the Red Sea rifting

    NASA Astrophysics Data System (ADS)

    Lancelot, Joël R.; Bosch, Delphine

    1991-12-01

    Up to now the age of granulite gneisses intruded by the Zabargad mantle diapir has been an unsolved problem. These gneisses may represent either a part of the adjacent continental crust primarily differentiated during the Pan African orogeny, or new crust composed of Miocene clastic sediments deposited in a developing rift, crosscut by a diabase dike swarm and gabbroic intrusions, and finally metamorphosed and deformed by the mantle diapir. Previous geochronological results obtained on Zabargad island and Al Lith and Tihama-Asir complexes (Saudi Arabia) suggest an Early Miocene age of emplacement for the Zabargad mantle diapir during the early opening of the Red Sea rift. In contrast, Sm sbnd Nd and Rb sbnd Sr internal isochrons yield Pan African dates for felsic and basic granulites collected 500-600 m from the contact zone with the peridotites. Devoid of evidence for retrograde metamorphic, minerals from a felsic granulite provide well-defined Rb sbnd Sr and Sm sbnd Nd dates of 655 ± 8 and 699 ± 34 Ma for the HP-HT metamorphic event (10 kbar, 850°C). The thermal event related to the diapir emplacement is not recorded in the Sm sbnd Nd and Rb sbnd Sr systems of the studied gneisses; in contrast, the development of a retrograde amphibolite metamorphic paragenesis strongly disturbed the Rb sbnd Sr isotopic system of the mafic granulite. The initial 143Nd/ 144Nd ratio of the felsic granulite is higher than the contemporaneous value for CHUR and is in agreement with other Nd isotopic data for samples of upper crust from the Arabian shield. This result suggests that source rocks of the felsic granulite were derived at 1.0 to 1.2 Ga from either an average MORB-type mantle or a local 2.2 Ga LREE-depleted mantle. Zabargad gneisses represent a part of the disrupted lower continental crust of the Pan African Afro-Arabian shield. During early stages of the Red Sea rifting in the Miocene, these Precambrian granulites were intruded and dragged upwards by a rising peridotite

  8. Composition of fluid inclusions in Permian salt beds, Palo Duro Basin, Texas, U.S.A.

    USGS Publications Warehouse

    Roedder, E.; d'Angelo, W. M.; Dorrzapf, A.F., Jr.; Aruscavage, P. J.

    1987-01-01

    Several methods have been developed and used to extract and chemically analyze the two major types of fluid inclusions in bedded salt from the Palo Duro Basin, Texas. Data on the ratio K: Ca: Mg were obtained on a few of the clouds of tiny inclusions in "chevron" salt, representing the brines from which the salt originally crystallized. Much more complete quantitative data (Na, K, Ca, Mg, Sr, Cl, SO4 and Br) were obtained on ??? 120 individual "large" (mostly ???500 ??m on an edge, i.e., ??? ??? 1.6 ?? 10-4 g) inclusions in recrystallized salt. These latter fluids have a wide range of compositions, even in a given piece of core, indicating that fluids of grossly different composition were present in these salt beds during the several (?) stages of recrystallization. The analytical results indicating very large inter-and intra-sample chemical variation verify the conclusion reached earlier, from petrography and microthermometry, that the inclusion fluids in salt and their solutes are generally polygenetic. The diversity in composition stems from the combination of a variety of sources for the fluids (Permian sea, meteoric, and groundwater, as well as later migrating ground-, formation, or meteoric waters of unknown age), and a variety of subsequent geochemical processes of dissolution, precipitation and rock-water interaction. The compositional data are frequently ambiguous but do provide constraints and may eventually yield a coherent history of the events that produced these beds. Such an understanding of the past history of the evaporite sequence of the Palo Duro Basin should help in predicting the future role of the fluids in the salt if a nuclear waste repository is sited there. ?? 1987.

  9. Sources and characteristics of fine particles over the Yellow Sea and Bohai Sea using online single particle aerosol mass spectrometer.

    PubMed

    Fu, Huaiyu; Zheng, Mei; Yan, Caiqing; Li, Xiaoying; Gao, Huiwang; Yao, Xiaohong; Guo, Zhigang; Zhang, Yuanhang

    2015-03-01

    Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer (SPAMS). The average hourly particle number (PN) was around 4560±3240 in the South Yellow Sea (SYS), 2900±3970 in the North Yellow Sea (NYS), and 1700±2220 in the Bohai Sea (BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm (ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt, and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN, respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a. PMID:25766014

  10. Electrolyte salts for power sources

    DOEpatents

    Doddapaneni, N.; Ingersoll, D.

    1995-11-28

    Electrolyte salts are disclosed for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts. 2 figs.

  11. Hygroscopic properties of large aerosol particles using the example of aged Saharan mineral dust - a semi-automated electron microscopy approach

    NASA Astrophysics Data System (ADS)

    Hartmann, Markus; Heim, Lars-Oliver; Ebert, Martin; Weinbruch, Stephan; Kandler, Konrad

    2015-04-01

    Fe-rich particles, sea-salt and soluble sulfate particles were abundant in our samples. Also, mixtures of the former were found. A chlorine-sulfur index (S/(Cl+S), based on atom%) was used to determine different grades of sea-salt aging. Growth factors are in general the highest for sea-salt particles. Within the sea-salt particle type, sea-salt with a Cl-S index between 0.05 and 0.1 has the highest growth factor. Second highest is the sea salt group with almost un-aged sea-salt (Cl-S index < 0.05). Soluble sulfate particles come right after the sea-salt group in terms of the growth factor. Even lower hygroscopic growth show the sea-salt-silicate mixtures and the silicates. Interestingly, the few silicates showing considerable hygroscopic growth (only at high RH) have a slightly higher growth factor than the silicate mixtures with sea-salt. The latter, however, have a lower deliquescence relative humidity, most likely due to the internal mixture with sea-salt.

  12. Radiocarbon content of pre-bomb marine mollusks and variations in the 14C Reservoir age for coastal areas of the Barents and Kara Seas, Russia

    NASA Astrophysics Data System (ADS)

    Forman, Steven L.; Polyak, Leonid

    Fourteen mollusks, collected alive between 1900 and 1945 from the Russian Barents and Kara seas, were analyzed by AMS 14C dating to evaluate variations in the 14C marine reservoir for arctic coastal sites, which is important for correcting ages in paleoenvironmental time-series and advancing understanding of the exchange of carbon. The 14C ages on the mollusks reveal a range of marine reservoir values (R(t)) from 159 14C yr to 764 14C yr. The oldest R(t) values of 764 to 620 14C yr are for the bivalve Portlandia arctica, which often inhabit cold and low salinity waters and muddy substrates. The depleted 14C content for this bivalve reflects possibly the incorporation of old carbon from freshwater inputs and/or the consumption of old organic matter from the underlying sediments and pore waters. Other mollusks with sessile habitats and pelagic food sources gave significantly lower R(t) values between 159 and 344 14C yr. The youngest R(t) values indicate enrichment in 14C and may partially reflect enhanced transfer of 14C-enriched CO2 from the atmosphere to the ocean surface with wind-generated wave agitation. This study underscores that a variety of processes can lead to variable 14C depletion and enrichment of surface waters yielding a ca. 600 year age span for contemporaneous arctic mollusks. There may be added uncertainty in the 14C reservoir correction for deposit-feeder species such as Portlandia sp. and perhaps for certain benthic foraminifera (e.g. Nonion labradoricum) because these taxa often incorporate old organic matter from the substrate. A reservoir correction of ≥700 years may be more appropriate for infaunal, deposit-eater species, particularly in glacier-dominated environments. Mollusks and foraminifera with sessile habits and pelagic food sources should be selected preferentially for 14C dating, because their shells may more closely reflect the 14C content of the global-ocean mixed layer.

  13. Offshore Stratigraphic Controls on Salt-Water Intrusion in Los Angeles Area Coastal Aquifers

    NASA Astrophysics Data System (ADS)

    Edwards, B. D.; Ponti, D. J.; Ehman, K. D.; Tinsley, J. C.; Reichard, E. G.

    2002-12-01

    Ground water is a major component of the water supply for the ~10 million residents of Los Angeles County. Ground water pumping, linked to population growth since the early 1900's, caused water levels to decline, reversed seaward hydraulic gradients in some coastal aquifers, and resulted in salt water intrusion. United States Geological Survey geologists and hydrologists are working cooperatively with local water agencies to (1) understand and model the process of salt-water intrusion in this siliciclastic, structurally complex basin, and (2) identify potential pathways for the salt-water intrusion. We collected over 2000 trackline-km of single- and multi-channel intermediate- and high-resolution seismic-reflection profiles (60 to 5000 Hz) from the Los Angeles/Long Beach Harbor complex and the adjacent San Pedro shelf to develop a 3-dimensional stratigraphic model of the coastal aquifer system. These data define stratal geometries, paleo-channels, and fault traces in the offshore that are potential pathways of salt-water intrusion. The offshore seismic-reflection profiles correlate with onshore geophysical and borehole data collected from four nearby drill sites that were cored continuously to depths ranging to 400 meters. These core holes provide detailed 1-dimensional reference sections that furnish stratigraphic, age, and facies control for the seismic-reflection profiles. The coastal aquifer system is described using sequence stratigraphic concepts as units deposited during eustatic sea level fluctuations during the Pleistocene to Recent. Seismic-reflection profiles identify sequence boundaries, and hence aquifer and aquitard units, by the truncation and onlap of reflectors. If and where the sequences crop out on the sea floor provides a potential pathway for intrusion. The youngest unit, the Gaspur aquifer, is intruded with salt water and consists of at least two flat-lying sequences, each marked by basal gravelly sands deposited by the ancestral Los Angeles

  14. Examining effects of sea level rise and marsh crabs on Spartina patens using mesocosms

    EPA Science Inventory

    Coastal salt marshes provide essential ecosystem services but face increasing threats from habitat loss, eutrophication, changing precipitation patterns, and accelerating rates of sea level rise (SLR). Recent studies have suggested that herbivory and burrowing by native salt mars...

  15. A universal salt model based on under-ground precipitation of solid salts due to supercritical water `out-salting'

    NASA Astrophysics Data System (ADS)

    Rueslåtten, H.; Hovland, M. T.

    2010-12-01

    One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a

  16. Volcanism on the Eggvin Bank (Central Norwegian-Greenland Sea, latitude ˜71°N): age, source, and relationship to the Iceland and putative Jan Mayen plumes

    NASA Astrophysics Data System (ADS)

    Mertz, Dieter F.; Sharp, Warren D.; Haase, Karsten M.

    2004-08-01

    The Eggvin Bank (Central Norwegian-Greenland Sea, latitude ˜71°N) is a topographically anomalous shallow area with scattered volcanic peaks extending between the island of Jan Mayen and East Greenland and straddling the northern segment of the mid-Atlantic Kolbeinsey Ridge axis. Basalts dredged from the Eggvin Bank range from variably depleted, tholeiitic, near-axis lavas to enriched, transitional-to-alkaline, off-axis seamount lavas. In terms of normalised incompatible element patterns, the most depleted, near-axis tholeiite is similar to neighbouring Kolbeinsey Ridge basalts, whereas the off-axis, transitional-to-alkaline lavas are similar to other alkaline basalts occurring close to the Eggvin Bank region, e.g., those of Jan Mayen. 40Ar/ 39Ar step heating data indicate that the off-axis seamount lavas are coeval with other alkaline lavas erupted in the Central Norwegian-Greeland Sea at ca. 0.6-0.7 Ma. In contrast, the Eggvin near-axis tholeiites are <0.1 Ma. Volcanic peaks west and north of Jan Mayen show no indication of a systematic age progression. Therefore, the Jan Mayen hot spot hypothesis is not supported by the available radiometric age data. Sr, Nd, and Pb isotope compositions of near-axis and off-axis Eggvin Bank lavas are distinct, implying differences in their mantle sources. Isotope ratios of the off-axis basalts ( 87Sr/ 86Sr=0.70344-0.70352, 143Nd/ 144Nd=0.51283-0.51288, 206Pb/ 204Pb=18.82-18.85) resemble those of neighbouring alkali basalt occurrences, however, isotope ratios of the near-axis tholeiites correspond to lavas erupting in the south-eastern volcanic zone of Iceland, e.g., at Vestmannaeyjar. The near-axis tholeiites are generated by an unusual source with highly radiogenic Pb ( 206Pb/ 204Pb=18.95) together with relatively radiogenic Nd ( 143Nd/ 144Nd=0.51295) and low-radiogenic Sr ( 87Sr/ 86Sr=0.70314), respectively, representing an unique composition in the mantle north of central Iceland. The overlap in isotope compositions between

  17. Salt tectonics on Venus

    SciTech Connect

    Wood, C.A.; Amsbury, D.

    1986-05-01

    The discovery of a surprisingly high deuterium/hydrogen ratio on Venus immediately led to the speculation that Venus may have once had a volume of surface water comparable to that of the terrestrial oceans. The authors propose that the evaporation of this putative ocean may have yielded residual salt deposits that formed various terrain features depicted in Venera 15 and 16 radar images. By analogy with models for the total evaporation of the terrestrial oceans, evaporite deposits on Venus should be at least tens to hundreds of meters thick. From photogeologic evidence and in-situ chemical analyses, it appears that the salt plains were later buried by lava flows. On Earth, salt diapirism leads to the formation of salt domes, anticlines, and elongated salt intrusions - features having dimensions of roughly 1 to 100 km. Due to the rapid erosion of salt by water, surface evaporite landforms are only common in dry regions such as the Zagros Mountains of Iran, where salt plugs and glaciers exist. Venus is far drier than Iran; extruded salt should be preserved, although the high surface temperature (470/sup 0/C) would probably stimulate rapid salt flow. Venus possesses a variety of circular landforms, tens to hundreds of kilometers wide, which could be either megasalt domes or salt intrusions colonizing impact craters. Additionally, arcurate bands seen in the Maxwell area of Venus could be salt intrusions formed in a region of tectonic stress. These large structures may not be salt features; nonetheless, salt features should exist on Venus.

  18. Biogeomorphically driven salt pan formation in Sarcocornia-dominated salt-marshes

    NASA Astrophysics Data System (ADS)

    Escapa, Mauricio; Perillo, Gerardo M. E.; Iribarne, Oscar

    2015-01-01

    Salt-marshes are under increasing threat, particularly from sea-level rise and increased wave action associated with climate change. The development and stability of these valuable habitats largely depend on complex interactions between biotic and abiotic processes operating at different scales. Also, interactions between biotic and abiotic processes drive internal morphological change in salt-marshes. In this paper we used a biogeomorphological approach to assess the impact of biological activities and interactions on salt pan formation in Sarcocornia-dominated salt marshes. Salt pans represent a key physiographic feature of salt-marshes and recent studies hypothesized that biogeomorphic processes could be related to salt pan formation in SW Atlantic salt-marshes. The glasswort Sarcocornia perennis is one of the dominant plants in the salt-marshes of the Bahía Blanca Estuary (Argentina) where they form patches up to 8 m in diameter. These salt-marshes are also inhabited in great densities by the burrowing crab Neohelice (Chasmagnathus) granulata whose bioturbation rates are among the highest reported for salt-marshes worldwide. A set of biological interactions between N. granulata and S. perennis appears to be responsible for salt pan development in these areas which has not been described elsewhere. The main objective of this work was to determine the ecological interactions occurring between plants and crabs that lead to salt pan formation by using field-based sampling and manipulative experiments. Our results showed that S. perennis facilitated crab colonization of the salt-marsh by buffering otherwise stressful physical conditions (e.g., temperature, desiccation). Crabs preferred to construct burrows underneath plants and, once they reach high densities (up to 40 burrows m- 2), the sediment reworking caused plant die-off in the central area of patches. At this state, the patches lose elevation and become depressed due to the continuous bioturbation by crabs

  19. What Are Bath Salts?

    MedlinePlus

    ... Are bath salts becoming more popular? Marsha Lopez Hi, Lauren. Nope! Actually quite the opposite! This family ... and how dangerous for your body? Michelle Rankin Hi ParkerPanella - Bath salts are drugs known as synthetic ...

  20. Low-salt diet

    MedlinePlus

    ... seasonings. Pepper, garlic, herbs, and lemon are good choices. Avoid packaged spice blends. They often contain salt. Use garlic and onion powder, not garlic and onion salt. Do not eat foods with monosodium glutamate (MSG). When you go out ...

  1. Molten salt electrolyte separator

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

    A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

  2. Utah: Salt Lake Region

    Atmospheric Science Data Center

    2014-05-15

    article title:  Winter and Summer Views of the Salt Lake Region     View Larger Image Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the ...

  3. Retrospective salt tectonics

    SciTech Connect

    Jackson, M.P.A.

    1996-12-31

    The conceptual breakthroughs in understanding salt tectonics can be recognized by reviewing the history of salt tectonics, which divides naturally into three parts: the pioneering era, the fluid era, and the brittle era. The pioneering era (1856-1933) featured the search for a general hypothesis of salt diapirism, initially dominated by bizarre, erroneous notions of igneous activity, residual islands, in situ crystallization, osmotic pressures, and expansive crystallization. Gradually data from oil exploration constrained speculation. The effects of buoyancy versus orogeny were debated, contact relations were characterized, salt glaciers were discovered, and the concepts of downbuilding and differential loading were proposed as diapiric mechanisms. The fluid era (1933-{approximately}1989) was dominated by the view that salt tectonics resulted from Rayleigh-Taylor instabilities in which a dense fluid overburden having negligible yield strength sinks into a less dense fluid salt layer, displacing it upward. Density contrasts, viscosity contrasts, and dominant wavelengths were emphasized, whereas strength and faulting of the overburden were ignored. During this era, palinspastic reconstructions were attempted; salt upwelling below thin overburdens was recognized; internal structures of mined diapirs were discovered; peripheral sinks, turtle structures, and diapir families were comprehended; flow laws for dry salt were formulated; and contractional belts on divergent margins and allochthonous salt sheets were recognized. The 1970s revealed the basic driving force of salt allochthons, intrasalt minibasins, finite strains in diapirs, the possibility of thermal convection in salt, direct measurement of salt glacial flow stimulated by rainfall, and the internal structure of convecting evaporites and salt glaciers. The 1980`s revealed salt rollers, subtle traps, flow laws for damp salt, salt canopies, and mushroom diapirs.

  4. Molten salt technology

    SciTech Connect

    Lovering, D.G.

    1982-01-01

    In this volume, the historical background, scope, problems, economics, and future applications of molten salt technologies are discussed. Topics presented include molten salts in primary production of aluminum, general principles and handling and safety of the alkali metals, first-row transition metals, group VIII metals and B-group elements, solution electrochemistry, transport phenomena, corrosion in different molten salts, cells with molten salt electrolytes and reactants, fuel cell design, hydrocracking and liquefaction, heat storage in phase change materials, and nuclear technologies.

  5. Salt weathering on Mars

    NASA Technical Reports Server (NTRS)

    Malin, M. C.

    1974-01-01

    Mariner 9 photographs of Mars indicate that significant erosion has occurred on that planet. Although several possible erosion mechanisms have been proposed, most terrestrial weathering mechanisms cannot function in the present Martian environment. Salt weathering, believed to be active in the Antarctic dry valleys, is especially suited to Mars, given the presence of salts and small amounts of water. Volcanic salts are probably available, and the association of salts and water is likely from both thermodynamic and geologic considerations.

  6. Study of settlement distribution pattern in the Kolkheti lowland (Black Sea coast of Georgia) starting from early Bronze Age - natural and human influence and adaptation to landscape evolution

    NASA Astrophysics Data System (ADS)

    Elashvili, Mikheil; Akhvlediani, Dimitri; Navrozashvili, Levan; Sukhishvili, Lasha; Kirkitadze, Giorgi; Kelterbaum, Daniel; Laermans, Hannes

    2015-04-01

    archaeological datasets are collected in the joint-venture project and in addition with known historical and old topographic maps of the region they represent a good start for the research. There are typical ancient settlements in the Kolkheti lowland, called locally "Dikhagudzuba", which are still identifiable on aerial imagery. Their structure, physical dimensions and locations were analyzed from aerial and on site studies. Data from existing archaeological studies and recent field works were analyzed to create a reliable database on the distribution of Bronze Age settlements. Changes in paleoclimate, sea level and river deltas represent the main components to form a paleolandscape of the study area. Based on the results of recent fieldwork and the analyses of regional historical maps in addition with the general geological and geomorphological settings paleogeographical scenarios were constructed. Proposed models of past landscape changes and human settlement pattern were merged and analyzed. From one hand the human settlement distribution (taking into account tells relation with the local landscape of the same period) help us to identify the best suitable scenario from the set of paleolandscape patterns. Moreover, paleogeographical scenarios provide a better understanding on the erection of human settlements in the past, and their influence and adaptation to ongoing changes.

  7. Hydromorphic to subaqueous soils transitions in the central Grado lagoon (Northern Adriatic Sea, Italy)

    NASA Astrophysics Data System (ADS)

    Vittori Antisari, Livia; De Nobili, Maria; Ferronato, Chiara; Natale, Marco; Pellegrini, Elisa; Vianello, Gilmo

    2016-05-01

    The Grado lagoon is among the largest in the Mediterranean sea and is characterized by salt marshes, where tides influenced the development of a complex micromorphology coupled to a micromosaic of vegetation covers. This study represents the first contribution to the understanding of the main processes governing formation, development and spatial transitions between hydromorphic and subaqueous soils in an Adriatic lagoon ecosystem. Physicochemical characteristics and development of soils were investigated in three salt marshes differing for their proximity to the open sea, textural composition and age of formation. Soils of back barrier salt marshes had A/C profiles and were mostly characterized by a sandy coarse texture that allows rapid drainage and subsurface oxygen exchanges. Soil sequences from the inner salt marsh to its submerged border slope or to a brackish waterhole do not simply represent a hydrosequence, but also reflect erosion/sorting/accumulation processes. The soils in the central part of the lagoon have finer texture and in displayed transition or cambic horizons. Silty clay loam textures and low positions allowed the development of more severe anoxic conditions and accumulation of sulphides. The tide oscillation strongly contributed to formation of redoximorphic features, intensity of anaerobic conditions but also colonization by different plant communities. Discriminant analysis was performed to identify physicochemical properties which discriminate the different soils according to geo-morphological position and prevailing plants. It confirmed that differentiation of plant communities occurred according to distinct morphological and physicochemical soil properties, but also acted as a primary affecting factor of pedogenesis.

  8. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  9. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  10. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  11. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  12. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  13. Dietary Salt Intake and Discretionary Salt Use in Two General Population Samples in Australia: 2011 and 2014.

    PubMed

    Nowson, Caryl; Lim, Karen; Grimes, Carley; O'Halloran, Siobhan; Land, Mary Anne; Webster, Jacqui; Shaw, Jonathan; Chalmers, John; Smith, Wayne; Flood, Victoria; Woodward, Mark; Neal, Bruce

    2015-12-01

    The limited Australian measures to reduce population sodium intake through national initiatives targeting sodium in the food supply have not been evaluated. The aim was, thus, to assess if there has been a change in salt intake and discretionary salt use between 2011 and 2014 in the state of Victoria, Australia. Adults drawn from a population sample provided 24 h urine collections and reported discretionary salt use in 2011 and 2014. The final sample included 307 subjects who participated in both surveys, 291 who participated in 2011 only, and 135 subjects who participated in 2014 only. Analysis included adjustment for age, gender, metropolitan area, weekend collection and participation in both surveys, where appropriate. In 2011, 598 participants: 53% female, age 57.1(12.0)(SD) years and in 2014, 442 participants: 53% female, age 61.2(10.7) years provided valid urine collections, with no difference in the mean urinary salt excretion between 2011: 7.9 (7.6, 8.2) (95% CI) g/salt/day and 2014: 7.8 (7.5, 8.1) g/salt/day (p = 0.589), and no difference in discretionary salt use: 35% (2011) and 36% (2014) reported adding salt sometimes or often/always at the table (p = 0.76). Those that sometimes or often/always added salt at the table and when cooking had 0.7 (0.7, 0.8) g/salt/day (p = 0.0016) higher salt excretion. There is no indication over this 3-year period that national salt reduction initiatives targeting the food supply have resulted in a population reduction in salt intake. More concerted efforts are required to reduce the salt content of manufactured foods, together with a consumer education campaign targeting the use of discretionary salt. PMID:26694459

  14. Dietary Salt Intake and Discretionary Salt Use in Two General Population Samples in Australia: 2011 and 2014

    PubMed Central

    Nowson, Caryl; Lim, Karen; Grimes, Carley; O’Halloran, Siobhan; Land, Mary Anne; Webster, Jacqui; Shaw, Jonathan; Chalmers, John; Smith, Wayne; Flood, Victoria; Woodward, Mark; Neal, Bruce

    2015-01-01

    The limited Australian measures to reduce population sodium intake through national initiatives targeting sodium in the food supply have not been evaluated. The aim was, thus, to assess if there has been a change in salt intake and discretionary salt use between 2011 and 2014 in the state of Victoria, Australia. Adults drawn from a population sample provided 24 h urine collections and reported discretionary salt use in 2011 and 2014. The final sample included 307 subjects who participated in both surveys, 291 who participated in 2011 only, and 135 subjects who participated in 2014 only. Analysis included adjustment for age, gender, metropolitan area, weekend collection and participation in both surveys, where appropriate. In 2011, 598 participants: 53% female, age 57.1(12.0)(SD) years and in 2014, 442 participants: 53% female, age 61.2(10.7) years provided valid urine collections, with no difference in the mean urinary salt excretion between 2011: 7.9 (7.6, 8.2) (95% CI) g/salt/day and 2014: 7.8 (7.5, 8.1) g/salt/day (p = 0.589), and no difference in discretionary salt use: 35% (2011) and 36% (2014) reported adding salt sometimes or often/always at the table (p = 0.76). Those that sometimes or often/always added salt at the table and when cooking had 0.7 (0.7, 0.8) g/salt/day (p = 0.0016) higher salt excretion. There is no indication over this 3-year period that national salt reduction initiatives targeting the food supply have resulted in a population reduction in salt intake. More concerted efforts are required to reduce the salt content of manufactured foods, together with a consumer education campaign targeting the use of discretionary salt. PMID:26694459

  15. Salt RNA protection against thermodegradation

    NASA Astrophysics Data System (ADS)

    Vergne, J.; Maurel, M.-C.

    2003-04-01

    We shown the structural integrity of tRNA at high temperature, 82^oC for 30h, in high salt concentrations (Tehei et al, 2002). Stability were also performed by measuring the residual specific tRNA charge capacity after heat treatment for 30 h at 82^oC. We have undertaken in vitro selection of RNA molecules at high temperature in presence of an ancient halite (NaCl) sample (reference : EZ08-K6-C9). This sample, collected in a borehole at 720.15 m depth, belongs to the Rupelian Upper Salt Formation of the Bresse salt basin (France). Its age is estimated to about 31±3 millions years. These studies provide support for the importance of salt to protect macromolecules against thermal degradation allowing activity to be recovered. These could be useful for searching traces of life in ancient sediments and in planetary exploration. Reference: Tehei Moeva, Franzetti Bruno, Maurel Marie-Christine, Vergne Jacques, Hountondji Codjo and Zaccai Giuseppe, Extremophiles, (2002), 6: 427-430.

  16. Mud volcano formation within the Western slope of the Nile Cone sourced from pre-salt layers

    NASA Astrophysics Data System (ADS)

    Kirkham, Christopher; Cartwright, Joseph; Hermanrud, Christian; Jebsen, Christopher

    2015-04-01

    Mud volcanos are prevalent in a variety of settings, particularly in those where rapid sedimentation, thrust loading or horizontal tectonic stresses are observed. Here we describe from a three-dimensional (3D) seismic survey located on the Western slope of the Nile Cone, a suite of mud volcanoes emplaced throughout the post-salt Pliocene-Recent succession. These mud volcanoes are highly variable in scale, some among the largest ever described. Extrusive volumes range from 100 km3. Evaporites are widely considered a world class seal which has given rise to the discovery of numerous pre-salt hydrocarbon accumulations. Pre-salt depletion features, contrasts in p-wave velocity and salt welding due to mud remobilisation, are all indicative of a pre-Messinian (sub-salt) primary mud source, predominantly Tortonian in age. This implies large scale mud remobilisation through the thick Messinian evaporite succession. It is our interpretation that the formation of mud volcanoes within this region is intimately related to the basinal hydrodynamics, which include undercompaction and subsequent fluid retention, local sea level variation and overpressure generation. These mechanisms are controlled by key events in the geological history of the basin such as the Messinian Salinity Crisis (MSC) and the Zanclean flood. We argue that the formation of these mud volcanoes is a direct response to overpressure generated primarily through rapid loading of pre-salt sediments during the MSC and catastrophic re-flooding during its immediate aftermath. Ultimately the location at which they form is associated with deeper features such as underlying faults and potential hydrocarbon plays. It is feasible that similar basin-scale remobilisation and overpressure could be expected for other salt basins world-wide that have undergone similar priming processes.

  17. Numerical simulation of salt cementation in the porous rocks adjacent to salt diapirs

    NASA Astrophysics Data System (ADS)

    Allstadt, Raphael; Li, Shiyuan; Marquart, Gabriele; Reuning, Lars; Niederau, Jan

    2015-04-01

    Porosity and permeability are among the most important petrophysical properties of reservoirs rocks in oil systems. Observations during exploration indicate that in the vicinity of salt domes the porosity of reservoir rocks is often reduced by halite cementation. In this study we present results of simulating the process of salt precipitation near salt diapirs by using a schematic model of a Zechstein diapir in the North Sea basin. The numerical simulation is based on solving the transport equations for heat, porous flow and dispersive and reactive chemical species. Chemical reaction and equilibrium is based on the PHREEQC computer code. In our model over-pressured brine is entering from below and is deflected towards the diapir due to an intermediate layer of low permeability. The high thermal conductivity of salt yields a lateral temperature gradient starting from the diapir. Due to this effect the simulated temperature profile shows lower temperatures close to the salt dome than in comparable depths further away. Caused by the temperature-controlled solubility of NaCl in the brine and supplied ions by the diapir, halite first precipitates near the salt diapir by cementing the pore spaces and thus reducing the porosity. Salt-precipitation in the simulation starts after 840 000 years and reduces the porosity from 10 % to 5.5 % after 19 Mill. years. The permanent influx of brine causes growth of the cementation area and the related reduction of porosity in the reservoir.

  18. Heat flow and gravity responses over salt bodies: A comparative model analysis

    SciTech Connect

    Corrigan, J.; Sweat, M.

    1995-07-01

    Two-dimensional numerical modeling of sea-floor heat flow and water-bottom gravity responses to systematic variations in simple subsurface salt body geometries provides insight on the relative usefulness of these two data types for extracting salt geometry information. For a given salt body geometry, diffusion of heat through overlying sediments results in a dramatic decrease in the amplitude of heat flow anomalies as the depth to the top of the salt body increases. For top-of-salt depths greater than about 1 km, the heat flow response is insensitive to the length of salt feeder stocks and to the thickness of salt tongues/sheets. This shallow depth-to-top-of-salt sensitivity range, in addition to a number of environmental factors that can adversely affect interpretation of heat flow anomalies in terms of heat refraction towards and through salt bodies, severely limits the usefulness of sea-floor heat flow data for constraining aspects of salt body geometry. For gravity data, the critical factor for addressing salt body geometry is the distribution of salt relative to the sediment-salt density crossover depth (above and below which salt is more and less dense, respectively, than the surrounding sediment). Except when ht relevant geometry information being sought (presence and/or length of feeder stock, thickness of salt tongue or sheet) is near the density crossover depth, the geometry-related information content of the gravity field is greater than that of the heat flow field. Based on these model results, measurement uncertainty considerations, and data limitations, the authors conclude that gravity data generally offer an order of magnitude greater resolution capability than sea-floor heat flow data for addressing salt body geometry issues of exploration interest.

  19. The Story of the Oceans and Salt. 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 provides information on: (1) the origin of the oceans; (2) sources of minerals and salt found in the sea; and (3) the role and uses of salt in various cultures (stating, for example, that the expression "salt of the earth" describes a person who is considered one of the best). (JN)

  20. Comparing salt tolerance of beet cultivars and their halophytic ancestor: consequences of domestication and breeding programmes

    PubMed Central

    Rozema, Jelte; Cornelisse, Danny; Zhang, Yuancheng; Li, Hongxiu; Bruning, Bas; Katschnig, Diana; Broekman, Rob; Ji, Bin; van Bodegom, Peter

    2015-01-01

    Salt tolerance of higher plants is determined by a complex set of traits, the timing and rate of evolution of which are largely unknown. We compared the salt tolerance of cultivars of sugar beet and their ancestor, sea beet, in hydroponic studies and evaluated whether traditional domestication and more recent breeding have changed salt tolerance of the cultivars relative to their ancestor. Our comparison of salt tolerance of crop cultivars is based on values of the relative growth rate (RGR) of the entire plant at various salinity levels. We found considerable salt tolerance of the sea beet and slightly, but significantly, reduced salt tolerance of the sugar beet cultivars. This indicates that traditional domestication by selection for morphological traits such as leaf size, beet shape and size, enhanced productivity, sugar content and palatability slightly affected salt tolerance of sugar beet cultivars. Salt tolerance among four sugar beet cultivars, three of which have been claimed to be salt tolerant, did not differ. We analysed the components of RGR to understand the mechanism of salt tolerance at the whole-plant level. The growth rate reduction at higher salinity was linked with reduced leaf area at the whole-plant level (leaf area ratio) and at the individual leaf level (specific leaf area). The leaf weight fraction was not affected by increased salinity. On the other hand, succulence and leaf thickness and the net assimilation per unit of leaf area (unit leaf rate) increased in response to salt treatment, thus partially counteracting reduced capture of light by lower leaf area. This compensatory mechanism may form part of the salt tolerance mechanism of sea beet and the four studied sugar beet cultivars. Together, our results indicate that domestication of the halophytic ancestor sea beet slightly reduced salt tolerance and that breeding for improved salt tolerance of sugar beet cultivars has not been effective. PMID:25492122

  1. SALT Science Conference 2015

    NASA Astrophysics Data System (ADS)

    Buckley, David; Schroeder, Anja

    The Southern African Large Telescope (SALT) has seen great changes in the last years following the beginning of full time science operations in 2011. The three first generation instruments, namely the SALTICAM imager, the Robert Stobie Spectrograph (RSS) and its multiple modes and finally in 2014, the new High Resolution Spectrograph (HRS), have commissioned it. The SALT community now eagerly anticipate the installation and commissioning of the near-infrared arm of RSS, likely to commence in 2016. The the third "Science with SALT" conference was held at the Stellenbosch Institute of Advanced Study from 1-5 June 2015. The goals of this conference were to: -Present and discuss recent results from SALT observations; -Anticipate scientific programs that will be carried out with new SALT instrumentation such as RSS-NIR; -Provide a scientific environment in which to foster inter-institutional and inter-facility collaborations between scientists at the different SALT partners; -Provide an opportunity for students and postdocs to become more engaged in SALT science and operations; -Encourage the scientific strategic planning that will be necessary to insure an important role for SALT in an era of large astronomical facilities in the southern hemisphere such as MeerKAT, the SKA, LSST, and ALMA; -Consider options for future instrumentation and technical development of SALT; and, -Present, discuss, and engage in the SALT Collateral Benefits program led by SAAO. Conference proceedings editors: David Buckley and Anja Schroeder

  2. Effects of Edible Seaweed on Physicochemical and Sensory Characteristics of Reduced-salt Frankfurters

    PubMed Central

    Hwang, Ko-Eun; Jeong, Tae-Jun; Kim, Cheon-Jei

    2015-01-01

    The effects of sea tangle, sea mustard, hijiki, and glasswort were investigated based on the proximate composition, salinity, cooking loss, emulsion stability, pH, color, texture profile analysis, apparent viscosity, and sensory characteristics of reduced-salt (NaCl) meat batter and frankfurters. The moisture content, salinity, lightness of the meat batter and frankfurter, hardness, gumminess, and chewiness of the reduced-salt frankfurters with sea weeds were lower than the control without seaweed (p<0.05). The protein content, springiness, and cohesiveness of the reduced-salt frankfurters were not significantly different among the treatments (p>0.05). The moisture content, salinity, cooking loss, lightness, redness, hardness, gumminess, and chewiness of treatments with sea tangle and with sea mustard were lower than the control (p<0.05). Among the sensory traits, color was highest in the control (p<0.05). The flavor was also highest in the control. The treatments with sea tangle and with sea mustard samples had high tenderness, juiciness, and overall acceptability scores similar to the control (p<0.05). The results of this study show that the combination of low-salt and seaweed in the formulation successfully improved reduced-salt frankfurters, improving sensory characteristics to levels similar to the regular salt control (1.5%). PMID:26877634

  3. Photochemistry of triarylsulfonium salts

    SciTech Connect

    Dektar, J.L.; Hacker, N.P. )

    1990-08-01

    The photolysis of triphenylsulfonium, tris(4-methylphenyl)sulfonium, tris(4-chlorophenyl)sulfonium, several monosubstituted (4-F, 4-Cl, 4-Me, 4-MeO, 4-PhS, and 4-PhCO), and disubstituted (4,4{prime}-Me{sub 2} and 4,4{prime}-(MeO){sub 2}) triphenylsulfonium salts was examined in solution. It was found that direct irradiation of triphenylsulfonium salts produced new rearrangement products, phenylthiobiphenyls, along with diphenyl sulfide, which had been previously reported. Similarly, the triarylsulfonium salts, with the exception of the (4-(phenylthio)phenyl)diphenylsulfonium salts produced new rearrangement products, phenylthiobiphenyls, along with diphenyl sulfide, which had been previously reported. Similarly, the triarylsulfonium salts, with the exception of the (4-(phenylthio)phenyl)diphenylsulfonium salts, gave the new rearrangement products. The mechanism for direct photolysis is proposed to occur from the singlet excited states to give a predominant heterolytic cleavage along with some homolytic cleavage.

  4. Distribution of atmospheric marine salt depositions over Continental Western Europe.

    PubMed

    Delalieux, F; van Grieken, R; Potgieter, J H

    2006-06-01

    This contribution describes the distribution of marine salt aerosols in Belgium, France and Spain, as obtained from applying a kriging model to a set of data. The data was collected over a period of nine years and included wet as well as dry deposition results. It was found that the concentration of the salt particles decreased the fastest in Spain and the slowest in Belgium with increasing inland distance from the sea. These findings have implications for the degradation of monuments and historical buildings as a result of salt attack and ingress that often accompany degradation due to air pollution. PMID:16772114

  5. Structural evolution of Alpine salt deposits, Austria and Bavaria

    NASA Astrophysics Data System (ADS)

    Leitner, Ch.; Neubauer, F.; Genser, H.; Borojevic Sostaric, S.

    2009-04-01

    Structural evolution of Alpine salt deposits, Austria and Bavaria Alpine salt deposits consist of a tectonic melange of rocksalt and shale called haselgebirge representing the Haselgebirge Formation of Permian to Early Triassic age and mainly exposed within the central and eastern Northern Calcareous Alps. The initial evaporitic sediments were transformed into a breccia (protocataclasite, mylonite) during Alpine orogeny. Residual rocks of shale, anhydrite, polyhalite, sandstone and limestone float as isolated bodies in the haselgebirge matrix. Field investigations of foliation, halite mineral lineation, fold axis, veins and the overall present slickensides in shale revealed an individual history for all investigated mines (Dürrnberg, Berchtesgaden, Altaussee, in part Hallstatt). Ar-Ar dating of various micostructural types of polyhalite yield several preliminary age groups: 235 Ma, 180 Ma, and 110 Ma. Fluid inclusion measurements on anhydrite together with vitrinite reflectance data showed that temperatures of 140-180 °C were reached in Berchtesgaden and around 250° C in Altaussee. Microstructural analysis of anhydrite reveals strong stretching structures with lobate grain boundaries and the fomation of large anhydrite crystals in polyhalite (locally called muriazite). Rock salt and Haselgebirge samples were gamma-irradiated to intensify contrasts in thin section analysis. No primary structures like fluid inclusion bands or chevrons were found. The oldest visible parts are innner cores of large residual grains. All other types of grains suffered grain size reduction during the subsequent deformation. Using subgrain piezometry, high differential stresses of around 5 MPa formed the present microstructure. The Alpine rock salt deposits suffered a complex deformation history. A first peak was the formation of polyhalite veins, 235 Ma ago. The overburden was around 800 m (Rantitsch & Russegger, 2005) and first differentiation of the sea floor occurred (Mandl, 1984

  6. Dosimetry using silver salts

    DOEpatents

    Warner, Benjamin P.

    2003-06-24

    The present invention provides a method for detecting ionizing radiation. Exposure of silver salt AgX to ionizing radiation results in the partial reduction of the salt to a mixture of silver salt and silver metal. The mixture is further reduced by a reducing agent, which causes the production of acid (HX) and the oxidized form of the reducing agent (R). Detection of HX indicates that the silver salt has been exposed to ionizing radiation. The oxidized form of the reducing agent (R) may also be detected. The invention also includes dosimeters employing the above method for detecting ionizing radiation.

  7. Submarine allochthonous salt sheets: Gravity-driven deformation of North African Cretaceous passive margin in Tunisia - Bled Dogra case study and nearby salt structures

    NASA Astrophysics Data System (ADS)

    Masrouhi, Amara; Bellier, Olivier; Ben Youssef, Mohamed; Koyi, Hemin

    2014-09-01

    We used structural, stratigraphic and sedimentologic data, together with a comparison of nearby structures and a Bouguer gravity map, to evaluate the evolution of the Bled Dogra salt structure (northern Tunisia) during the Cretaceous. Triassic salt sheets are recognized in the northwestern region of the Tunisian Atlas. These salt sheets are the result of Cretaceous thick and/or thin-skinned extension along the south Tethyan margin. The Bled Dogra salt structure is one of these submarine allochthonous salt sheets, which was emplaced during the Early Cretaceous. The geologic framework, during this period, produces conditions for a predominantly gravity-driven deformation: extension has produced space for the salt to rise; vigorous differential sedimentation created differential loading that resulted in the emplacement and extrusion of a large volume of Triassic salt and formation of large submarine salt sheets. Geologic field data suggest an interlayered Triassic salt sheet within Albian sequences. Salt was extruded at the sea floor during the Early-Middle Albian and was initially buried by Middle-Late Albian strata. The Coniacian corresponds to a second transgressive cover onto the salt sheet after the gliding of the first salt cover (Late Albian-Turonian). In addition, this northwest Tunisian area exposes evidences for salt flow and abundant slump features at the base of a northward facing submarine slope, which was probably dominant from the Early Cretaceous to Santonian. Two gravity deformation processes are recognized: gravity gliding and gravity spreading. Acting concurrently, these two processes appear indistinguishable in this geologic context. Like the present-day salt-involved passive margins - such as the northern Gulf of Mexico, the Atlantic margin of Morocco, the Brazilian Santos basin, the Angola margin, Cadiz in western Iberia, and the Red Sea - the North African Cretaceous passive margin in Tunisia provides evidences that deformation in a passive

  8. Dead Sea Minerals loaded polymeric nanoparticles.

    PubMed

    Dessy, Alberto; Kubowicz, Stephan; Alderighi, Michele; Bartoli, Cristina; Piras, Anna Maria; Schmid, Ruth; Chiellini, Federica

    2011-10-15

    Therapeutic properties of Dead Sea Water (DSW) in the treatment of skin diseases such as atopic dermatitis, psoriasis and photo aging UV damaged skin have been well established. DSW is in fact rich in minerals such as calcium, magnesium, sodium, potassium, zinc and strontium which are known to exploit anti-inflammatory effects and to promote skin barrier recovery. In order to develop a Dead Sea Minerals (DSM) based drug delivery system for topical therapy of skin diseases, polymeric nanoparticles based on Poly (maleic anhydride-alt-butyl vinyl ether) 5% grafted with monomethoxy poly(ethyleneglycol) 2000 MW (PEG) and 95% grafted with 2-methoxyethanol (VAM41-PEG) loaded with DSM were prepared by means of a combined miniemulsion/solvent evaporation process. The resulting nanoparticles were characterized in terms of dimension, morphology, biocompatibility, salt content and release. Cytocompatible spherical nanoparticles possessing an average diameter of about 300 nm, a time controlled drug release profile and a high formulation yield were obtained. PMID:21676600

  9. The bioenergetics of salt tolerance

    SciTech Connect

    Packer, L.

    1991-01-01

    The aims of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic activity which is partially injured and return to virtually normal growth rates. Identification of the temporal sequence of changes involved in adaptation to this stress was the rationale. Indeed this project employed a wide variety of biochemical and biophysical methods, including electron spin resonance techniques and nuclear magnetic resonance to study the bioenergetics and transport mechanisms, growth and energy changes in these organisms and how the structural components of the cells changed in response to adaptation to growth at high salinity. The problem has relevance for higher plants because most of the arable farmland in the world is already under use and that which is not used is usually in salite environments. Hence, understanding basic mechanisms of salt tolerance is a fundamental biological problem with great applications for bioproductivity and agriculture.

  10. The bioenergetics of salt tolerance

    SciTech Connect

    Packer, L.

    1991-01-01

    The aim of this project was to try to understand the adaptive mechanisms that organisms develop in order to respond to a sudden transformation in their environment to a salt shock.'' To study this problem we used a fresh water oxygenic photosynthetic cyanobacterium known as Synecoccus 6311. This organism suffers injury after this sudden exposure to high concentrations of sodium chloride equivalent to or even higher than that in sea water. Yet they are able to re-establish their photosynthetic activity which is partially injured and return to virtually normal growth rates. Identification of the temporal sequence of changes involved in adaptation to this stress was the rationale. Indeed this project employed a wide variety of biochemical and biophysical methods, including electron spin resonance techniques and nuclear magnetic resonance to study the bioenergetics and transport mechanisms, growth and energy changes in these organisms and how the structural components of the cells changed in response to adaptation to growth at high salinity. The problem has relevance for higher plants because most of the arable farmland in the work is already under use and that which is not used is usually in salite environments. Hence, understanding basic mechanisms of salt tolerance is a fundamental biological problem with great applications for bioproductivity and agriculture. 18 refs.

  11. Salton sea project, phase 1

    NASA Astrophysics Data System (ADS)

    Peelgren, M. L.

    1982-01-01

    A feasibility study was made for a salt gradient solar pond power plant in or near the Salton Sea of California. The conclusions support continuance 5-MWe proof-of-concept experiment, and ultimate construction by an electric utility company of a 600-MWe plant. The Solar Pond concept would be an environmental benefit to the Salton Sea by reversing the increasing salinity trend. The greatest cost drivers are the lake dike construction and pond sealing. Problems to be resolved include method of brine production from Salton Sea water for the first unit (which requires evaporation pond area and time), the high turbidity and color content of the Salton Sea water (which requires pretreatment), and other questions related to pond permeability, bio-activity and soil/brine chemical reactions. All technical and environmental problems appear solvable and/or manageable if care is taken in mitigating impacts.

  12. Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador - Pacific or Atlantic origin?

    NASA Astrophysics Data System (ADS)

    Makowski Giannoni, Sandro; Trachte, Katja; Rollenbeck, Ruetger; Lehnert, Lukas; Fuchs, Julia; Bendix, Joerg

    2016-08-01

    Sea salt (NaCl) has recently been proven to be of the utmost importance for ecosystem functioning in Amazon lowland forests because of its impact on herbivory, litter decomposition and, thus, carbon cycling. Sea salt deposition should generally decline as distance from its marine source increases. For the Amazon, a negative east-west gradient of sea salt availability is assumed as a consequence of the barrier effect of the Andes Mountains for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rainforest in the Andes of southern Ecuador. To analyse sea salt availability, we investigated the deposition of sodium (Na+) and chloride (Cl-), which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, sea salt deposition was analysed from both, rain and occult precipitation (OP) along an altitudinal gradient over a period between 2004 and 2009. To assess the influence of easterly and westerly air masses on the deposition of sodium and chloride over southern Ecuador, sea salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis data set and back-trajectory statistical methods were combined. Our results, based on deposition time series, show a clear difference in the temporal variation of sodium and chloride concentration and Na+ / Cl- ratio in relation to height and exposure to winds. At higher elevations, sodium and chloride present a higher seasonality and the Na+ / Cl- ratio is closer to that of sea salt. Medium- to long-range sea salt transport exhibited a similar seasonality, which shows the link between our measurements at high elevations and the sea salt synoptic transport. Although the influence of the easterlies was predominant regarding the atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the north equatorial Atlantic, Caribbean

  13. Plutonium and americium recovery from spent molten-salt-extraction salts with aluminum-magnesium alloys

    SciTech Connect

    Cusick, M.J.; Sherwood, W.G.; Fitzpatrick, R.F.

    1984-04-23

    Development work was performed to determine the feasibility of removing plutonium and americium from spent molten-salt-extraction (MSE) salts using Al-Mg alloys. If the product buttons from this process are compatible with subsequent aqueous processing, the complex chloride-to-nitrate aqueous conversion step which is presently required for these salts may be eliminated. The optimum alloy composition used to treat spent 8 wt % MSE salts in the past yielded poor phase-disengagement characteristics when applied to 30 mol % salts. After a limited investigation of other alloy compositions in the Al-Mg-Pu-Am system, it was determined that the Al-Pu-Am system could yield a compatible alloy. In this system, experiments were performed to investigate the effects of plutonium loading in the alloy, excess magnesium, age of the spent salt on actinide recovery, phase disengagement, and button homogeneity. Experimental results indicate that 95 percent plutonium recoveries can be attained for fresh salts. Further development is required for backlog salts generated prior to 1981. A homogeneous product alloy, as required for aqueous processing, could not be produced.

  14. Variability and Trends in Sea Ice Extent and Ice Production in the Ross Sea

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino; Kwok, Ronald; Martin, Seelye; Gordon, Arnold L.

    2011-01-01

    Salt release during sea ice formation in the Ross Sea coastal regions is regarded as a primary forcing for the regional generation of Antarctic Bottom Water. Passive microwave data from November 1978 through 2008 are used to examine the detailed seasonal and interannual characteristics of the sea ice cover of the Ross Sea and the adjacent Bellingshausen and Amundsen seas. For this period the sea ice extent in the Ross Sea shows the greatest increase of all the Antarctic seas. Variability in the ice cover in these regions is linked to changes in the Southern Annular Mode and secondarily to the Antarctic Circumpolar Wave. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate of increase in the net ice export of about 30,000 sq km/yr. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 cu km/yr, which is almost identical, within error bars, to our estimate of the trend in ice production. The increase in brine rejection in the Ross Shelf Polynya associated with the estimated increase with the ice production, however, is not consistent with the reported Ross Sea salinity decrease. The locally generated sea ice enhancement of Ross Sea salinity may be offset by an increase of relatively low salinity of the water advected into the region from the Amundsen Sea, a consequence of increased precipitation and regional glacial ice melt.

  15. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... Imaging SpectroRadiometer (MISR) image of the Red Sea was acquired on August 13, 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of algae,  Trichodesmium ...

  16. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Much of the Bering Sea is clear in this SeaWiFS image. The large expanse of bright aquamarine water is clearly visible. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  17. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The skies of the Bering Sea were relatively clear again in this SeaWiFS image showing a band of aquamarine colored water. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  18. Biogeochemistry of the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Amrhein, C.; Reese, B. K.; Anderson, M. A.

    2006-12-01

    The Salton Sea is a saline, closed basin lake 70 meters below MSL in the southern desert of California. It is the largest lake in California with a surface area of 945 km2 and an annual inflow of 1,600 million m3. The Sea is hypereutrophic due to nutrient inputs from farm runoff, and anaerobic conditions in the bottom water result in summer and fall releases of hydrogen sulfide and fish kills. The salinity of the Sea is 47 g/L and rising, with an annual salt load of 4 million metric tons. Plans are being developed for construction of a salt repository to control salinization, improve water quality, and maintain the Sea as a refuge for migratory waterfowl. We estimate 700,000 metric tons of calcite are precipitating in the Sea each year, along with 7,000 tons of iron sulfide minerals. Potentially, 70,000 metric tons of hydrogen sulfide are produced in the Sea each year. Measurements of hydrogen sulfide production, reoxidation in the water column, and atmospheric releases will be reported. Hydrodynamic modeling of the current Sea, and the proposed smaller Sea, indicate that partitioning the Sea could lead to persistent stratification and episodic releases of hydrogen sulfide during fall mixing.

  19. Structural evolution and petroleum potential of the Norwegian Barents Sea

    SciTech Connect

    Nilsen, K.T.

    1995-08-01

    The tectonic history of the Norwegian Barents Sea has provided potential hydrocarbon traps in clastic reservoirs associated with rotated fault blocks, compressional anticlines and salt domes. Significant stratigraphic potential also resides in Paleozoic carbonates. Drilling in the Hammerfest Basin has yielded large gas discoveries in rotated fault blocks, but other trapping concepts remain relatively untested. The undrilled arm north of 74{degrees} 30 minutes N, currently being mapped by the Norwegian Petroleum Directorate using exclusive seismic and geological data from shallow boreholes, represents a significant area for future exploration. Prospectivity is critically dependent on the scaling of traps following Neogene uplift of large areas of the Barents platform. The area is dominated by structural trends inherited from the Caledonian and older orogens. Carboniferous rifting established a system of half grabens and intervening highs, followed by late Permian faulting in the west which initiated regional subsidence continuing into the early Jurassic. Fault reactivation in early Triassic times triggered salt diapirism and provided structural control for the formation of Triassic shelf margins. During the late Jurassic-early Cretaceous western basins underwent tectonic subsidence, while the northeastern platform arm was subject to gentle compression. In the late Cretaceous salt was reactivated in the Nordkapp Basin and compressional structures developed west of the Loppa High. Further subsidence of the western basins was promoted by late Mesozoic and early Tertiary transtensional movements along the North Atlantic rift system. Subsequent regional compression in these basins, and basin inversion east of the Loppa High, are of post-Eocene age.

  20. Integrated Salt Studies

    NASA Astrophysics Data System (ADS)

    Urai, Janos L.; Kukla, Peter A.

    2015-04-01

    The growing importance of salt in the energy, subsurface storage, and chemical and food industries also increases the challenges with prediction of geometries, kinematics, stress and transport in salt. This requires an approach, which integrates a broader range of knowledge than is traditionally available in the different scientific and engineering disciplines. We aim to provide a starting point for a more integrated understanding of salt, by presenting an overview of the state of the art in a wide range of salt-related topics, from (i) the formation and metamorphism of evaporites, (ii) rheology and transport properties, (iii) salt tectonics and basin evolution, (iv) internal structure of evaporites, (v) fluid flow through salt, to (vi) salt engineering. With selected case studies we show how integration of these domains of knowledge can bring better predictions of (i) sediment architecture and reservoir distribution, (ii) internal structure of salt for optimized drilling and better cavern design, (iii) reliable long-term predictions of deformations and fluid flow in subsurface storage. A fully integrated workflow is based on geomechanical models, which include all laboratory and natural observations and links macro- and micro-scale studies. We present emerging concepts for (i) the initiation dynamics of halokinesis, (ii) the rheology and deformation of the evaporites by brittle and ductile processes, (iii) the coupling of processes in evaporites and the under- and overburden, and (iv) the impact of the layered evaporite rheology on the structural evolution.

  1. Molten salt electrolyte separator

    DOEpatents

    Kaun, T.D.

    1996-07-09

    The patent describes a molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication. 5 figs.

  2. Hydroxycarboxylic acids and salts

    DOEpatents

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  3. Progress in Studying Salt Secretion from the Salt Glands in Recretohalophytes: How Do Plants Secrete Salt?

    PubMed Central

    Yuan, Fang; Leng, Bingying; Wang, Baoshan

    2016-01-01

    To survive in a saline environment, halophytes have evolved many strategies to resist salt stress. The salt glands of recretohalophytes are exceptional features for directly secreting salt out of a plant. Knowledge of the pathway(s) of salt secretion in relation to the function of salt glands may help us to change the salt-tolerance of crops and to cultivate the extensive saline lands that are available. Recently, ultrastructural studies of salt glands and the mechanism of salt secretion, particularly the candidate genes involved in salt secretion, have been illustrated in detail. In this review, we summarize current researches on salt gland structure, salt secretion mechanism and candidate genes involved, and provide an overview of the salt secretion pathway and the asymmetric ion transport of the salt gland. A new model recretohalophyte is also proposed. PMID:27446195

  4. [Salt and cancer].

    PubMed

    Strnad, Marija

    2010-05-01

    Besides cardiovascular disease, a high salt intake causes other adverse health effects, i.e., gastric and some other cancers, obesity (risk factor for many cancer sites), Meniere's disease, worsening of renal disease, triggering an asthma attack, osteoporosis, exacerbation of fluid retention, renal calculi, etc. Diets containing high amounts of food preserved by salting and pickling are associated with an increased risk of cancers of the stomach, nose and throat. Because gastric cancer is still the most common cancer in some countries (especially in Japan), its prevention is one of the most important aspects of cancer control strategy. Observations among Japanese immigrants in the U.S.A. and Brazil based on the geographic differences, the trend in cancer incidence with time, and change in the incidence patterns indicate that gastric cancer is closely associated with dietary factors such as the intake of salt and salted food. The findings of many epidemiological studies suggest that high dietary salt intake is a significant risk factor for gastric cancer and this association was found to be strong in the presence of Helicobacter (H.) pylori infection with atrophic gastritis. A high-salt intake strips the lining of the stomach and may make infection with H. pylori more likely or may exacerbate the infection. Salting, pickling and smoking are traditionally popular ways of preparing food in Japan and some parts of Asia. In addition to salt intake, cigarette smoking and low consumption of fruit and vegetables increase the risk of stomach cancer. However, it is not known whether it is specifically the salt in these foods or a combination of salt and other chemicals that can cause cancer. One study identified a mutagen in nitrite-treated Japanese salted fish, and chemical structure of this mutagen suggests that it is derived from methionine and that salt and nitrite are precursors for its formation. Working under conditions of heat stress greatly increased the workers

  5. The Dead Sea

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop

  6. Modern sea power

    SciTech Connect

    Till, G.

    1987-01-01

    This book provides discussions of political, technical and military aspects of nuclear power. The contents include naval warfare in the nuclear age; politics, money, law and technology; a technological change; implications of technology; sea control; strategic deterrents; amphibious operations, maritime interdiction; inshore operations, naval diplomacy and conclusion.

  7. Water purification using organic salts

    DOEpatents

    Currier, Robert P.

    2004-11-23

    Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.

  8. Applying the Triangle Taste Test to Assess Differences between Low Sodium Salts and Common Salt: Evidence from Peru

    PubMed Central

    Saavedra-Garcia, Lorena; Bernabe-Ortiz, Antonio; Gilman, Robert H.; Diez-Canseco, Francisco; Cárdenas, María Kathia; Sacksteder, Katherine A.; Miranda, J. Jaime

    2015-01-01

    Background In resourced-constrained settings, daily cooking practices are still the norm. Replacing sodium in regular salt to produce potassium-enriched salts are potential alternative routes to reduce sodium intake, paired with the benefit associated with potassium intake. This change would likely have effects on palatability and taste of prepared foods, yet a threshold to discriminate sensorial changes can be determined. The main goal of this study was to assess if the use of potassium-enriched salt substitutes lead to perceived differences in taste utilizing a sensory discrimination test. Methods and Results A triangle taste test was conducted and participants were offered samples of cooked rice prepared with different salts. The only ingredient that differed in the preparation was the salt used: 100%NaCl (regular salt) and salts where sodium was replaced by 50%, 33% or 25% KCl (potassium-enriched salt). Comparisons were carried out according to the minimum number of correct judgments. A total of 156 subjects, 49% males, mean age 41.0 years (SD±15.5) years, participated in the study. Samples using 25% potassium-enrichment were indistinguishable in terms of taste from regular salt, whereas samples with 33% and 50% potassium-enrichment were distinguishable. Results were consistent when stratified by sex and age. Less than 10% of participants attributed the differences to bitterness or metallic flavor. Conclusions The 25% potassium-enriched salt is indistinguishable from regular salt. These findings suggest a potential to achieve sodium intake reduction strategies in cooking practices by substituting regular salt with potassium-enriched salt without affecting palatability. PMID:26225848

  9. Salt tectonics, patterns of basin fill, and reservoir distribution

    SciTech Connect

    Yorston, H.J.; Miles, A.E.

    1988-02-01

    Salt structures, which develop due to sediment loading, gravity creep, and/or buoyancy, include boundary-fault grabens and half grabens, rollers, anticlines, domes and walls, diapirs, sills, massifs, and compressional toe structures. Associated features include fault systems and turtle structures. Of these, six directly relate to basin fill and all directly influence the distribution of reservoir facies. Salt structuring is initiated by sedimentation, which in turn is localized by salt withdrawal. Withdrawal produces individual salt structures, migrating sills, dissected massifs, and regional depocenters bordered by salt walls. Composite withdrawals dictate the patterns of basin fill. Relative rates of structural growth and sedimentation control the distribution of reservoir facies. When growth dominates, sands are channeled into lows. When sedimentation dominates and maintains flat surfaces, facies distribution is not impacted except where faulting develops. Turtle structures, developed by the inversion of peripheral synclines, can move sands into favorable structural position and/or serve as platforms for carbonate reservoir development. Salt growth varies with type structure, stage of development, and rate of sedimentation. Sedimentation at a specific location depends on basin position, sediment transport system, sea level stand, and rate of salt withdrawal. This paper presents techniques for using seismic data to determine the controls on salt structural growth and sedimentation and the patterns of basin fill and reservoir distribution.

  10. Crushed Salt Constitutive Model

    SciTech Connect

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  11. Rapid coastal subsidence in the central Ganges-Brahmaputra Delta (Bangladesh) since the 17th century deduced from submerged salt-producing kilns

    NASA Astrophysics Data System (ADS)

    Hanebuth, T. J.; Kudrass, H.; Linstädter, J.; Islam, B.; Zander, A. M.

    2013-12-01

    The densely populated low lying Ganges-Brahmaputra Delta is highly vulnerable to the global sea-level rise. In order to estimate the subsidence of the delta over historical time scales, we examined submerged salt-producing kiln sites in the coastal Sundarbans. These kilns were built just above the previous winterly spring high-tide level, but are currently located ~155 × 15 cm below the corresponding modern level. According to optically stimulated luminescence (OSL) dating, the kilns were ultimately fired ~300 years ago (1705 × 35 AD) and salt production was terminated abruptly by a catastrophic event (major cyclone), which affected the kiln sites at different levels and locations. Two particular buried mangrove root horizons 80 cm below this kiln level also indicate catastrophic scenarios (probably subsidence events related to a regional earthquake). AMS-14C ages measured on the charcoal layers at the kiln's bases and on these associated mangrove stump horizons support the OSL dates. Based on the respective elevations of these kiln and mangrove palaeo-horizons and on the ages, the 300-year-average rate of sinking of the outer delta is 5.2 × 1.2 mm/a, which includes 0.8 mm/a of eustatic sea-level rise over this historical period. Expecting further acceleration of the eustatic sea-level rise of up to 7 mm/a, we calculate a rise in relative sea level of up to 8.9 × 3.3 mm/a for the next few decased, which will dramatically aggravate the already present problematic situation. Only a prudently-managed control of sediment accretion will keep southern Bangladesh above the sea level. (Hanebuth et al., Geology, Sept 2013, doi: 10.1130/G34646.1.)

  12. Salt matters: How salt affects the rheological and physical properties of gelatine for analogue modelling

    NASA Astrophysics Data System (ADS)

    Brizzi, S.; Funiciello, F.; Corbi, F.; Di Giuseppe, E.; Mojoli, G.

    2016-06-01

    Gelatine is extensively used as analogue material for the easiness to tune its physical and rheological properties. The addition of salt to gelatine is generally adopted to increase the density of the material, improving the scaling of the models. However, the way the addition of salt changes the rheological properties of gelatine is generally underestimated. Here, we investigate both rheological and physical properties (i.e., density and transparency) of type A pig-skin 2.5 wt.% gelatine at T = 10 °C as a function of salt concentration, cNaCl, and ageing time. We established a standard preparation recipe and measuring protocol, yielding to uniform samples with reproducible behaviour. Rheometric measurements show that the presence of salt weakens the gelatine structure, with a decrease of both material rigidity and viscosity as cNaCl increases. Salted gelatine behaviour moves from viscoelastic to dominantly elastic as the ageing time increases. Density and cloudiness also increase with cNaCl. Finally, we present results from subduction interplate seismicity models performed with pure and salted gelatines, showing that the modified material may improve the modelling performance and open new perspectives in experimental tectonics.

  13. Anatomizing one of the largest saltwater inflows into the Baltic Sea in December 2014

    NASA Astrophysics Data System (ADS)

    Gräwe, Ulf; Naumann, Michael; Mohrholz, Volker; Burchard, Hans

    2015-11-01

    In December 2014, an exceptional inflow event into the Baltic Sea was observed, a so-called Major Baltic Inflow (MBI). Such inflow events are important for the deep water ventilation in the Baltic Sea and typically occur every 3-10 years. Based on first observational data sets, this inflow had been ranked as the third largest since 100 years. With the help of a multinested modeling system, reaching from the North Atlantic (8 km resolution) to the Western Baltic Sea (600 m resolution, which is baroclinic eddy resolving), this event is reproduced in detail. The model gave a slightly lower salt transport of 3.8 Gt, compared to the observational estimate of four Gt. Moreover, by using passive tracers to mark the different inflowing water masses, including an age tracer, the inflowing water masses could be tracked and their paths and timing through the different basins could be reproduced and investigated. The analysis is supported by the recently developed Total Exchange Flow (TEF) to quantify the volume transport in different salinity classes. To account for uncertainties in the modeled velocity and tracer fields, a Monte Carlo Analysis (MCA) is applied to correct possible biases and errors. With the help of the MCA, 95% confidence intervals are computed for the transport estimates. Based on the MCA, the "best guess" of the volume transport is 291.0 ± 13.65 km3 and 3.89 ± 0.18 Gt for the total salt transport.

  14. Salting the landscapes in Transbaikalia: natural and technogenic factors

    NASA Astrophysics Data System (ADS)

    Peryazeva, E. G.; Plyusnin, A. M.; Chinavlev, A. M.

    2010-05-01

    Salting the soils, surface and subsurface waters is widespread in Transbaikalia. Hearths of salting occur within intermountain depressions of the Mesozoic and Cenozoic age both in the steppe arid and forest humid landscapes. Total water mineralization reaches 80 g/dm3 in lakes and 4-5 g/dm3 in subsurface waters. The waters belong to hydrocarbonate sodium and sulfate sodium types by chemical composition. The soda type of waters is widely spread through the whole area. Sulfate waters are found in several hearths of salting. Deposition of salts takes place in some lakes. Mirabilite and soda depositions are most commonly observed in muds of salt lakes. Deposition of salts occurs both as a result of evaporative concentrating and during freezing out the solvent. In the winter period, efflorescences of salts, where decawater soda is main mineral, are observed on ice surface. Solonchaks are spread in areas of shallow ground waters (1-2m). Soil salting is most intense in the lower parts of depressions, where surface of ground waters is at depth 0.5-1.0m. In soil cover of solonchaks, salt horizon is of various thicknesses, and it has various morphological forms of occurrence, i.e. as thick deposits of salts on soil surface and salting the surficial horizons. The soil has low alkaline reaction of medium and is characterized by high content of exchangeable bases with significant content of exchangeable sodium in the absorbing complex. Total amount of salts varies from 0.7 to 1.3%. Their maximal quantity (3.1%) is confined to the surficial layer. Sulfate-sodium type of salting is noted in the solonchak upper horizons and sulfate-magnesium-calcium one in the lower ones (Ubugunov et al, 2009). Formation of salting hearths is associated with natural and technogenic conditions. The Mesozoic depressions of Transbaikalia are characterized by intense volcanism. Covers of alkaline and moderately alkaline basalts that are enriched in potassium, sodium, carbon dioxide, fluorine, chlorine

  15. Cooking without salt

    MedlinePlus

    ... flavor and nutrition. Plant-based foods -- carrots, spinach, apples, and peaches -- are naturally salt-free. Sun-dried ... types of pepper, including black, white, green, and red. Experiment with vinegars (white and red wine, rice ...

  16. Shaking the Salt Habit

    MedlinePlus

    ... use the pepper shaker or mill. Add fresh lemon juice instead of salt to season fish and ... soups, salads, vegetables, tomatoes, potatoes Ginger: Chicken, fruits Lemon juice: Lean meats, fish, poultry, salads, vegetables Mace: ...

  17. Amine salts of nitroazoles

    DOEpatents

    Kienyin Lee; Stinecipher, M.M.

    1993-10-26

    Compositions of matter, a method of providing chemical energy by burning said compositions, and methods of making said compositions are described. These compositions are amine salts of nitroazoles. 1 figure.

  18. Salt intakes and salt reduction initiatives in Southeast Asia: a review.

    PubMed

    Batcagan-Abueg, Ada Portia M; Lee, Jeanette J M; Chan, Pauline; Rebello, Salome A; Amarra, Maria Sofia V

    2013-01-01

    Increased dietary sodium intake is a modifiable risk factor for cardiovascular disease. The monitoring of population sodium intake is a key part of any salt reduction intervention. However, the extent and methods used for as-sessment of sodium intake in Southeast Asia is currently unclear. This paper provides a narrative synthesis of the best available evidence regarding levels of sodium intake in six Southeast Asian countries: Indonesia, Malaysia, Philippines, Singapore, Thailand, Vietnam, and describes salt reduction measures being undertaken in these countries. Electronic databases were screened to identify relevant articles for inclusion up to 29 February 2012. Reference lists of included studies and conference proceedings were also examined. Local experts and researchers in nutrition and public health were consulted. Quality of studies was assessed using a modified version of the Downs and Black Checklist. Twenty-five studies fulfilled the inclusion criteria and were included in this review. Full texts of 19 studies including government reports were retrieved, with most studies being of good quality. In-sufficient evidence exists regarding salt intakes in Southeast Asia. Dietary data suggest that sodium intake in most SEA countries exceeded the WHO recommendation of 2 g/day. Studies are needed that estimate sodium intake using the gold standard 24-hour urinary sodium excretion. The greatest proportion of dietary sodium came from added salt and sauces. Data on children were limited. The six countries had salt reduction initiatives that differed in specificity and extent, with greater emphasis on consumer education. PMID:24231008

  19. Electrodialysis technology for salt recovery from aluminum salt cake

    SciTech Connect

    Hryn, J. N.; Krumdick, G.; Graziano, D.; Sreenivasarao, K.

    2000-02-02

    Electrodialysis technology for recovering salt from aluminum salt cake is being developed at Argonne National Laboratory. Salt cake, a slag-like aluminum-industry waste stream, contains aluminum metal, salt (NaCl and KCl), and nonmetallics (primarily aluminum oxide). Salt cake can be recycled by digesting with water and filtering to recover the metal and oxide values. A major obstacle to widespread salt cake recycling is the cost of recovering salt from the process brine. Electrodialysis technology developed at Argonne appears to be a cost-effective approach to handling the salt brines, compared to evaporation or disposal. In Argonne's technology, the salt brine is concentrated until salt crystals are precipitated in the electrodialysis stack; the crystals are recovered downstream. The technology is being evaluated on the pilot scale using Eurodia's EUR 40-76-5 stack.

  20. Seventy years of continuous encroachment substantially increases 'blue carbon' capacity as mangroves replace intertidal salt marshes.

    PubMed

    Kelleway, Jeffrey J; Saintilan, Neil; Macreadie, Peter I; Skilbeck, Charles G; Zawadzki, Atun; Ralph, Peter J

    2016-03-01

    Shifts in ecosystem structure have been observed over recent decades as woody plants encroach upon grasslands and wetlands globally. The migration of mangrove forests into salt marsh ecosystems is one such shift which could have important implications for global 'blue carbon' stocks. To date, attempts to quantify changes in ecosystem function are essentially constrained to climate-mediated pulses (30 years or less) of encroachment occurring at the thermal limits of mangroves. In this study, we track the continuous, lateral encroachment of mangroves into two south-eastern Australian salt marshes over a period of 70 years and quantify corresponding changes in biomass and belowground C stores. Substantial increases in biomass and belowground C stores have resulted as mangroves replaced salt marsh at both marine and estuarine sites. After 30 years, aboveground biomass was significantly higher than salt marsh, with biomass continuing to increase with mangrove age. Biomass increased at the mesohaline river site by 130 ± 18 Mg biomass km(-2)  yr(-1) (mean ± SE), a 2.5 times higher rate than the marine embayment site (52 ± 10 Mg biomass km(-2) yr(-1) ), suggesting local constraints on biomass production. At both sites, and across all vegetation categories, belowground C considerably outweighed aboveground biomass stocks, with belowground C stocks increasing at up to 230 ± 62 Mg C km(-2) yr(-1) (± SE) as mangrove forests developed. Over the past 70 years, we estimate mangrove encroachment may have already enhanced intertidal biomass by up to 283 097 Mg and belowground C stocks by over 500 000 Mg in the state of New South Wales alone. Under changing climatic conditions and rising sea levels, global blue carbon storage may be enhanced as mangrove encroachment becomes more widespread, thereby countering global warming. PMID:26670941

  1. Microstructural Considerations of Transporting Sea Ice Samples from Polar Regions

    NASA Astrophysics Data System (ADS)

    Lieb-Lappen, R.; Obbard, R. W.

    2012-12-01

    High latitude regions are at the forefront of climate change research as these regions have and will experience the greatest impact due to changing environmental conditions (e.g. Antarctic and recent Arctic stratospheric ozone holes, large temperature increases on the Antarctic Peninsula, changes in the extent and age of Arctic sea ice). One of the major challenges of polar scientific research is the preservation of frozen sea ice samples during their transport back to the laboratory and subsequent storage. Small fluctuations in temperature have been shown to have a significant effect on the microstructure of snow and ice samples. This is especially true for sea ice specimens where transport and storage temperatures are often only slightly below the eutectic point for its different constituents (i.e. salts). Furthermore, sea ice can have a 30 deg C in situ vertical temperature gradient that is lost during transport and storage. Sea ice plays a critical role in mediating the exchange of heat, gases, and chemical species across the ocean-atmosphere interface. The kinetics of these exchanges is highly dependent upon the brine channel microstructure, which is strongly coupled to temperature. To determine the degree of microstructural variation between samples shipped at different temperatures, ten samples of a single sea ice core collected in March 2012 were transported from Barrow, Alaska to Hanover, NH using two common techniques: with blue ice packs enclosed in a Styrofoam box (~ -25 deg C) and in a dry liquid nitrogen cryoshipper (~ -182 deg C). In addition, snow lying on the sea ice and blowing snow samples were collected and shipped via both techniques. All samples were then stored for analysis in a cold room maintained at ~ -33 deg C. The microstructure of both sets of samples was analyzed using x-ray micro-computed tomography (μ-CT), with samples on a Peltier cold stage to maintain a scanning temperature of -20 deg C. We compare sea ice porosity and brine

  2. Transport of salt and freshwater in the Atlantic Subpolar Gyre

    NASA Astrophysics Data System (ADS)

    Born, Andreas; Stocker, Thomas F.; Sandø, Anne Britt

    2016-08-01

    Transport of salt in the Irminger Current, the northern branch of the Atlantic Subpolar Gyre coupling the eastern and western subpolar North Atlantic, plays an important role for climate variability across a wide range of time scales. High-resolution ocean modeling and observations indicate that salinities in the eastern subpolar North Atlantic decrease with enhanced circulation of the North Atlantic subpolar gyre (SPG). This has led to the perception that a stronger SPG also transports less salt westward. In this study, we analyze a regional ocean model and a comprehensive global coupled climate model, and show that a stronger SPG transports more salt in the Irminger Current irrespective of lower salinities in its source region. The additional salt converges in the Labrador Sea and the Irminger Basin by eddy transports, increases surface salinity in the western SPG, and favors more intense deep convection. This is part of a positive feedback mechanism with potentially large implications for climate variability and predictability.

  3. The ecology of Dunaliella in high-salt environments.

    PubMed

    Oren, Aharon

    2014-12-01

    Halophilic representatives of the genus Dunaliella, notably D. salina and D. viridis, are found worldwide in salt lakes and saltern evaporation and crystallizer ponds at salt concentrations up to NaCl saturation. Thanks to the biotechnological exploitation of D. salina for β-carotene production we have a profound knowledge of the physiology and biochemistry of the alga. However, relatively little is known about the ecology of the members of the genus Dunaliella in hypersaline environments, in spite of the fact that Dunaliella is often the main or even the sole primary producer present, so that the entire ecosystem depends on carbon fixed by this alga. This review paper summarizes our knowledge about the occurrence and the activities of different Dunaliella species in natural salt lakes (Great Salt Lake, the Dead Sea and others), in saltern ponds and in other salty habitats where members of the genus have been found. PMID:25984505

  4. Effects of sea spray geoengineering

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-03-01

    Anthropogenic climate warming is leading to consideration of options for geoengineering to offset rising carbon dioxide levels. One potential technique involves injecting artificial sea spray into the atmosphere. The sea salt particles would affect Earth's radiation budget directly, by scattering incoming solar radiation, and indirectly, by acting as cloud condensation nuclei, which could lead to whiter clouds that reflect more radiation. However, the potential effects of this method, especially the direct effects, are not fully known. Partanen et al. studied the effects of artificial sea spray using climate model simulations. They found that outside of the most heavily clouded regions the direct effect of scattering of radiation was an important part of the total effect. They also examined the effect of particle size and found that decreasing the size of injected particles could improve the efficiency of the geoengineering technique.

  5. Progress report on studies of salt-water encroachment on Long Island, New York, 1953

    USGS Publications Warehouse

    Lusczynski, N.J.; Upson, J.E.

    1954-01-01

    Nearly all the water used on Long Island, N. Y., is derived by wells from the thick and extensive water-bearing formations that underlie and compose the entire island. The unconsolidated deposits, consisting of sand, gravel, and clay, range in thickness from a few feet in northern Queens County to more than 2,000 feet in southern Suffolk County. Four main and relatively distinct aquifers, all interconnected hydraulically to a greater or lesser degree, have been recognized and delineated at least in a general way. They are, from younger to older, the upper Pleistocene deposits, in which the ground water is mainly unconfined, and three formations in which the water is generally confined - the Jameco gravel, of Pleistocene age, and the Magothy (?) formation and the Lloyd sand member of the Rartian formation, both of Lake Cretaceous age. Except for some artificial recharge, these aquifers are replenished entirely by infiltration of precipitation. Under natural conditions, the fresh water moves into and through the formations, discharging into the sea. With the growth of population on Long Island and the continuously increasing use of water over the years, not only has the infiltration of precipitation been seriously impeded at places, but the withdrawals from the ground-water reservoir have increased markedly. These factors have upset the natural balance between the fresh surface and ground water of the island and the surrounding sea water, and with increased use of water will do so more and more, thus leading to salt-water encroachment. In a sense, the whole problem of utilization of ground water on Long Island is one of determining how much ground water can be withdrawn without serious salt-water encroachment.

  6. Massive Dissociation of Subsurface Gas Hydrates and Collapse of Gas Hydrate Mounds during the LGM in the Eastern Margin of Japan Sea: Evidence from Benthic Forams and U/Th ages of Authigenic Carbonates

    NASA Astrophysics Data System (ADS)

    Matsumoto, R.; Takeuchi, E.; Sanno, R.

    2008-12-01

    A number of gigantic methane plumes, ca. 600 m high, and massive blocks of gas hydrate, ca. 0.5 m x 1.0 m, have been observed on the Umitaka spur and Joetsu knoll, eastern margin of Japan Sea. Large pockmarks and mounds, ca. 0.5 km in diameter, develop on the spur and knoll. The mounds exhibit rough morphological features characterized by small valleys of 5m wide, steep cliffs, crater-like depressions of 10 m in diameter, and scattered carbonate nodules and crusts of various size and shape with occasional gas hydrate blocks and veins and gas venting. To the contrary, pockmarks are inactive, partly filled by well-stratified mud without any indication of gas venting. 2D and 3D seismic surveys have recognized widely distributed BSRs at around 150 mbsf over the spur and knoll. Seismic profiles delineated deep gas chimney structures below the pockmarks and mounds. Unusual pull-up structures within gas chimneys indicate massive accumulation of gas hydrate. All these findings are likely to suggest that massive hydrate deposits both in gas chimneys at depths and hydrate mounds on the spur and knoll were collapsed and floated up to the sea surface, leaving big holes (= pockmarks) on the seafloor. Quantitative analysis of foraminiferal assemblage has revealed that the well laminated, burrow-free 17 to 22 ka sediments are substantially barren for benthic forams but for unusual species which has been believed to survive under high methane environments. Shells of such a few benthic formas from around 20 ka sediments are anomalously depleted in C-13. U-Th ages of authigenic carbonates of CH4-induced carbonate nodules and crusts are likely to center around 20 ka. Above line of evidences all suggest that gas hydrate system was collapsed and methane fluxes were enhanced during the last glacial maximum (LGM), presumably due to low stand of sea level and pressure release. Broken gas hydrate blocks are expected to float up to the sea surface to supply significant amount of methane to

  7. Petrology and age of volcanic-arc rocks from the continental margin of the Bering Sea: implications for Early Eocene relocation of plate boundaries

    USGS Publications Warehouse

    Davis, A.S.; Pickthorn, L.-B.G.; Vallier, T.L.; Marlow, M. S.

    1989-01-01

    Eocene volcanic flow and dike rocks from the Beringian margin have arc characteristics, implying a convergent history for this region during the early Tertiary. Chemical and mineralogical compositions are similar to those of modern Aleutian-arc lavas. They also resemble volcanic-arc compositions from western mainland Alaska, although greater chemical diversity and a stronger continental influence are observed in the Alaskan mainland rocks. Early Eocene ages of 54.4-50.2 Ma for the Beringian samples are well constrained by conventional K-Ar ages of nine plagioclase separates and by concordant 40Ar/39Ar incremental heating and total-fusion experiments. A concordant U-Pb zircon age of 53 Ma for the quartz-diorite dike is in good agreement with the K-Ar data. Plate motion studies of the North Pacific Ocean indicate more northerly directed subduction prior to the Tertiary and a continuous belt of arc-type volcanism extending from Siberia, along the Beringian margin, into mainland Alaska. Around 56 Ma (chron 25-24), subduction changed to a more westerly direction and subduction-related volcanism ceased for most of mainland Alaska. The increasingly oblique angle of convergence should have ended subduction along the Beringian margin as well. However, consistent ages of 54-50 Ma indicate a final pulse in arc-type magmatism during this period of plate adjustment. -from Authors

  8. Barriers for progress in salt reduction in the general population. An international study.

    PubMed

    Newson, R S; Elmadfa, I; Biro, Gy; Cheng, Y; Prakash, V; Rust, P; Barna, M; Lion, R; Meijer, G W; Neufingerl, N; Szabolcs, I; van Zweden, R; Yang, Y; Feunekes, G I J

    2013-12-01

    Salt reduction is important for reducing hypertension and the risk of cardiovascular events, nevertheless worldwide salt intakes are above recommendations. Consequently strategies to reduce intake are required, however these require an understanding of salt intake behaviours to be effective. As limited information is available on this, an international study was conducted to derive knowledge on salt intake and associated behaviours in the general population. An online cohort was recruited consisting of a representative sample from Germany, Austria, United States of America, Hungary, India, China, South Africa, and Brazil (n=6987; aged 18-65 years; age and gender stratified). Participants completed a comprehensive web-based questionnaire on salt intake and associated behaviours. While salt reduction was seen to be healthy and important, over one third of participants were not interested in salt reduction and the majority were unaware of recommendations. Salt intake was largely underestimated and people were unaware of the main dietary sources of salt. Participants saw themselves as mainly responsible for their salt intake, but also acknowledged the roles of others. Additionally, they wanted to learn more about why salt was bad for health and what the main sources in the diet were. As such, strategies to reduce salt intake must raise interest in engaging in salt reduction through improving understanding of intake levels and dietary sources of salt. Moreover, while some aspects of salt reduction can be globally implemented, local tailoring is required to match level of interest in salt reduction. These findings provide unique insights into issues surrounding salt reduction and should be used to develop effective salt reduction strategies and/or policies. PMID:23891557

  9. The Antarctica component of postglacial rebound model ICE-6G_C (VM5a) based on GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories

    NASA Astrophysics Data System (ADS)

    Argus, Donald F.; Peltier, W. R.; Drummond, R.; Moore, Angelyn W.

    2014-07-01

    A new model of the deglaciation history of Antarctica over the past 25 kyr has been developed, which we refer to herein as ICE-6G_C (VM5a). This revision of its predecessor ICE-5G (VM2) has been constrained to fit all available geological and geodetic observations, consisting of: (1) the present day uplift rates at 42 sites estimated from GPS measurements, (2) ice thickness change at 62 locations estimated from exposure-age dating, (3) Holocene relative sea level histories from 12 locations estimated on the basis of radiocarbon dating and (4) age of the onset of marine sedimentation at nine locations along the Antarctic shelf also estimated on the basis of 14C dating. Our new model fits the totality of these data well. An additional nine GPS-determined site velocities are also estimated for locations known to be influenced by modern ice loss from the Pine Island Bay and Northern Antarctic Peninsula regions. At the 42 locations not influenced by modern ice loss, the quality of the fit of postglacial rebound model ICE-6G_C (VM5A) is characterized by a weighted root mean square residual of 0.9 mm yr-1. The Southern Antarctic Peninsula is inferred to be rising at 2 mm yr-1, requiring there to be less Holocene ice loss there than in the prior model ICE-5G (VM2). The East Antarctica coast is rising at approximately 1 mm yr-1, requiring ice loss from this region to have been small since Last Glacial Maximum. The Ellsworth Mountains, at the base of the Antarctic Peninsula, are inferred to be rising at 5-8 mm yr-1, indicating large ice loss from this area during deglaciation that is poorly sampled by geological data. Horizontal deformation of the Antarctic Plate is minor with two exceptions. First, O'Higgins, at the tip of the Antarctic Peninsula, is moving southeast at a significant 2 mm yr-1 relative to the Antarctic Plate. Secondly, the margins of the Ronne and Ross Ice Shelves are moving horizontally away from the shelf centres at an approximate rate of 0.8 mm yr-1, in