Science.gov

Sample records for deep water formation

  1. Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Killworth, P. D.

    1984-01-01

    Some simple arguments on plumes of dense water and filling boxes were given. What determines the time for a large-scale environment to be modified by the injection of dense water at its edge is the mass flux, not the buoyancy flux. However, it is the denser buoyancy flux, when there are several competing plumes (e.g., the Mediterranean outflow versus the Denmark Strait outflow) that determines which plume will provide the bottom water for that ocean basin. It was noted that the obvious laboratory experiment (rotate a pie-shaped annulus, and heat/cool it on the surface) had never been performed. Thus, to some extent our belief that deep convection is somehow automatic at high latitudes to close off some ill-defined meridional circulation has never been tested. A summary of deep convection was given. The two fundamental formation mechanisms were shown. Of the two, it is open-ocean convection which forms the water which supplies the Denmark Strait overflow -- in all likelihood, as formation in the Greenland Sea remains stubbornly unobserved. But it is the slope convection which finally creates North Atlantic deep water, following the Denmark Strait overspill.

  2. Intermediate and deep water formation in the Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Nakamura, Hirohiko; Nishina, Ayako; Liu, Zhaojun; Tanaka, Fumiyo; Wimbush, Mark; Park, Jae-Hun

    2013-12-01

    Water mass formation in the intermediate and deep layers of the Okinawa Trough is investigated using two distinct data sets: a quasi-climatological data set of the water properties of the minimum salinity surface produced from Argo float profiles and historical CTD data, and a velocity data set in the Kerama Gap measured by moored current meters during June 2009 to June 2011. The formation process of Okinawa Trough Intermediate Water is explained on the basis of horizontal advection and mixing of North Pacific Intermediate Water (NPIW) and South China Sea Intermediate Water (SCSIW). The salinity-minimum water intruding into the Okinawa Trough through the channel east of Taiwan is approximately composed of 45% NPIW and 55% SCSIW, while that through the Kerama Gap is 75% NPIW and 25% SCSIW. Salinities of these water masses increase in the Okinawa Trough due to strong diapycnal diffusion; its coefficient is estimated as 6.8-21.5 × 10-4 m2 s-1 based on a simple advection-diffusion equation. On the other hand, deep water in the Okinawa Trough, below the sill depth of the Kerama Gap (˜1100 m), is ventilated by overflow in the bottom layer of the Kerama Gap down to the deepest layer (˜2000 m) in the southern Okinawa Trough. A simple box model predicts that this bottom overflow (0.18-0.35 Sv) causes strong upwelling (3.8-7.6 × 10-6 m s-1) in the southern Okinawa Trough, which must be maintained by buoyancy gain of the deep water due to strong diapycnal diffusion (4.8-9.5 × 10-4 m2 s-1).

  3. Deep Water Compositions From the Los Angeles Basin and the Origin of Formation Water Salinity

    NASA Astrophysics Data System (ADS)

    Boles, J.; Giles, G.; Lockman, D.

    2005-12-01

    Deep basin formation waters represent original depositional waters that have been modified by diagenetic processes at elevated temperatures and pressures. In addition, they may be diluted by meteoric incursion from elevated structural blocks along basin flanks. It has long been thought that deep basin formation waters have salinities greater than sea water due to various processes like clay membrane filtration or other types of water-rock interaction. However, our work and similar studies in the San Joaquin basin show that formation waters in deep basins are more likely to become diluted rather than concentrated in the absence of soluble evaporite deposits that might underlie the basin. The idea of increased salinity with depth arose from studies in which the underpinning of the basin consisted of soluble evaporate deposits such as the Texas Gulf Coast, Illinois, Michigan, and some North Sea areas. There are very few deep formation water analyses from the Los Angeles Basin. Furthermore, very few of the current produced waters from any depth can be considered pristine because of the widespread formation water injection programs and commingling of fluids from different levels. Here, we describe the first analyses from a deep, previously untouched part of the basin that is currently being developed in the Inglewood Oil Field. We have analyzed a suite of formation waters from the mid-Miocene marine Sentous sandstone from sub-sea level depths of 2250 m to 2625 m at temperatures of about 110 to 126°C and pressures of about 27 MPa. The original depositional waters in the Sentous Formation were sea water whereas the sampled waters are diluted by about 20% from sea water and some show as much as 50% dilution. Based on comparison of oxygen and deuterium isotopes between the meteoric water trend and these waters, we conclude that the smectite to illite dehydration reaction is the major cause of dilution to the original formation water. Other notable differences include

  4. Early Oligocene initiation of North Atlantic Deep Water formation.

    PubMed

    Davies, R; Cartwright, J; Pike, J; Line, C

    2001-04-19

    Dating the onset of deep-water flow between the Arctic and North Atlantic oceans is critical for modelling climate change in the Northern Hemisphere and for explaining changes in global ocean circulation throughout the Cenozoic era (from about 65 million years ago to the present). In the early Cenozoic era, exchange between these two ocean basins was inhibited by the Greenland-Scotland ridge, but a gateway through the Faeroe-Shetland basin has been hypothesized. Previous estimates of the date marking the onset of deep-water circulation through this basin-on the basis of circumstantial evidence from neighbouring basins-have been contradictory, ranging from about 35 to 15 million years ago. Here we describe the newly discovered Southeast Faeroes drift, which extends for 120 km parallel to the basin axis. The onset of deposition in this drift has been dated to the early Oligocene epoch ( approximately 35 million years ago) from a petroleum exploration borehole. We show that the drift was deposited under a southerly flow regime, and conclude that the initiation of deep-water circulation from the Norwegian Sea into the North Atlantic Ocean took place much earlier than is currently assumed in most numerical models of ancient ocean circulation.

  5. Upwelling at the ice edge - A mechanism for deep water formation?

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa

    1987-01-01

    This study sets forward a hypothesis which anticipates deep water formation due to ice edge upwelling. The upwelling can raise thermocline waters (the lower Arctic Intermediate Water) to the surface or near it, where the water is exposed to cooling, evaporation, mixing, and oxygenation. Thus, upwelling can act as a preconditioning mechanism for deep convection. The conjecture would also explain the salinity range of the Greenland Sea Deep Water if the upper and lower Arctic Intermediate Water masses are mixed so that the latter has at least an 80-percent contribution. It is also anticipated that the convection events induced by ice edge upwelling during winter season could give rise to a new deep water annual production rate consistent with observations.

  6. Modeling the dispersal of Levantine Intermediate Water and its role in Mediterranean deep water formation

    NASA Astrophysics Data System (ADS)

    Wu, Peili; Haines, Keith

    1996-03-01

    This paper demonstrates the importance of Levantine Intermediate Water (LIW) in the deep water formation process in the Mediterranean using the modular ocean general circulation model at 0.25° resolution, 19 vertical levels, over the entire Mediterranean with an open Gibraltar strait. LIW formation is strongly prescribed in the Rhodes Gyre region by Haney [1971] relaxation, while in other regions, surface salinity relaxation is much reduced by applying the `mixed' thermohaline surface boundary conditions. Isopycnal diagnostics are used to trace water mass movements, and volume fluxes are monitored at straits. Low viscosity and diffusion are used to permit baroclinic eddies to play a role in water mass dispersal. The overall water budget is measured by an average flux at Gibraltar of 0.8 Sv, of which 0.7 Sv is exchanged with the eastern basin at Sicily. LIW (density around 28.95) spreads rapidly after formation throughout the entire Levantine due to baroclinic eddies. Toward the west, LIW accumulates in the northern and central Ionian, with some entering the Adriatic through Otranto and some mixing southward in eddies and exiting to the western Mediterranean through Sicily. LIW is converted to deep water in the south Adriatic at an average rate of 0.4 Sv. Water exchange through the Otranto strait appears to be buoyancy driven, with a strong bias to the end of winter (March-April), while at Sicily the exchange has a strong symmetric seasonal cycle, with maximum transport of 1.1 Sv in December indicating the effects of wind driving. LIW pathways in the west are complex and variable. In the Tyrrhenian, intermediate water becomes uniform on isopycnal surfaces due to eddy stirring. West of Sardinia, two LIW boundary currents are formed in the Balearic basin; one flows northward up the west coast of Sardinia and Corsica, and one westward along the northern African coast. The northward current is consistent with observations, while the westward current is intermittent for

  7. North Atlantic deep water formation and AMOC in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Heuzé, Céline

    2017-07-01

    Deep water formation in climate models is indicative of their ability to simulate future ocean circulation, carbon and heat uptake, and sea level rise. Present-day temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5) models are compared with observations to assess the biases, causes and consequences of North Atlantic deep convection in models. The majority of models convect too deep, over too large an area, too often and too far south. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. Half of the models convect in response to local cooling or salinification of the surface waters; only a third have a dynamic relationship between freshwater coming from the Arctic and deep convection. The models with the most intense deep convection have the warmest deep waters, due to a redistribution of heat through the water column. For the majority of models, the variability of the Atlantic Meridional Overturning Circulation (AMOC) is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas up to 2 years before. In turn, models with the strongest AMOC have the largest heat export to the Arctic. Understanding the dynamical drivers of deep convection and AMOC in models is hence key to realistically forecasting Arctic oceanic warming and its consequences for the global ocean circulation, cryosphere and marine life.

  8. North Atlantic deep water formation and AMOC in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Heuzé, Céline; Wåhlin, Anna

    2017-04-01

    North Atlantic deep water formation processes and properties in climate models are indicative of their ability to simulate future ocean circulation, ventilation, carbon and heat uptake, and sea level rise. Historical time series of temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5) models are compared with observations to reveal the causes and consequences of North Atlantic deep water formation in models. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. The trigger of deep convection varies among models; for one third it is intense surface cooling only, while the remaining two thirds also need upward mixing of subsurface warm salty water. The models with the most intense deep convection have the most accurate deep water properties, which are warmer and fresher than in the other models. They also have the strongest Atlantic Meridional Overturning Circulation (AMOC). For over half of the models, 40% of the variability of the AMOC is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas, with 3 and 4 years lag respectively. Understanding the dynamical drivers of the AMOC in models is key to realistically forecast a possible slow down and its consequences on the global circulation and marine life.

  9. Quaternary North Atlantic Surface Paleoceanography in Regions of Potential Deep-water Formation

    NASA Technical Reports Server (NTRS)

    Ruddiman, W. F.

    1984-01-01

    At the time scale of the Quaternary climate cycles, the sites of formation of North Atlantic Deep Water are not known. The interglacial extreme is presumably exemplified by the modern regions; the Norwegian, Greenland and Labrador Seas. During the major glacial-age coolings in the North Atlantic, the sites may have shifted well to the south, perhaps as far as the limit of the polar front at 40 to 50 N. Still other sites may have been important during intermediate climatic conditions. Because of the close coupling of high-latitude surface waters to North Atlantic Deep Water in the modern ocean, the history of sea-surface temperature (SST) oscillations across the high-latitude North Atlantic is relevant to an understanding of deep-water formation on the longer time scales.

  10. Deep water formation in the North Pacific and deglacial CO2 rise

    NASA Astrophysics Data System (ADS)

    Rae, James W. B.; Sarnthein, Michael; Foster, Gavin L.; Ridgwell, Andy; Grootes, Pieter M.; Elliott, Tim

    2014-06-01

    Deep water formation in the North Atlantic and Southern Ocean is widely thought to influence deglacial CO2 rise and climate change; here we suggest that deep water formation in the North Pacific may also play an important role. We present paired radiocarbon and boron isotope data from foraminifera from sediment core MD02-2489 at 3640 m in the North East Pacific. These show a pronounced excursion during Heinrich Stadial 1, with benthic-planktic radiocarbon offsets dropping to ~350 years, accompanied by a decrease in benthic δ11B. We suggest that this is driven by the onset of deep convection in the North Pacific, which mixes young shallow waters to depth, old deep waters to the surface, and low-pH water from intermediate depths into the deep ocean. This deep water formation event was likely driven by an increase in surface salinity, due to subdued atmospheric/monsoonal freshwater flux during Heinrich Stadial 1. The ability of North Pacific Deep Water (NPDW) formation to explain the excursions seen in our data is demonstrated in a series of experiments with an intermediate complexity Earth system model. These experiments also show that breakdown of stratification in the North Pacific leads to a rapid ~30 ppm increase in atmospheric CO2, along with decreases in atmospheric δ13C and Δ14C, consistent with observations of the early deglaciation. Our inference of deep water formation is based mainly on results from a single sediment core, and our boron isotope data are unavoidably sparse in the key HS1 interval, so this hypothesis merits further testing. However, we note that there is independent support for breakdown of stratification in shallower waters during this period, including a minimum in δ15N, younging in intermediate water 14C, and regional warming. We also re-evaluate deglacial changes in North Pacific productivity and carbonate preservation in light of our new data and suggest that the regional pulse of export production observed during the B

  11. Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface

    PubMed Central

    Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L.; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C.; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q.; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J.; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Motz, Holger; Neff, Max; Nezri, Emma nuel; Palioselitis, Dimitris; Păvălaş, Gabriela E.; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G.; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J. M.; Stolarczyk, Thierry; Taiuti, Mauro G. F.; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

    2013-01-01

    The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as “open-sea convection”. It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts. PMID:23874425

  12. Deep-sea bioluminescence blooms after dense water formation at the ocean surface.

    PubMed

    Tamburini, Christian; Canals, Miquel; Durrieu de Madron, Xavier; Houpert, Loïc; Lefèvre, Dominique; Martini, Séverine; D'Ortenzio, Fabrizio; Robert, Anne; Testor, Pierre; Aguilar, Juan Antonio; Samarai, Imen Al; Albert, Arnaud; André, Michel; Anghinolfi, Marco; Anton, Gisela; Anvar, Shebli; Ardid, Miguel; Jesus, Ana Carolina Assis; Astraatmadja, Tri L; Aubert, Jean-Jacques; Baret, Bruny; Basa, Stéphane; Bertin, Vincent; Biagi, Simone; Bigi, Armando; Bigongiari, Ciro; Bogazzi, Claudio; Bou-Cabo, Manuel; Bouhou, Boutayeb; Bouwhuis, Mieke C; Brunner, Jurgen; Busto, José; Camarena, Francisco; Capone, Antonio; Cârloganu, Christina; Carminati, Giada; Carr, John; Cecchini, Stefano; Charif, Ziad; Charvis, Philippe; Chiarusi, Tommaso; Circella, Marco; Coniglione, Rosa; Costantini, Heide; Coyle, Paschal; Curtil, Christian; Decowski, Patrick; Dekeyser, Ivan; Deschamps, Anne; Donzaud, Corinne; Dornic, Damien; Dorosti, Hasankiadeh Q; Drouhin, Doriane; Eberl, Thomas; Emanuele, Umberto; Ernenwein, Jean-Pierre; Escoffier, Stéphanie; Fermani, Paolo; Ferri, Marcelino; Flaminio, Vincenzo; Folger, Florian; Fritsch, Ulf; Fuda, Jean-Luc; Galatà, Salvatore; Gay, Pascal; Giacomelli, Giorgio; Giordano, Valentina; Gómez-González, Juan-Pablo; Graf, Kay; Guillard, Goulven; Halladjian, Garadeb; Hallewell, Gregory; van Haren, Hans; Hartman, Joris; Heijboer, Aart J; Hello, Yann; Hernández-Rey, Juan Jose; Herold, Bjoern; Hößl, Jurgen; Hsu, Ching-Cheng; de Jong, Marteen; Kadler, Matthias; Kalekin, Oleg; Kappes, Alexander; Katz, Uli; Kavatsyuk, Oksana; Kooijman, Paul; Kopper, Claudio; Kouchner, Antoine; Kreykenbohm, Ingo; Kulikovskiy, Vladimir; Lahmann, Robert; Lamare, Patrick; Larosa, Giuseppina; Lattuada, Dario; Lim, Gordon; Presti, Domenico Lo; Loehner, Herbert; Loucatos, Sotiris; Mangano, Salvatore; Marcelin, Michel; Margiotta, Annarita; Martinez-Mora, Juan Antonio; Meli, Athina; Montaruli, Teresa; Moscoso, Luciano; Motz, Holger; Neff, Max; Nezri, Emma Nuel; Palioselitis, Dimitris; Păvălaş, Gabriela E; Payet, Kevin; Payre, Patrice; Petrovic, Jelena; Piattelli, Paolo; Picot-Clemente, Nicolas; Popa, Vlad; Pradier, Thierry; Presani, Eleonora; Racca, Chantal; Reed, Corey; Riccobene, Giorgio; Richardt, Carsten; Richter, Roland; Rivière, Colas; Roensch, Kathrin; Rostovtsev, Andrei; Ruiz-Rivas, Joaquin; Rujoiu, Marius; Russo, Valerio G; Salesa, Francisco; Sánchez-Losa, Augustin; Sapienza, Piera; Schöck, Friederike; Schuller, Jean-Pierre; Schussler, Fabian; Shanidze, Rezo; Simeone, Francesco; Spies, Andreas; Spurio, Maurizio; Steijger, Jos J M; Stolarczyk, Thierry; Taiuti, Mauro G F; Toscano, Simona; Vallage, Bertrand; Van Elewyck, Véronique; Vannoni, Giulia; Vecchi, Manuela; Vernin, Pascal; Wijnker, Guus; Wilms, Jorn; de Wolf, Els; Yepes, Harold; Zaborov, Dmitry; De Dios Zornoza, Juan; Zúñiga, Juan

    2013-01-01

    The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.

  13. Antarctic climate, Southern Ocean circulation patterns, and deep water formation during the Eocene

    NASA Astrophysics Data System (ADS)

    Huck, Claire E.; van de Flierdt, Tina; Bohaty, Steven M.; Hammond, Samantha J.

    2017-07-01

    We assess early-to-middle Eocene seawater neodymium (Nd) isotope records from seven Southern Ocean deep-sea drill sites to evaluate the role of Southern Ocean circulation in long-term Cenozoic climate change. Our study sites are strategically located on either side of the Tasman Gateway and are positioned at a range of shallow (<500 m) to intermediate/deep ( 1000-2500 m) paleowater depths. Unradiogenic seawater Nd isotopic compositions, reconstructed from fish teeth at intermediate/deep Indian Ocean pelagic sites (Ocean Drilling Program (ODP) Sites 738 and 757 and Deep Sea Drilling Project (DSDP) Site 264), indicate a dominant Southern Ocean-sourced contribution to regional deep waters (ɛNd(t) = -9.3 ± 1.5). IODP Site U1356 off the coast of Adélie Land, a locus of modern-day Antarctic Bottom Water production, is identified as a site of persistent deep water formation from the early Eocene to the Oligocene. East of the Tasman Gateway an additional local source of intermediate/deep water formation is inferred at ODP Site 277 in the SW Pacific Ocean (ɛNd(t) = -8.7 ± 1.5). Antarctic-proximal shelf sites (ODP Site 1171 and Site U1356) reveal a pronounced erosional event between 49 and 48 Ma, manifested by 2 ɛNd unit negative excursions in seawater chemistry toward the composition of bulk sediments at these sites. This erosional event coincides with the termination of peak global warmth following the Early Eocene Climatic Optimum and is associated with documented cooling across the study region and increased export of Antarctic deep waters, highlighting the complexity and importance of Southern Ocean circulation in the greenhouse climate of the Eocene.

  14. Hydrogeochemical signatures of thermal springs compared to deep formation water of North Germany

    NASA Astrophysics Data System (ADS)

    Bozau, Elke; van Berk, Wolfgang

    2014-05-01

    Thermal springs and hot deep formation waters can be used for geothermal energy production. Depending on the chemical composition of the used waters, geothermal power plants have to deal with scaling and corrosion effects. Therefore, the understanding of the hydrogeochemical behaviour of such waters can be helpful to enhance the efficiency of the energy production. This study is comparing hydrogeochemical characteristics of thermal springs in the Harz Mountains (North Germany) and deep formation water of the North German Basin. The Harz Mountains consist of uplifted Palaeozoic rocks, whereas the North German Basin consists of sedimentary layers of Permian, Mesozoic and Cenozoic age. Volcanic rocks are included in the Permian layers. The thickness of the sedimentary basin varies between 2 km and more than 8 km. The deep aquifers of the North German Basin are mostly not involved in the recent meteoric water cycle. Their waters have contents of Total Dissolved Solids (TDS) up to about 400 g/L. Thermal springs of the Harz Mountains are situated close to the main fracture system of the region. These springs are connected to the meteoric water cycle and display lower contents of TDS (< 25 g/L). In both geological systems the TDS content is increasing with depth and temperature. The elemental ratios of the waters (e.g., Na/Cl, Cl/Br, Na/Ca) indicate similar hydrogeochemical formation processes in the Harz Mountains and the North German Basin. The concentrations of calcium, sodium, and chloride differ due to salt dissolution and feldspar transformation (albitisation) in the thermal springs as well as in the deep formation waters. Based on today's knowledge hydrochemical and stratigraphical data from the North German Basin can be used to elucidate the geological origin of the thermal springs in the Harz Mountains. Acknowledgements. The presented data are results of the collaborative research program "gebo" (Geothermal energy and high performance drilling), financed by the

  15. Periodic fluctuations in deep water formation due to sea ice

    NASA Astrophysics Data System (ADS)

    Saha, R.

    2012-12-01

    During the last ice age, several abrupt warming events took place, known as Dansgaard-Oeschger (D-O) events. Their effects were felt globally, although the North Atlantic experienced the largest temperature increase. The leading hypothesis to explain their occurrence postulates that the warming was caused by abrupt disruptions of the North Atlantic Current due to meltwater discharge from destabilized ice sheets (Heinrich events). However, the number of warming events outnumber the those of ice-sheet collapse. Thus, the majority of D-O events are not attributed to surface freshwater anomalies, and the underlying mechanism behind their occurrence remain unexplained. Using a simple dynamical model of sea ice and an overturning circulation, I show the existence of self-sustained relaxation oscillations in the overturning circulation. The insulating effect of sea ice is shown to paradoxically lead to a net loss of heat from the top layer of the polar ocean when sea ice retreats. Repeated heat loss results in a denser top layer and a destabilized water column, which triggers convection. The convective state pulls the system out of its preferred mode of circulation, setting up relaxation oscillations. The period of oscillations in this case is linked to the geometry of the ocean basin, if solar forcing is assumed to remain constant. If appropriate glacial freshwater forcing is applied to the model, a pattern of oscillation is produced that bears remarkable similarity to the observed fluctuations in North Atlantic climate between 50,000 and 30,000 years before present.; Comparison of NGRIP δ 18-O (proxy for near surface air temperature) between 50,000 and 30,000 years before present, showing Bond cycles (left) with the model output when forced with appropriate glacial freshwater forcing (right).

  16. Climatic Impact of a Change in North Atlantic Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Rind, D.

    1984-01-01

    The response of the ocean to climate changes is one of the most uncertain questions regarding the impact of increasing CO2 on climate and society. North Atlantic deep water (NADW) formation apparently depends on a complex confluence of different water masses originating in different areas, all of which will presumably be affected by changes in wind, evaporation, etc., as the atmosphere warms. To analyze from first principles what the effect will be on NADW formation is a task which requires an ocean modeling capability not yet available. As a substitute, past climates can be investigated to see if there is any evidence for alterations in NADW formation. In addition, the possible impact of such changes on climate can be explored. An estimate of NADW sensitivity (at least in the past) and of the climate consequences can be studied. The North Atlantic surface water temperatures can be reconstructed to indicate a substantial cooling between 11,000 and 10,000 years B.P. Were NADW formation to have ceased, it would have resulted in cooler surface waters; whether the reconstructed temperatures were due to this or some other effect cannot be determined at this time. Nevertheless, it was decided that it would be useful to see what the effect these colder temperatures would have had on the climate.

  17. Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution

    NASA Astrophysics Data System (ADS)

    Sultan, N.; Bohrmann, G.; Ruffine, L.; Pape, T.; Riboulot, V.; Colliat, J.-L.; De Prunelé, A.; Dennielou, B.; Garziglia, S.; Himmler, T.; Marsset, T.; Peters, C. A.; Rabiu, A.; Wei, J.

    2014-04-01

    In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate-bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of free gas and gas hydrate indicate rapid hydrate growth. On the other hand, slow hydrate dissolution is evident by low methane concentrations and almost constant sulfate values 2 m above the Gas Hydrate Occurrence Zone.

  18. On the Impacts of Different Surface Forcing Regimes for Deep Water Formation in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Josey, S.; Tsimplis, M.; Gomis, D.; Ruiz, S.; Marcos, M.; Somot, S.

    2009-04-01

    Deep water formation is known to occur at 3 major sites (the Gulf of Lions, Adriatic and Aegean Seas) in the Mediterranean basin. However, the role played by air-sea interaction in setting the frequency and strength of formation events (including major transient episodes such as that experienced in the Aegean sea in the early 1990s) is not well understood. We will explore this relationship using air-sea heat, freshwater and density flux fields, including output from downscaled versions (HIPOCAS and ARPERA) of the NCEP/NCAR and ECMWF reanalyses. The downscaled fields reveal small scale forcing features (including jet-like structures over the dense water formation sites) that are not present in the coarser resolution reanalysis datasets. They also show greater variability in the forcing of the Aegean and the Gulf of Lions than the Adriatic Sea. The differences between the forcing distributions of the Aegean and Adriatic will be discussed in detail and will be advanced as a potential cause for variations in frequency of dense water formation in these two regions.

  19. Deep formation waters of Western Europe, Russia and North America characterised by sodium, calcium, magnesium and chloride concentrations

    NASA Astrophysics Data System (ADS)

    Bozau, Elke; Hemme, Christina; Sattler, Carl-Diedrich; van Berk, Wolfgang

    2015-04-01

    Deep formation water can be classified according to depth, temperature, and salinity (e.g., Graf et al. 1966, Kharaka & Hanor 2007). Most of the deep formation waters contain dissolved solids in excess of sea water. The hydrogeochemical development of formation water has been discussed for a long time. It is widely accepted that deep aquifers are influenced by the meteoric cycle and geochemical processes within the crust (e.g., Hebig et al. 2012). Similar hydrogeochemical signatures are found in deep formation waters of all continents and can be explained by general geochemical processes within the deep reservoirs (e.g., Land 1995). Therefore, data of deep formation waters from Western Europe, Russia, and North America are collected and classified by the major water components. The data are used to identify important hydrogeochemical processes (e.g., halite dissolution and albitisation) leading to different compositions of formation water. Two significant water types are identified: Na-Cl water and Na-Ca-Cl water. Based on the collected hydrogeochemical data, development trends are stated for the formation waters, and albitisation is favoured as the main process for calcium enrichment. Furthermore, differences of formation water according to stratigraphical units are shown for deep reservoirs of the North German Basin and the North Sea. References: Graf, D.L., 1982. Chemical osmosis, reverse chemical osmosis, and the origin of subsurface brines. Geochimica Cosmochimica Acta 46, 1431-1448. Hebig, K.H., Ito, N., Scheytt, T., Marui, A., 2012. Review: Deep groundwater research with focus on Germany. Hydrogeology Journal 20, 227-243. Kharaka, Y.K., Hanor, J.S., 2007. Deep fluids in continents: I. Sedimentary Basins. Treatise on Geochemistry 5, 1-48. Land, L.S., 1995. The role of saline formation water in the crustal cycling. Aquatic Geochemistry 1, 137-145. Acknowledgements: The presented data are results of the collaborative research program "gebo" (Geothermal energy

  20. Evidence for deep-water evaporite deposition in the Miocene Kareem Formation, Gemsa basin, eastern Egypt

    SciTech Connect

    May, J.A.; Stonecipher, S.A.; Steinmetz, J.C. ); Dyess, J.N. )

    1991-03-01

    The correct interpretation of intercalated Miocene siliciclastics and evaporites of Gemsa basin is crucial for understanding early rift tectonics of the Gulf of Suez, pinpointing the timing of isolation of the Gulf from the Mediterranean, and developing exploration plays. Evaporites of the Kareem Formation comprise celestites and massive, 'chicken-wire,' and laminated anhydrites. Although previously interpreted as sabkha deposits; sedimentologic, petrographic, and paleontologic analyses indicate these evaporites more likely formed in a submarine setting. Marls that encase the evaporites contain a diverse and abundant assemblage of nannoplankton, planktonic foraminifera, diatoms, pteropods, and fish scales indicative of basinal deposition. Associated turbidites also denote deep-water sedimentation. The paucity of benthic diatoms and foraminifera, plus the presence of unburrowed shales, phosphate nodules, early ferroan carbonate cements, and authigenic pyrite, suggest periodic anoxic, or at least disaerobic, bottom waters. These sequences probably represent partial isolation of the Gulf of Suez by middle Miocene, producing periodic basin restriction and evaporative drawdown. Episodes of increasing salinity likely caused the progressive decreases in foram abundance and diversity in marls beneath the anhydrites, culminating in subaqueous evaporite formation. Diverse, indigenous nannoplankton assemblages from shale seams within the anhydrites suggest Gemsa basin was stratified; shallow open-marine conditions coexisted with anhydrite crystallization from deeper hypersaline waters.

  1. Simulated interannual variability of the Greenland Sea deep water formation and its connection to surface forcing

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa

    1995-01-01

    A fully prognostic Arctic ice-ocean model is used to study the interannual variability of deepwater formation in the Greenland Sea Gyre based on the simulations for the Arctic ice-ocean system for the period 1955 and 1960 - 1985. The model uses monthly climatology for thermodynamic forcing components (such as air temperature and cloudiness), together with constant annual net precipitation and river runoff. The daily wind forcing is derived from analyzed sea level air pressures from the National Center for Atmospheric Research (NCAR). In summary, the model shows that the occurence of deep convection in the Greenland Sea Gyre is controlled by the extensive Fram Strait ice export and/or local wind conditions in the Greenland Sea. In the latter case the weakening of the local wind curl allows the Polar Front to move eastward. The movement of the Polar Front causes adverse ice conditions, often together with much larger than normal ice export from the Arctic, such as in 1968, which can block convection in the gyre. The density difference between upper and lower layers is investigated as an indication of water mass formation through convection, occurring as strong diffusion in the model. The model-simulated density difference between the average top 100 m and deep levels reveals that the period 1960 - 1985 had only a few distinct years with weak stratification, and, especially, the model predicts no deep convection since the nid-1970s. The common factor for the years of the weakest decrease of the model-predicted heat content of the upper 2000 m which can, to a high degree, be explained by local heat loss.

  2. Simulated interannual variability of the Greenland Sea deep water formation and its connection to surface forcing

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa

    1995-01-01

    A fully prognostic Arctic ice-ocean model is used to study the interannual variability of deepwater formation in the Greenland Sea Gyre based on the simulations for the Arctic ice-ocean system for the period 1955 and 1960 - 1985. The model uses monthly climatology for thermodynamic forcing components (such as air temperature and cloudiness), together with constant annual net precipitation and river runoff. The daily wind forcing is derived from analyzed sea level air pressures from the National Center for Atmospheric Research (NCAR). In summary, the model shows that the occurence of deep convection in the Greenland Sea Gyre is controlled by the extensive Fram Strait ice export and/or local wind conditions in the Greenland Sea. In the latter case the weakening of the local wind curl allows the Polar Front to move eastward. The movement of the Polar Front causes adverse ice conditions, often together with much larger than normal ice export from the Arctic, such as in 1968, which can block convection in the gyre. The density difference between upper and lower layers is investigated as an indication of water mass formation through convection, occurring as strong diffusion in the model. The model-simulated density difference between the average top 100 m and deep levels reveals that the period 1960 - 1985 had only a few distinct years with weak stratification, and, especially, the model predicts no deep convection since the nid-1970s. The common factor for the years of the weakest decrease of the model-predicted heat content of the upper 2000 m which can, to a high degree, be explained by local heat loss.

  3. Climatic forcing of eastern Mediterranean deep-water formation and benthic ecosystems during the past 22 000 years

    NASA Astrophysics Data System (ADS)

    Schmiedl, Gerhard; Kuhnt, Tanja; Ehrmann, Werner; Emeis, Kay-Christian; Hamann, Yvonne; Kotthoff, Ulrich; Dulski, Peter; Pross, Jörg

    2010-11-01

    Lateglacial and Holocene faunal and stable-isotope records from benthic foraminifers in the eastern Mediterranean Sea (EMS) suggest a high spatiotemporal variability of deep-water oxygenation and biogeochemical processes at the sea floor during that time. Changes in the oxygenation and food availability of the deep-sea ecosystems are closely linked to the hydrology of the EMS borderlands; they reflect orbital and suborbital climate variations of the high northern latitudes and the African monsoon system. During the last glacial maximum, cool surface waters and high evaporation resulted in maximum convection and oxic deep-waters in all sub-basins. Strong wind-induced mixing fostered surface-water production with seasonal phytodetritus fluxes. During the glacial termination and the Holocene, oxygenation and food availability of deep-sea benthic ecosystems were characterized by a pronounced regional differentiation. Local deep-water formation and trophic conditions were particularly variable in the northern Aegean Sea as a response to changes in riverine runoff and Black Sea outflow. During the interval of sapropel S1 formation in the early Holocene, average oxygen levels decreased exponentially with increasing water depth, suggesting a basin-wide shallowing of vertical convection superimposed by local signals. In the northernmost Aegean Sea, deep-water ventilation persisted during the early period of S1 formation, owing to temperature-driven local convection and the absence of low-salinity Black Sea outflow. At the same time, severe temporary anoxia occurred in the eastern Levantine basin at water depths as shallow as 900 m. This area was likely influenced by enhanced nutrient input of the Nile river that resulted in high organic matter fluxes and related high oxygen-consumption rates in the water column. In the southern Aegean and Levantine Seas, we observe a gradual increase in deep-water residence times, preceding S1 formation by approximately 1-1.5 kyr. Once

  4. Noble gas tracers of ventilation during deep-water formation in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Nicholson, D. P.; Khatiwala, S.; Heimbach, P.

    2016-05-01

    To explore the dynamics and implications of incomplete air-sea equilibration during the formation of abyssal water masses, we simulated noble gases in the Estimating the Circulation & Climate of the Ocean (ECCO) global ocean state estimate. A novel computation approach utilizing a matrix-free Newton-Krylov (MFNK) scheme was applied to quickly compute the periodic seasonal solutions for noble gas tracers. MFNK allows for quick computation of a cyclo-stationary solution for tracers (i.e., a spun-up, repeating seasonal cycle), which would otherwise be computationally infeasible due to the long time scale of dynamic adjustment of the abyssal ocean (1000’s of years). A suite of experiments isolates individual processes, including atmospheric pressure effects, the solubility pump and air-sea bubble fluxes. In addition to these modeled processes, a volumetric contribution of 0.28 ± 0.07% of glacial melt water is required to reconcile deep-water observations in the Weddell Sea. Another primary finding of our work is that the saturation anomaly of heavy noble gases in model simulations is in excess of two-fold more negative than is suggested from Weddell Sea observations. This result suggests that model water masses are insufficiently ventilated prior to subduction and thus there is insufficient communication between atmosphere and ocean at high latitudes. The discrepancy between noble gas observations and ECCO simulations highlights that important inadequacies remain in how we model high-latitude ventilation with large implications for the oceanic uptake and storage of carbon.

  5. Millennial-scale oscillations between sea ice and convective deep water formation

    NASA Astrophysics Data System (ADS)

    Saha, Raj

    2015-11-01

    During the last ice age there were several quasiperiodic abrupt warming events. The climatic effects of the so-called Dansgaard-Oeschger (D-O) events were felt globally, although the North Atlantic experienced the largest and most abrupt temperature anomalies. Similar but weaker oscillations also took place during the interglacial period. This paper proposes an auto-oscillatory mechanism between sea ice and convective deep water formation in the North Atlantic as the source of the persistent cycles. A simple dynamical model is constructed by coupling and slightly modifying two existing models of ocean circulation and sea ice. The model exhibits mixed mode oscillations, consisting of decadal-scale small-amplitude oscillations and a large-amplitude relaxation fluctuation. The decadal oscillations occur due to the insulating effect of sea ice and leads to periodic ventilation of heat from the polar ocean. Gradually, an instability builds up in the polar column and results in an abrupt initiation of convection and polar warming. The unstable convective state relaxes back to the small-amplitude oscillations from where the process repeats in a self-sustained manner. Freshwater pulses mimicking Heinrich events cause the oscillations to be grouped into packets of progressively weaker fluctuations, as observed in proxy records. Modulation of this stable oscillation mechanism by freshwater and insolation variations could account for the distribution and pacing of D-O and Bond events. Physical aspects of the system such as sea ice extent and oceanic advective flow rates could determine the characteristic 1500 year time scale of D-O events. The model results with respect to the structure of the water column in the Nordic seas during stadial and interstadial phases are in agreement with paleoproxy observations.

  6. Monitoring of Intense Events of Deep Water Formations in the Northwestern Mediterranean over the last five years

    NASA Astrophysics Data System (ADS)

    Houpert, Loïc; Durrieu de Madron, Xavier; Testor, Pierre; Bosse, Anthony; Mortier, Laurent

    2014-05-01

    A multi-platforms and integrated monitoring system in the framework of the Mediterranean Ocean Observing System on Environment (MOOSE) enables to monitor the deep water formation processes. Since 2007, it provides high frequency in-situ temperature, salinity vertical profiles, derived from CTD measurements on moorings, ships, and gliders, as well as horizontal and vertical currents from moorings. The aim of this study is to investigate the temporal scales associated to the deep convection phases. We also studied the interannual variability of the deep convection and its implication in the evolution of deep water thermohaline characteristics. Recent measurements from the mooring lines reveal the temporal evolution of the physical processes interfering in the phases of deep convection. Horizontal currents were strongly equivalent barotropic during each deployment and strong currents were also recorded during the different events of deep ocean convection: high frequencies vertical velocities exceeded 10 cm.s-1 during the violent vertical mixing phase and strong mesoscale horizontal currents reached 40cm.s-1 during the spreading/restratification phase. Using a eddy-detection method based on a kinematic model, more than 34 eddies crossing the mooring line were detected between November 2009 and July 2012, 19 cyclones and 15 anticyclones. The radii (resp. velocities) ranging from 1.9 km to 20.0 km (resp. 2.5 cm.s-1 to 25.1 cm.s-1 ). The main mode of the distribution of eddies radii is centered at 4km for the cyclones and 5km for the anticyclones. The apparition of newly-formed deep waters was detected in winter 2009, 2010, 2011 and 2012. In winter 2010, two newly-formed deep waters were detected after the deep convection event, both present a different potential temperature but a similar salinity, suggesting that both might be formed in the cyclonic gyre, but in different locations. In 2012, two new deep waters were detected at the mooring location, one was identified as

  7. A study on chemical interactions between waste fluid, formation water, and host rock during deep well injection

    SciTech Connect

    Spycher, Nicolas; Larkin, Randy

    2004-05-14

    A new disposal well was drilled in the vicinity of an injection well that had been in operation for 12 years. The drilling activities provided an opportunity to assess the fate and transport of waste products injected in the nearby well, and the impact, if any, on the host geologic formation. The origin of the fluid collected while drilling the new well and the interaction between injected waste and the formation were investigated using analyses of formation waters, waste, and formation minerals, by applying traditional graphical methods and sophisticated numerical models. This approach can be used to solve a wide range of geochemical problems related to deep well injection of waste. Trilinear Piper diagrams, Stiff diagrams, and correlation plots show that the chemical characteristics of recovered fluid at the new well are similar to those of formation water. The concentrations of most major constituents in the fluid appear diluted when compared to formation water sampled at other locations. This could be explained by mixing with waste, which is less saline than formation water. However, the waste injected near the new well consists primarily of ammonia and sulfate, and these waste constituents are not found at concentrations elevated enough to suggest that significant mixing of formation water with waste has occurred. To determine whether chemical interactions between injected waste and formation could explain the chemistry of fluid recovered from the new well, we simulated the chemical reaction between waste, formation water, and the formation rock by numerical modeling. Initial modeling calculations were done using a multicomponent geochemical reaction-path model to simulate fresh waste reacting with the formation. A more complex simulation coupling flow, transport, and reaction was then run using a multicomponent geochemical reactive transport model. These numerical simulations were carried out to calculate porosity changes and evaluate chemical processes

  8. An eddy resolving numerical study of the general circulation and deep-water formation in the Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Mantziafou, A.; Lascaratos, A.

    2004-07-01

    General circulation and deep-water formation (DWF) processes in the Adriatic basin in a climatological year were numerically simulated in a high-resolution (1/20th of a degree) implementation of the Princeton Ocean Model (POM). The "perpetual" year atmospheric data were computed from the ECMWF Reanalysis data (1°×1°) covering the period 1979-1994. The model reproduces the main basin features of the general circulation, water mass distribution and their seasonal variability. The Adriatic Deep Water exiting through the Otranto Strait is produced with two different mechanisms inside the basin: (a) by open ocean deep convection over the Southern Adriatic Pit and Middle Adriatic Pit (b) on the continental shelf of the Northern and Middle Adriatic. The estimated contributions of both mechanisms suggest that 82% of the Adriatic Deep Water is formed inside the Southern Adriatic Pit, while all the higher density water in this water mass comes from the northern regions. The role of mesoscale eddies at the periphery of the dense-water chimney in the Southern Adriatic Pit was examined and their contribution to the lateral buoyancy flux, during the convection process, found to be small. The DWF rate at Otranto Strait is 0.28 Sv with σθ over 29.15. The sensitivity of the DWF processes to interannual variability of the buoyancy forcing and river runoff was assessed with a number of process-study numerical experiments. In these experiments the effect of an imposed "extreme" buoyancy forcing during 1 year, on the DWF rates, was to modify them during the specific year, but the effects were still present in the following normal climatological year. This shows that the DWF rates and their mass characteristics at a specific year depend not only on the atmospheric conditions prevailing that specific year but on the previous year's as well, thus leading to the concept of a "memory" of the basin.

  9. Localized sub-glacial deep karst formation due to water infiltration into glacier crevasses: A case study from Asiago, Italy

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Frehner, Marcel; Busellato, Leonardo; Grasselli, Giovanni

    2015-04-01

    In karstic plateaus, deep karst phenomena (e.g. abysses) are the preferential pathways for surface water to penetrate the Earth's crust. After percolation along diaclases and meanders, the infiltrated water often springs at the foot of the karstic plateau, potentially representing a valuable water resource. Thus, it is crucial to understand the formation and distribution of deep karst phenomena, for instance to predict karstic groundwater flow paths or to preserve water resources from pollution. The role of glaciers in enhancing the formation of deep karst is not yet clear. On the one hand, chilly water retains more CO2 which increases its acidity and efficiency in corroding carbonates. On the other hand, glaciers obliterate the soil and vegetation covering the developing karst decreasing the quantity of humic acids dissolved in the surface water. Nevertheless, ice-caps may play a key role in controlling how and where surface water can access the developing karstic system. Due to the presence of a glacier, some sub-glacial areas may not be reached by surface water, which prevents karstification, while other areas may be connected to intra- or sub-glacial flow paths possibly leading to localized kartification in these areas. Here we investigate the relationship between sub-glacial topography and the development of preferred intra-glacier flow paths and how this relationship leads to localized sub-glacial karstification. As a case study site, we use the karstic plateau of Asiago in Northern Italy. The Asiago plateau (https://goo.gl/maps/bLezx) is mainly composed of Permian to Cretaceous rocks. The northern and southern boundaries of the plateau are marked by two Alpine trusts, which uplifted the plateau during the Alpine orogeny to ~1500 m above the Po flood plain delimiting the plateau to the South. The Asiago plateau extends for ~600 km2 and contains ~2100 natural caves, including many significantly deep caves such as the deepest cave of Veneto: the 1011 m deep

  10. Eastern-Mediterranean ventilation variability during sapropel S1 formation, evaluated at two sites influenced by deep-water formation from Adriatic and Aegean Seas

    NASA Astrophysics Data System (ADS)

    Filippidi, A.; Triantaphyllou, M. V.; De Lange, G. J.

    2016-07-01

    Present-day bottom-water ventilation in the Eastern Mediterranean basin occurs through deep-water convection originating from the two marginal basins, i.e. Adriatic and Aegean Seas. In the paleo record, long periods of enhanced deep-water formation have been alternating with shorter periods of reduced deep-water formation. The latter is related mainly to low-latitude humid climate conditions and the enhanced deposition and preservation of organic-rich sediment units (sapropels). This study focuses on sedimentary archives of the most-recent sapropel S1, retrieved from two sites under the direct influence of the two deep-water formation areas. Restricted oxygen conditions have developed rapidly at the beginning of S1 deposition in the Adriatic site, but bottom-water conditions have not persistently remained anoxic during the full interval of sapropel deposition. In fact, the variability in intensity and persistence of sedimentary redox conditions at the two deep-water formation sites is shown to be related to brief episodes of climate cooling. In the Adriatic site, sapropel deposition appears to have been interrupted twice. The 8.2 ka event, only recovered at the Adria site, is characterized by gradually increasing suboxic to possibly intermittently oxic conditions and decreasing Corg fluxes, followed by an abrupt re-establishment of anoxic conditions. Another important event that disrupted sapropel S1 formation, has taken place at ca. 7.4 cal ka BP. The latter event has been recovered at both sites. In the Adriatic site it is followed by a period of sedimentary conditions that gradually change from suboxic to more permanently oxic, as deduced from the Mn/Al pattern. Using the same proxy for suboxic/oxic sedimentary redox conditions, we observe that conditions in the Aegean Sea site shift to more permanently oxic from the 7.4 ka event onwards. However, at both sites the accumulation and preservation of enhanced amounts of organic matter have continued under these

  11. Links Between the Deep Western Boundary Current, Labrador Sea Water Formation and Export, and the Meridional Overturning Circulation

    NASA Astrophysics Data System (ADS)

    Myers, Paul G.; Kulan, Nilgun

    2010-05-01

    Based on an isopyncal analysis of historical data, 3-year overlapping triad fields of objectively analysed temperature and salinity are produced for the Labrador Sea, covering 1949-1999. These fields are then used to spectrally nudge an eddy-permitting ocean general circulation model of the sub-polar gyre, otherwise forced by inter annually varying surface forcing based upon the Coordinated Ocean Reference Experiment (CORE). High frequency output from the reanalysis is used to examine Labrador Sea Water formation and its export. A number of different apprpoaches are used to estimate Labrador Sea Water formation, including an instanteous kinematic approach to calculate the annual rate of water mass subduction at a given density range. Historical transports are computed along sections at 53 and 56N for several different water masses for comparison with recent observations, showing a decline in the stength of the deep western boundary current with time. The variability of the strength of the meridional overturning circulation (MOC) from the reanalysis is also examined in both depth and density space. Linkages between MOC variability and water mass formation variability is considered.

  12. Generic models of deep formation water calculated with PHREEQC using the "gebo"-database

    NASA Astrophysics Data System (ADS)

    Bozau, E.; van Berk, W.

    2012-04-01

    To identify processes during the use of formation waters for geothermal energy production an extended hydrogeochemical thermodynamic database (named "gebo"-database) for the well known and commonly used software PHREEQC has been developed by collecting and inserting data from literature. The following solution master species: Fe(+2), Fe(+3), S(-2), C(-4), Si, Zn, Pb, and Al are added to the database "pitzer.dat" which is provided with the code PHREEQC. According to the solution master species the necessary solution species and phases (solid phases and gases) are implemented. Furthermore, temperature and pressure adaptations of the mass action law constants, Pitzer parameters for the calculation of activity coefficients in waters of high ionic strength and solubility equilibria among gaseous and aqueous species of CO2, methane, and hydrogen sulphide are implemented into the "gebo"-database. Combined with the "gebo"-database the code PHREEQC can be used to test the behaviour of highly concentrated solutions (e.g. formation waters, brines). Chemical changes caused by temperature and pressure gradients as well as the exposure of the water to the atmosphere and technical equipments can be modelled. To check the plausibility of additional and adapted data/parameters experimental solubility data from literature (e.g. sulfate and carbonate minerals) are compared to modelled mineral solubilities at elevated levels of Total Dissolved Solids (TDS), temperature, and pressure. First results show good matches between modelled and experimental mineral solubility for barite, celestite, anhydrite, and calcite in high TDS waters indicating the plausibility of additional and adapted data and parameters. Furthermore, chemical parameters of geothermal wells in the North German Basin are used to test the "gebo"-database. The analysed water composition (starting with the main cations and anions) is calculated by thermodynamic equilibrium reactions of pure water with the minerals found in

  13. Insights into North Atlantic deep water formation during the peak interglacial interval of Marine Isotope Stage 9 (MIS 9)

    NASA Astrophysics Data System (ADS)

    Mokeddem, Zohra; McManus, Jerry F.

    2017-01-01

    Foraminifera abundance and stable isotope records from ODP Site 984 (61.25°N, 24.04°W, 1648 m) in the North Atlantic are used to reconstruct surface circulation variations and the relative strength of the North Atlantic Deep Water (NADW) formation over the period spanning the peak warmth of Marine Interglacial Stage (MIS) 9e ( 324-336 ka). This interval includes the preceding deglaciation, Termination 4 (T4), and the subsequent glacial inception of MIS 9d. The records indicate a greatly reduced contribution of NADW during T4, as observed in more recent deglaciations. In contrast with the most recent deglaciation, the lack of a significant NADW signal extended from T4 well into the peak interglacial MIS 9e and persisted nearly until the transition to the subsequent glacial stage MIS 9d. Although NADW formation resumed during MIS 9e, only depths greater than 2000 m appear to have been ventilated. The poorly ventilated intermediate depth of Site 984 (<2000 m) may have resulted on one hand from a general reduction of deep water ventilation by NADW during the study interval or, on the other hand, from different pathways of the spread of newly formed NADW that bypassed the study location. The intermediate depths may have also been invaded by southern-sourced waters as the formation of intermediate depth NADW weakened. The absence of any significant NADW signal at the water depth of Site 984 during the climatic optimum contrasts sharply with subsequent interglacial peaks (MIS 5e and the Holocene). Despite the perturbed intermediate depth circulation, oceanic heat transport northeastward was not interrupted and may have contributed to the relatively mild interglacial conditions of MIS 9e.

  14. Sensitivity of biogenic carbon export to ocean climate in the Labrador Sea, a deep-water formation region

    NASA Astrophysics Data System (ADS)

    Tian, Ru Cheng; VéZina, Alain F.; Deibel, Don; Rivkin, Richard B.

    2003-12-01

    We used a physical-biogeochemical model to examine the sensitivity of biogenic carbon export to ocean climate in the Labrador Sea, a subpolar, deep-water formation region. Documented changes in winter mixed layer depth between the late 1960s and the mid-1990s were used to construct scenarios of weak, moderate, and strong winter convection that drive the biogeochemical model. The model simulations suggest that the total biogenic carbon export (particle sinking flux + DOC export) is higher under strong winter convection (e.g., during the early 1990s) than under weak winter convection (e.g., during the late 1960s), by ˜70% across the 200-m isobath and nearly double at 500 m and 1000 m depth. These large variations in total biogenic carbon export are essentially due to the response of DOC export to ocean climate conditions. Sensitivity analyses indicate that the variations in DOC export from the euphotic zone are due to the impact of the convection regime on the development of the microbial food web and on the bacterial consumption of DOC in surface waters. Although DOC downward fluxes within the mesopelagic zone (below ˜500 m) are largely controlled by physical processes, the effect of convection on microbial dynamics can potentially amplify the year-to-year variations in the transport of DOC to the deep ocean due to convection.

  15. Characterizing the chemical pathways for water formation--a deep search for hydrogen peroxide.

    PubMed

    Parise, Bérengère; Bergman, Per; Menten, Karl

    2014-01-01

    In 2011, hydrogen peroxide (HOOH) was observed for the first time outside the solar system (Bergman et al., Astron. Astrophys., 2011, 531, L8). This detection appeared a posteriori to be quite natural, as HOOH is an intermediate product in the formation of water on the surface of dust grains. Following up on this detection, we present a search for HOOH in a diverse sample of sources in different environments, including low-mass protostars and regions with very high column densities, such as Infrared Dark Clouds (IRDCs). We do not detect the molecule in any other source than Oph A, and derive 3sigma upper limits for the abundance of HOOH relative to H2 lower than that in Oph A for most sources. This result sheds a different light on our understanding of the detection of HOOH in Oph A, and shifts the question of why this source seems to be special. Therefore we rediscuss the detection of HOOH in Oph A, as well as the implications of the low abundance of HOOH, and its similarity with the case of O2. Our chemical models show that the production of HOOH is extremely sensitive to temperature, and is favored only in the range 20-30 K. The relatively high abundance of HOOH observed in Oph A suggests that the bulk of the material lies at a temperature in the range 20-30 K.

  16. Cool Water Formation and Trout Habitat Use in a Deep Pool in the Sierra Nevada, California

    Treesearch

    KATHLEEN R. MATTHEWS; NEIL H. BERG; AZUMA DAVID L.

    1994-01-01

    We documented temperature stratification in a deep bedrock pool in the North Fork of the American River, described the diel movement of rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta. and determined whether these trout used cooler portions of the pool.From July 30 to October 10, 1992, the main study pool and an adjacent pool were stratified(temperature...

  17. A deep water turbidity origin for the Altuda Formation (Capitanian, Permian), Northwest Glass Mountains, Texas

    USGS Publications Warehouse

    Haneef, Mohammad; Rohr, D.M.; Wardlaw, B.R.

    2000-01-01

    The Altuda Formation (Capitanian) in the northwestern Glass Mountains is comprised of thin, even bedded limestones, dolostones, mixed clastic-carbonates, and silt/sandstones interbedded with basin-ward dipping wedge-shaped clinoforms of the Captian Limestone. The formation is characterized by graded bedding, planar laminations, flame structures, contorted/convolute bedding, horizontal branching burrows, and shelf-derived normal marine fauna. A detailed study of the Altuda Formation north of Old Blue Mountain, Glass Mountains, reveals that the formation in this area was deposited by turbidity currents in slope to basinal settings.

  18. Characterizing, modelling and understanding the climate variability of the deep water formation in the North-Western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Somot, Samuel; Houpert, Loic; Sevault, Florence; Testor, Pierre; Bosse, Anthony; Taupier-Letage, Isabelle; Bouin, Marie-Noelle; Waldman, Robin; Cassou, Christophe; Sanchez-Gomez, Emilia; Durrieu de Madron, Xavier; Adloff, Fanny; Nabat, Pierre; Herrmann, Marine

    2016-08-01

    Observing, modelling and understanding the climate-scale variability of the deep water formation (DWF) in the North-Western Mediterranean Sea remains today very challenging. In this study, we first characterize the interannual variability of this phenomenon by a thorough reanalysis of observations in order to establish reference time series. These quantitative indicators include 31 observed years for the yearly maximum mixed layer depth over the period 1980-2013 and a detailed multi-indicator description of the period 2007-2013. Then a 1980-2013 hindcast simulation is performed with a fully-coupled regional climate system model including the high-resolution representation of the regional atmosphere, ocean, land-surface and rivers. The simulation reproduces quantitatively well the mean behaviour and the large interannual variability of the DWF phenomenon. The model shows convection deeper than 1000 m in 2/3 of the modelled winters, a mean DWF rate equal to 0.35 Sv with maximum values of 1.7 (resp. 1.6) Sv in 2013 (resp. 2005). Using the model results, the winter-integrated buoyancy loss over the Gulf of Lions is identified as the primary driving factor of the DWF interannual variability and explains, alone, around 50 % of its variance. It is itself explained by the occurrence of few stormy days during winter. At daily scale, the Atlantic ridge weather regime is identified as favourable to strong buoyancy losses and therefore DWF, whereas the positive phase of the North Atlantic oscillation is unfavourable. The driving role of the vertical stratification in autumn, a measure of the water column inhibition to mixing, has also been analyzed. Combining both driving factors allows to explain more than 70 % of the interannual variance of the phenomenon and in particular the occurrence of the five strongest convective years of the model (1981, 1999, 2005, 2009, 2013). The model simulates qualitatively well the trends in the deep waters (warming, saltening, increase in the

  19. Influence of runoff, high frequency atmospheric forcing and model resolution on deep water mass formation regions and Atlantic Meridional Overturning Circulation, from a numerical model.

    NASA Astrophysics Data System (ADS)

    Garcia Quintana, Yarisbel; Courtois, Peggy; Hu, Xianmin; Pennelly, Clark; Myers, Paul G.

    2016-04-01

    Water mass formation regions act as windows to the deep ocean where surface waters are transformed to intermediate and deep waters. Within the North Atlantic, Labrador Sea Water (LSW) is convectively produced in the Labrador Sea while in the Nordic Seas the source waters for Denmark Strait Overflow Water (DSOW) and Iceland-Scotland Overflow Water (NEADW) are formed. They are the main components of the North Atlantic Deep Water (NADW) which forms the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). We explore the changes of the LSW formation rates and in AMOC strength as consequence of runoff glacial melt, high frequency atmospheric forcing influence and variations in model's resolution. We use 1/4° resolution Arctic and Northern Hemisphere Atlantic (ANHA4) configuration from the Nucleus for European Modelling of the Ocean (NEMO) model. A nest using ANHA4 and the Adaptive Grid Refinement in FORTRAN (AGRIF) package was used to increase the resolution to 1/12° in the sub-polar gyre. The formation rate is calculated based upon a kinematic subduction approach where the exchange through the dynamic mixed layer base is calculated based on shallowing and deepening in the mixed layer, and convergence of horizontal transport into or out of the mixed layer. Lastly we use a Lagrangian tool (Ariane) to track the path of the DSOW and the NEADW from their formation source.

  20. Modelling the circulation and deep water formation in the Labrador Sea: sensitivity to Nordic Sea exchange

    NASA Astrophysics Data System (ADS)

    Czeschel, L.; Böning, C. W.

    2003-04-01

    Using an eddy-permitting model of the North Atlantic Ocean (part of the FLAME hierarchy) we investigate the impact of variable freshwater fluxes on the circulation, deep convection and the mixing between the boundary currents and the interior of the Labrador Sea. In this study, we use different forcing functions at the northern boundary (70N) to simulate variable freshwater (heat) exchanges with the Nordic Seas. In contrast to restoring to a climatology in a sponge layer, model versions with a prescribed streamfunction in an open boundary formulation give a better agreement with observational estimates of the circulation in this area. Varying the strength of the streamfunction at the northern boundary leads to fluctuations in the transport of the western boundary currents (East/West Greenland Current and Labrador Current) and thus to different freshwater budgets in the Labrador Sea.

  1. Stratigraphic hierarchy of organic carbon rich siltstones in deep-water facies, Brushy Canyon Formation (Guadalupian), Delaware Basin, West Texas

    NASA Astrophysics Data System (ADS)

    Sageman, Bradley B.; Gardner, Michael H.; Armentrout, John M.; Murphy, Adam E.

    1998-05-01

    The first systematic test for a predictive relationship between organic carbon content and stratigraphic hierarchy in a deep-water slope to basin-floor deposit was performed. The studied section includes the Pipeline Shale, the Brushy Canyon Formation, and the lower part of the Cherry Canyon Formation of the Delaware Mountain Group, West Texas. This interval represents one large-scale, 3rd-order genetic sequence within which 4th- and 5th-order stratigraphic cycles are recognized. Samples of fine-grained facies throughout the section were collected from outcrop and analyzed for organic carbon content and hydrogen index. Degree of pyritization was also determined for a subset of the samples. The results indicate that organic enrichment is closely correlated to the stratigraphic hierarchy at the 3rd-, 4th-, and 5th-order levels. The data suggest that quantity and quality of preserved organic matter are controlled by changes in bulk sedimentation rate (dilution vs. condensation), which affect organic matter inputs to the sediment, as well as the balance between (1) burial and preservation of organic matter and (2) its degradation on the sea floor during times of sediment starvation.

  2. Formation and pathways of North Atlantic Deep Water in a coupled ice-ocean model of the Arctic-North Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Bailey, David A.; Rhines, Peter B.; Häkkinen, Sirpa

    2005-10-01

    We investigate the formation process and pathways of deep water masses in a coupled ice-ocean model of the Arctic and North Atlantic Oceans. The intent is to determine the relative roles of these water masses from the different source regions (Arctic Ocean, Nordic Seas, and Subpolar Atlantic) in the meridional overturning circulation. The model exhibits significant decadal variability in the deep western boundary current and the overturning circulation. We use detailed diagnostics to understand the process of water mass formation in the model and the resulting effects on the North Atlantic overturning circulation. Particular emphasis is given to the multiple sources of North Atlantic Deep Water, the dominant deep water masses of the world ocean. The correct balance of Labrador Sea, Greenland Sea and Norwegian Sea sources is difficult to achieve in climate models, owing to small-scale sinking and convection processes. The global overturning circulation is described as a function of potential temperature and salinity, which more clearly signifies dynamical processes and clarifies resolution problems inherent to the high latitude oceans. We find that fluxes of deep water masses through various passages in the model are higher than observed estimates. Despite the excessive volume flux, the Nordic Seas overflow waters are diluted by strong mixing and enter the Labrador Sea at a lighter density. Through strong subpolar convection, these waters along with other North Atlantic water masses are converted into the densest waters [similar density to Antarctic Bottom Water (AABW)] in the North Atlantic. We describe the diminished role of salinity in the Labrador Sea, where a shortage of buoyant surface water (or excess of high salinity water) leads to overly strong convection. The result is that the Atlantic overturning circulation in the model is very sensitive to the surface heat flux in the Labrador Sea and hence is correlated with the North Atlantic Oscillation. As strong

  3. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-12-22

    Final Report 3. DATES COVERED (From - To) 7/1/15 to 12/22/16 4. TITLE AND SUBTITLE Deep Water Ocean Acoustics 5a. CONTRACT NUMBER...NUMBER Ocean Acoustical Services and Instrumentation Systems, Inc. 5 Militia Drive, Ste. 104 Lexington, MA 02421-4706...FR-14C0172- Ocean Acoustics- 123116 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) Office of Naval

  4. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-10-07

    OASIS, INC. 1 Report No. QSR-14C0172- Ocean Acoustics-093016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...Award No.: N00014-14-C-0172 Report No. QSR-14C0172- Ocean Acoustics-093016 Prepared for: Office of Naval Research For the period: July 1, 2016...to September 30, 2016 Submitted by: Principal Investigator/Author: Kevin Heaney Ocean Acoustical Services and Instrumentation Systems, Inc. 5

  5. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-08-03

    OASIS, INC. 1 Report No. QSR-14C0172- Ocean Acoustics-063016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...Award No.: N00014-14-C-0172 Report No. QSR-14C0172- Ocean Acoustics-063016 Prepared for: Office of Naval Research For the period: April 1...2016 to June 30, 2016 Submitted by: Principal Investigator/Author: Kevin Heaney Ocean Acoustical Services and Instrumentation Systems, Inc. 5

  6. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-04-30

    OASIS, INC. 1 Report No. QSR-14C0172- Ocean Acoustics-043016 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...Award No.: N00014-14-C-0172 Report No. QSR-14C0172- Ocean Acoustics-093015 Prepared for: Office of Naval Research For the period: January 1...2016 to March 31, 2015 Submitted by: Principal Investigator/Author: Kevin Heaney Ocean Acoustical Services and Instrumentation Systems, Inc. 5

  7. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2015-07-17

    under-ice scattering , bathymetric diffraction and the application of the ocean acoustic Parabolic Equation to infrasound. 2. Tasks a. Task 1...QSR-14C0172-Ocean Acoustics -063015 Figure 10. Estimated reflection coefficient as a function of frequency by taking the difference of downgoing and...OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics -063015 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics

  8. Microbiology of formation waters from the deep repository of liquid radioactive wastes Severnyi.

    PubMed

    Nazina, Tamara N; Kosareva, Inessa M; Petrunyaka, Vladimir V; Savushkina, Margarita K; Kudriavtsev, Evgeniy G; Lebedev, Valeriy A; Ahunov, Viktor D; Revenko, Yuriy A; Khafizov, Robert R; Osipov, George A; Belyaev, Sergey S; Ivanov, Mikhail V

    2004-07-01

    The presence, diversity, and geochemical activity of microorganisms in the Severnyi repository of liquid radioactive wastes were studied. Cultivable anaerobic denitrifiers, fermenters, sulfate-reducers, and methanogens were found in water samples from a depth of 162-405 m below sea level. Subsurface microorganisms produced methane from [2-(14)C]acetate and [(14)C]CO(2), formed hydrogen sulfide from Na(2) (35)SO(4), and reduced nitrate to dinitrogen in medium with acetate. The cell numbers of all studied groups of microorganisms and rates of anaerobic processes were higher in the zone of dispersion of radioactive wastes. Microbial communities present in the repository were able to utilise a wide range of organic and inorganic compounds and components of waste (acetate, nitrate, and sulfate) both aerobically and anaerobically. Bacterial production of gases may result in a local increase of the pressure in the repository and consequent discharge of wastes onto the surface. Microorganisms can indirectly decrease the mobility of radionuclides due to consumption of oxygen and production of sulfide, which favours deposition of metals. These results show the necessity of long-term microbiological and radiochemical monitoring of the repository.

  9. Availability of free oxygen in deep bottom water of some Archean-Early Paleoproterozoic ocean basins as derived from iron formation facies analyses

    NASA Astrophysics Data System (ADS)

    Beukes, N. J.; Smith, A.

    2013-12-01

    Archean to Early Paleoproterozoic ocean basins are commonly, although not exclusively, depicted as rather static systems; either permanently stratified with shallow mixed oxygenated water overlying anoxic deep water or with a totally anoxic water column. The anoxic water columns are considered enriched in dissolved ferrous iron derived from hydrothermal plume activity. These sourced deposition of iron formations through precipitation of mainly ferrihydrite via reaction with free oxygen in the stratified model or anaerobic iron oxidizing photoautotrophs in the anoxic model. However, both these models face a simple basic problem if detailed facies reconstructions of deepwater microbanded iron formations (MIFs) are considered. In such MIFs it is common that the deepest water and most distal facies is hematite rich followed shoreward by magnetite, iron silicate and siderite facies iron formation. Examples of such facies relations are known from jaspilitic iron formation of the ~3,2 Ga Fig Tree Group (Barberton Mountainland), ~ 2,95 Ga iron formations of the Witwatersrand-Mozaan basin and the ~2,5 Ga Kuruman Iron Formation, Transvaal Supergroup, South Africa. Facies relations of these MIFs with associated siliciclastics or carbonates also indicate that the upper water columns of the basins, down to below wave base, were depleted in iron favoring anoxic-oxic stratification rather than total anoxia. In the MIFs it can be shown that hematite in the distal facies represents the earliest formed diagenetic mineral; most likely crystallized from primary ferrihydrite. The problem is one of how ferrihydrite could have been preserved on the ocean floor if it was in direct contact with reducing ferrous deep bottom water. Rather dissolved ferrous iron would have reacted with ferrihydrite to form diagenetic magnetite. This dilemma is resolved if in the area of deepwater hematite MIF deposition, the anoxic ferrous iron enriched plume was detached from the basin floor due to buoyancy

  10. Coring in deep hardrock formations

    SciTech Connect

    Drumheller, D.S.

    1988-08-01

    The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.

  11. Circulation and north atlantic deep water formation rates based on evolution of the cfc signal in the north atlantic ocean

    NASA Astrophysics Data System (ADS)

    Smethie, W.; Lebel, D.

    2003-04-01

    The first high quality CFC measurements in the North Atlantic were made in 1981 as part of the TTO program. The WOCE survey in 1996-1998 provided the first synoptic CFC survey of the entire North Atlantic, but CFC measurements were made throughout the North Atlantic on a non-synoptic basis prior to WOCE. The pre-WOCE and WOCE CFC data sets will be compared on a regional basis using maps of concentrations on neutral density surfaces, maps of CFC-11 inventories, and plots of CFCs verses potential temperature for the major components of NADW. Circulation patterns and time scales inferred from the CFC distributions will be presented. The CFC inventories reflect the formation rate of a given water mass and formation rates calculated from the CFC inventories will be presented and compared for pre-WOCE and WOCE data.

  12. Deep-water archeology.

    PubMed

    Bascom, W

    1971-10-15

    There is reason to believe that some old wooden ships on the deep-sea floor have survived for thousands of years without much change. They will not be covered with much sediment, and it will be possible to find them using new searching techniques. These are embodied in the system of the Alcoa Seaprobe, which is also equipped to identify and raise old ships.

  13. Sedimentology of rift climax deep water systems; Lower Rudeis Formation, Hammam Faraun Fault Block, Suez Rift, Egypt

    NASA Astrophysics Data System (ADS)

    Leppard, Christopher W.; Gawthorpe, Rob L.

    2006-09-01

    In most marine rift basins, subsidence outpaces sedimentation during rift climax times. Typically this results in sediment-starved hangingwall depocentres dominated by deep-marine mudstones, with subordinate local development of coarser clastics in the immediate hangingwall derived from restricted catchments on the immediate footwall scarp. To highlight the spatial variability of rift climax facies and the controls upon them, we have investigated the detailed three-dimensional geometry and facies relationships of the extremely well exposed Miocene, rift climax Lower Rudeis Formation in the immediate hangingwall to the Thal Fault Zone, Suez Rift, Egypt. Detailed sedimentological analyses allows the Lower Rudeis Formation to be divided into two contemporaneous depositional systems, (1) a laterally continuous slope system comprising, hangingwall restricted (< 250 m wide) slope apron, slope slumps, fault scarp degradation complex and laterally extensive lower slope-to-basinal siltstones, and (2) a localized submarine fan complex up to 1 km wide and extending at least 2 km basinward of the fault zone. Interpretation of individual facies, facies relationships and their spatial variability indicate that deposition in the immediate hangingwall to the Thal Fault occurred via a range of submarine concentrated density flows, surge-like turbidity flows, mass wasting and hemipelagic processes. Major controls on the spatial variability and stratigraphic architecture of the depositional systems identified reflect the influence of the steep footwall physiography, accommodation and drainage evolution associated with the growth of the Thal Fault. The under-filled nature of the hangingwall depocentre combined with the steep footwall gradient result in a steep fault-controlled basin margin characterised by either slope bypass or erosion, with limited coastal plain or shelf area. Sediment supply to the slope apron deposits is controlled in part by the evolution and size of small

  14. Deep-space glycine formation via Strecker-type reactions activated by ice water dust mantles. A computational approach.

    PubMed

    Rimola, Albert; Sodupe, Mariona; Ugliengo, Piero

    2010-01-01

    A Strecker-type synthesis of glycine by reacting NH(3), H(2)C=O and HCN in presence of ice water (H(2)O-ice) as a catalyst has been theoretically studied at B3LYP/6-31+G(d,p) level within a cluster approach in order to mimic reactions occurring in the interstellar and circumstellar medium (ICM). Results indicate that, despite the exoergonic character of the considered reactions occurring at the H(2)O-ice surface, the kinetics are slow due to relatively high electronic energy barriers (ΔU(0)(≠)=15-45 kcal mol(-1)). Reactions occurring within H(2)O-ice cavities, in which ice bulk effects have been modeled by assuming a dielectric continuum (ε=78), show energy barriers low enough to allow NH(2)CH(2)OH formation but not NH=CH2 (ΔU(0)(≠)= 2 and 21 kcal mol(-1), respectively) thus hindering the NH(2)CH(2)CN formation, i.e. the precursor of glycine, through Strecker channels. Moreover, hydrolysis of NH(2)CH(2)CN to give glycine is characterized by high electronic energy barriers (ΔU(0)(≠)=27-34 kcal mol(-1)) and cannot readily occur at cryogenic temperatures. Nevertheless, the facts that NH=CH(2) formation can readily be achieved through the radical-radical HCN+2H - NH−−>CH2 reaction [D. E. Woon, Astrophys. J., 2002, 571, L177-L180], and that present results indicate that the Strecker step of NH=CH(2)+HCN−−>NH(2)CH(2)CN exhibits a relative low energy barrier (ΔU(0)(≠)=8–9 kcal mol(-1)), suggest that a combination of these two mechanisms allows for the formation of NH(2)CH(2)CN in the ICM. These results strengthen the thesis that NH(2)CH(2)CN could have been formed and protected by icy dust particles, and then delivered through micro-bombardments onto the early Earth, leading to glycine formation upon contact with the primordial ocean.

  15. Features of the propagation of pseudorandom pulse signals from the shelf to deep water in the presence of gyre formation on the acoustic track

    NASA Astrophysics Data System (ADS)

    Akulichev, V. A.; Burenin, A. V.; Ladychenko, S. Yu.; Lobanov, V. B.; Morgunov, Yu. N.

    2017-08-01

    The paper discusses the results of an experiment conducted in the Sea of Japan in March 2016 on an acoustic track 194 km long in winter hydrological conditions. The most complex case of propagation of pseudorandom pulse signals from the shelf to deep water in the presence of gyre formation on the acoustic track. An analysis of the experimentally obtained pulse characteristics show that at all points, a maximum, in terms of amplitude, first arrival of acoustic energy is recorded. This is evidence that at a given depth horizon, pulses that have passed the shortest distance through a near-surface sound channel at small angles close to zero are received first. The calculation method of mean sound velocity on the track, based on the satellite data of surface temperature monitoring, is proposed. We expect that the results obtained with this method can be successfully used for the purposes of acoustic range finding and navigation.

  16. Deep water recycling through time

    PubMed Central

    Magni, Valentina; Bouilhol, Pierre; van Hunen, Jeroen

    2014-01-01

    We investigate the dehydration processes in subduction zones and their implications for the water cycle throughout Earth's history. We use a numerical tool that combines thermo-mechanical models with a thermodynamic database to examine slab dehydration for present-day and early Earth settings and its consequences for the deep water recycling. We investigate the reactions responsible for releasing water from the crust and the hydrated lithospheric mantle and how they change with subduction velocity (vs), slab age (a) and mantle temperature (Tm). Our results show that faster slabs dehydrate over a wide area: they start dehydrating shallower and they carry water deeper into the mantle. We parameterize the amount of water that can be carried deep into the mantle, W (×105 kg/m2), as a function of vs (cm/yr), a (Myrs), and Tm (°C):. We generally observe that a 1) 100°C increase in the mantle temperature, or 2) ∼15 Myr decrease of plate age, or 3) decrease in subduction velocity of ∼2 cm/yr all have the same effect on the amount of water retained in the slab at depth, corresponding to a decrease of ∼2.2×105 kg/m2 of H2O. We estimate that for present-day conditions ∼26% of the global influx water, or 7×108 Tg/Myr of H2O, is recycled into the mantle. Using a realistic distribution of subduction parameters, we illustrate that deep water recycling might still be possible in early Earth conditions, although its efficiency would generally decrease. Indeed, 0.5–3.7 × 108 Tg/Myr of H2O could still be recycled in the mantle at 2.8 Ga. Key Points Deep water recycling might be possible even in early Earth conditions We provide a scaling law to estimate the amount of H2O flux deep into the mantle Subduction velocity has a a major control on the crustal dehydration pattern PMID:26321881

  17. Deep water recycling through time.

    PubMed

    Magni, Valentina; Bouilhol, Pierre; van Hunen, Jeroen

    2014-11-01

    We investigate the dehydration processes in subduction zones and their implications for the water cycle throughout Earth's history. We use a numerical tool that combines thermo-mechanical models with a thermodynamic database to examine slab dehydration for present-day and early Earth settings and its consequences for the deep water recycling. We investigate the reactions responsible for releasing water from the crust and the hydrated lithospheric mantle and how they change with subduction velocity (vs ), slab age (a) and mantle temperature (Tm). Our results show that faster slabs dehydrate over a wide area: they start dehydrating shallower and they carry water deeper into the mantle. We parameterize the amount of water that can be carried deep into the mantle, W (×10(5) kg/m(2)), as a function of vs (cm/yr), a (Myrs), and Tm (°C):[Formula: see text]. We generally observe that a 1) 100°C increase in the mantle temperature, or 2) ∼15 Myr decrease of plate age, or 3) decrease in subduction velocity of ∼2 cm/yr all have the same effect on the amount of water retained in the slab at depth, corresponding to a decrease of ∼2.2×10(5) kg/m(2) of H2O. We estimate that for present-day conditions ∼26% of the global influx water, or 7×10(8) Tg/Myr of H2O, is recycled into the mantle. Using a realistic distribution of subduction parameters, we illustrate that deep water recycling might still be possible in early Earth conditions, although its efficiency would generally decrease. Indeed, 0.5-3.7 × 10(8) Tg/Myr of H2O could still be recycled in the mantle at 2.8 Ga.

  18. Deep learning for SAR image formation

    NASA Astrophysics Data System (ADS)

    Mason, Eric; Yonel, Bariscan; Yazici, Birsen

    2017-04-01

    The recent success of deep learning has lead to growing interest in applying these methods to signal processing problems. This paper explores the applications of deep learning to synthetic aperture radar (SAR) image formation. We review deep learning from a perspective relevant to SAR image formation. Our objective is to address SAR image formation in the presence of uncertainties in the SAR forward model. We present a recurrent auto-encoder network architecture based on the iterative shrinkage thresholding algorithm (ISTA) that incorporates SAR modeling. We then present an off-line training method using stochastic gradient descent and discuss the challenges and key steps of learning. Lastly, we show experimentally that our method can be used to form focused images in the presence of phase uncertainties. We demonstrate that the resulting algorithm has faster convergence and decreased reconstruction error than that of ISTA.

  19. Hydrogeochemistry and geothermometry of deep thermal water in the carbonate formation in the main urban area of Chongqing, China

    NASA Astrophysics Data System (ADS)

    Yang, Pingheng; Cheng, Qun; Xie, Shiyou; Wang, Jianli; Chang, Longran; Yu, Qin; Zhan, Zhaojun; Chen, Feng

    2017-06-01

    Many geothermal reservoirs in Chongqing in southwestern China are located in carbonate rock aquifers and exploited through drilling. Water samples from 36 geothermal wells have been collected in the main urban area of Chongqing. Chemical types of the thermal water samples are Ca·Mg-SO4 and Ca-SO4. High contents of Ca2+ and SO42- in the thermal water samples are derived from the dissolution of evaporates. Furthermore, the HCO3- concentration is constrained by the common ion effect. Drilling depth has no effect on the physical and chemical characteristics according to the results of a t-test. The geothermal reservoir's temperature can be estimated to be 64.8-93.4 °C (average 82 °C) using quartz and improved SiO2 geothermometers. Values of δD and δ18O for the thermal water samples indicate that the thermal water resources originate from local precipitation with a recharge elevation between 838 and 1130 m and an annual air temperature between 10.4 and 13.9 °C. A conceptual model of regional scale groundwater flow for the thermal water is proposed. The thermal water mainly originates from the meteoric water recharged in the elevated areas of northeastern Tongluoshan and Huayingshan by means of percolation through exposed carbonate before becoming groundwater. The groundwater is heated at depth and moves southwest along the fault and the anticlinal core in a gravity-driven regime. The thermal water is exposed in the form of artesian hot springs in river cutting and low-elevation areas or in wells.

  20. Deep Landslides in flysch formations

    NASA Astrophysics Data System (ADS)

    Marinos, Vassilis

    2017-04-01

    Flysch, linked with the tectonic development of an area, has suffered from compressional forces being highly deformed by thrust faults and folds, containing thus often tectonically pre-sheared zones of various size. These geological characteristics may produce weak to very weak rock masses which may present instability and landslides in both mountain and local slope scale. The paper mainly discusses the "mountain" scale phenomena. The size of these masses can reach hundreds of meters in both depth and width on the valley sides. A brief presentation of the flysch formation is presented. A typology is presented with 11 types of flysch, depending on the persistence and participation or not of the strong members (as sandstones) against the weak ones (as siltstones, shales) and the degree and scale of tectonic disturbance. These rock mass types are connected with the landslide mechanism. In all cases the tectonic conditions of a broader area are responsible and the establishment of the tectonic-paleogeographic model is necessary before the conceptual study and design of any major infrastructure work and the choice of its alignment or location. Given the size of such instability areas remedial measures are in most cases not feasible and the realignment or relocation from the initial plans are often the only solution. Cases from highways and pipelines in Greek and Albanian territory are presented. A large number of information from lab tests, geotechnical classifications and back analyses collected from a wide variety of flysch formations is presented and discussed.

  1. North Atlantic Deep Water Formation

    NASA Technical Reports Server (NTRS)

    Bennett, T. (Editor); Broecker, W. S. (Editor); Hansen, J. (Editor)

    1984-01-01

    Various studies concerning differing aspects of the North Atlantic are presented. The three major topics under which the works are classified include: (1) oceanography; (2) paleoclimate; and (3) ocean, ice and climate modeling.

  2. Facies Variations Along an Ancient Deep-Water Axial Channel Belt: Insights from the Upper Cretaceous Cerro Toro Formation, Magallanes-Austral Basin, Patagonia

    NASA Astrophysics Data System (ADS)

    Malkowski, M. A.; Jobe, Z. R.; Sharman, G.; Graham, S. A.

    2015-12-01

    The Upper Cretaceous Cerro Toro Formation preserves a >150 kilometer long deep-water axial channel belt in the Magallanes-Austral Basin in southern Patagonia. Considerable work over the past decade in the Chilean basin sector reveals a 3.5-8 km wide channel-levee system that transported coarse-grained sediment from north to south via a range of low- to high-density turbidity currents, debris flows, and transitional/hybrid flows. In contrast, the more proximal deposits preserved in the Argentine basin sector to the north received little focus. This study documents new sedimentology, stratigraphy, and U-Pb geochronology from the Cerro Toro Formation in Argentina, allowing for a basin-scale comparison of the timing of deposition, sediment sources, and facies and grain size variability. Two ash beds from the base of the section yield U-Pb zircon ages of 90.4 ± 2 Ma and 88.0 ± 3 Ma, suggesting similar, if not slightly older, ages for the lower Cerro Toro Formation when compared to equivalent units to the south. U-Pb detrital zircon age spectra reveal similar provenance trends along the entire outcrop belt, with peak age populations at 310-260, 160-135, and 110-82 Ma. Preliminary statistical analyses of more than 5700 meters of new and previously published detailed stratigraphic sections suggest that, in general, characteristics such as mean bed thickness and net to gross remain fairly consistent along the outcrop belt. However, the bed thickness distributions are log-normal, and the northern sector has higher maximum bed thickness than the southern sector. There are also gradual variations in the down-system (north to south) proportion of lithofacies. For instance, in the northern (Argentine) sector, lithofacies representing mass wasting processes (e.g., debris flow conglomerates and mass-transport deposits) account for as much as ~80 percent of the stratigraphic thickness, whereas near the southern end of the channel belt, coarse-grained facies are almost entirely

  3. GCM studies of intermediate and deep waters in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Haines, Keith; Wu, Peili

    1998-12-01

    Results from GCM simulations of the Mediterranean thermohaline circulation are presented under repeating year wind and surface buoyancy forcings and the reproduction of important physical processes is discussed. It is shown that baroclinic eddies are critical to the effective dispersal of Levantine intermediate water (LIW) throughout the eastern Mediterranean basin. These develop rapidly even in a 1/4 degree model which does not resolve the deformation radius, provided horizontal friction is small enough. It is shown that LIW enters the Adriatic basin and pre-conditions deep water formation which would not otherwise occur due to low surface salinity in winter. The dispersal of Adriatic deep waters is modelled, and it is shown that the introduction of the Gent and McWilliams advective scheme greatly improves the distribution of deep waters in the eastern basin by permitting the formation of dense overflow waters from the Otranto straits. This is achieved with very small parametrised advection that still permits the formation of baroclinic eddies unlike most applications which use the scheme to replace eddies. Results from a 100-year climate simulation are then presented in which the thermohaline circulation has reached equilibrium conditions. Dense water formation in both eastern and western basin still occur after 100 years. While the eastern basin water masses are reasonably realistic, the western basin is a little too cold and fresh, suggesting that insufficient LIW is reaching the deep water formation site in the northwest basin. Further work is needed in this area.

  4. Deep South Atlantic carbonate chemistry and increased interocean deep water exchange during last deglaciation

    NASA Astrophysics Data System (ADS)

    Yu, Jimin; Anderson, Robert F.; Jin, Zhangdong; Menviel, Laurie; Zhang, Fei; Ryerson, Fredrick J.; Rohling, Eelco J.

    2014-04-01

    Carbon release from the deep ocean at glacial terminations is a critical component of past climate change, but the underlying mechanisms remain poorly understood. We present a 28,000-year high-resolution record of carbonate ion concentration, a key parameter of the global carbon cycle, at 5-km water depth in the South Atlantic. We observe similar carbonate ion concentrations between the Last Glacial Maximum and the late Holocene, despite elevated concentrations in the glacial surface ocean. This strongly supports the importance of respiratory carbon accumulation in a stratified deep ocean for atmospheric CO2 reduction during the last ice age. After ˜9 μmol/kg decline during Heinrich Stadial 1, deep South Atlantic carbonate ion concentration rose by ˜24 μmol/kg from the onset of Bølling to Pre-boreal, likely caused by strengthening North Atlantic Deep Water formation (Bølling) or increased ventilation in the Southern Ocean (Younger Drays) or both (Pre-boreal). The ˜15 μmol/kg decline in deep water carbonate ion since ˜10 ka is consistent with extraction of alkalinity from seawater by deep-sea CaCO3 compensation and coral reef growth on continental shelves during the Holocene. Between 16,600 and 15,000 years ago, deep South Atlantic carbonate ion values converged with those at 3.4-km water depth in the western equatorial Pacific, as did carbon isotope and radiocarbon values. These observations suggest a period of enhanced lateral exchange of carbon between the deep South Atlantic and Pacific Oceans, probably due to an increased transfer of momentum from southern westerlies to the Southern Ocean. By spreading carbon-rich deep Pacific waters around Antarctica for upwelling, invigorated interocean deep water exchange would lead to more efficient CO2 degassing from the Southern Ocean, and thus to an atmospheric CO2 rise, during the early deglaciation.

  5. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water.

    PubMed

    Frank, Alexander H; Garcia, Juan A L; Herndl, Gerhard J; Reinthaler, Thomas

    2016-06-01

    To decipher the influence of depth stratification and surface provincialism on the dark ocean prokaryotic community composition, we sampled the major deep-water masses in the eastern North Atlantic covering three biogeographic provinces. Their diversity was evaluated using ordination and canonical analysis of 454 pyrotag sequences. Variance partitioning suggested that 16% of the variation in the bacterial community composition was based on depth stratification while 9% of the variation was due to geographic location. General linear mixed effect models showed that the community of the subsurface waters was connected to the dark ocean prokaryotic communities in different biogeographic provinces. Cluster analysis indicated that some prokaryotic taxa are specific to distinct regions in bathypelagic water masses. Taken together, our data suggest that the dark ocean prokaryotic community composition of the eastern North Atlantic is primed by the formation and the horizontal transport of water masses. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Using synthetic forward seismic models of channelized deep-water slope deposits to inform stratigraphic interpretation, Tres Pasos Formation, Magallanes Basin, Chile

    NASA Astrophysics Data System (ADS)

    Nielson, A.; Stright, L.; Hubbard, S. M.; Romans, B.

    2016-12-01

    Subsurface interpretation of deep-water channels from seismic-reflection profiles is inherently challenging due to the sub-seismic scale of key stratigraphic surfaces and facies transitions. Synthetic seismic modeling can provide valuable insight into multi-scale (bed to composite channel complexes) stratigraphic architecture and is ideal for understanding uncertainties inherent to seismic interpretation through seismic attributes and assessing the interpretation error from seismic reflectivity profiles at different frequencies. Cretaceous slope channel-fill deposits in the Magallanes Basin of southern Chile were used as the basis for a bed-scale model (0.25 m vertical resolution) of a single 14 m thick by 300 m wide channel element. This channel element was used to generate synthetic seismic models using rock properties from analogous deep-water Gulf of Mexico deposits. The results were analyzed to quantify the error in predicting channel thickness at different frequencies and how the error scales with true channel thickness, internal channel architecture, and wavelet frequency. Two channel elements were then stacked to elucidate the stacking patterns and seperability of multiple channel elements and finally expanded to a composite channel complex ( 100 m thick). Single channel elements are tuned at 60 Hz and below, upon which a predictive error model was generated relating true channel thickness to interpreted thickness as a function of frequency. Furthermore, RMS amplitude analysis of a single symmetrical channel element shows a linear relationship between decreasing frequency and increasing RMS amplitude as well as a positive correlation between increasing channel thickness and increasing amplitude. Tuning effects are dampened by the natural heterogeneity of the channels towards the margins. These seismic attributes aid in the recognition of channel stacking patterns and enhance channel seperability within a composite channel complex.

  7. Coordinated motility of cyanobacteria favor mat formation, photosynthesis and carbon burial in low-oxygen, high-sulfur shallow sinkholes of Lake Huron; whereas deep-water aphotic sinkholes are analogs of deep-sea seep and vent ecosystems

    NASA Astrophysics Data System (ADS)

    Biddanda, B. A.; McMillan, A. C.; Long, S. A.; Snider, M. J.; Weinke, A. D.; Dick, G.; Ruberg, S. A.

    2016-02-01

    Microbial life in submerged sinkhole ecosystems of the Laurentian Great Lakes is relatively understudied in comparison to seeps and vents of the deep-sea. We studied the filamentous benthic mat-forming cyanobacteria consisting primarily of Oscillatoria-like cells growing under low-light, low-oxygen and high-sulfur conditions in Lake Huron's submerged sinkholes using in situ observations, in vitro measurements and time-lapse microscopy. Gliding movement of the cyanobacterial trichomes revealed individual as well as group-coordinated motility. When placed in a petri dish and dispersed in ground water from the sinkhole, filaments re-aggregated into defined colonies within minutes. Measured speed of individual filaments ranged from 50 µm minute-1 or 15 body lengths minute-1 to 215 µm minute-1 or 70 body lengths minute-1 - rates that are rapid relative to non-flagellated/ciliated microbes. Filaments exhibited precise and coordinated positive phototaxis towards pinpoints of light and congregated under the light of foil cutouts. Such light-responsive clusters showed an increase in photosynthetic yield - suggesting phototactic motility aids in light acquisition as well as photosynthesis. Pebbles and pieces of broken shells placed upon the mat in intact sediemnt cores were quickly covered by vertically motile filaments within hours and became fully buried in the anoxic sediments over 3-4 diurnal cycles - likely facilitating the preservation of falling plankton debris. Coordinated horizontal and vertical filament motility optimize mat cohesion and dynamics, photosynthetic efficiency and sedimentary carbon burial in modern-day sinkhole habitats where life operates across sharp redox gradients. Analogous cyanobacterial motility in the shallow seas during Earth's early history, may have played a key role in the oxygenation of the planet by optimizing photosynthesis while favoring carbon burial. We are now eagerly mapping and exploring life in deep-water aphotic sinkholes of

  8. Biology of deep-water chondrichthyans: Introduction

    NASA Astrophysics Data System (ADS)

    Cotton, C. F.; Grubbs, R. D.

    2015-05-01

    Approximately half of the known chondrichthyans (sharks, skates, rays, and chimaeras), 575 of 1207 species (47.6%, Table 1), live in the deep ocean (below 200 m), yet little is known of the biology or life histories of most of these fishes (Kyne and Simpfendorfer, 2007). The limited information available for deep-water chondrichthyans is compounded by their rarity, as well as the prevalent uncertainty in the alpha taxonomy of deep-water species. Many species are known only from the type materials, which are generally limited to nondestructive sampling, e.g., morphometrics, imaging (X-ray, MRI, CT scanning). Thus, research has been hindered by a lack of specimens available for investigation that requires destructive sampling or live specimens (e.g., life history, diet, telemetry). The need for more research and dissemination of information about deep-water chondrichthyans has become imperative as fisheries worldwide continue to expand into deeper waters and exploit deep-water stocks, usually in the absence of data required for appropriate management (Morato et al., 2006; Kyne and Simpfendorfer, 2010).

  9. Long Range Acoustic Communication in Deep Water

    DTIC Science & Technology

    2013-09-30

    ocean is challenging due to the substantial propagation loss, multipath delay spread , and channel variability. Analysis of deep-water data collected...were exploited. In addition, a robust algorithm (double differentially coded spread spectrum) was demonstrated recently using the LRAC10 data [10...Spray gliders with a commercial acoustic modem for data retrieval from subsurface moorings and seafloor systems installed with a similar modem in deep

  10. Formation of water bells

    NASA Astrophysics Data System (ADS)

    Ybert, Christophe; Clanet, Christophe; Bocquet, Lyderic; Duez, Cyril

    2007-11-01

    We study experimentally the situation that consist in a liquid jet impacting normally onto a fixed solid disk. Depending on the experimental conditions, the thin liquid film that spreads onto the solid surface can either pour along the surface, or detach form the disk and form a so-called water bell. The dynamics and the stability of such bells as a function of the hydrodynamic parameters such as the jet and disk diameters or the jet velocity, have already been the object of detailed characterization [1]. This experiment of bell formation appears as the symmetric situation compared to that of a solid body impacting a quiescent liquid. In the latter case, it was recently shown [2] that despite large Re and We numbers, the solid surface characteristics were dramatically influencing the impact scenario. In the present study, we consequently revisit this problem of water bell formation by systematically varying the solid surface characteristics (roughness, surface properties, etc.). It is shown here again that surface parameters strongly influence the domain of bell existence. Our measurements are rationalized by a subtle balance between inertia versus capillary forces and wetting contributions on the liquid film in the ejection region. [1] C. Clanet, J. Fluid Mech., 430, 111-147 (2001) [2] C. Duez et al., Nature Physics, 3, 180-183 (2007)

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

    ERIC Educational Resources Information Center

    Soltow, Willow

    1984-01-01

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

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

    ERIC Educational Resources Information Center

    Soltow, Willow

    1984-01-01

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

  13. Pressure induced breather overturning on deep water: Exact solution

    NASA Astrophysics Data System (ADS)

    Abrashkin, A. A.; Oshmarina, O. E.

    2014-08-01

    A vortical model of breather overturning on deep water is proposed. The action of wind is simulated by nonuniform pressure on the free surface. The fluid motion is described by an exact solution of 2D hydrodynamic equations for an inviscid fluid in Lagrangian variables. Fluid particles rotate in circles of different radii. Formation of contraflexure points on the breather profile is studied. The mechanism of wave breaking and the role of flow vorticity are discussed.

  14. North Atlantic Deep Water and the World Ocean

    NASA Technical Reports Server (NTRS)

    Gordon, A. L.

    1984-01-01

    North Atlantic Deep Water (NADW) by being warmer and more saline than the average abyssal water parcel introduces heat and salt into the abyssal ocean. The source of these properties is upper layer or thermocline water considered to occupy the ocean less dense than sigma-theta of 27.6. That NADW convects even though it's warmer than the abyssal ocean is obviously due to the high salinity. In this way, NADW formation may be viewed as saline convection. The counter force removing heat and salinity (or introducing fresh water) is usually considered to to take place in the Southern Ocean where upwelling deep water is converted to cold fresher Antarctic water masses. The Southern ocean convective process is driven by low temperatures and hence may be considered as thermal convection. A significant fresh water source may also occur in the North Pacific where the northward flowing of abyssal water from the Southern circumpolar belt is saltier and denser than the southward flowing, return abyssal water. The source of the low salinity input may be vertical mixing of the low salinity surface water or the low salinity intermediate water.

  15. Deep Water Single Point Mooring Design

    DTIC Science & Technology

    1997-09-10

    Technology E-1 Introduction This Appendix provides design and performance information for various types of tension members which might be used as mooring...TTINwSC.6OI AD-A286 939 Inulun Deep Water Single Point Mooring Design John F. Flory Henry A. McKenna Tension Technology International, Inc. 9...ORGANIZATIONJ (if appdicable) Tension Technology International J Naval Surface Warfare Center, Carderock Division Sc. ADDRESS (City, State, and ZIP Code

  16. Deep Water Ambient Noise and Mode Processing

    DTIC Science & Technology

    2012-09-30

    Deep Water Ambient Noise and Mode Processing Kathleen E. Wage George Mason University Electrical and Computer Engineering Department 4400...UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) George Mason University Electrical and Computer Engineering Department 4400 University...analysis of the Church Opal data set showed that noise levels decreased substantially (on the order of 20 dB) below the critical depth [5]. This project

  17. Hawaii Deep Water Cable Program: Executive Summary

    SciTech Connect

    1990-09-01

    The Hawaii Deep Water Cable Program has succeeded unequivocally in determining the feasibility of deploying a submarine power cable system between the islands of Hawaii and Oahu. Major accomplishments of the program include designing, fabricating and testing an appropriate power cable, developing an integrated system to control all aspects of the cable laying operation, and testing all deployment systems at sea in the most challenging sections of the route.

  18. Spreading of the Western Mediterranean Deep Water after winter 2005: Time scales and deep cyclone transport

    NASA Astrophysics Data System (ADS)

    Beuvier, J.; BéRanger, K.; Lebeaupin Brossier, C.; Somot, S.; Sevault, F.; Drillet, Y.; Bourdallé-Badie, R.; Ferry, N.; Lyard, F.

    2012-07-01

    This work is dedicated to the study of the propagation of the Western Mediterranean Deep Water (WMDW) formed in the Gulf of Lions during the exceptional winter 2005. A simulation of the 1998-2008 period has been carried out with an eddy-resolving Ocean General Circulation Model of the Mediterranean Sea, driven by interannual high-resolution air-sea fluxes. This study first presents a validation of the recently improved model configuration against satellite observations. Then, we assess the ability of the model to reproduce the particularly intense deep convection event of winter 2005 in the Gulf of Lions. A huge volume of very dense water is formed in the simulation at that time (annual formation rate higher than 3 Sv). The thermohaline characteristics of the new WMDW allow a monitoring of its deep propagation. We identify several deep cyclones as mainly responsible of the fast spreading of the WMDW southwards in the Western Mediterranean. By comparing Eulerian and Lagrangian approaches, we estimate different transport times of the WMDW by these cyclonic eddies and compare them to those deduced from several observations. Finally, we argue that these cyclones favor the propagation of the WMDW thermohaline characteristics toward the Channel of Sardinia and decrease the volume of WMDW which can reach the Strait of Gibraltar.

  19. From Offshore to Onshore: Multiple Origins of Shallow-Water Corals from Deep-Sea Ancestors

    PubMed Central

    Lindner, Alberto; Cairns, Stephen D.; Cunningham, Clifford W.

    2008-01-01

    Shallow-water tropical reefs and the deep sea represent the two most diverse marine environments. Understanding the origin and diversification of this biodiversity is a major quest in ecology and evolution. The most prominent and well-supported explanation, articulated since the first explorations of the deep sea, holds that benthic marine fauna originated in shallow, onshore environments, and diversified into deeper waters. In contrast, evidence that groups of marine organisms originated in the deep sea is limited, and the possibility that deep-water taxa have contributed to the formation of shallow-water communities remains untested with phylogenetic methods. Here we show that stylasterid corals (Cnidaria: Hydrozoa: Stylasteridae)—the second most diverse group of hard corals—originated and diversified extensively in the deep sea, and subsequently invaded shallow waters. Our phylogenetic results show that deep-water stylasterid corals have invaded the shallow-water tropics three times, with one additional invasion of the shallow-water temperate zone. Our results also show that anti-predatory innovations arose in the deep sea, but were not involved in the shallow-water invasions. These findings are the first robust evidence that an important group of tropical shallow-water marine animals evolved from deep-water ancestors. PMID:18560569

  20. Temporal and Spatial Scales of Labrador Sea Water Formation

    NASA Technical Reports Server (NTRS)

    Clarke, R. A.

    1984-01-01

    Labrador Sea Water is an intermediate water found at the same density and depth range in the North Atlantic as the Mediterranean water. It is formed by convection from the sea surface to depths greather than 2 km in winter in the Western Labrador Sea. The processes leading to deep convection begin with the formation of a 200 km scale cyclonic circulation about denser than average upper layer water in the Western Labrador Sea. This circulation pattern is hypothesized to be driven by an ocean/atmosphere heat exchange that has its maximum in this region. By early March, if deep convection is taking place, one sees that this body of denser upper waters penetrates to the top of the deep temperature/salinity maximum marking the core of the North Atlantic Deep Water. We note that the horizontal scale of this body is still 100-200 km normal to the coastline.

  1. Temporal and Spatial Scales of Labrador Sea Water Formation

    NASA Technical Reports Server (NTRS)

    Clarke, R. A.

    1984-01-01

    Labrador Sea Water is an intermediate water found at the same density and depth range in the North Atlantic as the Mediterranean water. It is formed by convection from the sea surface to depths greather than 2 km in winter in the Western Labrador Sea. The processes leading to deep convection begin with the formation of a 200 km scale cyclonic circulation about denser than average upper layer water in the Western Labrador Sea. This circulation pattern is hypothesized to be driven by an ocean/atmosphere heat exchange that has its maximum in this region. By early March, if deep convection is taking place, one sees that this body of denser upper waters penetrates to the top of the deep temperature/salinity maximum marking the core of the North Atlantic Deep Water. We note that the horizontal scale of this body is still 100-200 km normal to the coastline.

  2. Sub-surface investigations on deep saline groundwater of Charnockite rock formation, Kalpakkam, India.

    PubMed

    Gurumoorthy, C; Sasidhar, P; Arumugham, V; Mathur, R K

    2004-02-01

    Investigations on geohydrological aspects of coastal aquifer are important in order to understand the mechanism of ground water salinisation. The present study describes the salinity variations of ground water in deep boreholes drilled in Charnockite rock formation of Kalpakkam, on the eastern coast of India. Water samples collected up to 600m depth were analyzed for salinity variation. It is noticed that in one of the boreholes, (borehole K1), the salinity level is found to be 74 parts per thousand (ppt) at 400 m depth. Influence of surface saline water bodies viz., sea (26-28.5 ppt), backwaters (27-30 pt) and Buckingham canal (27-32 ppt) as the possible sources of recharge of fresh waters through joint and fracture system of the rock are discussed in this paper. Studies would assist in understanding the geohydrological characteristics of deep geological formation.

  3. Implications of Subduction Rehydration for Earth's Deep Water Cycle

    NASA Astrophysics Data System (ADS)

    Ruepke, L. H.; Phipps Morgan, J.; Dixon, J.

    2006-12-01

    The presence of liquid water is the principle difference between our Earth and other planets in the solar system. The global ocean is the obvious surface expression of this. The 'standard model' for the genesis of the oceans is that they are exhalations from Earth's deep interior continually rinsed through surface rocks by the global hydrologic cycle. The question of how much water resides within the Earth's deep interior remains unresolved and is a matter of vigorous ongoing scientific debate. We have addressed the question of water distribution between the exosphere and the mantle throughout Earth's history with simple mass balance considerations. In our model, water is outgassed from the mantle into the exosphere (atmosphere + continental crust) during pressure-release melting at mid-ocean ridges and hotspots. Plate subduction may transport water back from the surface into the deeper mantle thereby 'closing' the global geologic water cycle. In series of some 5000 model runs we have thoroughly explored the mutual effect of model parameters. All models correctly predict the formation of the present-day oceans but differ in their predicted sea-level changes through time and in the amount of water in the present-day mantle. To distinguish which model runs are the most realistic we use geochemical constraints and observed sealevel changes during the Phanerozoic. Recently Dixon et al. [2002] estimated water concentrations for some of the major mantle components and concluded that the most primitive (FOZO) are significantly wetter than the recycling associated EM or HIMU mantle components and the even drier depleted mantle source that melts to form MORB. Sealevel changes over hundreds of million of years are notoriously bad constrained. But a maximum drop in sealevel of 400-600m appears to be an upper bound. We find that only those model runs are consistent with these constraints in which deep water subduction is limited and in which the present-day mantle is

  4. Climate variability and deep water mass characteristics in the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Georgiou, S.; Mantziafou, A.; Sofianos, S.; Gertman, I.; Özsoy, E.; Somot, S.; Vervatis, V.

    2015-01-01

    The main objective of this study is to investigate the variability of the thermohaline characteristics of the deep-water masses in the Aegean Sea and the possible impact of the regional atmospheric forcing variability by analyzing the available oceanographic and atmospheric datasets for the period of 1960-2012. During this period the variability of the deep water characteristics of the Aegean sub-basins is found to be very large as well as the diversity of the deep water characteristics among the sub-basins. The Central Aegean seems to play the key role in the Aegean deep water formation processes. Due to its small size, the Aegean Sea surface responds rapidly to the meteorological changes and/or the variability of the lateral fluxes and this variability propagates in the thermohaline characteristics of the deep water masses of the basin through deep water formation processes. There are many episodes characterized by a tight coupling of the atmosphere and the ocean during the examined period, with the Eastern Mediterranean Transient (EMT) being the most prominent case. We suggest that deep water formation is triggered mostly by the combination of preconditioning during early winter and/or previous winters together with the number of subsequent extreme events during present winter and not only by the total amount of the extreme heat loss winter days.

  5. A Modeling Study of Deep Water Renewal in the Red Sea

    NASA Astrophysics Data System (ADS)

    Yao, F.; Hoteit, I.

    2016-02-01

    Deep water renewal processes in the Red Sea are examined in this study using a 50-year numerical simulation from 1952-2001. The deep water in the Red Sea below the thermocline ( 200 m) exhibits a near-uniform vertical structure in temperature and salinity, but geochemical tracer distributions, such as 14C and 3He, and dissolved oxygen concentrations indicate that the deep water is renewed on time scales as short as 36 years. The renewal process is accomplished through a deep overturning cell that consists of a southward bottom current and a northward returning current at depths of 400-600 m. Three sources regions are proposed for the formation of the deep water, including two deep outflows from the Gulfs of Aqaba and Suez and winter deep convections in the northern Red Sea. The MITgcm (MIT general circulation model), which has been used to simulate the shallow overturning circulations in the Red Sea, is configured in this study with increased resolutions in the deep water. During the 50 years of simulation, artificial passive tracers added in the model indicate that the deep water in the Red Sea was only episodically renewed during some anomalously cold years; two significant episodes of deep water renewal are reproduced in the winters of 1983 and 1992, in accordance with reported historical hydrographic observations. During these renewal events, deep convections reaching the bottom of the basin occurred, which further facilitated deep sinking of the outflows from the Gulfs of Aqaba and Suez. Ensuing spreading of the newly formed deep water along the bottom caused upward displacements of thermocline, which may have profound effects on the water exchanges in the Strait of Bab el Mandeb between the Red Sea and the Gulf of Aden and the functioning of the ecosystem in the Red Sea by changing the vertical distributions of nutrients.

  6. Power, fresh water, and food from cold, deep sea water.

    PubMed

    Othmer, D F; Roels, O A

    1973-10-12

    Many times more solar heat energy accumulates in the vast volume of warm tropic seas than that produced by all of our power plants. The looming energy crisis causes a renewal of interest in utilizing this stored solar heat to give, in addition to electric power, vast quantities of fresh water. Warm surface water, when evaporated, generates steam, to power a turbine, then fresh water when the steam is condensed by the cold water. A great increase in revenues over that from power and fresh water is shown by a substantial mariculture pilot plant. Deep sea water contains large quantities of nutrients. These feed algae which feed shellfish, ultimately shrimps and lobsters, in shallow ponds. Wastes grow seaweed of value; and combined revenues from desalination, power generation, and mariculture will give substantial profit.

  7. Variability in Labrador Sea Water formation

    NASA Astrophysics Data System (ADS)

    Gelderloos, R.

    2012-05-01

    The Atlantic Meridional Overturning Circulation (AMOC) transports of a large amount of heat towards the North Atlantic region. Since this circulation is considered to have shown pronounced variability in the past, and a weakening is projected for the 21st century, it is very important to understand and monitor the mechanisms that determine its variability. Deep water formation is one of the most important of these mechanisms as it plays an important role in setting the shape and strength of the AMOC. It only takes place in a few locations in the ocean, one of which is the Labrador Sea. In this thesis two processes that play an important role in determining the variability of Labrador Sea Water formation are studied as well as the possibility to monitor this variability using satellite altimetry measurements. The first process study focused on the restratification period after a deep convection event. The dense water in the area affected by deep convection is then (partly) replaced by more buoyant water originating from the boundary currents that encircle the interior. Using a numerical model in an idealized configuration, the roles of three eddy types that are known to play a role in the restratification process were studied. It was found that the presence of Irminger Rings is essential for a realistic amount of restratification in the Labrador Sea. The second process study focused on the effects of a very fresh surface layer, which makes the surface layer lighter and can, if light enough, inhibit convective mixing. The well-known case of the Great Salinity Anomaly (1969-1971), which was fortuitously well documented by the measurements taken at ocean weather station “Bravo” in the central Labrador Sea, has been analyzed. In contrast to what is commonly assumed, only a combination of the fresh surface layer and the very mild winter conditions in 1969 could have started the convective shutdown, and only a combination of the extremely harsh winter and a

  8. Seismological constraints on Earth's Deep Water Cycle

    NASA Astrophysics Data System (ADS)

    Van der Lee, S.

    2011-12-01

    Water is a ubiquitous volatile, relatively small amounts of which can be present in the mantle in the form of hydrous melts, hydrous phases, or incorporated into the crystal structure of nominally anhydrous minerals of the major mantle mineralogy. In whichever form the water or another volatile is, even small amounts will likely affect the seismic properties of the mantle in various ways, such that seismic observations contain unique and valuable information on the amount and distribution of volatiles in the Earth's mantle. It is, however, challenging to extract this information because of limitations in the amount and density of available seismic data, multiple interpretations of similar observations, and limited quantification of the effects of volatiles and other parameters on the seismic properties. Wet polymorphs of olivine tend to lower the seismic velocity relatively gradually throughout the upper mantle, while deep carbon tends to be have fewer host mineralogies, leaving its signature more precipitous. Water can also stretch and elevate seismic discontinuities related to mineralogical phase changes. Overall in the mantle, the seismic effects of volatiles are small compared those of heat. Various types of observations have been combined to infer water content in the mantle, ranging from a few hundredths of weight percent to several weight percent. Altogether, the seismological literature suggests that the mantle is heterogeneously hydrated. There does not appear to be an obvious correlation between present tectonic environment and mantle water content, though a tendency exists to interpret possibly hydrous regions in the mid mantle as being related to past subduction of oceanic lithosphere. More recently, a new tendency relates possibly hydrous regions in the mid mantle to future subduction of oceanic lithosphere.

  9. North Atlantic Deep Water Production during the Last Glacial Maximum

    PubMed Central

    Howe, Jacob N. W.; Piotrowski, Alexander M.; Noble, Taryn L.; Mulitza, Stefan; Chiessi, Cristiano M.; Bayon, Germain

    2016-01-01

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial–interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters. PMID:27256826

  10. North Atlantic Deep Water Production during the Last Glacial Maximum.

    PubMed

    Howe, Jacob N W; Piotrowski, Alexander M; Noble, Taryn L; Mulitza, Stefan; Chiessi, Cristiano M; Bayon, Germain

    2016-06-03

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ(13)C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.

  11. Deep convection and deepwater formation: Progress and new directions

    NASA Astrophysics Data System (ADS)

    Gascard, Jean-Claude

    Focused interest in deep convection and deepwater formation was evidenced as early as 1972, when an international colloquium entirely dedicated to oceanic deepwater formation was convened by the Laboratoire d'Oceanographie du Museum in Paris. Discussions concentrated heavily, but not exclusively, on observations taken in the northwest Mediterranean Sea by the Medoc Group [1970], who proposed that processes leading to deepwater formation could be divided into three phases: preconditioning, violent mixing, and sinking and spreading. A new feature—the chimney—was identified, which tends to define the horizontal extent of an area where deep convection occurs to great depths and leads to deepwater formation.In terms of mechanisms for destroying stratification, double diffusion was the prevalent choice at that time among most participants. However, the effect of advection was also considered. Stommel [1972] claimed that the deep convection observed in the Mediterranean Sea was of a nonpenetrative type, since the density of the mixed layer increased steadily with thickness and time instead of decreasing as for penetrative convection. Most of these conclusions were based on the fact that the problem was believed to be truly one dimensional. Stommel recognized that the small size of the sinking area was not related to a hydrodynamical phenomenon such as the one he described in 1962 [Stommel, 1962] nor even directly forced by the atmosphere, which acts at a much larger scale. Rather, he indicated that the small size of a deep convective area was preconditioned by the general circulation in the basin. The major discovery during the following 10-year period (1973-1983) was realization of the important role played by baroclinic instability, active during ALL phases including the initial preconditioning.

  12. Patterns in life history traits of deep-water chondrichthyans

    NASA Astrophysics Data System (ADS)

    Rigby, Cassandra; Simpfendorfer, Colin A.

    2015-05-01

    Life history traits are important indicators of the productivity of species, and their ability to tolerate fishing pressure. Using a variety of life history traits (maximum size, size and age at maturity, longevity, growth rate, litter and birth size) we demonstrated differences in chondrichthyan life histories between shelf, pelagic and deep-water habitats and within the deep habitat down the continental slope and across geographic regions. Deep-water species had lower growth rates, later age at maturity, and higher longevity than both shelf and pelagic species. In the deep habitat, with increasing depth, species matured later, lived longer, had smaller litters and bred less frequently; regional differences in traits were also apparent. Deep-water species also had a smaller body size and the invariants of relative size and age at maturity were higher in deep water. The visual interaction hypothesis offers a potential explanation for these findings and it is apparent habitat influences the trade-offs in allocation of energy for survival and reproduction. Body size is not appropriate as a predictor of vulnerability in deep-water chondrichthyans and regional trait differences are possibly due to a fishing pressure response. Deep-water chondrichthyans are more vulnerable to exploitation than shelf and pelagic species and this vulnerability markedly increases with increasing depth. The life history traits of deep-water chondrichthyans are unique and reflect adaptations driven by both mortality and resource limitations of their habitat.

  13. Distributed control topologies for deep space formation flying spacecraft

    NASA Technical Reports Server (NTRS)

    Hadaegh, F. Y.; Smith, R. S.

    2002-01-01

    A formation of satellites flying in deep space can be specified in terms of the relative satellite positions and absolute satellite orientations. The redundancy in the relative position specification generates a family of control topologies with equivalent stability and reference tracking performance, one of which can be implemented without requiring communication between the spacecraft. A relative position design formulation is inherently unobservable, and a methodology for circumventing this problem is presented. Additional redundancy in the control actuation space can be exploited for feed-forward control of the formation centroid's location in space, or for minimization of total fuel consumption.

  14. Distributed control topologies for deep space formation flying spacecraft

    NASA Technical Reports Server (NTRS)

    Hadaegh, F. Y.; Smith, R. S.

    2002-01-01

    A formation of satellites flying in deep space can be specified in terms of the relative satellite positions and absolute satellite orientations. The redundancy in the relative position specification generates a family of control topologies with equivalent stability and reference tracking performance, one of which can be implemented without requiring communication between the spacecraft. A relative position design formulation is inherently unobservable, and a methodology for circumventing this problem is presented. Additional redundancy in the control actuation space can be exploited for feed-forward control of the formation centroid's location in space, or for minimization of total fuel consumption.

  15. The Mechanism of First Raindrops Formation in Deep Convective Clouds

    SciTech Connect

    Khain, Alexander; Prabha, Thara; Benmoshe, Nir; Pandithurai, G.; Ovchinnikov, Mikhail

    2013-08-22

    The formation of first raindrops in deep convective clouds is investigated. A combination of observational data analysis and 2-D and 3-D numerical bin microphysical simulations of deep convective clouds suggests that the first raindrops form at the top of undiluted or slightly diluted cores. It is shown that droplet size distributions in these regions are wider and contain more large droplets than in diluted volumes. The results of the study indicate that the initial raindrop formation is determined by the basic microphysical processes within ascending adiabatic volumes. It allows one to predict the height of the formation of first raindrops considering the processes of nucleation, diffusion growth and collisions. The results obtained in the study explain observational results reported by Freud and Rosenfeld (2012) according to which the height of first raindrop formation depends linearly on the droplet number concentration at cloud base. The results also explain why a simple adiabatic parcel model can reproduce this dependence. The present study provides a physical basis for retrieval algorithms of cloud microphysical properties and aerosol properties using satellites proposed by Rosenfeld et al. ( 2012). The study indicates that the role of mixing and entrainment in the formation of the first raindrops is not of crucial importance. It is also shown that low variability of effective and mean volume radii along horizontal traverses, as regularly observed by in situ measurements, can be simulated by high-resolution cloud models, in which mixing is parameterized by a traditional 1.5 order turbulence closure scheme.

  16. Breaking of waves in deep water

    NASA Astrophysics Data System (ADS)

    Ruiz-Chavarria, Gerardo

    2013-11-01

    The breaking of waves is a nonlinear phenomenon during which a fraction of the energy is dissipated. In the previous stage the wave undergoes a growth of its amplitude and the wave pattern is modified in the sense that the crests become more pronounced than the troughs. The breaking has been extensively studied in the case of waves approaching the shore. However, the wave breaking in deep water remains an open problem in fluid dynamics. In this work we study the wave breaking due to focusing of an initially parabolic wave front. To this end the evolution of wave is numerically investigated using a meshless code (Smoothed Particle Hydrodynamics). We present some results about the evolution of waves excited by a parabolic wave maker, among others, the growth induced by the focusing, the behavior around the Huygens' cusp and the process of wave breaking. Then, we compare the numerical results with the criteria given in the literature about the onset of breaking and we discuss how the energy dissipates, for example by the rise of short waves. In addition we compare the numerical results with data obtained in two different experiments made by our team. Author acknowledges DGAPA-UNAM by support under project IN116312, ``Vorticidad y ondas no lineales en fluidos.''

  17. The deep-water circulation during the Neogene and the impact of the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Blanc, Paul-Louis; Duplessy, Jean-Claude

    1982-12-01

    The 13C: 12C ratio of benthic foraminiferal calcite preserves the indications of the 13C: 12C ratio of the total dissolved CO 2 and can be used as a tracer of the residence time of the oceanic deep water. The tracer is applied to the reconstruction of the deep-water exchanges between the Atlantic and Pacific oceans, from middle Miocene times (15 × 10 6 y ago) to the Pliocene. Results from two Atlantic DSDP sites are compared with results from another Atlantic and three Pacific sites. The present pattern of thermohaline circulation was initiated 13.2 × 10 6 y ago, when the Scotland-Faeroe-Iceland-Greenland Ridge was sufficiently subsided to allow Arctic Bottom Water (ABW) to overflow the ridge. During the Messinian the salt deficiency due to the closure of the Mediterranean Sea caused all deep-water formation in the northern hemisphere to stop; the present deep circulation started again in the North Atlantic when the Mediterranean reopened at the beginning of the Pliocene, but deep-water formation did not resume in the North Pacific because the transfer of deep, saline water from the Atlantic was hindered by the shoaling of the Balboa Sill.

  18. Annealing ambient controlled deep defect formation in InP

    NASA Astrophysics Data System (ADS)

    Zhao, Y. W.; Dong, Z. Y.; Duan, M. L.; Sun, W. R.; Zeng, Y. P.; Sun, N. F.; Sun, T. N.

    2004-07-01

    Deep defects in annealed InP have been investigated by deep level transient capacitance spectroscopy (DLTS), photo induced current transient spectroscopy (PICTS) and thermally stimulated current spectroscopy (TSC). Both DLTS results of annealed semiconducting InP and PICTS and TSC results of annealed semi-insulating InP indicate that InP annealed in phosphorus ambient has five defects, while InP annealed in iron phosphide ambient has two defects. Such a defect formation phenomenon is explained in terms of defect suppression by the iron atom diffusion process. The correlation of the defects and the nature of the defects in annealed InP are discussed based on the results.

  19. Messinian Salinity Crisis' Primary Evaporites: the shallow gypsum vs. deep dolomite formation paradox solved

    NASA Astrophysics Data System (ADS)

    De Lange, G. J.; Krijgsman, W.

    2015-12-01

    The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, resulting in deposition of 1-3 km thick evaporites at the Mediterranean seafloor. A considerable, long-lasting controversy existed on the modes of their formation, including the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions at a precessional rhythm. Gypsum precipitation only occurred at marginal- and dolomite formation at deeper settings. A range of potential explanations was given, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are commonly neglected but may explain that different deposits formed in shallow vs deep environments without exceptional physical boundary conditions for each. A unifying mechanism is presented in which gypsum formation occurs at all shallow water depths but its preservation is limited to shallow sedimentary settings. In contrast, ongoing deep-basin anoxic organic matter (OM) degradation processes result in dolomite formation. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always oversaturated relative to dolomite but its formation is inhibited by the presence of dissolved sulphate. Thus conditions for formation of gypsum exclude those for formation of dolomite and vice versa. Another process linking the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, ongoing OM-degradation may result in reducing the sulphate and enhancing the dissolved carbonate content. Such low-sulphate / high carbonate conditions in MSC deepwater are. unfavorable for gypsum preservation and favorable for dolomite formation, and always coincide with anoxic, i.e. oxygen-free conditions. Including dynamic biogeochemical processes in the thusfar static

  20. Hummocky cross-stratification-like structures and combined-flow ripples in the Punta Negra Formation (Lower-Middle Devonian, Argentine Precordillera): A turbiditic deep-water or storm-dominated prodelta inner-shelf system?

    NASA Astrophysics Data System (ADS)

    Basilici, Giorgio; de Luca, Pedro Henrique Vieira; Poiré, Daniel G.

    2012-08-01

    Turbidity-current and storm-induced deposits may exhibit similarities, in particularly when the latter is laid down by a combination of oscillatory and unidirectional flows. Recent progress in facies analysis helps to discriminate the sedimentary effects of oscillatory from unidirectional components of the flow. On the basis of detailed analysis of sedimentary facies, strata geometry, and palaeocurrent data, the present study reinterprets the Punta Negra Formation (PNF) (Lower-Middle Devonian, Argentine Precordillera), previously considered as a depositional system of deep-water, as a storm-dominated prodeltaic shelf depositional system. In the sandstone beds of the PNF, planar, low-angle and undulating laminations with weakly asymmetric hummocky and swaley bedforms, combined-flow ripples, accretionary hummocky cross-stratification-like (HCS-like), and anisotropic HCS-like suggest the action of oscillatory currents combined with unidirectional currents in forming the deposits. Different hypotheses on the origin of the oscillatory currents have been examined. The most convincing interpretation is that the oscillatory component of the velocity is attributed to storm-induced waves. The palaeocurrent data indicate offshore current directions, suggesting that the unidirectional flow was a gravity-induced bottom current. Inverse grading at the base and overlying normally graded divisions of the sandstone beds testify to waxing-waning behaviour of the depositional flows; interbedding of sedimentary structures (undulating laminations, low-angle and parallel laminations, and combined-flow ripples) in the lower and intermediate divisions of the beds indicate fluctuations of flow velocity. This organisation of the sedimentary structures permits association of the unidirectional component with hyperpycnal bottom currents. The terrestrial origin of the hyperpycnal flows is suggested by the abundance of terrestrial plant remains, the mineralogical and textural immaturity of the

  1. Deep-water antipatharians: Proxies of environmental change

    USGS Publications Warehouse

    Williams, B.; Risk, Michael J.; Ross, S.W.; Sulak, K.J.

    2006-01-01

    Deep-water (307-697 m) antipatharian (black coral) specimens were collected from the southeastern continental slope of the United States and the north-central Gulf of Mexico. The sclerochronology of the specimens indicates that skeletal growth takes place by formation of concentric coeval layers. We used 210Pb to estimate radial growth rate of two specimens, and to establish that they were several centuries old. Bands were delaminated in KOH and analyzed for carbon and nitrogen stable isotopes. Carbon values ranged from -16.4??? to -15.7???; oldest specimen displayed the largest range in values. Nitrogen values ranged from 7.7??? to 8.6???. Two specimens from the same location and depth had similar 15N signatures, indicating good reproducibility between specimens. ?? 2006 Geological Society of America.

  2. The intensification of deep-water mass changes in the deep Atlantic Ocean throughout the Mid-Pleistocene climate transition

    NASA Astrophysics Data System (ADS)

    Poirier, R. K.; Billups, K.

    2012-12-01

    We examine the deep-water hydrography at Ocean Drilling Project (ODP) Site 1063 (subtropical North Atlantic, ~4600 meter water depth) using high-resolution benthic stable isotope (δ18O, δ13C) and grain size (% coarse, % Sortable Silt - SS, SS mean diameter) analyses from ~490 to 740 ka. The benthic foraminiferal δ13C record from Site 1063 provides a proxy for changes in the relative flux of lower North Atlantic Deep Water (NADW) through time. This record will refine the timing of increases in the formation of the densest components of NADW on the orbital and millennial-scale. We explore whether or not grain size analyses provide a proxy for changes in the relative velocity of the deep current. The new stable isotope data from Site 1063, when combined with the records of Poli et al. (2000), Ferretti et al. (2005), and Billups et al. (2011), tuned to the global benthic isotope stack (LR05) of Liesicki and Raymo (2004), provides a complete deep water record spanning Marine Isotope Stage (MIS) 25 to MIS 8 (~1020 to ~240 ka). Compiling published records from 16 additional sites, we use the Ocean Data View (ODV) program (Schlitzer, 2012) to map deep-water mass distributions through time. Results reveal an increasing distribution and influence of the NADW in relation to the Antarctic Bottom Water mass within interglacial periods beginning at MIS 15 continuing though the end of the Site 1063 record within MIS 9. Preliminary grain size analyses over a short interval of time reveal regular high frequency variations on the millennial scale. We anticipate having complete, high-resolution stable isotope and grain size records to discuss the hydrographic changes within the MIS 16/15 glacial/interglacial transition, as well as throughout the Mid-Pleistocene transition (MPT).

  3. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water

    PubMed Central

    Frank, Alexander H.; Garcia, Juan A. L.; Herndl, Gerhard J.

    2016-01-01

    Summary To decipher the influence of depth stratification and surface provincialism on the dark ocean prokaryotic community composition, we sampled the major deep‐water masses in the eastern North Atlantic covering three biogeographic provinces. Their diversity was evaluated using ordination and canonical analysis of 454 pyrotag sequences. Variance partitioning suggested that 16% of the variation in the bacterial community composition was based on depth stratification while 9% of the variation was due to geographic location. General linear mixed effect models showed that the community of the subsurface waters was connected to the dark ocean prokaryotic communities in different biogeographic provinces. Cluster analysis indicated that some prokaryotic taxa are specific to distinct regions in bathypelagic water masses. Taken together, our data suggest that the dark ocean prokaryotic community composition of the eastern North Atlantic is primed by the formation and the horizontal transport of water masses. PMID:26914787

  4. North Pacific Acoustic Laboratory and Deep Water Acoustics

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. North Pacific Acoustic Laboratory and Deep Water...coherence of the received signal, while the ambient noise field is in direct competition with the received signal. Research conducted in the North Pacific ...The scientific objectives of the North Pacific Acoustic Laboratory and Deep Water Acoustics research are: 1. To study the spatial and temporal

  5. Deep-Water Waves: on the Nonlinear Schrödinger Equation and its Solutions

    NASA Astrophysics Data System (ADS)

    Vitanov, Nikolay K.; Chabchoub, Amin; Hoffmann, Norbert

    2013-06-01

    We present a brief discussion on the nonlinear Schrödinger equation for modelling the propagation of the deep-water wavetrains and a discussion on its doubly-localized breather solutions, that can be connected to the sudden formation of extreme waves, also known as rogue waves or freak waves.

  6. Primary Evaporites for the Messinian Salinity Crisis: the shallow gypsum vs. deep dolomite formation paradox solved

    NASA Astrophysics Data System (ADS)

    De Lange, Gert J.; Krijgsman, Wout

    2014-05-01

    The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, and resulted in the deposition of 0.3-3 km thick evaporites at the Mediterranean seafloor. A considerable and long-lasting controversy existed on the modes of their formation. During the CIESM Almeria Workshop a consensus was reached on several aspects. In addition, remaining issues to be solved were identified, such as for the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions. Gypsum precipitation only occurred at marginal settings, while dolomite containing rocks have been reported from deeper settings. A range of potential explanations have been reported, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are poorly understood and commonly neglected. These may, however, explain that different deposits formed in shallow versus deep environments without needing exceptional physical boundary conditions for each. We present here a unifying mechanism in which gypsum formation occurs at all shallow water depths but its preservation is mostly limited to shallow sedimentary settings. In contrast, ongoing anoxic organic matter (OM) degradation processes in the deep basin result in the formation of dolomite. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always largely oversaturated relative to dolomite but its formation is thought to be inhibited by the presence of dissolved sulphate. Thus the conditions for formation of gypsum exclude those for the formation of dolomite and vice versa. Another process that links the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, oxygen is rapidly depleted through OM degradation, then sulphate becomes the main oxidant for OM

  7. Experimental Investigation of CO2 Trapping and Leakage Mechanisms in Deep Geologic Formations for Model Improvement

    NASA Astrophysics Data System (ADS)

    Illangasekare, T. H.; Trevisan, L.; Agartan, E.; Vargas-Johnson, J.; Plampin, M. R.; Pini, R.; Pawar, R.; Cihan, A.; Birkholzer, J. T.; Zhou, Q.

    2014-12-01

    A fundamental and a comprehensive understanding of trapping and leakage processes will be of value to develop strategies for efficient and secure storage of CO2 in deep geologic formations and assess environmental and ecological risks associated with potential leakage. It is our contention that to make observations and collect data to obtain a fundamental understanding of how the natural formation heterogeneity manifested at all scales affects trapping is highly challenging or impossible to obtain in real field settings in deep geologic formations. A test scale intermediary between small laboratory columns and field scales that is referred to as "intermediate scale" provides an attractive alternative to investigate these processes under controlled conditions in the laboratory. Heterogeneities at all needed test scales can be designed using soils with known properties and experiments can be conducted under controlled conditions to obtain accurate data. Conducting intermediate scale laboratory experiments under ambient pressure and temperature conditions to understand the processes that occur in deep formations with very higher pressures and drastically different temperatures pose many challenges. This paper presents the approaches that were used to conduct multi-scale experiments from column to intermediate scale to understand the factors that contribute to capillary and dissolution trapping using surrogate fluids for supercritical CO2 and saline water combination. In addition, experiments were conducted in soil columns and two-dimensional tanks to study the effects of formation heterogeneity on CO2 gas evolution during leakage of water with dissolved CO2. The results from these experiments are presented to show how the new insights have helped to improve the conceptual understanding of effects of heterogeneity on CO2 trapping and leakage. This understanding has helped to improve numerical models that can be used to better engineer CO2 storage systems for permanence

  8. Analysis of deep-water exchange in the Caspian Sea based on environmental tracers

    NASA Astrophysics Data System (ADS)

    Peeters, F.; Kipfer, R.; Achermann, D.; Hofer, M.; Aeschbach-Hertig, W.; Beyerle, U.; Imboden, D. M.; Rozanski, K.; Fröhlich, K.

    2000-04-01

    In order to quantify deep-water exchange in the Caspian Sea, the world's largest inland water body, water samples were analyzed for the transient tracers H3, He3, He4, CFC-11, CFC-12 and atmospheric noble gases. Measurements of temperature, salinity (calculated from conductivity for the ionic composition of Caspian Sea water), and dissolved oxygen were employed to investigate the processes responsible for deep-water renewal. The Caspian Sea consists of two deep basins, the southern and central basins, separated by a sill, and a shallow northern basin. The deep water (below 200 m) accounts for almost 60% of the total water mass. Below 200 m the concentrations of H3 and He3 are much lower in the southern basin than at the same depths in the central basin, but this is not the case for either of the CFCs. However, apparent water ages calculated from H3-He3 and from CFC-12 concentrations are the same for the deep water of the southern and central basins, and yield deep-water exchange rates of approximately 7% per year for each of the two basins. This implies volume fluxes across the 200-m level of about 2220 km 3 yr -1 within the southern basin and 770 km 3 yr -1 within the central basin. Based on the apparent water ages, the oxygen depletion in the deep water is estimated to be about 0.35 mg l -1 yr -1. The processes responsible for deep-water exchange have not yet been identified conclusively. However, vertical temperature and salinity gradients observed during two expeditions, in September 1995 and 1996, suggest that within the southern and central basins large-scale convection cannot be triggered by seasonal cooling alone, but requires the surface water to be cold/saline or to contain high suspended sediment loads. In the central basin the increase in salinity occurring during ice formation in early winter is possibly sufficient to cause convection. In late summer, the horizontal transport of water from the upper 170 m of the central basin into the southern basin

  9. Archaeal Diversity in Waters from Deep South African Gold Mines

    SciTech Connect

    Takai, Ken; Moser, Duane P.; Deflaun, Mary; Onstott, Tullis C.; Fredrickson, Jim K.

    2001-12-01

    Culture-independent molecular analysis of archaeal communities in waters collected from deep South African gold (Au) mines was performed by PCR-mediated terminal restriction fragment length polymorphism (T-RFLP) analysis of rRNA genes (rDNA) in conjunction with sequencing analysis of archaeal rDNA clone libraries. Water samples represented various environments including: deep fissure water; mine service water; and water from an overlying dolomite aquifer. T-RFLP analysis revealed that the ribotype distribution of archaea varied directly with the source of the water. The archaeal communities in the deep Au mine environments revealed a large phylogenetic diversity; the majority of members were most closely related to uncultivated species. Some archaeal rDNA clones obtained from mine service water and dolomite aquifer water samples were most closely related to the environmental rDNA clones from surface soil (Soil clones) and marine environments (Marine Group I; MGI). Other clones possessed an intermediate phylogenetic affiliation between soil clones and MGI within the Crenarchaea. Fissure water samples, derived from active or dormant geothermal environments, yielded archaeal sequences of novel phylogeny including a novel lineage of Euryarchaeota. These results suggest that deep South African Au mines harbor novel archaeal communities distinct from those observed in other environments. Based on the phylogenetic analysis of archaeal strains and rDNA clones, including these newly discovered archaeal rDNA clones, the evolutionary relationship and the phylogenetic organization of the domain Archaea is reevaluated.

  10. Archaeal Diversity in Waters from Deep South African Gold Mines

    PubMed Central

    Takai, Ken; Moser, Duane P.; DeFlaun, Mary; Onstott, Tullis C.; Fredrickson, James K.

    2001-01-01

    A culture-independent molecular analysis of archaeal communities in waters collected from deep South African gold mines was performed by performing a PCR-mediated terminal restriction fragment length polymorphism (T-RFLP) analysis of rRNA genes (rDNA) in conjunction with a sequencing analysis of archaeal rDNA clone libraries. The water samples used represented various environments, including deep fissure water, mine service water, and water from an overlying dolomite aquifer. T-RFLP analysis revealed that the ribotype distribution of archaea varied with the source of water. The archaeal communities in the deep gold mine environments exhibited great phylogenetic diversity; the majority of the members were most closely related to uncultivated species. Some archaeal rDNA clones obtained from mine service water and dolomite aquifer water samples were most closely related to environmental rDNA clones from surface soil (soil clones) and marine environments (marine group I [MGI]). Other clones exhibited intermediate phylogenetic affiliation between soil clones and MGI in the Crenarchaeota. Fissure water samples, derived from active or dormant geothermal environments, yielded archaeal sequences that exhibited novel phylogeny, including a novel lineage of Euryarchaeota. These results suggest that deep South African gold mines harbor novel archaeal communities distinct from those observed in other environments. Based on the phylogenetic analysis of archaeal strains and rDNA clones, including the newly discovered archaeal rDNA clones, the evolutionary relationship and the phylogenetic organization of the domain Archaea are reevaluated. PMID:11722932

  11. The Circulation of Newly Formed Deep Water in the Atlantic

    NASA Astrophysics Data System (ADS)

    Rhein, M.; Kieke, D.; Steinfeldt, R.

    2012-04-01

    The circulation of newly formed deep water masses (Labrador Sea Water, LSW, and Denmark Strait Overflow Water, DSOW) is examined by discussing the distribution of two parameters (age τ and fraction F of young water) calculated from the chlorofluorocarbon data measured between 1980 and 2005 in the Atlantic. Compared to previous studies, a much larger data set was used with an improved gridding procedure, allowing to resolve the distributions in more detail.

  12. Cosmic Star-Formation History and Deep ALMA imaging of the Hubble Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Dunlop, James

    2015-08-01

    I will give an overview of how recent work at UV, optical, infrared, mm and radio wavelengths have impacted on our current understanding of the cosmic evolution of co-moving star-formation rate density. I will review recent progress at redshifts z ~ 2 - 3, corresponding to the putative peak of star-formation activity. However, I will focus primarily on new results at the very highest redshifts, within 1 Gyr of the Big Bang, where dramatic recent observational progress with Hubble, Spitzer, Vista, and spectrographs on 8-m telescopes has enabled us to chart the rise of the early galaxy population back to redshifts z ~ 10, and to deduce the basic physical properties of galaxies at these early times. We have also been able to estimate the contribution of young galaxies to the reionization of the Universe, and I will show that the inferred progress of reionization is now in excellent agreement with new measurements of the Thomson scattering optical depth from microwave background observations with Planck. I will conclude with a discussion of how new results from deep ALMA imaging have the potential to clarify and complete our understanding of cosmic star-formation history.

  13. Seismic evidence for water deep in Earth's upper mantle.

    PubMed

    van der Meijde, Mark; Marone, Federica; Giardini, Domenico; van der Lee, Suzan

    2003-06-06

    Water in the deep upper mantle can influence the properties of seismic discontinuities in the mantle transition zone. Observations of converted seismic waves provide evidence of a 20- to 35-kilometer-thick discontinuity near a depth of 410 kilometers, most likely explained by as much as 700 parts per million of water by weight.

  14. Radiocarbon age of waters in the deep Atlantic revisited

    SciTech Connect

    Broecker, W.S.; Virgilio, A. ); Peng, T.H. )

    1991-01-01

    The authors use a simple box model to evaluate the impact of temporal changes of the atmosphere's {sup 14}C/C on ventilation fluxes for the deep Atlantic calculated from radiocarbon measurements. The conclusion is that despite the fact that over the 300 year period from 1650 to 1950 the atmosphere's radiocarbon content declined at the same rate as radiocarbon decays, this temporal change has a relatively small impact (10-15%) on radiocarbon-based estimates of the ventilation rate of the deep Atlantic. The reason is that the radiocarbon content of the source waters for deep Atlantic are reasonably well buffered against changes in atmospheric {sup 14}C/C.

  15. Shelf-to-basin iron shuttling enhances vivianite formation in deep Baltic Sea sediments

    NASA Astrophysics Data System (ADS)

    Reed, Daniel C.; Gustafsson, Bo G.; Slomp, Caroline P.

    2016-01-01

    Coastal hypoxia is a growing and persistent problem largely attributable to enhanced terrestrial nutrient (i.e., nitrogen and phosphorus) loading. Recent studies suggest phosphorus removal through burial of iron (II) phosphates, putatively vivianite, plays an important role in nutrient cycling in the Baltic Sea - the world's largest anthropogenic dead zone - yet the dynamics of iron (II) phosphate formation are poorly constrained. To address this, a reactive-transport model was used to reconstruct the diagenetic and depositional history of sediments in the Fårö basin, a deep anoxic and sulphidic region of the Baltic Sea where iron (II) phosphates have been observed. Simulations demonstrate that transport of iron from shelf sediments to deep basins enhances vivianite formation while sulphide concentrations are low, but that pyrite forms preferentially over vivianite when sulphate reduction intensifies due to elevated organic loading. Episodic reoxygenation events, associated with major inflows of oxic waters, encourage the retention of iron oxyhydroxides and iron-bound phosphorus in sediments, increasing vivianite precipitation as a result. Results suggest that artificial reoxygenation of the Baltic Sea bottom waters could sequester up to 3% of the annual external phosphorus loads as iron (II) phosphates, but this is negligible when compared to potential internal phosphorus loads due to dissolution of iron oxyhydroxides when low oxygen conditions prevail. Thus, enhancing vivianite formation through artificial reoxygenation of deep waters is not a viable engineering solution to eutrophication in the Baltic Sea. Finally, simulations suggest that regions with limited sulphate reduction and hypoxic intervals, such as eutrophic estuaries, could act as important phosphorus sinks by sequestering vivianite. This could potentially alleviate eutrophication in shelf and slope environments.

  16. viral abundance distribution in deep waters of the Northern of South China Sea

    NASA Astrophysics Data System (ADS)

    He, Lei; Yin, Kedong

    2017-04-01

    Little is known about the vertical distribution and interaction of viruses and bacteria in the deep ocean water column. The vertical distribution of viral-like particles and bacterial abundance was investigated in the deep water column in the South China Sea during September 2005 along with salinity, temperature and dissolved oxygen. There were double maxima in the ratio of viral to bacterial abundance (VBR) in the water column: the subsurface maximum located at 50-100 m near the pycnocline layer, and the deep maximum at 800-1000 m. At the subsurface maximum of VBR, both viral and bacterial abundance were maximal in the water column, and at the deep maximum of VBR, both viral and bacterial abundance were low, but bacterial abundance was relatively lower than viral abundance. The subsurface VBR maximum coincided with the subsurface chlorophyll maximum while the deep VBR maximum coincided with the minimum in dissolved oxygen (2.91mg L-1). Therefore, we hypothesize that the two maxima were formed by different mechanisms. The subsurface VBR maximum was formed due to an increase in bacterial abundance resulting from the stimulation of abundant organic supply at the subsurface chlorophyll maximum, whereas the deep VBR maximum was formed due to a decrease in bacterial abundance caused by more limitation of organic matter at the oxygen minimum. The evidence suggests that viruses play an important role in controlling bacterial abundance in the deep water column due to the limitation of organic matter supply. In turn, this slows down the formation of the oxygen minimum in which oxygen may be otherwise lower. The mechanism has a great implication that viruses could control bacterial decomposition of organic matter, oxygen consumption and nutrient remineralization in the deep oceans.

  17. Seismological constraints on Earth's deep water cycle

    NASA Astrophysics Data System (ADS)

    van der Lee, Suzan; Wiens, Douglas A.

    Water can be present in the mantle in the form of hydrous melts, hydrous phases, or incorporated into the crystal structure of nominally anhydrous minerals of the major mantle mineralogy. The first two forms are likely in the uppermost mantle, where water solubility in major mantle minerals is low, whereas the latter form may be more important deeper in the upper mantle and transition zone. Seismological data contain unique and valuable information on the amount and distribution of water in the Earth's mantle. It is, however, challenging to extract this information because of limitations in the amount and density of available seismic data, multiple interpretations of similar observations, and limited quantification of the effects of water and other parameters on the seismic properties. While increased water content and elevated temperatures both lower seismic velocities, they have opposing effects on the depths of the discontinuities that bound the transition zone. And, while they both increase attenuation, they have opposing effects on the sharpness of these discontinuities. Independent geophysical observations, such a gravity, electrical conductivity, and surface heat flow, can further help to discriminate between temperature, water, and other compositional anomalies as the cause of observed seismic heterogeneity. Various types of observations have been combined to infer water content in the mantle, ranging from a few hundredths of weight percent to several weight percent. Altogether, the seismological literature suggests that the mantle is heterogeneously hydrated. However, with the limited studies available, there does not appear to be an obvious correlation between present tectonic environment and water content, though the literature shows a tendency to interpret inferred anomalously hydrous regions in the mid mantle as being related in one way or another to past subduction of oceanic lithosphere.

  18. Southern Ocean ventilation and bottom water formation driven by Weddell Sea polynyas

    NASA Astrophysics Data System (ADS)

    Rheinlaender, Jonathan; Nisancioglu, Kerim; Smedsrud, Lars Henrik

    2017-04-01

    A distinct feature of the last glacial period, are the abrupt temperature fluctuations in Greenland associated with Dansgaard-Oeschger events and a similar but opposite response in Antarctica. The prevailing hypothesis behind this inter-hemispheric coupling, points to changes in deep water formation as the main driver, thus highlighting the pivotal role of the high latitude oceans in global climate. Bottom water formation through open-ocean deep convection in an Antarctic polynya, a large open water area inside the winter sea ice cover, provide a potential mechanism to trigger such changes in ocean circulation. In this study, an ocean-sea ice only version of the Norwegian Earth System Model (NorESM) is explored and shows strong open-ocean deep convection associated with large polynyas in the Weddell Sea. This provides us with an opportunity to test (1) how internal ocean dynamics can trigger abrupt changes in sea-ice cover and (2) how these polynyas affect the overturning circulation through changes in bottom water formation. During the 1,000 year long free-running simulation two polynyas are observed. We show, that the polynya is caused by subsurface warming leading to a gradual weakening of the surface stratification which destabilizes the whole water column and eventually triggers deep convective overturning. This mixes up relatively warm deep water causing extensive melt of sea ice in the Weddell Sea, while cold and fresh surface water sinks to the bottom. Consequently, the polynya leads to extensive bottom water formation and increase in the northward flow of Antarctic Bottom Water, while the southward flow of North Atlantic Deep Water is reduced. Finally, our results suggest that a decrease in the temperature of warm deep water in the Weddell Sea leads to cessation of open-ocean deep convection. This raises the question if open-ocean deep convection associated with polynyas in the Southern Ocean could be a realistic feature in a cold, glacial climate.

  19. Deep challenges for China's war on water pollution.

    PubMed

    Han, Dongmei; Currell, Matthew J; Cao, Guoliang

    2016-11-01

    China's Central government has released an ambitious plan to tackle the nation's water pollution crisis. However, this is inhibited by a lack of data, particularly for groundwater. We compiled and analyzed water quality classification data from publicly available government sources, further revealing the scale and extent of the crisis. We also compiled nitrate data in shallow and deep groundwater from a range of literature sources, covering 52 of China's groundwater systems; the most comprehensive national-scale assessment yet. Nitrate pollution at levels exceeding the US EPA's maximum contaminant level (10 mg/L NO3N) occurs at the 90th percentile in 25 of 36 shallow aquifers and 10 out of 37 deep or karst aquifers. Isotopic compositions of groundwater nitrate (δ(15)N and δ(18)ONO3 values ranging from -14.9‰ to 35.5‰ and -8.1‰ to 51.0‰, respectively) indicate many nitrate sources including soil nitrogen, agricultural fertilizers, untreated wastewater and/or manure, and locally show evidence of de-nitrification. From these data, it is clear that contaminated groundwater is ubiquitous in deep aquifers as well as shallow groundwater (and surface water). Deep aquifers contain water recharged tens of thousands of years before present, long before widespread anthropogenic nitrate contamination. This groundwater has therefore likely been contaminated due to rapid bypass flow along wells or other conduits. Addressing the issue of well condition is urgently needed to stop further pollution of China's deep aquifers, which are some of China's most important drinking water sources. China's new 10-point Water Pollution Plan addresses previous shortcomings, however, control and remediation of deep groundwater pollution will take decades of sustained effort. Copyright © 2016. Published by Elsevier Ltd.

  20. Geology of Sarawak deep water and its surroundings

    SciTech Connect

    Ismail, M.I.; Mohamad, A.M.; Ganesan, M.S.; Aziz, S.A. )

    1994-07-01

    A geological and geophysical investigation based primarily on seismic data indicates that four tectonostratigraphic zonations are recognizable in the Sarawak deep water and its surroundings. Zone A is a 7-8-km-thick Tertiary sedimentary basin in Sarawak deep water characterized by north-south-trending buried hills, extensional fault-bounded features, and local occurrences of compressional structures, and is separated from the northwest Sabah platform (zone B) by a major north-south-trending basin margin fault. This margin fault is distinct from the northwest-southeast transform fault known as Baram-Tinjar Line. The northwest Sabah platform, an attenuated continental crust that underwent late Mesozoic-Tertiary crystal stretching and rifting, is characterized by northeast-southwest-tending rift systems and generally up to 4 km-thick sedimentary cover. The leading edge of the northwest Sabah platform that was subducted beneath the northwest Borneo crust is marked by the Sabah trough (zone C). The western Sarawak deep water is occupied by a 13-km-thick, north-south-trending basin, the west Luconia delta province (zone D), demonstrating post mid-Miocene deltaic growth faults and toe-thrusts. Crustal offsets of the South China Sea Basin, north-south-trending basin margin fault between zones A and B, and extensional and compressional structures in zone A are evidence for north-south-directed transform motions leading to the development of the Sarawak deep-water Tertiary basin. Four main sedimentation phases describe the sedimentation history in Sarawak deep water and its surroundings. Oligocene-Miocene coastal plain sediments form the main hydrocarbon plays in the Sarawak deep water, and the numerous occurrences of amplitude anomalies clearly suggest a working hydrocarbon charge system.

  1. Sense Things in the Big Deep Water Bring the Big Deep Water to Computers so People can understand the Deep Water all the Time without getting wet

    NASA Astrophysics Data System (ADS)

    Pelz, M.; Heesemann, M.; Scherwath, M.; Owens, D.; Hoeberechts, M.; Moran, K.

    2015-12-01

    Senses help us learn stuff about the world. We put sense things in, over, and under the water to help people understand water, ice, rocks, life and changes over time out there in the big water. Sense things are like our eyes and ears. We can use them to look up and down, right and left all of the time. We can also use them on top of or near the water to see wind and waves. As the water gets deep, we can use our sense things to see many a layer of different water that make up the big water. On the big water we watch ice grow and then go away again. We think our sense things will help us know if this is different from normal, because it could be bad for people soon if it is not normal. Our sense things let us hear big water animals talking low (but sometimes high). We can also see animals that live at the bottom of the big water and we take lots of pictures of them. Lots of the animals we see are soft and small or hard and small, but sometimes the really big ones are seen too. We also use our sense things on the bottom and sometimes feel the ground shaking. Sometimes, we get little pockets of bad smelling air going up, too. In other areas of the bottom, we feel hot hot water coming out of the rock making new rocks and we watch some animals even make houses and food out of the hot hot water that turns to rock as it cools. To take care of the sense things we use and control water cars and smaller water cars that can dive deep in the water away from the bigger water car. We like to put new things in the water and take things out of the water that need to be fixed at least once a year. Sense things are very cool because you can use the sense things with your computer too. We share everything for free on our computers, which your computer talks to and gets pictures and sounds for you. Sharing the facts from the sense things is the best part about having the sense things because we can get many new ideas about understanding the big water from anyone with a computer!

  2. Strong linkages between surface and deep-water dissolved organic matter in the East/Japan Sea

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hoon; Kim, Guebuem; Shen, Yuan; Benner, Ronald

    2017-05-01

    Vertical and horizontal distributions of total dissolved amino acids (TDAAs), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) were measured in the East/Japan Sea (EJS). The euphotic zone of this sea is N-limited, and the N : P ratio is ˜ 13 below 200 m depth. Elevated TDAA concentrations (137 ± 34 nM) and DOC-normalized yields (0.8 ± 0.2 % of DOC) were observed in deep waters ( ≥ 1000 m) of the EJS and compared with those in the deep North Pacific Ocean. Significantly high TDAA concentrations and yields were observed in a region of deep-water formation, indicating the convection of margin-derived bioavailable dissolved organic matter (DOM) to deep waters. Declining TDAA concentrations (36 ± 12 %) and yields (33 ± 13 %) were observed between 1000 and 3000 m throughout the EJS, indicating the utilization of bioavailable DOM in deep waters. Concentrations of the D-enantiomers of amino acids (Ala, Glx, Asx, and Ser) were relatively high in deep waters of the EJS, indicating substantial bacterial contributions to DOM from surface and upper mesopelagic waters. Climate warming during the past few decades in the EJS is weakening deep convection during the winter, and one consequence of this reduction in deep convection is a decline in the supply of bioavailable DOM from surface waters.

  3. Water Recycling, Lower Mantle Slab Subduction, and Viscous Layering of the Deep Mantle

    NASA Astrophysics Data System (ADS)

    Williams, Q.; McNamara, A.; Garnero, E.

    2005-12-01

    We explore the causes and possible consequences of a water/hydrogen-depleted layer in the lowermost ~1000 km of Earth`s mantle. At least three distinct, non-exclusive mechanisms exist that could generate such a layer: (1) descending melts could extract water from the deep mantle, and possibly sequester it within D``; (2) hydrogen could be stripped from deep mantle material during core formation, through formation of iron hydrides; and (3) the accreting planet could have nearly completely degassed, with the terrestrial water budget being accreted in a late hydrous veneer. In the latter two instances, the water budget of the mantle, and particularly the deep mantle, must entirely be generated by injection of water into the interior from the near surface. Our hypothesis is thus that the lower portion of Earth`s mantle might be (or have been) essentially dry, in contrast to the possible presence of 10's to 100's of ppm water in the overlying material. The principal geophysical effect of a water-depleted zone likely involves a marked increase in viscosity: for reference, such a decrease in water content produces about a 2-order of magnitude increase in the viscosity of upper mantle material. Fluid dynamic simulations show that a layer with a 2-order of magnitude viscosity increase in the bottom 1000 km of Earth`s mantle produces a substantial impediment to subduction, with subducted material laterally spreading out above this viscous layer. This behavior is compatible with tomographic images showing a lack of slab continuity into the deepest mantle, and the viscosity contrast thus produces a barrier to water ingress into the deep viscous layer, allowing it to remain anhydrous for extended time periods. Notably, the boundary between the viscous layer and overlying mantle and slab material undergoes substantial deflections, and because of the chemical similarity of the layers, should be seismically undetectable. Our results provide a straightforward mechanism through

  4. Cluster formation in rarefied water vapour plume

    NASA Astrophysics Data System (ADS)

    Bykov, Nikolay Y.; Gorbachev, Yuriy E.

    2017-07-01

    Mathematical model of water cluster formation has been developed and applied for the Direct Simulation Monte Carlo of water vapour expansion from the reservoir with constant stagnation parameters. The influence of flow rarefaction on plume parameters and on peculiarities of cluster formation process are analyzed. Comparison of simulation results with experimental data is performed.

  5. Deep-water anoxygenic photosythesis in a ferruginous chemocline.

    PubMed

    Crowe, S A; Maresca, J A; Jones, C; Sturm, A; Henny, C; Fowle, D A; Cox, R P; Delong, E F; Canfield, D E

    2014-07-01

    Ferruginous Lake Matano, Indonesia hosts one of the deepest anoxygenic photosynthetic communities on Earth. This community is dominated by low-light adapted, BChl e-synthesizing green sulfur bacteria (GSB), which comprise ~25% of the microbial community immediately below the oxic-anoxic boundary (OAB; 115-120 m in 2010). The size of this community is dependent on the mixing regime within the lake and the depth of the OAB-at ~117 m, the GSB live near their low-light limit. Slow growth and C-fixation rates suggest that the Lake Matano GSB can be supported by sulfide even though it only accumulates to scarcely detectable (low μm to nm) concentrations. A model laboratory strain (Chlorobaculum tepidum) is indeed able to access HS- for oxidation at nm concentrations. Furthermore, the GSB in Lake Matano possess a full complement of S-oxidizing genes. Together, this physiological and genetic information suggests that deep-water GSB can be supported by a S-cycle, even under ferruginous conditions. The constraints we place on the metabolic capacity and physiology of GSB have important geobiological implications. Biomarkers diagnostic of GSB would be a good proxy for anoxic conditions but could not discriminate between euxinic and ferruginous states, and though GSB biomarkers could indicate a substantial GSB community, such a community may exist with very little metabolic activity. The light requirements of GSB indicate that at light levels comparable to those in the OAB of Lake Matano or the Black Sea, GSB would have contributed little to global ocean primary production, nutrient cycling, and banded iron formation (BIF) deposition in the Precambrian. Before the proliferation of oxygenic photosynthesis, shallower OABs and lower light absorption in the ocean's surface waters would have permitted greater light availability to GSB, potentially leading to a greater role for GSB in global biogeochemical cycles.

  6. An effect of CO2 leakage from deep geological formations on the quality of shallow aquifers

    NASA Astrophysics Data System (ADS)

    Wang, Sookyun; Nam, Ji Eun

    2013-04-01

    Injection of CO2 into deep geological formations is a promising technique for Sequestration of large amount of CO2. If some fraction of the stored CO2 were to leak and reach shallow groundwater aquifers, however, it would lead to geochemical alteration that could have detrimental effects on the water quality. A series of experiments were performed on dissolution kinetics of a trace metal, galena, to evaluate the change in groundwater pH and the enhanced dissolution as carbon dioxide introduces into the aquifer. The conventional rate law was applied to obtain reaction parameters on dissolution kinetics for further modeling studies. The results from batch experiments and kinetic analysis were applied to develop a 1D mathematical model to simulate the fate and transport of dissolved trace metals in shallow aquifers. Results show that CO2 dissolution in groundwater aquifers can solubilize trace metals to levels that exceed drinking water standards. This approach allows for a reasonable assessment of the risks on tha quality of freshwater aquifers due to the escape of CO2 from deep geological formations.

  7. Carbon isotope evidence for a northern source of deep water in the glacial western North Atlantic

    NASA Astrophysics Data System (ADS)

    Keigwin, Lloyd D.; Swift, Stephen A.

    2017-03-01

    The prevailing view of western Atlantic hydrography during the Last Glacial Maximum (LGM) calls for transport and intermixing of deep southern and intermediate northern end members. However, δ13C and Δ14C results on foraminifera from a sediment core at 5.0 km in the northern subtropics show that there may have also been a northern source of relatively young, very dense, nutrient-depleted water during the LGM (18 ky to 21 ky ago). These results, when integrated with data from other western North Atlantic locations, indicate that the ocean was poorly ventilated at 4.2 km, with better ventilation above and below that depth. If this is a signal of water mass source and not nutrient storage, it would indicate that a previously unrecognized deep water end member originated along the western margin of the Labrador Sea, analogous to dense water formation today around Antarctica and in the Okhotsk Sea.

  8. Microfabric analysis of Mn-carbonate laminae deposition and Mn-sulfide formation in the Gotland Deep, Baltic Sea

    NASA Astrophysics Data System (ADS)

    Burke, Ian T.; Kemp, Alan E. S.

    2002-05-01

    The manganese carbonate deposits of the anoxic Littorina sediments of the Gotland Deep have been commonly related to the periodic renewal of deep water by inflowing saline water from the North Sea. The use of scanning electron microscopy-based techniques allows identification of small-scale sedimentary and geochemical features associated with Mn-carbonate laminae, which has significant implications for models of Mn-carbonate formation. Varves occurring in the Littorina sequence contain up to four laminae that may be placed in a seasonal cycle, and kutnahorite laminae occur within varves only as a winter-early spring deposit. This kutnahorite laminae seasonality is in agreement with the seasonal distribution of major Baltic inflow events recorded in historical records, and a direct causal link between inflows and kutnahorite deposition is implied. Benthic foraminifera tests are found to be heavily encrusted in kutnahorite, implying that benthic recolonization during oxidation events occurs concurrently with kutnahorite formation. The relatively common occurrence of small (50 to 100 μm) hexagonal γ-Mn-sulfide pseudomorphs, associated with 13% of kutnahorite laminae studied, is reported in Gotland Deep sediments for the first time. Although Mn-sulfide crystals are not usually preserved in the sediment, the discovery of Mn-sulfide pseudomorphs suggests that initial formation of Mn-sulfide in the Gotland Deep may occur much more commonly during the process of kutnahorite formation than previous reports of Mn-sulfide occurrence have implied.

  9. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-01-22

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  10. Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-10-31

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  11. Dense water plumes modulate richness and productivity of deep sea microbes.

    PubMed

    Luna, Gian Marco; Chiggiato, Jacopo; Quero, Grazia Marina; Schroeder, Katrin; Bongiorni, Lucia; Kalenitchenko, Dimitri; Galand, Pierre E

    2016-12-01

    Growing evidence indicates that dense water formation and flow over the continental shelf is a globally relevant oceanographic process, potentially affecting microbial assemblages down to the deep ocean. However, the extent and consequences of this influence have yet to be investigated. Here it is shown that dense water propagation to the deep ocean increases the abundance of prokaryotic plankton, and stimulates carbon production and organic matter degradation rates. Dense waters spilling off the shelf modifies community composition of deep sea microbial assemblages, leading to the increased relevance of taxa likely originating from the sea surface and the seafloor. This phenomenon can be explained by a combination of factors that interplay during the dense waters propagation, such as the transport of surface microbes to the ocean floor (delivering in our site 0.1 megatons of C), the stimulation of microbial metabolism due to increased ventilation and nutrients availability, the sediment re-suspension, and the mixing with ambient waters along the path. Thus, these results highlight a hitherto unidentified role for dense currents flowing over continental shelves in influencing deep sea microbes. In light of climate projections, this process will affect significantly the microbial functioning and biogeochemical cycling of large sectors of the ocean interior.

  12. Formation of Denmark strait overflow water by mixing in the East Greenland Current

    SciTech Connect

    Strass, V.H.; Fahrbach, E.; Schauer, U.; Sellmann, L. )

    1993-04-15

    The Greenland, Iceland, and Norwegian seas are major sources of water feeding the North Atlantic Deep Water in the worlds present ocean circulation. The authors report on data collected in 1987 through 1989 which indicate that a mass of water with characteristics of the Denmark Strait Overflow Water (DSOW) is formed in the East Greenland Current. The DSOW has been observed to have a residence time of 3 to 4 years at the surface before spilling southward. This provides a very fast transfer of surface water with atmospheric signatures into the deep ocean. They offer explanations for the formation of this water mass.

  13. Deep drainage and water use of forests and pastures grown on deep sands in a Mediterranean environment

    NASA Astrophysics Data System (ADS)

    Carbon, B. A.; Roberts, F. J.; Farrington, P.; Beresford, J. D.

    1982-02-01

    The neutron scattering technique was used to measure soil-moisture storage beneath native hardwood forests, plantations of softwood forests, perennial pastures and winter annual pastures growing in deep sands of the southwest of Western Australia. The seasonal patterns of water use and of deep drainage to groundwater were calculated using measured soil-moisture characteristics. Fourteen-year-old Pinus pinaster (Ait.) plantations, containing ˜1200 trees per hectare, transpired more water than the native forest they replaced. The pines depleted the soil water faster, and to a greater degree. Deep drainage beyond 6 m was much less in the soil below the pine plantations, indicating a decrease in recharge of shallow groundwaters. The perennial pastures showed a pattern of water use, soil-water depletion and deep drainage similar to the native forests. The winter annual pastures, however, used less water than the native forest, and deep drainage was increased.

  14. Contributions of the Siberian shelf polynyas to the Arctic Ocean intermediate and deep water

    NASA Technical Reports Server (NTRS)

    Martin, Seelye; Cavalieri, Donald J.

    1989-01-01

    To investigate the role of Siberian Shelf polynyas in water mass formation, and that of Whalers Bay in the cooling of the West Spitsbergen Current, satellite observations from the Nimbus 7 scanning multichannel microwave radiometer are used to determine the size and location of polynyas for November-March, 1978-1982. If salt contributes only to the Arctic Intermediate Water, the results show that the continental shelves can produce 20-60 percent of this water. Alternatively, if the salt contributes only to the deep water of the Eurasian Basin, then without consideration of the mixing of the bottom water with the Greenland and Norwegian Sea water, the contribution from the shelves yields a renewal time of about 100 years. These results imply that there is insufficient water produced in the shelf polynyas to perform all of the roles that have historically been assigned to it.

  15. Deep oxygenated ground water: Anomaly or common occurrence?

    USGS Publications Warehouse

    Winograd, I.J.; Robertson, F.N.

    1982-01-01

    Contrary to the prevailing notion that oxygen-depleting reactions in the soil zone and in the aquifer rapidly reduce the dissolved oxygen content of recharge water to detection limits, 2 to 8 milligrams per liter of dissolved oxygen is present in water from a variety of deep (100 to 1000 meters) aquifers in Nevada, Arizona, and the hot springs of the folded Appalachians and Arkansas. Most of the waters sampled are several thousand to more than 10,000 years old, and some are 80 kilometers from their point of recharge. Copyright ?? 1982 AAAS.

  16. Deep-ocean field test of methane hydrate formation from a remotely operated vehicle

    USGS Publications Warehouse

    Brewer, P.G.; Orr, F.M.; Friederich, G.; Kvenvolden, K.A.; Orange, D.L.; McFarlane, J.; Kirkwood, W.

    1997-01-01

    We have observed the process of formation of clathrate hydrates of methane in experiments conducted on the remotely operated vehicle (ROY) Ventana in the deep waters of Monterey Bay. A tank of methane gas, acrylic tubes containing seawater, and seawater plus various types of sediment were carried down on Ventana to a depth of 910 m where methane gas was injected at the base of the acrylic tubes by bubble stream. Prior calculations had shown that the local hydrographic conditions gave an upper limit of 525 m for the P-T boundary defining methane hydrate formation or dissociation at this site, and thus our experiment took place well within the stability range for this reaction to occur. Hydrate formation in free sea-water occurred within minutes as a buoyant mass of translucent hydrate formed at the gas-water interface. In a coarse sand matrix the Filling of the pore spaces with hydrate turned the sand column into a solidified block, which gas pressure soon lifted and ruptured. In a fine-grained black mud the gas flow carved out flow channels, the walls of which became coated and then filled with hydrate in larger discrete masses. Our experiment shows that hydrate formation is rapid in natural seawater, that sediment type strongly influences the patterns of hydrate formation, and that the use of ROV technologies permits the synthesis of large amounts of hydrate material in natural systems under a variety of conditions so that fundamental research on the stability and growth of these substances is possible.

  17. Temporal coherence of sound transmissions in deep water revisited.

    PubMed

    Yang, T C

    2008-07-01

    This paper examines the signal coherence loss due to internal waves in deep water in terms of the signal coherence time and compare to data reported in the literature over the past 35 years. The coherence time of the early raylike arrivals was previously modeled by Munk and Zachariasen ["Sound propagation through a fluctuating stratified ocean: Theory and observation," J. Acoust. Soc. Am. 59, 818-838 (1976)] using the supereikonal approximation and by Dashen et al. ["Path-integral treatment of acoustic mutual coherence functions for arrays in a sound channel," J. Acoust. Soc. Am. 77, 1716-1722 (1985)] using the path integral approach; a -1 [corrected] power frequency dependence and a -1/2 [corrected] power range dependence were predicted. Recent data in shallow water in downward refractive environments with internal waves suggested that the signal coherence time of the mode arrivals follows a -3/2 power frequency dependence and a -1/2 power range dependence. Since the temporal coherence of the acoustic signal is related to the temporal coherence of the internal waves, based on the observation that the (linear) internal waves in deep and shallow waters have a similar frequency spectrum, it is argued that the modelike arrivals in deep water should exhibit a similar frequency dependence in deep and shallow waters. This argument is supported by a brute-force application of the path integral to mode arrivals based on the WKB relation between the ray and mode. It is found that the data are consistent with the -3/2 power frequency dependence but more data are needed to further test the hypothesis.

  18. Deep ocean mineral water accelerates recovery from physical fatigue

    PubMed Central

    2013-01-01

    Background Deep oceans have been suggested as a possible site where the origin of life occurred. Along with this theoretical lineage, experiments using components from deep ocean water to recreate life is underway. Here, we propose that if terrestrial organisms indeed evolved from deep oceans, supply of deep ocean mineral water (DOM) to humans, as a land creature, may replenish loss of molecular complexity associated with evolutionary sea-to-land migration. Methods We conducted a randomized, double-blind, placebo-controlled crossover human study to evaluate the effect of DOM, taken from a depth of 662 meters off the coast of Hualien, Taiwan, on time of recovery from a fatiguing exercise conducted at 30°C. Results The fatiguing exercise protocol caused a protracted reduction in aerobic power (reduced VO2max) for 48 h. However, DOM supplementation resulted in complete recovery of aerobic power within 4 h (P < 0.05). Muscle power was also elevated above placebo levels within 24 h of recovery (P < 0.05). Increased circulating creatine kinase (CK) and myoglobin, indicatives of exercise-induced muscle damage, were completely eliminated by DOM (P < 0.05) in parallel with attenuated oxidative damage (P < 0.05). Conclusion Our results provide compelling evidence that DOM contains soluble elements, which can increase human recovery following an exhaustive physical challenge. PMID:23402436

  19. Deep ocean mineral water accelerates recovery from physical fatigue.

    PubMed

    Hou, Chien-Wen; Tsai, Yung-Shen; Jean, Wei-Horng; Chen, Chung-Yu; Ivy, John L; Huang, Chih-Yang; Kuo, Chia-Hua

    2013-02-12

    Deep oceans have been suggested as a possible site where the origin of life occurred. Along with this theoretical lineage, experiments using components from deep ocean water to recreate life is underway. Here, we propose that if terrestrial organisms indeed evolved from deep oceans, supply of deep ocean mineral water (DOM) to humans, as a land creature, may replenish loss of molecular complexity associated with evolutionary sea-to-land migration. We conducted a randomized, double-blind, placebo-controlled crossover human study to evaluate the effect of DOM, taken from a depth of 662 meters off the coast of Hualien, Taiwan, on time of recovery from a fatiguing exercise conducted at 30°C. The fatiguing exercise protocol caused a protracted reduction in aerobic power (reduced VO2max) for 48 h. However, DOM supplementation resulted in complete recovery of aerobic power within 4 h (P < 0.05). Muscle power was also elevated above placebo levels within 24 h of recovery (P < 0.05). Increased circulating creatine kinase (CK) and myoglobin, indicatives of exercise-induced muscle damage, were completely eliminated by DOM (P < 0.05) in parallel with attenuated oxidative damage (P < 0.05). Our results provide compelling evidence that DOM contains soluble elements, which can increase human recovery following an exhaustive physical challenge.

  20. Biofilm formation in a hot water system.

    PubMed

    Bagh, L K; Albrechtsen, H J; Arvin, E; Ovesen, K

    2002-01-01

    The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d(-1) to 2.3 d(-1)) than in the hot water tank (1.4 d(-1) to 2.2 d(-1)) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.

  1. Modulational instabilities of periodic traveling waves in deep water

    NASA Astrophysics Data System (ADS)

    Akers, Benjamin F.

    2015-04-01

    The spectrum of periodic traveling waves in deep water is discussed. A multi-scale method is used, expanding the spectral data and the Bloch parameter in wave amplitude, to compute the size and location of modulated instabilities. The role of these instabilities in limiting the spectrum's analyticity is explained. Both two-dimensional and three-dimensional instabilities are calculated. The asymptotic predictions are compared to numerical simulations.

  2. Ocean Ambient Noise Studies for Shallow and Deep Water Environments

    DTIC Science & Technology

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Ocean Ambient Noise Studies for Shallow and Deep Water...Siderius.php LONG-TERM GOALS The objective of this research is to study the ocean ambient noise field by means of new physics-based processing... ambient -noise field using a vertical line array has been developed by Harrison and Simons [Harrison, 2002]. The advantages of passive bottom-survey

  3. Do the stability indices indicate the formation of deep convection?

    NASA Astrophysics Data System (ADS)

    Uma, K. N.; Das, S. K.

    2017-09-01

    The present study investigates the relation between the stability indices and different types of precipitating clouds during the active and the suppressed periods of deep convection of the Madden-Julian oscillation. This is achieved by utilizing three-hourly radiosonde (RS92) data and merged cloud radar data over the Gan Island (0.69°S, 73.15°E) from October 2011 to January, 2012. The active and the suppressed periods are defined based on the rainfall. Three periods of active (15-27 October, 15-28 November and 15-27 December) and suppressed periods (01-14 November, 0-14 December and 01-14 January) are identified. During the above periods, the stability indices are calculated to distinguish the background meteorological conditions. The analysis shows that during both the active and the suppressed periods, the magnitude of the stability indices are not much different. During both the periods, the indices attain their respective threshold corresponding to the occurrence of deep convection. However, the third suppressed period shows a dry condition compared to the other two suppressed periods. The relation between the stability indices and the precipitating cloud categories (shallow, congestus and deep) indicate that even though the threshold in the stability indices were attained, deep convective clouds were not observed during the suppressed periods. The active period correlates well with the stability indices. Therefore, the stability indices do not clearly and directly determine the state of the atmosphere during deep convection. The result shows stability indices need to be substantially improved in the context of deep convection prediction.

  4. Halonitromethane formation potentials in drinking waters.

    PubMed

    Hu, Jia; Song, Hocheol; Addison, Jesse W; Karanfil, Tanju

    2010-01-01

    Halonitromethanes (HNMs) are highly cyto- and genotoxic nitrogenous disinfection by-products (DBPs) that have been detected in some water distribution systems. In this study, a systematic investigation was conducted to examine the formation potential of HNMs in drinking waters under different oxidation conditions. Formation potential tests of samples obtained from various drinking water sources showed that ozonation-chlorination produced the highest HNM yields followed by in the order of chlorination, ozonation-chloramination, and chloramination. Similar or higher HNM yields were observed in the treated waters (i.e., after conventional water treatment) than in the raw waters, indicating that hydrophilic natural organic matter (NOM) components that are not effectively removed by conventional treatment processes are likely the main precursors of HNMs. This was further confirmed by examining HNM formation potentials of NOM fractions obtained with resin fractionation. Hydrophilic NOM fractions (HPI) showed significantly higher HNM yields than hydrophobic (HPO) and transphilic (TPH) fractions. The correlation analysis of HNM formation potentials during ozonation-chlorination with various water quality parameters showed the best correlation between the HNM yields and the ratio of dissolved organic carbon to dissolved organic nitrogen concentrations in the water samples tested.

  5. The hydrography of the mid-latitude northeast Atlantic Ocean. I: The deep water masses

    NASA Astrophysics Data System (ADS)

    van Aken, Hendrik M.

    2000-05-01

    The circulation of the deep water masses in the mid-latitude northeast Atlantic Ocean was studied by analysis of the distributions of potential temperature, salinity, dissolved oxygen, phosphate, nitrate, and silicate. Pre-formed nutrients were used to allow a quantitative description of the deep water masses, especially the Northeast Atlantic Deep Water, in terms of four local source water types: Iceland-Scotland Overflow Water, Lower Deep Water, Labrador Sea Water, and Mediterranean Sea Water. Over the Porcupine Abyssal Plain between 2500 and 2900 dbar Northeast Atlantic Deep Water appears to be a mixture of mainly Iceland-Scotland Overflow Water and Labrador Sea Water (˜80%), with minor contributions of Lower Deep Water and Mediterranean Sea Water. When the Northeast Atlantic Deep Water re-circulates in the north-eastern Atlantic and flows southwards towards the Madeira Abyssal Plain, contributions of the former two water types of northern origin diminish to about 50% due to diapycnal mixing with the overlying and underlying water masses. The observed meridional and zonal trends of dissolved oxygen and nutrients in the Northeast Atlantic Deep Water appear to be caused both by diapycnal mixing with the underlying Lower Deep Water and by mineralization of organic matter. The eastward decrease of oxygen and increase of nutrients especially require considerable mineralization of organic matter near the European continental margin. At deeper levels (˜4100 dbar), where the nutrient rich Lower Deep Water is found near the bottom, the meridional gradients of oxygen and nutrients are opposite to those found between 2500 and 2900 dbar. Diapycnal mixing cannot explain this change in gradients, which is therefore considered to be a qualitative indication of ageing of the Lower Deep Water when it flows northwards. A considerable part of the Iceland-Scotland Overflow Water and the Lower Deep Water that enter the northeast Atlantic may be removed by deep upwelling in the Bay

  6. The formation of deep basins in High Arctic from metamorphism in continental crust

    NASA Astrophysics Data System (ADS)

    Artyushkov, Eugene; Belyaev, Igor; Chekhovich, Peter; Petrov, Eugene; Poselov, Viktor

    2014-05-01

    In the East Barents and North Chukchi basins, 16-20 km deep, the crystalline crust is attenuated to 12-18 km (reference profiles 2-AR, 4-AR and 5-AR). P-wave velocities and densities in this layer are characteristic of the oceanic crust. However, the subsidence history in the basins is quite different from that typical of the oceanic crust. In both basins the subsidence continued for several hundred million years and one half of the deposits or more was formed long after the start of the subsidence when cooling of the oceanic plate would be already over. Moreover, the basins are 4-5 km deeper than it could be expected according to the thickness of the crystalline crust above the Moho boundary. In the absence of large free-air gravity anomalies, joint analysis of the gravity and seismic data indicates the existence under the Moho of thick layers of high-density and high-velocity eclogites. As can be seen in high resolution seismic profiles, the intensity of crustal stretching did not exceed 10% in the basins, and their formation can be predominantly attributed to a high-grade metamorphism in the mafic lower part of continental crust. At some episodes, strong increase in the rate of subsidence occurred in the basins. This indicates acceleration of metamorphism catalyzed by infiltration of mantle fluids. A set of the above features, abnormally large depth, long subsidence history with its acceleration at the late stages, and episodes of pronounced acceleration of the subsidence represent characteristic features of some other large hydrocarbon basins, e.g., of the North and South Caspian basins. These features can be used for prospecting new prolific provinces on the Arctic shelf. The Lomonosov ridge, Mendeleev high and the Makarov basin pertain to the same structural type. In the Oligocene they underwent erosion near to sea level with the formation of pronounced unconformity. Then at the end of Oligocene deep-water basins were formed in these regions. Rapid crustal

  7. Maximal physiological responses to deep water running at thermoneutral temperature.

    PubMed

    Nakanishi, Y; Kimura, T; Yokoo, Y

    1999-03-01

    This study investigated the metabolic demands of deep water running (DWR) compared with those of treadmill running (TMR) while the water and ambient temperatures were kept under thermoneutral condition. Two maximal tests, one on treadmill and the other running in deep water using the Wet Vest (Lincoln life jacket) were undertaken by twenty healthy non-smoker males (Age = 28.0 +/- 9.2 years). The order of trials was counterbalanced with half of the subjects completing the treadmill first and the rest completing the water running first. Oxygen consumption (VO2), ventilation, heart rate (HR), respiratory exchange ratio (RQ), ratings of perceived exertion (RPE) and blood lactate were measured. VO2max (2.68 vs 3.40 ml/kg/min), HRmax (171.5 vs 190.8 beats/min), maximal minute ventilation (98.5 vs 113.31/min), and peak blood lactate value (10.44 vs 12.47 mmol/l) in response to DWR were significantly lower than those of TMR in the thermoneutral conditions. The lower VO2max and HRmax values of DWR compared to those of TMR are shown to be attributed to the hydrostatic effects caused by water and different muscle recruitment patterns between DWR and TMR.

  8. Exploring deep potential aquifer in water scarce crystalline rocks

    NASA Astrophysics Data System (ADS)

    Chandra, Subash; Nagaiah, E.; Reddy, D. V.; Rao, V. Ananda; Ahmed, Shakeel

    2012-12-01

    Characterization of the shear zone with pole-pole electrical resistivity tomography (ERT) was carried out to explore deep groundwater potential zone in a water scarce granitic area. As existing field conditions does not always allow to plant the remote electrodes at sufficiently far of distance, the effect of insufficient distance of remote electrodes on apparent resistivity measurement was studied and shown that the transverse pole-pole array affects less compared to the collinear pole-pole array. Correction factor have been computed for transverse pole-pole array for various positions of the remote electrodes. The above results helped in exploring deep aquifer site, where a 270 m deep well was drilled. Temporal hydro-chemical samples collected during the pumping indicated the hydraulic connectivity between the demarcated groundwater potential fractures. Incorporating all the information derived from different investigations, a subsurface model was synthetically simulated and generated 2D electrical resistivity response for different arrays and compared with the field responses to further validate the geoelectrical response of deep aquifer set-up associated with lineament.

  9. Is Centrophorus squamosus a highly migratory deep-water shark?

    NASA Astrophysics Data System (ADS)

    Rodríguez-Cabello, Cristina; Sánchez, Francisco

    2014-10-01

    Deep-water sharks are considered highly vulnerable species due to their life characteristics and very low recovery capacity against overfishing. However, there is still limited information on the ecology or population connectivity of these species. The aim of this study was to investigate if the species Centrophorus squamosus could make long displacements and thus confirm the existence of connectivity between different deep-water areas. In addition, the study was the first attempt to use tagging techniques on deep-water sharks, since it has never been undertaken before. Five C. squamosus were tagged with satellite tags (PAT) in the El Cachucho Marine Protected Area (Le Danois Bank) located in waters of the North of Spain, Cantabrian Sea (NE Atlantic). Data from four of these tags were recovered. One of the sharks travelled approximately 287 nm toward the north east (French continental shelf) hypothetically following the continental slope at a mean depth of 901±109 m for 45 days. Two other sharks spent almost 4 months traveling, in which time they moved 143 and 168 nm, respectively, to the west (Galician coast). Finally, another leafscale gulper shark travelled to the NW (Porcupine Bank) during a period of 3 months at a mean depth of 940±132 m. Depth and temperature preferences for all the sharks are discussed. Minimum and maximum depths recorded were 496 and 1848 m, respectively. The temperature range was between 6.2 and 11.4 °C, but the mean temperature was approximately 9.9±0.7 °C. The sharks made large vertical displacements throughout the water column with a mean daily depth range of 345±27 m. These preliminary results support the suggestion of a whole population in the NE Atlantic and confirm the capacity of this species to travel long distances.

  10. Hydrologic hydrochemical characterization of texas frio formation used for deep-well injection of chemical wastes

    NASA Astrophysics Data System (ADS)

    Kreitler, Charles W.; Akhter, M. Saleem; Donnelly, Andrew C. A.

    1990-09-01

    Hydrologic hydrochemical investigations were conducted to determine the long-term fate of hazardous chemical waste disposed in the Texas Gulf Coast Tertiary formations by deep-well injection. The study focused on the hydrostatic section of the Frio Formation because it is the host of a very large volume of injected waste and because large data bases of formation pressures and water chemistry are available. Three hydrologic regimes exist within the Frio Formation: a shallow fresh to moderately saline water section in the upper 3,000 4,000 ft (914 1,219 m); an underlying 4,000- to 5,000-ft-thick (1,219- to 1,524-m) section with moderate to high salinities: and a deeper overpressured section with moderate to high salinities. The upper two sections are normally pressured and reflect either freshwater or brine hydrostatic pressure gradients. Geopressured conditions are encountered as shallow as 6,000 ft (1,829 m). The complexity of the hydrologic environment is enhanced due to extensive depressurization in the 4,000- to 8,000-ft-depth (1,219- to 2,438-m) interval, which presumably results from the estimated production of over 10 billion barrels (208 × 106 m3) of oil equivalent and associated brines from the Frio in the past 50 yr. Because of the higher fluid density and general depressurization in the brine hydrostatic section, upward migration of these brines to shallow fresh groundwaters should not occur. Depressured oil and gas fields, however, may become sinks for the injected chemical wastes. Water samples appear to be in approximate oxygen isotopic equilibrium with the rock matrix, suggesting that active recharge of the Frio by continental waters is not occurring. In the northern Texas Gulf Coast region salt dome dissolution is a prime process controlling water chemistry. In the central and southern Frio Formation, brines from the deeper geopressured section may be leaking into the hydrostatic section. The lack of organic acids and the alteration of Frio oils

  11. Chronobiology of deep-water decapod crustaceans on continental margins.

    PubMed

    Aguzzi, Jacopo; Company, Joan B

    2010-01-01

    Species have evolved biological rhythms in behaviour and physiology with a 24-h periodicity in order to increase their fitness, anticipating the onset of unfavourable habitat conditions. In marine organisms inhabiting deep-water continental margins (i.e. the submerged outer edges of continents), day-night activity rhythms are often referred to in three ways: vertical water column migrations (i.e. pelagic), horizontal displacements within benthic boundary layer of the continental margin, along bathymetric gradients (i.e. nektobenthic), and endobenthic movements (i.e. rhythmic emergence from the substrate). Many studies have been conducted on crustacean decapods that migrate vertically in the water column, but much less information is available for other endobenthic and nektobenthic species. Also, the types of displacement and major life habits of most marine species are still largely unknown, especially in deep-water continental margins, where steep clines in habitat factors (i.e. light intensity and its spectral quality, sediment characteristics, and hydrography) take place. This is the result of technical difficulties in performing temporally scheduled sampling and laboratory testing on living specimens. According to this scenario, there are several major issues that still need extensive research in deep-water crustacean decapods. First, the regulation of their behaviour and physiology by a biological clock is almost unknown compared to data for coastal species that are easily accessible to direct observation and sampling. Second, biological rhythms may change at different life stages (i.e. size-related variations) or at different moments of the reproductive cycle (e.g. at egg-bearing) based on different intra- and interspecific interactions. Third, there is still a major lack of knowledge on the links that exist among the observed bathymetric distributions of species and selected autoecological traits that are controlled by their biological clock, such as the

  12. The structure and circulation of intermediate, deep and bottom water masses of the North Atlantic

    NASA Astrophysics Data System (ADS)

    Khmelnitskaya, Olga

    2014-05-01

    Water mass is one of the basic concepts of oceanography. Changing the characteristics of the main water masses in the North Atlantic can be causes of climate variability. The purpose of the present study is a quantitative assessment of the characteristics of water masses using the Optimum multiparameter (OMP) analysis. OMP analysis of water masses is a continuation of the thermohaline analysis. To study water mass mixing besides temperature and salinity such advanced features as concentration of nutrients, CFCs, isotopes, Redfield ratios and potential vorticity are used. Mathematically the OMP analysis is a system of linear equations for each point of the observations. Using four parameters of the water masses one can find the ratio of five water masses in the volume of water being under investigation. To study the structure of the North Atlantic Ocean we were identified eight major water masses: 1) ABW - Antarctic Bottom Water; 2) DSOW - Denmark Strait Overflow Water; 3) ISOW - Iceland-Scotland Overflow Water; 4) LSW - Labrador Sea Water; 5) MW - Mediterranean Water; 6) AIW - Antarctic Intermediate Water; 7) SPMW - Subpolar Mode Water; 8) STMW - Subtropical Mode Water. Percentage of each water mass was calculated for each section. Upon solving equation systems a data array was performed using the algorithm written in Fortran. The calculations were performed for 12 oceanographic sections made in the North Atlantic (24-64°N) in 1980-2004. We investigated the water masses located deeper than 500 m where there are practically no seasonal changes. On analysis of the water mass percentage in the vertical water sections pathways of intermediate and deep waters can be traced. Comparison of the percentage in the different sections gives an indication of the variability in the intermediate and deep circulation. We calculated the volume of each water mass in the North Atlantic Ocean (24-64°N, 0-77°W) below 500 meters on the basis of data on the percentage of water masses

  13. Deep-water fisheries at the Atlantic Frontier

    NASA Astrophysics Data System (ADS)

    Gordon, J. D. M.

    2001-05-01

    The deep sea is often thought of as a cold, dark and uniform environment with a low-fish biomass, much of which is highly adapted for life in a food-poor environment. While this might be true of the pelagic fish living in the water column, it is certainly not true of the demersal fish which live on or close to the bottom on the continental slopes around the British Isles (the Atlantic Frontier). These fish are currently being commercially exploited. There is growing evidence to support the view that success of the demersal fish assemblages depends on the pelagic or benthopelagic food sources that impinge both vertically and horizontally onto the slope. There are several quite separate and distinct deep-water fisheries on the Atlantic Frontier. It is a physical barrier, the Wyville-Thomson Ridge, which results in the most significant division of the fisheries. The Ridge, which has a minimum depth of about 500 m, separates the warmer deep Atlantic waters from the much colder Norwegian Sea water and as a result, the deep-water fisheries to the west of the Hebrides and around the offshore banks are quite different from those of the Faroe-Shetland Channel (West of Shetland). The fisheries to the West of the Hebrides can be further divided by the fishing method used into bottom trawl, semipelagic trawl and longline. The bottom-trawl fisheries extend from the shelf-slope break down to about 1700 m and the target species varies with depth. The smallest vessels in the fleet fish on the upper slope, where an important target species is the anglerfish or monkfish ( Lophius spp.). On the mid-slope the main target species are blue ling ( Molva dypterygia) and roundnose grenadier ( Coryphaenoides rupestris), with bycatches of black scabbardfish ( Aphanopus carbo) and deep-water sharks. On the lower slope orange roughy ( Hoplostethus atlanticus) is an important target species. The major semipelagic trawl fishery is a seasonal fishery on spawning aggregations of blue whiting

  14. Deep water drilling risers in calm and harsh environments

    SciTech Connect

    Olufsen, A.; Nordsve, N.T.

    1994-12-31

    The overall objective of the work presented in this paper is to increase the knowledge regarding application of deep water drilling risers in different environmental conditions. Identification of key parameters and their impact on design and operation of deep water drilling risers are emphasized. Riser systems for two different cases are evaluated. These are: drilling offshore Nigeria in 1,200 m water depth; drilling at the Voering Plateau offshore Northern Norway in 1,500 m water depth. The case studies are mainly referring to requirements related to normal drilling operation of the riser. They are not complete with respect to describe of total riser system design. The objectives of the case studies have been to quantify the important of various parameters and to establish limiting criteria for drilling. Dynamic riser analyses are also performed. For the Nigeria case, results for a design wave with 100 years return period show that the influence of dynamic response is only marginal (but it may of course be significant for fatigue damage/life time estimation). The regularity of the drilling operation is given as the probability that jointly occurring wave heights and current velocities are within the limiting curve.

  15. [Effects of deep plowing and mulch in fallow period on soil water and yield of wheat in dryland].

    PubMed

    Deng, Yan; Gao, Zhi-Qiang; Sun, Min; Zhao, Wei-Feng; Zhao, Hong-Mei; Li, Qing

    2014-01-01

    A field test was carried out in Qiujialing Village, Wenxi, Shanxi from 2009 to 2011 to study the soil water movement of 0-300 cm layer, yield formation and water use efficiency (WUE) of wheat with deep plowing and mulching the whole ground immediately (no mulch as control) 15 days and 45 days after harvest. The results indicated that deep plowing and mulch in fallow period could improve soil water storage of the 100-180 cm layer before sowing, the soil water storage efficiency in fallow period, and soil water storage from pre-wintering stage to booting stage. Compared with deep plowing 15 days after wheat harvest, deep plowing 45 days after wheat harvest did better in improving soil water storage and water use efficiency, as well as ear number and yield, which was more conducive in the year with more precipitation. Generally, deep plowing and mulching after raining during fallow period could benefit the soil water storage and conservation, thus would be helpful to improve wheat yield in dryland.

  16. Deep injection of waste water in the Western Canada sedimentary basin.

    PubMed

    Ferguson, Grant

    2015-01-01

    Injection of wastes into the deep subsurface has become a contentious issue, particularly in emerging regions of oil and gas production. Experience in other regions suggests that injection is an effective waste management practice and that widespread environmental damage is unlikely. Over the past several decades, 23 km(3) of water has been injected into the Western Canada Sedimentary Basin (WCSB). The oil and gas industry has injected most of this water but large amounts of injection are associated with mining activities. The amount of water injected into this basin during the past century is 2 to 3 orders magnitude greater than natural recharge to deep formations in the WCSB. Despite this large-scale disturbance to the hydrogeological system, there have been few documented cases of environmental problems related to injection wells. Deep injection of waste appears to be a low risk activity based on this experience but monitoring efforts are insufficient to make definitive statements. Serious uncharacterized legacy issues could be present. Initiating more comprehensive monitoring and research programs on the effects of injection in the WCSB could provide insight into the risks associated with injection in less developed sedimentary basins. © 2014, National Ground Water Association.

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

    NASA Technical Reports Server (NTRS)

    Inazawa, H.; Kobayakawa, K.

    1985-01-01

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

  18. Units of freezing of deep supercooled water in woody xylem.

    PubMed

    Hong, S G; Sucoff, E

    1980-07-01

    The low temperature exotherms (LTE) of 1-year-old twigs of Haralson apple (Malus pumila Mill.), shagbark hickory (Carya ovata [Mill.] K. Koch), green ash (Fraxinus pennsylvanica Marsh), honey locust (Gleditsia triacanthos L.), American chestnut (Castanea dentata [Marsh] Borkh.), and red oak (Quercus rubra L.) were determined by differential thermal analysis (DTA). In one type of experiment freezing during a DTA experiment was halted for up to 2.5 hours after part of the supercooled water had frozen at temperatures between -25 and -42 C. Upon resumption of cooling the freezing started within 2 C of the stopping temperature. In a second type of experiment living and dead cells were microscopically observed in the same ray after partial freezing in the DTA apparatus. In another experiment, the LTE persisted even after tangential and radial sectioning of the twig to 0.13 millimeters. In a final experiment the LTE of a single multiseriate ray of red oak had the same shape as the LTE of wood with many uniseriate rays.These experiments confirm that the deep supercooled water in woody xylem or pith freezes in numerous independent events over a span of as much as 20 C. The units which freeze in an event are single cells or small groups of cells. Ice grows very slowly if at all from these units, and water moves very slowly from unfrozen cells to frozen ones. Deep supercooling of ray parenchyma does not require an intact ray.

  19. Deep water installation -- Heavy mooring and riser systems

    SciTech Connect

    Alvheim, N.

    1995-12-31

    While the move into deep water has provided exciting challenges often resulting in ingenious and novel equipment it is usually the equipment or the solution itself that is remembered and discussed. Too often one overlooks just how that novel equipment was actually installed. Perhaps one of the most exciting and ingenious equipment designs of recent times is the Submerged Turret Loading (STL) system. To date the authors have had the privilege of installing each of the 3 systems so far produced. Their work is well on course for installing the fourth during the coming summer. This paper addresses the installation of two of these systems in the summer of 94 in 350m of the hostile Halten Bank waters as part of the Conoco Heidrun development. Because the Norwegian oil industry has always been at the cutting edge of technology each new development results in the usual plethora of statistics which when presented in papers Re this are accompanied with a long list of superlatives like tallest, heaviest, deepest, quickest etc. etc. Installation work at Heidrun has a similar list. Because the 2 STL systems at Heidrun (called Direct Shuttle Loading DSL) were to be installed in such deep water the sheer size of the system components are worthy of review.

  20. Atlantic Deep-water Response to the Early Pliocene Shoaling of the Central American Seaway

    PubMed Central

    Bell, David B.; Jung, Simon J. A.; Kroon, Dick; Hodell, David A.; Lourens, Lucas J.; Raymo, Maureen E.

    2015-01-01

    The early Pliocene shoaling of the Central American Seaway (CAS), ~4.7–4.2 million years ago (mega annum-Ma), is thought to have strengthened Atlantic Meridional Overturning Circulation (AMOC). The associated increase in northward flux of heat and moisture may have significantly influenced the evolution of Pliocene climate. While some evidence for the predicted increase in North Atlantic Deep Water (NADW) formation exists in the Caribbean and Western Atlantic, similar evidence is missing in the wider Atlantic. Here, we present stable carbon (δ13C) and oxygen (δ18O) isotope records from the Southeast Atlantic-a key region for monitoring the southern extent of NADW. Using these data, together with other δ13C and δ18O records from the Atlantic, we assess the impact of the early Pliocene CAS shoaling phase on deep-water circulation. We find that NADW formation was vigorous prior to 4.7 Ma and showed limited subsequent change. Hence, the overall structure of the deep Atlantic was largely unaffected by the early Pliocene CAS shoaling, corroborating other evidence that indicates larger changes in NADW resulted from earlier and deeper shoaling phases. This finding implies that the early Pliocene shoaling of the CAS had no profound impact on the evolution of climate. PMID:26193070

  1. Atlantic Deep-water Response to the Early Pliocene Shoaling of the Central American Seaway.

    PubMed

    Bell, David B; Jung, Simon J A; Kroon, Dick; Hodell, David A; Lourens, Lucas J; Raymo, Maureen E

    2015-07-20

    The early Pliocene shoaling of the Central American Seaway (CAS), ~4.7-4.2 million years ago (mega annum-Ma), is thought to have strengthened Atlantic Meridional Overturning Circulation (AMOC). The associated increase in northward flux of heat and moisture may have significantly influenced the evolution of Pliocene climate. While some evidence for the predicted increase in North Atlantic Deep Water (NADW) formation exists in the Caribbean and Western Atlantic, similar evidence is missing in the wider Atlantic. Here, we present stable carbon (δ(13)C) and oxygen (δ(18)O) isotope records from the Southeast Atlantic-a key region for monitoring the southern extent of NADW. Using these data, together with other δ(13)C and δ(18)O records from the Atlantic, we assess the impact of the early Pliocene CAS shoaling phase on deep-water circulation. We find that NADW formation was vigorous prior to 4.7 Ma and showed limited subsequent change. Hence, the overall structure of the deep Atlantic was largely unaffected by the early Pliocene CAS shoaling, corroborating other evidence that indicates larger changes in NADW resulted from earlier and deeper shoaling phases. This finding implies that the early Pliocene shoaling of the CAS had no profound impact on the evolution of climate.

  2. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    SciTech Connect

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our

  3. In-situ formation compaction monitoring in deep reservoirs by use of fiber optics

    NASA Astrophysics Data System (ADS)

    Murai, Daisuke; Kunisue, Shoji; Higuchi, Tomoyuki; Kokubo, Tatsuo

    2013-04-01

    1. Background The Southern Kanto gas field, the largest field of natural gas dissolved in water in Japan, is located primarily under the Chiba Prefecture. In this field 8 companies produce 460*10^6m3/y of natural gas. In addition, the concentration of the iodine in the brine is almost 2000 times that in seawater and the iodine as well as natural gas is collected from the brine. Iodine is industrially useful and essential for the human body. About 30% of world production is produced in this area in recent years. On the other hand, the land subsidence has become the big problem since 1965 and more than 10cm/mm of land subsidence was observed by leveling in 1972. The natural gas and iodine producers in this area have made a land subsidence prevention agreement with the local government and made effort to prevent and control land subsidence. Although their pumping brine for the gas and the iodine production is inferred to be the main cause of land subsidence from that time, the ratio of the formation compaction caused by pumping brine in the total land subsidence hasn't been well known. Therefore, the measurement of the actual formation compaction has become an important technological issue for the companies and they jointly have developed a new monitoring system for the formation compaction. 2. Contents (1) By using fiber optics technology, we have developed a world's first monitoring system which measures each of the in-situ formation compactions continuously without running tools into the well. (2) In order to check a reliability of this system and the problems when construction, we carried out the preliminary test. We installed the prototype system in the shallow observation well with a depth of 80 m and measured the actual formation compaction. The water well was drilled at the 10m away from the observation well and the formation was artificially compacted by pumping groundwater from it. (3) We installed the monitoring system in the deep observation well with a

  4. Circulation and deep water export of the subpolar North Atlantic during the 1990's

    NASA Astrophysics Data System (ADS)

    Schott, Friedrich A.; Brandt, Peter

    Moored array observations and deep float trajectories have allowed an improved quantification of the deep subpolar circulation, in particular regarding the Deep Western Boundary Currents (DWBCs) at the exit of the subpolar gyre and the circulation of Labrador Sea Water (LSW). With the decrease of Labrador Sea deep convection during the mid 1990's, LSW salinity and temperature increased by 0.005/yr and 0.06°C/yr, respectively, over the past decade through eddy exchange with the warmer, saltier boundary current water. At the same time, water masses with upper LSW properties were generated in large quantities by shallow convection compensating the lack of classical LSW formation. Sea-level observations and model simulations have pointed to a decrease of the large-scale near-surface cyclonic subpolar gyre circulation over the past decade and we compare the associated gyre indices. The LSW-level currents at the exit of the Labrador Sea, however, show a strengthening during 1997-2005, while the DWBC east of the Grand Banks showed no significant changes from the period 1993-95 to 2005. The mean Meridional Overturning Circulation (MOC) at the exit of the subpolar gyre has been estimated by several inverse model studies to be 16±2 Sv and the corresponding heat transport at 0.61±0.07 PW. Inverse analysis for MOC variations among five hydrographic sections taken during 1993-2000 across the North Atlantic at approximately 48°N found no detectable decadal trend nor large changes, with the estimates of the MOC intensity varying among the five realizations only from 13.8 to 16.6 Sv. Two assimilation models, ECCO and SODA-POP, are evaluated for MOC variability at the exit of the subpolar basin. Only small MOC changes are found, with no indication of a decadal "MOC slowdown", in agreement also with the observed deep boundary currents in the western outflow regime.

  5. Nuclear Waste Disposal in Deep Geological Formations: What are the Major Remaining Scientific Issues?

    SciTech Connect

    Toulhoat, Pierre

    2007-07-01

    For more than thirty years, considerable efforts have been carried out in order to evaluate the possibility of disposing of high level wastes in deep geological formations. Different rock types have been examined, such as water-under-saturated tuffs (USA), granites or crystalline rocks (Canada, Sweden, and Finland), clays (France, Belgium, and Switzerland), rock-salt (Germany). Deep clays and granites, (provided that the most fractured zones are avoided in the second case) are considered to fulfill most allocated functions, either on short term (reversibility) or long term. Chemically reducing conditions favor the immobilization of actinides and most fission products by precipitation, co-precipitation and sorption. If oxidizing conditions prevail, the safety demonstration will mostly rely on the performance of artificial confinement systems. Rock-salt offers limited performance considering the issue of reversibility, which is now perceived as essential, mostly for ethical and sociological reasons. However, several issues would deserve additional research programs, and as a first priority, a clear description of time/space succession of processes during the evolution of the repository. This will allow a better representation of coupled processes in performance assessment, such as the influence of gases (H{sub 2}) generated by corrosion, on the long term dynamics of the re-saturation. Geochemical interactions between the host formation and the engineered systems (packages + barriers) are still insufficiently described. Additional gains in performance could be obtained when taking into account processes such as isotopic exchange. Imaginative solutions, employing ceramic- carbon composite materials could be proposed to replace heavy and gas-generating overpacks, or to accommodate the small but probably significant amount of 'ultimate' wastes that will be inevitably produced by Generation IV reactor systems. (author)

  6. Deep-sea channel/submarine-yazoo system of the Labrador Sea: A new deep-water facies model

    SciTech Connect

    Hesse, R.; Rakofsky, A. )

    1992-05-01

    The deep-sea channel/submarine-yazoo system is a newly recognized deep-water depositional environment that is significantly different from previously documented turbidite environments. The new system is in many ways the antithesis of classical deep-sea fans. The purpose of this paper is to present the characteristics and elements of the system, develop a facies model for it, establish the system variables, and discuss its possible significance in the geologic record and in subsurface exploration. Previous investigators of deepwater turbidite sediments often faced difficulties in trying to fit their sequences into traditional single-source, deep-sea fan models. The present model fills part of an obvious gap in interpretation schemes for deep-water clastic sediments.

  7. Adaptation to deep-sea methane seeps from Cretaceous shallow-water black shale environments?

    NASA Astrophysics Data System (ADS)

    Kiel, Steffen; Wiese, Frank; Titus, Alan

    2013-04-01

    Sulfide-enriched environments in shallow water were considered as sites where animals acquire pre-adaptations enabling them to colonize deep-sea hydrothermal vents and seeps or where they survived extinction events in their deep-sea habitats. Here we present upper Cenomanian (early Late Cretaceous) shallow-water seep communities from the Tropic Shale in the Western Interior Seaway, USA, that lived during a time of extremely warm deep-water temperatures, which supposedly facilitates adaptations to the deep sea, and time-equivalent with a period of widespread oceanic and photic zone anoxia (OAE 2) that supposedly extinguished deep-water vent and seep faunas. Contrary to the expectation, the taxa inhabiting the Tropic Shale seeps were not found at any coeval or younger deep-water seep or vent deposit. This suggests that (i) pre-adaptations for living at deep-sea vents and seeps do not evolve at shallow-water methane seeps, and probably also not in sulfide-rich shallow-water environments in general; (ii) a low temperature gradient from shallow to deep water does not facilitate onshore-offshore adaptations to deep-sea vents and seeps; and (iii) shallow-water seeps did not act as refuges for deep-sea vent and seep animals. We hypothesize that the vast majority of adaptations to successfully colonize deep-sea vents and seeps are acquired below the photic zone.

  8. Nonlinear vibration behaviors of casing pipe in the deep water

    NASA Astrophysics Data System (ADS)

    Tang, You-Gang; Zhang, Su-Xia; Yi, Cong

    2006-10-01

    The vortex-induced nonlinear vibration of casing pipes in the deep water was investigated considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up with considering the beam mode and Morison's nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin's method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160 m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.

  9. Global distribution of beryllium isotopes in deep ocean water as derived from Fe-Mn crusts

    USGS Publications Warehouse

    Von Blanckenburg, F.; O'Nions, R. K.; Belshaw, N.S.; Gibb, A.; Hein, J.R.

    1996-01-01

    The direct measurement of the ratio of cosmogenic 10Be (T1/2 = 1.5 Ma) to stable terrigenously sourced 9Be in deep seawater or marine deposits can be used to trace water mass movements and to quantify the incorporation of trace metals into the deep sea. In this study a SIMS-based technique has been used to determine the 10Be/9Be ratios of the outermost millimetre of hydrogenetic ferromanganese crusts from the worlds oceans. 10Be/9Be ratios, time-corrected for radioactive decay of cosmogenic 10Be using 234U/ 238U, are in good agreement with AMS measurements of modern deep seawater. Ratios are relatively low in the North and equatorial Atlantic samples (0.4-0.5 ?? 10-7). In the Southwest Atlantic ratios increase up to 1 ?? 10-7, they vary between 0.7 and 1.0 ?? 10-7 in Indian Ocean samples, and have a near constant value of 1.1 ?? 0.2 ?? 10-7 for all Pacific samples. If the residence time of 10Be (??10Be) in deep water is constant globally, then the observed variations in 10Be/9Be ratios could be caused by accumulation of 10Be in deep water as it flows and ages along the conveyor, following a transient depletion upon its formation in the Northern Atlantic. In this view both 10Be and 9Be reach local steady-state concentration in Pacific deep water and the global ??10Be ??? 600 a. An alternative possibility is that the Be isotope abundances are controlled by local scavenging. For this scenario ??10Be would vary according to local particle concentration and would ??? 600 a in the central Pacific, but ??10Be ??? 230 a in the Atlantic. Mass balance considerations indicate that hydrothermal additions of 9Be to the oceans are negligible and that the dissolved riverine source is also small. Furthermore, aeolian dust input of 9Be appears insufficient to provide the dissolved Be inventory. The dissolution of only a small proportion (2%) of river-derived particulates could in principle supply the observed seawater Be content. If true, ocean margins would be the sites for 9Be

  10. Property changes of deep and bottom waters in the Western Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Herrford, Josefine; Brandt, Peter; Zenk, Walter

    2017-06-01

    The flow of North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) contributes to the Atlantic meridional overturning circulation. Changes in the associated water mass formation might impact the deep ocean's capacity to take up anthropogenic CO2 while a warming of the deep ocean significantly contributes to global sea level rise. Here we compile historic and recent shipboard measurements of hydrography and velocity to provide a comprehensive view of water mass distribution, pathways, along-path transformation and long-term temperature changes of NADW and AABW in the western South and Equatorial Atlantic. We confirm previous results which show that the northwest corner of the Brazil Basin represents a splitting point for the southward/northward flow of NADW/AABW. The available measurements sample water mass transformation along the two major routes for deep and bottom waters in the tropical to South Atlantic - along the deep western boundary and eastward, parallel to the equator - as well as the hot-spots of extensive mixing. We find lower NADW and lighter AABW to form a highly interactive transition layer in the northern Brazil Basin. The AABW north of 5°S is relatively homogeneous with only lighter AABW being able to pass through the Equatorial Channel (EQCH) into the North Atlantic. Spanning a period of 26 years, our data also allow an estimation of long-term temperature trends in abyssal waters. We find a warming of 2.5±0.7•10-3 °C yr-1 of the waters in the northern Brazil Basin at temperatures colder than 0.6 °C throughout the period 1989-2014 and can relate this warming to a thinning of the dense AABW layer. Whereas isopycnal heave is the dominant effect which defines the vertical distribution of temperature trends on isobars, we also find temperature changes on isopycnals in the lower NADW and AABW layers. There temperatures on isopycnals exhibit decadal variations with warming in the 1990s and cooling in the 2000s - the contributions to the

  11. Will hypolimnetic waters become anoxic in all deep tropical lakes?

    NASA Astrophysics Data System (ADS)

    Fukushima, Takehiko; Matsushita, Bunkei; Subehi, Luki; Setiawan, Fajar; Wibowo, Hendro

    2017-03-01

    To elucidate trends of hypolimnetic oxygen concentrations, vertical distributions of dissolved oxygen were measured in eight deep tropical bodies of water (one natural lake with two basins, five natural lakes, and one reservoir) in Indonesia. A comparison of those concentrations with previously reported data revealed that shoaling of hypolimnetic oxygen-deficient (around a few decimeters to a few meter per year) water had occurred in all of the lakes. Calculated areal hypolimnetic oxygen depletion rates were 0.046-5.9 g m-2 y-1. The oligomictic or meromictic characteristics of the bodies of water suppressed circulation and mixing in the hypolimnions and thus resulted in continuous shoaling of the uppermost oxygen-deficient layers. In some lakes, millions of fish sometimes died suddenly, probably owing to upward movement of oxygen-deficient water to near the surface during periods of strong winds. In the future, the rate of shoaling will be accelerated by human impacts in the basins and by climate warming, the influence of which has already been manifested by rising water temperatures in these lakes. Appropriate monitoring and discussions of future restoration challenges are urgently needed to prevent the hypolimnions of the lakes from becoming completely anoxic.

  12. High archaeal diversity in Antarctic circumpolar deep waters.

    PubMed

    Alonso-Sáez, Laura; Andersson, Anders; Heinrich, Friederike; Bertilsson, Stefan

    2011-12-01

    Archaea are abundant in polar oceans but important ecological aspects of this group remain enigmatic, such as patterns of diversity and biogeography. Here, we provide the first high-throughput sequencing population study of Antarctic archaea based on 198 bp fragments of the 16S rRNA gene, targeting different water masses across the Amundsen and Ross Seas. Our results suggest that archaeal community composition is strongly shaped by hydrography and significantly influenced by environmental parameters. Archaeal communities from cold continental shelf waters (SW) of the Ross Sea were similar over depth with a single thaumarchaeal phylotype dominating Antarctic surface waters (AASW) and deeper SW (contributing up to 80% of reads). However, this phylotype contributed less than 8% of reads in circumpolar deep waters (CDW). A related thaumarchaeon (98% identity) was almost absent in AASW, but contributed up to 30% of reads in CDW, suggesting ecological differentiation of closely related phylotypes. Significantly higher archaeal richness and evenness were observed in CDW, with Shannon indices (c. 2.5) twice as high as for AASW, and high contributions of Group II Euryarchaeota. Based on these results, we suggest that CDW is a hotspot of archaeal diversity and may play an important role in the dispersal of archaeal phylotypes to other oceanic water masses.

  13. Will hypolimnetic waters become anoxic in all deep tropical lakes?

    PubMed Central

    Fukushima, Takehiko; Matsushita, Bunkei; Subehi, Luki; Setiawan, Fajar; Wibowo, Hendro

    2017-01-01

    To elucidate trends of hypolimnetic oxygen concentrations, vertical distributions of dissolved oxygen were measured in eight deep tropical bodies of water (one natural lake with two basins, five natural lakes, and one reservoir) in Indonesia. A comparison of those concentrations with previously reported data revealed that shoaling of hypolimnetic oxygen-deficient (around a few decimeters to a few meter per year) water had occurred in all of the lakes. Calculated areal hypolimnetic oxygen depletion rates were 0.046–5.9 g m−2 y−1. The oligomictic or meromictic characteristics of the bodies of water suppressed circulation and mixing in the hypolimnions and thus resulted in continuous shoaling of the uppermost oxygen-deficient layers. In some lakes, millions of fish sometimes died suddenly, probably owing to upward movement of oxygen-deficient water to near the surface during periods of strong winds. In the future, the rate of shoaling will be accelerated by human impacts in the basins and by climate warming, the influence of which has already been manifested by rising water temperatures in these lakes. Appropriate monitoring and discussions of future restoration challenges are urgently needed to prevent the hypolimnions of the lakes from becoming completely anoxic.

  14. Implementation and testing of a Deep Water Correlation Velocity Sonar

    SciTech Connect

    Dickey, F.R.; Bookheimer, W.C.; Rhoades, K.W.

    1983-05-01

    The paper describes a new sonar designated the Magnavox MX 810 Deep Water Correlation Sonar which is under development by the General Electric Company and the Magnavox Advanced Products and Systems Company. The sonar measures ship's velocity relative to the bottom but instead of using the conventional doppler effect, it uses the correlation method described by Dickey and Edward in 1978. In this method, the narrow beams required for doppler are not needed and a low frequency that penetrates to the bottom in deep water is used. The sonar was designed with the constraint that it use a transducer that mounts through a single 12 inch gate valve. Most offshore geophysical surveys at present make use of an integrated navigation system with bottom referenced velocity input from a doppler sonar which, because of limitations on the sonar bottomtracking range, has difficulty in areas where the water depth is greater than about 500 meters. The MX 810 provides bottom tracking in regions of much greater water depth. It also may be applied as an aid in continuous positioning of a vessel over a fixed location. It also should prove useful as a more general navigation aid. The sonar is undergoing a series of tests using Magnavox's facilities for the purpose of verifying the performance and obtaining data to support and quantify planned improvements in both software and hardware. A prototype transducer of only 5 watts power output was used, but in spite of this low power, successful operation to depths of 1900 meters was obtained. Extrapolation to system parameters to be implemented in production models predicts operation to depths of 5000 meters.

  15. Robust, Optimal Water Infrastructure Planning Under Deep Uncertainty Using Metamodels

    NASA Astrophysics Data System (ADS)

    Maier, H. R.; Beh, E. H. Y.; Zheng, F.; Dandy, G. C.; Kapelan, Z.

    2015-12-01

    Optimal long-term planning plays an important role in many water infrastructure problems. However, this task is complicated by deep uncertainty about future conditions, such as the impact of population dynamics and climate change. One way to deal with this uncertainty is by means of robustness, which aims to ensure that water infrastructure performs adequately under a range of plausible future conditions. However, as robustness calculations require computationally expensive system models to be run for a large number of scenarios, it is generally computationally intractable to include robustness as an objective in the development of optimal long-term infrastructure plans. In order to overcome this shortcoming, an approach is developed that uses metamodels instead of computationally expensive simulation models in robustness calculations. The approach is demonstrated for the optimal sequencing of water supply augmentation options for the southern portion of the water supply for Adelaide, South Australia. A 100-year planning horizon is subdivided into ten equal decision stages for the purpose of sequencing various water supply augmentation options, including desalination, stormwater harvesting and household rainwater tanks. The objectives include the minimization of average present value of supply augmentation costs, the minimization of average present value of greenhouse gas emissions and the maximization of supply robustness. The uncertain variables are rainfall, per capita water consumption and population. Decision variables are the implementation stages of the different water supply augmentation options. Artificial neural networks are used as metamodels to enable all objectives to be calculated in a computationally efficient manner at each of the decision stages. The results illustrate the importance of identifying optimal staged solutions to ensure robustness and sustainability of water supply into an uncertain long-term future.

  16. Low trihalomethane formation in Korean drinking water.

    PubMed

    Yoon, Jeyong; Choi, Youshik; Cho, Soonhang; Lee, Dongsoo

    2003-01-20

    Organics in water have the potential to generate harmful disinfection by-products (DBPs) such as trihalomethanes (THMs) during the chlorination process. To clarify the regulatory implications of Korean THMs levels which appear to be significantly lower than those in the US where the Stage 1 and 2 D/DBPs rule has been promulgated, the characteristics of THMs formation were investigated on five major river waters in Korea. Water samples were taken from 12 water treatment plants on five major rivers that serve as drinking water sources for more than 90% of the Korean population. Trihalomethane formation potential (THMFP), total organic halide formation potential (TOXFP) and ultraviolet absorbance at 254 nm (UV(254)) were determined and compared with those from US data. A survey of existing data [J Korean Soc Water Qual; 16(4) 2000b 431-443] provided evidence that THMs levels in treated drinking water in Korea were one-third of those reported in the US. The lower THMs levels were mainly attributable to the differences in the level and THMFP of dissolved organic carbon (DOC). The DOC levels and the THMFP normalized to DOC were approximately 60% of those in the US. Results which combined could quantitatively account for the lower THMs levels (i.e. 0.6 x 0.6 approximately 1/3) in Korea. The observed Korean THMs levels were over-predicted by the THMs model () developed in the US. The level of THMFP was found to be similar if normalized for aromaticity as measured by UV(254). These findings suggest that: (i) the case for more stringent THMs control is not likely to be a high priority among issues of drinking water quality in Korea; and (ii) significant variation of THMFP level may exist over different geographic regions; hence (iii) independent THMs models should be developed to make accurate predictions for different regions.

  17. Calculations of Asteroid Impacts into Deep and Shallow Water

    NASA Astrophysics Data System (ADS)

    Gisler, Galen; Weaver, Robert; Gittings, Michael

    2011-06-01

    Contrary to received opinion, ocean impacts of small (<500 m) asteroids do not produce tsunamis that lead to world-wide devastation. In fact the most dangerous features of ocean impacts, just as for land impacts, are the atmospheric effects. We present illustrative hydrodynamic calculations of impacts into both deep and shallow seas, and draw conclusions from a parameter study in which the size of the impactor and the depth of the sea are varied independently. For vertical impacts at 20 km/s, craters in the seafloor are produced when the water depth is less than about 5-7 times the asteroid diameter. Both the depth and the diameter of the transient crater scale with the asteroid diameter, so the volume of water excavated scales with the asteroid volume. About a third of the crater volume is vaporised, because the kinetic energy per unit mass of the asteroid is much larger than the latent heat of vaporisation of water. The vaporised water carries away a considerable fraction of the impact energy in an explosively expanding blast wave which is responsible for devastating local effects and may affect worldwide climate. Of the remaining energy, a substantial portion is used in the crown splash and the rebound jet that forms as the transient crater collapses. The collapse and rebound cycle leads to a propagating wave with a wavelength considerably shorter than classical tsunamis, being only about twice the diameter of the transient crater. Propagation of this wave is hindered somewhat because its amplitude is so large that it breaks in deep water and is strongly affected by the blast wave's perturbation of the atmosphere. Even if propagation were perfect, however, the volume of water delivered per metre of shoreline is less than was delivered by the Boxing Day 2004 tsunami for any impactor smaller than 500 m diameter in an ocean of 5 km depth or less. Near-field effects are dangerous for impactors of diameter 200 m or greater; hurricane-force winds can extend tens of

  18. Role of Deep Convection in Establishing the Isotopic Composition of Water Vapor in the Tropical Transition Layer

    NASA Technical Reports Server (NTRS)

    Smith, Jamison A.; Ackerman, Andrew S.; Jensen, Eric J.; Toon, Owen B.

    2006-01-01

    The transport of H2O and HDO within deep convection is investigated with 3-D large eddy simulations (LES) using bin microphysics. The lofting and sublimation of HDO-rich ice invalidate the Rayleigh fractionation model of isotopologue distribution within deep convection. Bootstrapping the correlation of the ratio of HDO to H2O (deltaD) to water vapor mixing ratio (q(sub v)) through a sequence of convective events produced non-Rayleigh correlations resembling observations. These results support two mechanisms for stratospheric entry. Deep convection can inject air with water vapor of stratospheric character directly into the tropical transition layer (TTL). Alternatively, moister air detraining from convection may be dehydrated via cirrus formation n the TTL to produce stratospheric water vapor. Significant production of subsaturated air in the TTL via convective dehydration is not observed in these simulations, nor is it necessary to resolve the stratospheric isotope paradox.

  19. Role of Deep Convection in Establishing the Isotopic Composition of Water Vapor in the Tropical Transition Layer

    NASA Technical Reports Server (NTRS)

    Smith, Jamison A.; Ackerman, Andrew S.; Jensen, Eric J.; Toon, Owen B.

    2006-01-01

    The transport of H2O and HDO within deep convection is investigated with 3-D large eddy simulations (LES) using bin microphysics. The lofting and sublimation of HDO-rich ice invalidate the Rayleigh fractionation model of isotopologue distribution within deep convection. Bootstrapping the correlation of the ratio of HDO to H2O (deltaD) to water vapor mixing ratio (q(sub v)) through a sequence of convective events produced non-Rayleigh correlations resembling observations. These results support two mechanisms for stratospheric entry. Deep convection can inject air with water vapor of stratospheric character directly into the tropical transition layer (TTL). Alternatively, moister air detraining from convection may be dehydrated via cirrus formation n the TTL to produce stratospheric water vapor. Significant production of subsaturated air in the TTL via convective dehydration is not observed in these simulations, nor is it necessary to resolve the stratospheric isotope paradox.

  20. Cestodes from deep-water squaliform sharks in the Azores

    NASA Astrophysics Data System (ADS)

    Caira, Janine N.; Pickering, Maria

    2013-12-01

    The majority of our knowledge on marine tapeworms (cestodes) is limited to taxa that are relatively easy to obtain (i.e., those that parasitize shallower-water species). The invitation to participate in a deep-water research survey off the Condor seamount in the Azores offered the opportunity to gain information regarding parasites of the less often studied sharks of the mesopelagic and bathypelagic zone. All tapeworms (Platyhelminthes: Cestoda) found parasitizing the spiral intestine of squaliform shark species (Elasmobranchii: Squaliformes) encountered as part of this survey, as well as some additional Azorean sampling from previous years obtained from local fishermen are reported. In total, 112 shark specimens of 12 species of squaliform sharks representing 4 different families from depths ranging between 400 and 1290 m were examined. Cestodes were found in the spiral intestines from 11 of the 12 squaliform species examined: Deania calcea, D. cf. profundorum, D. profundorum, Etmopterus princeps, E. pusillus, E. spinax, Centroscyllium fabricii, Centroscymnus coelolepis, C. cryptacanthus, C. crepidater, and Dalatias licha. No cestodes were found in the spiral intestines of Centrophorus squamosus. Light microscopy and scanning electron microscopy revealed several potentially novel trypanorhynch and biloculated tetraphyllidean species. Aporhynchid and gilquiniid trypanorhynchs dominated the adult cestode fauna of Etmopterus and Deania host species, respectively, while larval phyllobothriids were found across several host genera, including, Deania, Centroscyllium, and Centroscymnus. These results corroborate previous findings that deep-water cestode faunas are relatively depauperate and consist primarily of trypanorhynchs of the families Gilquiniidae and Aporhynchidae and larval tetraphyllideans. A subset of specimens of most cestode species was preserved in ethanol for future molecular analysis to allow more definitive determinations of the identification of the

  1. Experiments of water formation on warm silicates

    SciTech Connect

    He, Jiao; Vidali, Gianfranco

    2014-06-10

    When dust grains have a higher temperature than they would have in dense clouds, and when H, H{sub 2}, and O{sub 2} have a negligible residence time on grains, the formation of water should still be possible via the hydrogenation of OH and Eley-Rideal-type reactions. We determined that the OH desorption energy from an amorphous silicate surface is at least 143 meV (1656 K). This is 400 K higher than the value previously used in chemical models of the interstellar medium and is possibly as high as 410 meV (4760 K). This extends the temperature range for the efficient formation of water on grains from about 30 K to at least 50 K, and possibly over 100 K. We do not find evidence that water molecules leave the surface upon formation. Instead, through a thermal programmed desorption experiment, we find that water formed on the surface of an amorphous silicate desorbs at around 160 K. We also measured the cross-sections for the reaction of H and D with an O{sub 3} layer on an amorphous silicate surface at 50 K. The values of the cross-sections, σ{sub H} = 1.6 ± 0.27 Å{sup 2} and σ{sub D} = 0.94 ± 0.09 Å{sup 2}, respectively, are smaller than the size of an O{sub 3} molecule, suggesting the reaction mechanism is more likely Eley-Rideal than hot-atom. Information obtained through these experiments should help theorists evaluate the relative contribution of water formation on warm grains versus in the gas phase.

  2. Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation.

    PubMed

    Hernandéz-Gatón, Patrícia; Serrano, César Ruiz; Nelson Filho, Paulo; De Castañeda, Esther Ruiz; Lucisano, Marília P; Silva, Raquel A B da; Silva, Léa A B da

    2015-01-01

    This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis.

  3. Deep porosity preservation in the Norphlet Formation, Mobil Bay, Alabama

    SciTech Connect

    Ajdukiewicz, J.M.; Paxton, S.T.; Szabvo, J.O. )

    1991-03-01

    Compaction and pressure solution have commonly been assumed to destroy primary intergranular porosity in deeply buried sandstones. However, primary porosities of up to 20% are preserved at depths greater than 20,000 feet in the Norphlet Formation of Mobile Bay. Previous workers have called upon a number of mechanisms to preserve these high porosities in the Norphlet, specifically chlorite rim cements, gas emplacement, overpressuring, and decementation. In contrast, our study of data from 23 Norphlet wells, including 450 thin sections, indicates that these suggested mechanisms are not the primary cause of porosity preservation in the Norphlet. The authors propose an alternative interpretation: that in the Norphlet, as in other well-sorted, ductile-grain-poor sandstones, porosity loss from compaction did not go to completion under reservoir (premetamorphic) conditions, but stabilized at depths of about 5,000-8,000 feet and porosity values of about 26%. Porosity loss below these values is due to cementation. For cementation to occur, both an adequate source of cement and geochemical conditions favoring cement precipitation must be present. Computer simulations of Norphlet burial history, including post-depositional fluid-flow patterns, suggest that conditions favorable to quartz cementation never occurred in the bulk of the Norphlet because of the formation's stratigraphic position and isolation from a basinward source of silica-saturated fluids.

  4. Extant or Absent: Formation Water in New York State Drinking Water Wells

    NASA Astrophysics Data System (ADS)

    Christian, K.; Lautz, L. K.

    2013-12-01

    The current moratorium on hydraulic fracturing in New York State (NYS) provides an opportunity to collect baseline shallow groundwater quality data pre-hydraulic fracturing, which is essential for determining the natural variability of groundwater chemistry and to evaluate future claims of impaired groundwater quality if hydraulic fracturing occurs in the State. Concerns regarding the future environmental impact of shale gas extraction in NYS include potential shallow groundwater contamination due to migration of methane or formation water from shale gas extraction sites. Treatment, storage and disposal of saline flowback fluids after gas extraction could also be a source of water contamination. In this study, we combine southern NYS shallow groundwater chemistry data from Project Shale-Water Interaction Forensic Tools (SWIFT, n=60), the National Uranium Resource Evaluation program (NURE, n=684), and the USGS 305(b) Ambient Groundwater Quality Monitoring program (USGS, n=89) to examine evidence of formation water mixing with groundwater using the methodology of Warner et al. (2012). Groundwater characterized as low salinity (<20 mg/L Cl-) accounted for 72% of samples and 28% of samples had high salinity (>20 mg/L Cl-). A plot of bromide versus chloride shows high salinity groundwater samples with Br/Cl ratios >0.0001 fall on the mixing line between low salinity groundwater and Appalachian Basin formation water. Based on the observed linear relationship between bromide and chloride, it appears there is up to 1% formation water mixing with shallow groundwater in the region. The presence of formation water in shallow groundwater would indicate the existence of natural migratory pathways between deep formation wells and shallow groundwater aquifers. A plot of sodium versus chloride also illustrates a linear trend for Type D waters (R^2= 0.776), but the relationship is weaker than that for bromide versus chloride (R^2= 0.924). Similar linear relationships are not

  5. Rock species formation due to deep-mantle melting

    NASA Astrophysics Data System (ADS)

    Fomin, Ilya; Tackley, Paul

    2017-04-01

    Melting and melting migration are processes leading to chemically distinct rock species from a homogeneous substrate in the Earth mantle. Iron-rich melts and corresponding rock species are proposed to result from magma ocean progressive crystallization [Labrosse et al., 2007], and modern geophysical models of ULVZ (e.g. [Beuchert & Schmeling, 2013]) discuss their presence at around the CMB today. We perform long-term (tens of millions of years) numerical simulations of the Earth's mantle for a plausible range of CMB temperatures to understands the possibility of melting and it's consequences. Our model of melting is based on experimental data and ab initio simulations. Physical properties (liquid-solid density differences) are adjusted with data of [de Koker et al., 2013; Mosenfelder et al., 2007; Stixrude & Lithgow-Bertelloni, 2011; Thomas & Asimow, 2013]. This model is included in StagYY numerical code (e.g. [Tackley, 2008]) to simulate mass and thermal fluxes within the Earth mantle. Melt segregation (rocks' permeability and velocities) is considered using equations listed in [Abe, 1995; Solomatov, Stevenson, 1993; Martin & Nokes, 1989]. Thermal effects (adiabatic heating and viscous dissipation) are considered. Viscous dissipation term includes Darcy flux term, but omits highly non-linear Brinkman contribution [Nield, 2007]. Modeling predicts formation of melt if temperature at CMB exceeds 4000-4050K. It's segregation and reequilibration results in sufficient volumes of slightly iron-enriched melt lighter than solid counterpart and moving upward. However, it's propagation is strongly controlled by temperature. Partial melting atop the molten layer results in formation of refractory iron-poor restite which delaminates and sink down, so that a layer of iron-depleted material forms underneath the molten layer. Our model applied to homogeneous pyrolitic mantle results in formation of layers of iron-depleted material with average FeO around 4.6 mol.% and iron

  6. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    SciTech Connect

    M. Batzle; D-h Han; R. Gibson; O. Djordjevic

    2003-03-20

    The ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' (Grant/Cooperative Agreement DE-FC26-02NT15342) began September 1, 2002. During this second quarter: A Direct Hydrocarbon Indicator (DHI) symposium was held at UH; Current DHI methods were presented and forecasts made on future techniques; Dr. Han moved his laboratory from HARC to the University of Houston; Subcontracts were re-initiated with UH and TAMU; Theoretical and numerical modeling work began at TAMU; Geophysical Development Corp. agreed to provide petrophysical data; Negotiations were begun with Veritas GDC to obtain limited seismic data; Software licensing and training schedules were arranged with Paradigm; and Data selection and acquisition continues. The broad industry symposium on Direct Hydrocarbon Indicators was held at the University of Houston as part of this project. This meeting was well attended and well received. A large amount of information was presented, not only on application of the current state of the art, but also on expected future trends. Although acquisition of appropriate seismic data was expected to be a significant problem, progress has been made. A 3-D seismic data set from the shelf has been installed at Texas A&M University and analysis begun. Veritas GDC has expressed a willingness to provide data in the deep Gulf of Mexico. Data may also be available from TGS.

  7. Deep subsurface drip irrigation using coal-bed sodic water: Part I. Water and solute movement

    SciTech Connect

    Bern, Carleton R; Breit, George N; Healy, Richard W; Zupancic, John W; Hammack, Richard

    2013-02-01

    Water co-produced with coal-bed methane (CBM) in the semi-arid Powder River Basin of Wyoming and Montana commonly has relatively low salinity and high sodium adsorption ratios that can degrade soil permeability where used for irrigation. Nevertheless, a desire to derive beneficial use from the water and a need to dispose of large volumes of it have motivated the design of a deep subsurface drip irrigation (SDI) system capable of utilizing that water. Drip tubing is buried 92 cm deep and irrigates at a relatively constant rate year-round, while evapotranspiration by the alfalfa and grass crops grown is seasonal. We use field data from two sites and computer simulations of unsaturated flow to understand water and solute movements in the SDI fields. Combined irrigation and precipitation exceed potential evapotranspiration by 300–480 mm annually. Initially, excess water contributes to increased storage in the unsaturated zone, and then drainage causes cyclical rises in the water table beneath the fields. Native chloride and nitrate below 200 cm depth are leached by the drainage. Some CBM water moves upward from the drip tubing, drawn by drier conditions above. Chloride from CBM water accumulates there as root uptake removes the water. Year over year accumulations indicated by computer simulations illustrate that infiltration of precipitation water from the surface only partially leaches such accumulations away. Field data show that 7% and 27% of added chloride has accumulated above the drip tubing in an alfalfa and grass field, respectively, following 6 years of irrigation. Maximum chloride concentrations in the alfalfa field are around 45 cm depth but reach the surface in parts of the grass field, illustrating differences driven by crop physiology. Deep SDI offers a means of utilizing marginal quality irrigation waters and managing the accumulation of their associated solutes in the crop rooting zone.

  8. Deep subsurface drip irrigation using coal-bed sodic water: part I. water and solute movement

    USGS Publications Warehouse

    Bern, Carleton R.; Breit, George N.; Healy, Richard W.; Zupancic, John W.; Hammack, Richard

    2013-01-01

    Water co-produced with coal-bed methane (CBM) in the semi-arid Powder River Basin of Wyoming and Montana commonly has relatively low salinity and high sodium adsorption ratios that can degrade soil permeability where used for irrigation. Nevertheless, a desire to derive beneficial use from the water and a need to dispose of large volumes of it have motivated the design of a deep subsurface drip irrigation (SDI) system capable of utilizing that water. Drip tubing is buried 92 cm deep and irrigates at a relatively constant rate year-round, while evapotranspiration by the alfalfa and grass crops grown is seasonal. We use field data from two sites and computer simulations of unsaturated flow to understand water and solute movements in the SDI fields. Combined irrigation and precipitation exceed potential evapotranspiration by 300-480 mm annually. Initially, excess water contributes to increased storage in the unsaturated zone, and then drainage causes cyclical rises in the water table beneath the fields. Native chloride and nitrate below 200 cm depth are leached by the drainage. Some CBM water moves upward from the drip tubing, drawn by drier conditions above. Chloride from CBM water accumulates there as root uptake removes the water. Year over year accumulations indicated by computer simulations illustrate that infiltration of precipitation water from the surface only partially leaches such accumulations away. Field data show that 7% and 27% of added chloride has accumulated above the drip tubing in an alfalfa and grass field, respectively, following 6 years of irrigation. Maximum chloride concentrations in the alfalfa field are around 45 cm depth but reach the surface in parts of the grass field, illustrating differences driven by crop physiology. Deep SDI offers a means of utilizing marginal quality irrigation waters and managing the accumulation of their associated solutes in the crop rooting zone.

  9. Potential Health Benefits of Deep Sea Water: A Review

    PubMed Central

    Jaafar, A. B.; Mahdzir, A.; Musa, M. N.

    2016-01-01

    Deep sea water (DSW) commonly refers to a body of seawater that is pumped up from a depth of over 200 m. It is usually associated with the following characteristics: low temperature, high purity, and being rich with nutrients, namely, beneficial elements, which include magnesium, calcium, potassium, chromium, selenium, zinc, and vanadium. Less photosynthesis of plant planktons, consumption of nutrients, and organic decomposition have caused lots of nutrients to remain there. Due to this, DSW has potential to become a good source for health. Research has proven that DSW can help overcome health problems especially related to lifestyle-associated diseases such as cardiovascular disease, diabetes, obesity, cancer, and skin problems. This paper reviews the potential health benefits of DSW by referring to the findings from previous researches. PMID:28105060

  10. Precession resonance mechanism in deep-water gravity surface waves

    NASA Astrophysics Data System (ADS)

    Bustamante, Miguel; Lucas, Dan

    2016-11-01

    Discovered by Bustamante et al. in 2014 and published in Phys. Rev. Lett. in the same year, precession resonance is a mechanism whereby strong nonlinear energy transfers occur between modes of oscillations whose frequencies are detuned: the amplitude-dependent precession frequencies of the phases help restore the resonance, hence the name "precession resonance". After explaining how this mechanism works and how robust it is, we will discuss new applications of this effect in systems of technological interest, focusing on deep-water gravity surface waves. We report transfer efficiencies of up to 40%, depending on the numerical-experimental setup. All evidence gathered so far points to the conclusion that, to leading order, this effect is dominated by triad interactions at small (but finite) amplitudes. Joint work with Dan Lucas (DAMTP, Cambridge). Financially supported by Science Foundation Ireland (SFI) under research Grant No. 12/IP/1491.

  11. Potential Health Benefits of Deep Sea Water: A Review.

    PubMed

    Mohd Nani, Samihah Zura; Majid, F A A; Jaafar, A B; Mahdzir, A; Musa, M N

    2016-01-01

    Deep sea water (DSW) commonly refers to a body of seawater that is pumped up from a depth of over 200 m. It is usually associated with the following characteristics: low temperature, high purity, and being rich with nutrients, namely, beneficial elements, which include magnesium, calcium, potassium, chromium, selenium, zinc, and vanadium. Less photosynthesis of plant planktons, consumption of nutrients, and organic decomposition have caused lots of nutrients to remain there. Due to this, DSW has potential to become a good source for health. Research has proven that DSW can help overcome health problems especially related to lifestyle-associated diseases such as cardiovascular disease, diabetes, obesity, cancer, and skin problems. This paper reviews the potential health benefits of DSW by referring to the findings from previous researches.

  12. Modelling trihalomethanes formation in water supply systems.

    PubMed

    Di Cristo, Cristiana; Esposito, Giovanni; Leopardi, Angelo

    2013-01-01

    Chlorination is the most widely used method for disinfection of drinking water, but there are concerns about the formation of by-products, such as trihalomethanes (THMs), since the chronic exposure to them may pose risks to human health. For these reasons regulations fix maximum acceptable THMs levels throughout distribution networks, so it is very important to be able to correctly reproduce their formation. In the literature many models for predicting THMs formation have been developed, both based on empirical relationships and on kinetics involved during chlorine reactions. In this work the use of some of these models and their reliability in real situations is investigated through the application to the Aurunci-Valcanneto Water Supply System in Southern Lazio (Italy). The comparison of the performances of 18 selected literature empirical models furnishes interesting observations, indicating that the formula, developed using field data, results in being more suitable for reproducing THMs formation for the presented case study. Other considerations are also offered from the comparison with the results obtained using a simple first order kinetic model, calibrated using measured data.

  13. Ireland's deep-water coral carbonate mounds: multidisciplinary research results

    NASA Astrophysics Data System (ADS)

    Kozachenko, M.; Wheeler, A.; Beyer, A.; Blamart, D.; Masson, D.; Olu-Le Roy, K.

    2003-04-01

    Recent international research activity, involving a strong Irish collaboration, has shown that coral reefs are not exclusively associated with warm tropical waters but are also present in the deeper and colder Northeast Atlantic. In the Porcupine Seabight west of Ireland, coral-colonised carbonate mounds (up to 350m high) are present at 600-900m water depth. The corals Lophelia pertusa L. and Madrepora oculata L. contribute to this diverse ecosystem that may also play a significant role in expanding deep-water fisheries. New side-scan sonar, multibeam echosounder, sub-bottom profiler and underwater video imagery supplemented with sedimentological sample material were used to map the seabed in the environs of the Belgica Carbonate Mound province, eastern Porcupine Seabight. The data were integrated in a GIS and provides information on sediment pathways and benthic current patterns within the study area. A facies map of the study area highlights differing sedimentary processes showing evidences for strong northward bottom currents whose interaction has an influence on mounds growth and morphology. This survey revealed mound flanks dominated by sediment waves that give way to coral banks towards the mound summits. A form of coral accumulation was also documented. Detailed analyses of sediment properties from long cores through sediment drifts have generated a high-resolution palaeoclimate record revealing temporal patterns in bottom current strength variations. An accurate assessment of this influence on mound through a comparison with coral growth rates is ongoing.

  14. Dense water formation in the Laptev Sea flaw lead

    NASA Astrophysics Data System (ADS)

    Dethleff, Dirk

    2010-12-01

    Two primitive equation-based models are used to estimate the formation of total volumes either of Arctic cold halocline water (CHW), intermediate water (IMW), or deep water (DW) through freeze-related salt rejection in the Siberian Laptev Sea flaw lead system. Model A assumes that the rejected salt remixes with surface mixed water (SMW) beyond the leads until salinities allow for contribution to the midlayers of either the CHW, the IMW, or the DW. Model B simulates direct salt rejection to the upper layer of the cold halocline, and, after remixing here, further contribution to the midlayers of CHW, IMW, or DW. Averaging both model estimates, Laptev leads contribute either 0.161 Sv of CHW, 0.075 Sv of IMW, or 0.065 Sv of DW, which represents as much as ˜23%, ˜16%, or ˜30% of Arctic-wide lead derived dense water contribution to the appropriate layer, respectively. Northwestern Laptev leads produce the greatest amount of dense water. These lead sections show very short buoyancy equilibrium timescales (˜6 to ˜13 days), and local dense water production may potentially be amplified by lateral brine injection into the cold halocline through bottom eddies. Central-southern and southeastern leads generally produce little salt due to low surface water salinities. As definite separation mechanisms and proportion distributions of rejected lead brines into CHW, IWM, and DW are still unidentified in nature, a combination of lead salt rejection and remixing (model A) and direct downward expulsion of brine packages (model B) is assumed to steer Laptev lead dense water production.

  15. On the deep water masses outflow in the Aegean Sea: a pre- and post-EMT analysis

    NASA Astrophysics Data System (ADS)

    Bellacicco, Marco; Falcini, Federico; Salusti, Ettore

    2017-04-01

    In the last decades, the Aegean Sea (AS) has drawn attention and interest from the oceanographic community about the role that this sea has played in the Eastern Mediterranean Transient (EMT), with the key result of a "new" deep-water formation site in the eastern Mediterranean basin. This deep-water formation was due to different reasons: i) water budget anomalies that increased salinity of the surface and intermediate water masses; ii) the enters of these waters in the AS from Eastern Mediterranean Sea thought the Cretan Straits, and iii) episodes of strong winter cooling. Here, we explore the importance of deep water masses outflow from Aegean Sea throughout the Cretan Sea into the oriental basin of the Mediterranean Sea, in relation to last recent studies, focusing on the EMT event and its time table. To such goal we use all available, in situ, hydrologic data collected in the period 1985-1999, by trying to describe the outflow of the deep-water masses in the Levantine basin. Preliminary results revealed that the main source of dense water was beween Samarcande and its northern coast while the entrance of dense water in the Cyclades Plateau was essentially a flow between the Islands of Euboea and Andros, confirming what found by Bellacicco et al. (2016) from numerical results and marine geological evidences. The new analysis, moreover, points out the presence of a dense water mass debouching in the Levantine from the Cretean Sea during the spring time (i.e., maximum mixing period)of 1986-1988.Our results may allow to open new research question on the actual EMT timing and triggering, also considering theoretical model analyses (Smith 1975, Bellacicco et al., 2016).

  16. Formation of metal and dielectric liners using a solution process for deep trench capacitors.

    PubMed

    Ham, Yong-Hyun; Kim, Dong-Pyo; Baek, Kyu-Ha; Park, Kun-Sik; Kim, Moonkeun; Kwon, Kwang-Ho; Shin, Hong-Sik; Lee, Kijun; Do, Lee-Mi

    2012-07-01

    We demonstrated the feasibility of metal and dielectric liners using a solution process for deep trench capacitor application. The deep Si trench via with size of 10.3 microm and depth of 71 microm were fabricated by Bosch process in deep reactive ion etch (DRIE) system. The aspect ratio was about 7. Then, nano-Ag ink and poly(4-vinylphenol) (PVPh) were used to form metal and dielectric liners, respectively. The thicknesses of the Ag and PVPh liners were about 144 and 830 nm, respectively. When the curing temperature of Ag film increased from 120 to 150 degrees C, the sheet resistance decreased rapidly from 2.47 to 0.72 Omega/sq and then slightly decreased to 0.6 Omega/sq with further increasing the curing temperature beyond 150 degrees C. The proposed liner formation method using solution process is a simple and cost effective process for the high capacity of deep trench capacitor.

  17. Makah Formation; a deep-marginal-basin sequence of late Eocene and Oligocene age in the northwestern Olympic Peninsula, Washington

    USGS Publications Warehouse

    Snavely, P. D.; Niem, A.R.; MacLeod, N.S.; Pearl, J.E.; Rau, W.W.

    1980-01-01

    The Makah Formation of the Twin River Group crops out in a northwest-trending linear belt in the northwesternmost part of the Olympic Peninsula, Wash. This marine sequence consists of 2800 meters of predominantly thin-bedded siltstone and sandstone that encloses six distinctive newly named members--four thick-bedded amalgamated turbidite sandstone members, an olistostromal shallow-water marine sandstone and conglomerate member, and a thin-bedded water-laid tuff member. A local unconformity of submarine origin occurs within the lower part of the Makah Formation except in the central part of the study area, where it forms the contact between the older Hoko River Formation and the Makah. Foraminiferal faunas indicate that the Makah Formation ranges in age from late Eocene (late Narizian) to late Oligocene (Zemorrian) and was deposited in a predominantly lower to middle bathyal environment. The Makah Formation is part of a deep-marginalbasin facies that crops out in the western part of the Olympic Peninsula, in southwesternmost Washington and coastal embayments in northwestern Oregon, and along the central part of the coast of western Vancouver Island. On the basis of limited subsurface data from exploratory wells, correlative deep-marginal-basin deposits underlie the inner continental shelf of Oregon and the continental shelf (Tofino basin) along the southwestern side of Vancouver Island. Directional structures in the Makah Formation indicate that the predominantly lithic arkosic sandstone that forms the turbidite packets was derived from the northwest. A possible source of the clastic material is the dioritic, granitic, and volcanic terranes in the vicinity of the Hesquiat Peninsula and Barkley Sound on the west coast of Vancouver Island. Vertical and lateral variations of turbidite facies suggest that the four packets of sandstone were formed as depositional lobes on an outer submarine fan. The thin-bedded strata between the turbidite packets have characteristics of

  18. Exceptional dense water formation on the Adriatic shelf in the winter of 2012

    NASA Astrophysics Data System (ADS)

    Mihanović, H.; Vilibić, I.; Carniel, S.; Tudor, M.; Russo, A.; Bergamasco, A.; Bubić, N.; Ljubešić, Z.; Viličić, D.; Boldrin, A.; Malačič, V.; Celio, M.; Comici, C.; Raicich, F.

    2013-06-01

    In this paper we document dense water formation throughout the Adriatic shelf and coastal area in January/February 2012, resulting in record-breaking densities observed during and after the event. The unprecedented dense water generation was preconditioned by a dry and warm year which resulted in a significant reduction of coastal freshwaters, superimposed on a long-term basin-wide salinity increase. The final event that triggered the dense water formation was an extended period of cold weather with strong and severe winds. Record-breaking potential density anomalies (above 30 kg m-3) were measured at several formation sites. Accumulated surface net heat and water losses in some coastal regions exceeded 1.5 GJ m-2 and 250 kg m-2 over 21 days, respectively. Excessiveness, importance of shelf-type dense water formation and effects on the thermohaline circulation and deep aquatic systems are discussed.

  19. Belly River Formation of western Alberta, Canada: anatomy of an emerging deep basin oil play

    SciTech Connect

    Putnam, P.E.

    1989-03-01

    The Campanian Belly River Formation of western Alberta appears to form a largely bypassed deep basin type of oil play. In this setting hydrocarbons are found in lenticular fluvial reservoirs located upon folds or intersected by northwest-striking thrust faults and northeast-striking fractures. In the western fold and thrust belt, primary porosity is preserved within relatively thick and widespread grain-supported conglomerates. To the east, secondary porosity predominates in sandy lithofacies, and the best developed porosity is found proximal to fractures which enhanced fluid migration and grain dissolution. To the west, the unit exhibits progressive underpressuring, which reflects postorogenic sediment stripping combined with westward ground-water flow. A manifestation of the hydrodynamic regime is that many wells appear to have damaged Belly River zones because historically most exploration has been focused on deeper targets which require heavier mud weights. This style of hydrocarbon accumulation in the Belly River zone appears to cover several thousand square kilometers. The prior emphasis on deeper targets has also inhibited seismic delineation of Belly River reservoirs. Seismic acquisition must be designed to account for the relatively shallow depth and complex geometry of potential targets. Shear wave data appear to be a promising source of information in locating the distribution of reservoirs relative to fractures. The structural, depositional, diagenetic, and hydrodynamic development of the Belly River in western Alberta is similar to other clastic wedges formed during Laramide orogenic events. Thus, hydrocarbon accumulations may be anticipated in these other areas as well.

  20. Gas hydrate formation in the deep sea: In situ experiments with controlled release of methane, natural gas, and carbon dioxide

    USGS Publications Warehouse

    Brewer, P.G.; Orr, F.M.; Friederich, G.; Kvenvolden, K.A.; Orange, D.L.

    1998-01-01

    We have utilized a remotely operated vehicle (ROV) to initiate a program of research into gas hydrate formation in the deep sea by controlled release of hydrocarbon gases and liquid CO2 into natural sea water and marine sediments. Our objectives were to investigate the formation rates and growth patterns of gas hydrates in natural systems and to assess the geochemical stability of the reaction products over time. The novel experimental procedures used the carrying capacity, imaging capability, and control mechanisms of the ROV to transport gas cylinders to depth and to open valves selectively under desired P-T conditions to release the gas either into contained natural sea water or into sediments. In experiments in Monterey Bay, California, at 910 m depth and 3.9??C water temperature we find hydrate formation to be nearly instantaneous for a variety of gases. In sediments the pattern of hydrate formation is dependent on the pore size, with flooding of the pore spaces in a coarse sand yielding a hydrate cemented mass, and gas channeling in a fine-grained mud creating a veined hydrate structure. In experiments with liquid CO2 the released globules appeared to form a hydrate skin as they slowly rose in the apparatus. An initial attempt to leave the experimental material on the sea floor for an extended period was partially successful; we observed an apparent complete dissolution of the liquid CO2 mass, and an apparent consolidation of the CH4 hydrate, over a period of about 85 days.

  1. Preparative scale and convenient synthesis of a water-soluble, deep cavitand.

    PubMed

    Mosca, Simone; Yu, Yang; Rebek, Julius

    2016-08-01

    Cavitands are established tools of supramolecular chemistry and molecular recognition, and they are finding increasing application in sensing and sequestration of physiologically relevant molecules in aqueous solution. The synthesis of a water-soluble, deep cavitand is described. The route comprises six (linear) steps from commercially available precursors, and it relies on the fourfold oligomeric cyclization reaction of resorcinol with 2,3-dihydrofuran that leads to the formation of a shallow resorcinarene framework; condensation with aromatic panels, which deepens the hydrophobic binding cavity; construction of rigid urea functionalities on the upper rim; and the introduction of the water-solubilizing methylimidazolium groups on the lower rim. Late intermediates of the synthesis can be used in the preparation of congener cavitands with different properties and applications, and a sample of such a synthetic procedure is included in this protocol. Emphasis is placed on scaled-up reactions and on purification procedures that afford materials in high yield and avoid chromatographic purification. This protocol provides improvements over previously described procedures, and it enables the preparation of sizable amounts of deep cavitands: 7 g of a water-soluble cavitand can be prepared from resorcinol in 13 working days.

  2. Distribution of deep-water Scleractinian corals in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Keller, N. B.; Oskina, N. S.; Savilova, T. A.

    2017-03-01

    The distribution pattern of deep-water Scleractinian corals was studied in the Atlantic Ocean at a depth more than 2 km on the basis of our own and published data. It was shown that deep-water corals predominate (with respect to species diversity and number) in the eastern part of the ocean. In its western part, some species ( Desmophyllum dianthus, Flabellum angulare, etc.) were not revealed. In the tropical zone of the North Atlantic, the distribution pattern of shallow- and deep-water corals differs. At the coast of South America, deepwater corals are absent, which is probably related to the deep part of the global oceanic conveyor belt.

  3. Population Differentiation and Species Formation in the Deep Sea: The Potential Role of Environmental Gradients and Depth

    PubMed Central

    Jennings, Robert M.; Etter, Ron J.; Ficarra, Lynn

    2013-01-01

    Ecological speciation probably plays a more prominent role in diversification than previously thought, particularly in marine ecosystems where dispersal potential is great and where few obvious barriers to gene flow exist. This may be especially true in the deep sea where allopatric speciation seems insufficient to account for the rich and largely endemic fauna. Ecologically driven population differentiation and speciation are likely to be most prevalent along environmental gradients, such as those attending changes in depth. We quantified patterns of genetic variation along a depth gradient (1600-3800m) in the western North Atlantic for a protobranch bivalve (Nuculaatacellana) to test for population divergence. Multilocus analyses indicated a sharp discontinuity across a narrow depth range, with extremely low gene flow inferred between shallow and deep populations for thousands of generations. Phylogeographical discordance occurred between nuclear and mitochondrial loci as might be expected during the early stages of species formation. Because the geographic distance between divergent populations is small and no obvious dispersal barriers exist in this region, we suggest the divergence might reflect ecologically driven selection mediated by environmental correlates of the depth gradient. As inferred for numerous shallow-water species, environmental gradients that parallel changes in depth may play a key role in the genesis and adaptive radiation of the deep-water fauna. PMID:24098590

  4. Experimental study on plunging breaking waves in deep water

    NASA Astrophysics Data System (ADS)

    Lim, Ho-Joon; Chang, Kuang-An; Huang, Zhi-Cheng; Na, Byoungjoon

    2015-03-01

    This study presents a unique data set that combines measurements of velocities and void fraction under an unsteady deep water plunging breaker in a laboratory. Flow properties in the aerated crest region of the breaking wave were measured using modified particle image velocimetry (PIV) and bubble image velocimetry (BIV). Results show that the maximum velocity in the plunging breaker reached 1.68C at the first impingement of the overturning water jet with C being the phase speed of the primary breaking wave, while the maximum velocity reached 2.14C at the beginning of the first splash-up. A similarity profile of void fraction was found in the successive impinging and splash-up rollers. In the highly foamy splashing roller, the increase of turbulent level and vorticity level were strongly correlated with the increase of void fraction when the range of void fraction was between 0 and 0.4 (from the trough level to approximately the center of the roller). The levels became constant when void fraction was greater than 0.5. The mass flux, momentum flux, kinetic energy, potential energy, and total energy were computed and compared with and without the void fraction being accounted for. The results show that all the mean and turbulence properties related to the air-water mixture are considerably overestimated unless void fraction is considered. When including the density variation due to the air bubbles, the wave energy dissipated exponentially a short distance after breaking; about 54% and 85% of the total energy dissipated within one and two wavelengths beyond the breaking wave impingement point, respectively.

  5. Deep water current velocity data in the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Razavi Arab, Azadeh; Haghshenas, S. Abbas; Zaker, Homayoun

    2015-04-01

    Establishment of a nowcasting/forecasting system is a perquisite for the development of coastal and marine areas. This research is performed in order to offer a sophisticated response for the arisen needs via providing a better understanding of coastal and gulf-scale hydrodynamic processes in the Persian Gulf. A comprehensive measurement program is designed whose main objective is to collect sufficient and reliable input data for current forecast simulations in the Persian Gulf which in turn would provide reliable and realistic current parameters, by employing 3D hydrodynamic modeling. Survey parameters are mainly focused on 1) vertical profiling of current speed and direction, 2) mid-depth current speed and direction measurements, 3) tidal (water level) measurements, and 4) wind speed and direction measurements. Moreover, other required data which were collected according to necessities of the studies are meteorological data, including temperature, relative humidity, solar radiation, rain fall, and sea water temperature. A quasi-three-dimensional hydrodynamic model is applied to the Persian Gulf and the current field for a 1-year period is simulated. The results are finally compared to a unique set of field data including depth profiles of current velocity and direction collected inside the Persian Gulf, where the depth varies between 30 and 80 m. Through this field experience, the collected velocity data which clarifies the vertical profile of the velocity in the middle part of the Persian Gulf were analyzed to obtain a better understanding of the general circulation pattern in the deep parts of the water body. Moreover, the variation of the horizontal velocity in vertical direction was sophisticatedly reproduced by the numerical model. The results of this research are of help to understand the gulf-scale processes of the Persian Gulf.

  6. Changes in the South Pacific deep water Nd isotope composition over the last 140 ka

    NASA Astrophysics Data System (ADS)

    Fröllje, Henning; Basak, Chandranath; Lamy, Frank; Gersonde, Rainer; Ullermann, Johannes; Pahnke, Katharina

    2015-04-01

    The Southern Ocean plays a central role in the global overturning circulation of the ocean through the formation of intermediate and bottom waters and the import and redistribution of deep waters from all major ocean basins that make up Circumpolar Deep Water (CDW). The South Pacific is an ideal location to study the evolution of CDW over the last glacial-interglacial cycles with little direct overprint by fluctuating North Atlantic Deep Water (NADW) input. Here were present a 140ky-long record of neodymium isotope ratios (143Nd/144Nd, expressed as ɛNd) analyzed on fossil fish teeth and debris from sediment core PS75/056-1 (55° 09.74 S, 114° 47.31 W, 3581 m water depth) in the open South Pacific that is bathed today by Lower Circumpolar Deep Water (LCDW) with a small contribution from Pacific Deep Water. The Late Holocene and Marine Isotope Stage (MIS) 5 ɛNd values of -7.5 to -7.7 are close to the modern seawater isotopic composition near the core site [1]. Glacial ɛNd of about -6 is observed during MIS 2 and 6. The decrease in the ɛNd record during the penultimate deglaciation is more gradual compared to that during the last deglaciation and the most negative values of the last interglacial are reached during MIS 5c. The transition from MIS 5 into MIS 4 is characterized by a shift towards more negative ɛNd (-6.5) but full glacial values are not reached. The change to more positive ɛNd at the MIS 4/3 transition is followed by a long-term increase to maximum values reached during the last glacial maximum. The timing of the observed transitions is comparable to a nearby δ13C record (core E11-2) [2] and to published ɛNd records from the deep South Atlantic and Indian Oceans [3, 4]. We observe consistently more positive absolute ɛNd values in the South Pacific compared to the Atlantic. The offset is around one ɛNd unit during cold periods (MIS 2, 4, 6) and 1.5 ɛNd units during the interglacials. During MIS 3, on the other hand, there is little difference

  7. APL-UW Deep Water Propagation: Philippine Sea Signal Physics and North Pacific Ambient Noise

    DTIC Science & Technology

    2015-10-15

    DISTRIBUTION STATEMENT A: Approved for public release: distribution is unlimited APL-UW Deep Water Propagation: Philippine Sea Signal Physics and...2015 1 Abstract We proposed a program involving two inter-related components of ASW: signal and noise. Deep water signal propagation is largely thought...fundamental statis- tics of broadband low-frequency acoustical signals evolve during propagation through a dynamically-varying deep ocean, and how

  8. Advection of North Atlantic Deep Water from the Labrador Sea to the southern hemisphere

    NASA Astrophysics Data System (ADS)

    Rhein, Monika; Kieke, Dagmar; Steinfeldt, Reiner

    2015-04-01

    Recently formed Labrador Seawater (LSW) and overflow water from Denmark Strait (DSOW) are main components of the Atlantic Meridional Overturning Circulation. Both exhibit a distinct chlorofluorocarbon (CFC) maximum. Here we use 25 years of CFC observations in the Atlantic to study the main features of the circulation of LSW and DSOW. From the CFC data, the age and fraction of young deep water are inferred. Due to the superior spatial data resolution compared to former attempts, regional differences in the spreading velocity and pathways of young deep water become evident, dependent on the regional circulation. The observed distributions of young LSW and DSOW showed that the DWBC is the fastest pathway to reach the southern hemisphere. The downstream decrease of the fractions of young LSW in the DWBC is slower compared to model studies. From 47°N to 42°N, DWBC transports of young LSW and DSOW decrease by 44% and 49%, respectively. At 26°N, the DWBC transport of young water is still 39% of the LSW formation rate and 44% of the DSOW overflow transport. Interior pathways also exist, especially in the subpolar North Atlantic and in the transition zone between the subpolar and subtropical gyre. Compared to DSOW, the distributions indicate a higher tendency for LSW to follow additional interior pathways. North of 45°N the major part of LSW is younger than 20 years. The general weakening of new LSW formation since the 1990s worked toward a homogenization between the LSW in the western and the eastern subpolar North Atlantic.

  9. Source and transport of human enteric viruses in deep municipal water supply wells

    USDA-ARS?s Scientific Manuscript database

    Until recently, few water utilities or researchers were aware of possible virus presence in deep aquifers and wells. Over the past several years, repeated detection of enteric viruses in water from deep wells in south-central Wisconsin, shows that viruses can be significant groundwater contaminants ...

  10. Carbon Sequestration through Sustainably Sourced Algal Fertilizer: Deep Ocean Water.

    NASA Astrophysics Data System (ADS)

    Sherman, M. T.

    2014-12-01

    Drawing down carbon from the atmosphere happens in the oceans when marine plants are growing due to the use of carbon dioxide for biological processes and by raising the pH of the water. Macro- and microscopic marine photosynthesizers are limited in their growth by the availability of light and nutrients (nitrogen, phosphorous, iron, etc.) Deep ocean water (DOW), oceanic water from bellow about 1000m, is a natural medium for marine algae, which contains all (except in rare circumstances) necessary components for algal growth and represents over 90% of the volume of the ocean. The introduction of DOW to a tropical or summer sea can increase chlorophyll from near zero to 60 mg per M3 or more. The form of the utilization infrastructure for DOW can roughly be divided into two effective types; the unconstrained release and the open pond system. Unconstrained release has the advantage of having relatively low infrastructure investment and is available to any area of the ocean. The open pond system has high infrastructure costs but enables intensive use of DOW for harvesting macro- and microalgae and sustainable mariculture. It also enables greater concomitant production of DOW's other potential products such as electricity or potable water. However, unlike an unconstrained release the open pond system can capture much of the biomaterial from the water and limits the impact to the surrounding ecosystem. The Tidal Irrigation and Electrical System (TIESystem), is an open pond that is to be constructed on a continental shelf. It harnesses the tidal flux to pump DOW into the pond on the rising tide and then uses the falling tide to pump biologically rich material out of the pond. This biomaterial represents fixed CO2 and can be used for biofuel or fertilizers. The TIESystem benefits from an economy of scale that increases at a rate that is roughly equal to the relationship of the circumference of a circle (the barrier that creates the open pond) to the area of the pond

  11. Suboxic deep seawater in the late Paleoproterozoic: Evidence from hematitic chert and iron formation related to seafloor-hydrothermal sulfide deposits, central Arizona, USA

    USGS Publications Warehouse

    Slack, J.F.; Grenne, Tor; Bekker, A.; Rouxel, O.J.; Lindberg, P.A.

    2007-01-01

    A current model for the evolution of Proterozoic deep seawater composition involves a change from anoxic sulfide-free to sulfidic conditions 1.8??Ga. In an earlier model the deep ocean became oxic at that time. Both models are based on the secular distribution of banded iron formation (BIF) in shallow marine sequences. We here present a new model based on rare earth elements, especially redox-sensitive Ce, in hydrothermal silica-iron oxide sediments from deeper-water, open-marine settings related to volcanogenic massive sulfide (VMS) deposits. In contrast to Archean, Paleozoic, and modern hydrothermal iron oxide sediments, 1.74 to 1.71??Ga hematitic chert (jasper) and iron formation in central Arizona, USA, show moderate positive to small negative Ce anomalies, suggesting that the redox state of the deep ocean then was at a transitional, suboxic state with low concentrations of dissolved O2 but no H2S. The presence of jasper and/or iron formation related to VMS deposits in other volcanosedimentary sequences ca. 1.79-1.69??Ga, 1.40??Ga, and 1.24??Ga also reflects oxygenated and not sulfidic deep ocean waters during these time periods. Suboxic conditions in the deep ocean are consistent with the lack of shallow-marine BIF ??? 1.8 to 0.8??Ga, and likely limited nutrient concentrations in seawater and, consequently, may have constrained biological evolution. ?? 2006 Elsevier B.V. All rights reserved.

  12. Suboxic deep seawater in the late Paleoproterozoic: Evidence from hematitic chert and iron formation related to seafloor-hydrothermal sulfide deposits, central Arizona, USA

    NASA Astrophysics Data System (ADS)

    Slack, J. F.; Grenne, T.; Bekker, A.; Rouxel, O. J.; Lindberg, P. A.

    2007-03-01

    A current model for the evolution of Proterozoic deep seawater composition involves a change from anoxic sulfide-free to sulfidic conditions 1.8 Ga. In an earlier model the deep ocean became oxic at that time. Both models are based on the secular distribution of banded iron formation (BIF) in shallow marine sequences. We here present a new model based on rare earth elements, especially redox-sensitive Ce, in hydrothermal silica-iron oxide sediments from deeper-water, open-marine settings related to volcanogenic massive sulfide (VMS) deposits. In contrast to Archean, Paleozoic, and modern hydrothermal iron oxide sediments, 1.74 to 1.71 Ga hematitic chert (jasper) and iron formation in central Arizona, USA, show moderate positive to small negative Ce anomalies, suggesting that the redox state of the deep ocean then was at a transitional, suboxic state with low concentrations of dissolved O 2 but no H 2S. The presence of jasper and/or iron formation related to VMS deposits in other volcanosedimentary sequences ca. 1.79-1.69 Ga, 1.40 Ga, and 1.24 Ga also reflects oxygenated and not sulfidic deep ocean waters during these time periods. Suboxic conditions in the deep ocean are consistent with the lack of shallow-marine BIF ˜ 1.8 to 0.8 Ga, and likely limited nutrient concentrations in seawater and, consequently, may have constrained biological evolution.

  13. Flood frequency matters: Why climate change degrades deep-water quality of peri-alpine lakes

    NASA Astrophysics Data System (ADS)

    Fink, Gabriel; Wessels, Martin; Wüest, Alfred

    2016-09-01

    Sediment-laden riverine floods transport large quantities of dissolved oxygen into the receiving deep layers of lakes. Hence, the water quality of deep lakes is strongly influenced by the frequency of riverine floods. Although flood frequency reflects climate conditions, the effects of climate variability on the water quality of deep lakes is largely unknown. We quantified the effects of climate variability on the potential shifts in the flood regime of the Alpine Rhine, the main catchment of Lake Constance, and determined the intrusion depths of riverine density-driven underflows and the subsequent effects on water exchange rates in the lake. A simplified hydrodynamic underflow model was developed and validated with observed river inflow and underflow events. The model was implemented to estimate underflow statistics for different river inflow scenarios. Using this approach, we integrated present and possible future flood frequencies to underflow occurrences and intrusion depths in Lake Constance. The results indicate that more floods will increase the number of underflows and the intensity of deep-water renewal - and consequently will cause higher deep-water dissolved oxygen concentrations. Vice versa, fewer floods weaken deep-water renewal and lead to lower deep-water dissolved oxygen concentrations. Meanwhile, a change from glacial nival regime (present) to a nival pluvial regime (future) is expected to decrease deep-water renewal. While flood frequencies are not expected to change noticeably for the next decades, it is most likely that increased winter discharge and decreased summer discharge will reduce the number of deep density-driven underflows by 10% and favour shallower riverine interflows in the upper hypolimnion. The renewal in the deepest layers is expected to be reduced by nearly 27%. This study underlines potential consequences of climate change on the occurrence of deep river underflows and water residence times in deep lakes.

  14. Fluorescence characteristics in the deep waters of South Gulf of México.

    PubMed

    Schifter, I; Sánchez-Reyna, G; González-Macías, C; Salazar-Coria, L; González-Lozano, C

    2017-09-07

    Vertical profiles of deep-water fluorescence determined by the chlorophyll sensor, polycyclic aromatic hydrocarbons, biomarkers, and other miscellaneous parameters measured in the southern Gulf of Mexico are reported. In the course of the survey, unexpected deep fluorescences were recorded (>1100m depth) in half of the 40 stations studied, a novel finding in this area of the Gulf. Currently, the deep-water fluorescence phenomenon is not completely understood, however we observe linear correlation between the fluorescence intensity and chlorophyll-α concentrations and coincidence of higher number of hydrocarbonoclastic bacteria in samples collected precisely in the deep-water fluorescence. This information is particularly interesting in relation to the Deepwater Horizon oil spill in 2010, in view that the aftermaths of the spill can be observed till today as oil plumes trapped in deep water layers that may disturb the natural water ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Climatically induced sedimentary cycles in Pliocene deep-water carbonates

    SciTech Connect

    Gardulski, A.F. )

    1991-03-01

    Two DSDP sites (86 and 94) on the Campeche ramp in the southern Gulf of Mexico penetrated more than 100 m of Pliocene pelagic ooze. The ooze is primarily carbonate, with a much smaller volcanic ash component than occurs in some Pleistocene sediments at these sites. Cores recovered from these holes display variations in carbonate mineralogy as well as total carbonate and sand abundances that are correlated with the oxygen isotope stratigraphy. Diagenetic loss of Mg-calcite is complete by the base of the Pleistocene, but aragonite, especially high-Sr aragonite forming algal needles that were transported off the shelf to the slope, persists through upper Pliocene cores. Variations in oxygen isotope ratios in planktonic foraminifera occur throughout the Pliocene, although the amplitude of those cycles is smaller than for the Pleistocene, with its more dramatic glacial-interglacial contrasts. As in overlying Pleistocene slope sediments, cooler intervals correspond with greater abundances of aragonite in the upper Pliocene section, reflecting a shift of the shallow, productive shelf seaward across the ramp surface during times of relatively low sea level. However, the aragonite abundances in the Pliocene are reduced on average compared to the Pleistocene. This difference is due in part to diagenetic loss, but also it likely reflects the overall higher sea level that apparently characterized Pliocene oceans, trapping more algal aragonite landward. Although sea level and climatic fluctuations were indeed less extreme in the Pliocene, they were still sufficient to generate sedimentary cycles in deep-water carbonates.

  16. Cellulomonas marina sp. nov., isolated from deep-sea water.

    PubMed

    Zhang, Limin; Xi, Lijun; Qiu, Danheng; Song, Lei; Dai, Xin; Ruan, Jisheng; Huang, Ying

    2013-08-01

    A bacterial strain FXJ8.089(T) was isolated from deep-sea water collected from the southwest Indian Ocean (49° 39' E 37° 47' S) at a depth of 2800 m, and its taxonomic position was investigated by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FXJ8.089(T) belonged to the genus Cellulomonas and had the highest similarities with Cellulomonas oligotrophica (96.9 %) and Cellulomonas aerilata (96.6 %). It contained MK-9(H4) as the predominant menaquinone. The polar lipids were diphosphatidylglycerol and phosphatidylinositol mannosides. The cell-wall peptidoglycan type was A4β with an interpeptide bridge L-Orn-D-Glu. The cell-wall sugars were glucose, mannose and ribose. The DNA G+C content was 70.3 mol%. The strain also showed a number of physiological and biochemical characteristics that were distinct from the closely related species. Based on phenotypic and genotypic data, strain FXJ8.089(T) (= CGMCC 4.6945(T) = DSM 24960(T)) represents a novel species of the genus Cellulomonas, for which the name Cellulomonas marina sp. nov. is proposed.

  17. Deuterium in interstitial water from deep-sea cores

    USGS Publications Warehouse

    Friedman, I.; Hardcastle, K.

    1988-01-01

    As part of the Joint Oceanographic Institutions Deep Earth Sampling project, the interstitial waters of cores from 69 holes were sampled for deuterium analysis to examine changes in the deuterium content of the oceans with time. Changes in the abundance of deuterium can be related to changes in the amount of ice stored in continental glaciers, inasmuch as precipitation in the form of snow is highly depleted in deuterium compared with the oceans. Many of the cores show a change in isotopic composition of samples from early to late Miocene that can be ascribed to the buildup of the Antarctic ice sheets. After correcting for the role of diffusion in reducing the isotopic contrast between samples from a single core, we estimate an incrase of 10 per mil (???) ??D (corresponding to a ??18O change of about 1.2???) between the early and late Miocene. A similar analysis of Pleistocene to Holocene changes indicates a ??D rise of 8??? during the time of maximum continental ice, which corresponds to a ??18O increase of about 1.0???. On the basis of limited data, we find no ??D change in the oceans from Cretaceous to Miocene. -from Authors

  18. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    SciTech Connect

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-08-12

    We are now entering the final stages of our ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342). We have now developed several techniques to help distinguish economic hydrocarbon deposits from false ''Fizz'' gas signatures. These methods include using the proper in situ rock and fluid properties, evaluating interference effects on data, and doing better constrained inversions for saturations. We are testing these techniques now on seismic data from several locations in the Gulf of Mexico. In addition, we are examining the use of seismic attenuation as indicated by frequency shifts below potential reservoirs. During this quarter we have: Began our evaluation of our latest data set over the Neptune Field; Developed software for computing composite reflection coefficients; Designed and implemented stochastic turbidite reservoir models; Produced software & work flow to improve frequency-dependent AVO analysis; Developed improved AVO analysis for data with low signal-to-noise ratio; and Examined feasibility of detecting fizz gas using frequency attenuation. Our focus on technology transfer continues, both by generating numerous presentations for the upcoming SEG annual meeting, and by beginning our planning for our next DHI minisymposium next spring.

  19. Measurement techniques for in situ stresses around underground constructions in a deep clay formation

    NASA Astrophysics Data System (ADS)

    Verstricht, J.; Areias, L.; Bastiaens, W.; Li, X. L.

    2010-06-01

    Disposal in deep underground geological formations is internationally recognized as the most viable option for the long-term management of high-level radioactive waste. In Belgium, the Boom clay formation is extensively studied in this context, in particular at the 225 m deep HADES Underground Research Facility in Mol. A cost-effective design of deep underground structures requires an accurate assessment of the in situ stresses; a good estimation of these stresses is also essential when interpreting in situ experiments regarding the hydro-mechanical behaviour of the host formation. Different measurement techniques are available to provide data on the stress evolution and other mechanical properties of the geological formation. The measurement can be direct (measurement of total pressure), or it can be an indirect technique, deriving the stress from related quantities such as strain (changes) in structural members. Most total stress measurements are performed through permanently installed sensors; also once-only measurements are performed through specific methods (e.g. pressuremeter). Direct measurement of the stress state is challenging due to the complex mechanical behaviour of the clay, and the fact that the sensor installation inevitably disturbs the original stress field. This paper describes ways to deal with these problems and presents the results obtained using different techniques at HADES.

  20. Deep-sea water improves cardiovascular hemodynamics in Kurosawa and Kusanagi-Hypercholesterolemic (KHC) rabbits.

    PubMed

    Katsuda, Shin-Ichiro; Yasukawa, Takeshi; Nakagawa, Koji; Miyake, Masao; Yamasaki, Masao; Katahira, Kiyoaki; Mohri, Motohiko; Shimizu, Tsuyoshi; Hazama, Akihiro

    2008-01-01

    Deep-sea water is rich in minerals, e.g., Mg, Ca, and K which have been considered to be associated with prevention of cardiovascular disease. We investigated the effect of deep-sea water on cardiovascular hemodynamics in Kurosawa and Kusanagi-Hypercholesterolemic (KHC) rabbits. Deep-sea water was pumped in the offing of Cape Muroto in Japan and the mineral constituents were refined to a degree of hardness of 1,000. Twenty four 4-month-old KHC rabbits were given refined deep-sea water (n=12) and tap water (n=12) for 6 months. Pressure and flow waves at the ascending aorta were recorded under pentobarbital anesthesia. Systolic, diastolic, pulse and mean arterial pressures and total peripheral resistance were significantly lower in the deep-sea water group than in the control group. There were no significant differences in changes in serum lipid levels, plasma renin and angiotensin converting enzyme activities and electrolyte levels except for Mg(2+) after the feeding of the water between the two groups. A slight increase in serum Mg(2+) level in the deep-sea water group may not account for the inhibition of mild hypertension. From our results, we conclude that deep-sea water could improve cardiovascular hemodynamics, even though the factors which affect the blood pressure are still unknown.

  1. Stability of steep gravity capillary solitary waves in deep water

    NASA Astrophysics Data System (ADS)

    Calvo, David C.; Akylas, T. R.

    2002-02-01

    The stability of steep gravity capillary solitary waves in deep water is numerically investigated using the full nonlinear water-wave equations with surface tension. Out of the two solution branches that bifurcate at the minimum gravity capillary phase speed, solitary waves of depression are found to be stable both in the small-amplitude limit when they are in the form of wavepackets and at finite steepness when they consist of a single trough, consistent with observations. The elevation-wave solution branch, on the other hand, is unstable close to the bifurcation point but becomes stable at finite steepness as a limit point is passed and the wave profile features two well-separated troughs. Motivated by the experiments of Longuet-Higgins & Zhang (1997), we also consider the forced problem of a localized pressure distribution applied to the free surface of a stream with speed below the minimum gravity capillary phase speed. We find that the finite-amplitude forced solitary-wave solution branch computed by Vanden-Broeck & Dias (1992) is unstable but the branch corresponding to Rayleigh’s linearized solution is stable, in agreement also with a weakly nonlinear analysis based on a forced nonlinear Schrödinger equation. The significance of viscous effects is assessed using the approach proposed by Longuet-Higgins (1997): while for free elevation waves the instability predicted on the basis of potential-flow theory is relatively weak compared with viscous damping, the opposite turns out to be the case in the forced problem when the forcing is strong. In this régime, which is relevant to the experiments of Longuet-Higgins & Zhang (1997), the effects of instability can easily dominate viscous effects, and the results of the stability analysis are used to propose a theoretical explanation for the persistent unsteadiness of the forced wave profiles observed in the experiments.

  2. Reduced admixture of North Atlantic Deep Water to the deep central South Pacific during the last two glacial periods

    NASA Astrophysics Data System (ADS)

    Molina-Kescher, Mario; Frank, Martin; Tapia, Raúl; Ronge, Thomas A.; Nürnberg, Dirk; Tiedemann, Ralf

    2016-06-01

    The South Pacific is a sensitive location for the variability of the global oceanic thermohaline circulation given that deep waters from the Atlantic Ocean, the Southern Ocean, and the Pacific Basin are exchanged. Here we reconstruct the deep water circulation of the central South Pacific for the last two glacial cycles (from 240,000 years ago to the Holocene) based on radiogenic neodymium (Nd) and lead (Pb) isotope records complemented by benthic stable carbon data obtained from two sediment cores located on the flanks of the East Pacific Rise. The records show small but consistent glacial/interglacial changes in all three isotopic systems with interglacial average values of -5.8 and 18.757 for ɛNd and 206Pb/204Pb, respectively, whereas glacial averages are -5.3 and 18.744. Comparison of this variability of Circumpolar Deep Water (CDW) to previously published records along the pathway of the global thermohaline circulation is consistent with reduced admixture of North Atlantic Deep Water to CDW during cold stages. The absolute values and amplitudes of the benthic δ13C variations are essentially indistinguishable from other records of the Southern Hemisphere and confirm that the low central South Pacific sedimentation rates did not result in a significant reduction of the amplitude of any of the measured proxies. In addition, the combined detrital Nd and strontium (87Sr/86Sr) isotope signatures imply that Australian and New Zealand dust has remained the principal contributor of lithogenic material to the central South Pacific.

  3. [Microbiological processes at the interface of aerobic and anaerobic waters in the deep-water zone of the Black Sea].

    PubMed

    Pimenov, N V; Rusanov, I I; Iusupov, S K; Fridrich, J; Lein, A Iu; Wehrli, B; Ivanov, M V

    2000-01-01

    Chemical and key microbiological processes (assimilation of carbon dioxide, oxidation and formation of methane, and sulfate reduction) occurring at the boundary between the aerobic-anaerobic interface in the deep-water zone of the Black Sea were investigated. Measurements were taken at depths from 90 to 300 m at intervals of 5-10 m. The integral rate of the dark assimilation of carbon dioxide varied from 120 to 207 mg C/(m2 day) with a maximum at the boundary of cyclonic currents. The organic matter (OM) formed from methane comprised less than 5% of the OM formed from carbon dioxide. A comparison between the rates of methane oxidation and methane production suggests that methane that is oxidized at depths from 100 to 300 m was formed in deeper water horizons. The maximum rate of sulfate reduction (1230 mg S/(m2 day)) was observed in the western halistatic region, and the minimum rate (490 mg S/(m2 day)), in the eastern halistatic region. The average rate of hydrogen sulfide production measured at three deep-sea stations amounted to 755 mg S/(m2 day), or 276 g S/(m2 year).

  4. Nonrainfall water origins and formation mechanisms

    PubMed Central

    Kaseke, Kudzai Farai; Wang, Lixin; Seely, Mary K.

    2017-01-01

    Dryland ecosystems cover 40% of the total land surface on Earth and are defined broadly as zones where precipitation is considerably less than the potential evapotranspiration. Nonrainfall waters (for example, fog and dew) are the least-studied and least-characterized components of the hydrological cycle, although they supply critical amounts of water for dryland ecosystems. The sources of nonrainfall waters are largely unknown for most systems. In addition, most field and modeling studies tend to consider all nonrainfall inputs as a single category because of technical constraints, which hinders prediction of dryland responses to future warming conditions. This study uses multiple stable isotopes (2H, 18O, and 17O) to show that fog and dew have multiple origins and that groundwater in drylands can be recycled via evapotranspiration and redistributed to the upper soil profile as nonrainfall water. Surprisingly, the non–ocean-derived (locally generated) fog accounts for more than half of the total fog events, suggesting a potential shift from advection-dominated fog to radiation-dominated fog in the fog zone of the Namib Desert. This shift will have implications on the flora and fauna distribution in this fog-dependent system. We also demonstrate that fog and dew can be differentiated on the basis of the dominant fractionation (equilibrium and kinetic) processes during their formation using the 17O-18O relationship. Our results are of great significance in an era of global climate change where the importance of nonrainfall water increases because rainfall is predicted to decline in many dryland ecosystems. PMID:28345058

  5. Nonrainfall water origins and formation mechanisms.

    PubMed

    Kaseke, Kudzai Farai; Wang, Lixin; Seely, Mary K

    2017-03-01

    Dryland ecosystems cover 40% of the total land surface on Earth and are defined broadly as zones where precipitation is considerably less than the potential evapotranspiration. Nonrainfall waters (for example, fog and dew) are the least-studied and least-characterized components of the hydrological cycle, although they supply critical amounts of water for dryland ecosystems. The sources of nonrainfall waters are largely unknown for most systems. In addition, most field and modeling studies tend to consider all nonrainfall inputs as a single category because of technical constraints, which hinders prediction of dryland responses to future warming conditions. This study uses multiple stable isotopes ((2)H, (18)O, and (17)O) to show that fog and dew have multiple origins and that groundwater in drylands can be recycled via evapotranspiration and redistributed to the upper soil profile as nonrainfall water. Surprisingly, the non-ocean-derived (locally generated) fog accounts for more than half of the total fog events, suggesting a potential shift from advection-dominated fog to radiation-dominated fog in the fog zone of the Namib Desert. This shift will have implications on the flora and fauna distribution in this fog-dependent system. We also demonstrate that fog and dew can be differentiated on the basis of the dominant fractionation (equilibrium and kinetic) processes during their formation using the (17)O-(18)O relationship. Our results are of great significance in an era of global climate change where the importance of nonrainfall water increases because rainfall is predicted to decline in many dryland ecosystems.

  6. Volume and accessibility of entrained (solution) methane in deep geopressured reservoirs - tertiary formations of the Texas Gulf Coast. Final report

    SciTech Connect

    Gregory, A.R.; Dodge, M.M.; Posey, J.S.; Morton, R.A.

    1980-10-01

    The objective of this project was to appraise the total volume of in-place methane dissolved in formation waters of deep sandstone reservoirs of the onshore Texas Gulf Coast within the stratigraphic section extending from the base of significant hydrocarbon production (8000 ft)* to the deepest significant sandstone occurrence. The area of investigation is about 50,000 mi/sup 2/. Factors that determine the total methane resource are reservoir bulk volume, porosity, and methane solubility; the latter is controlled by the temperature, pressure, and salinity of formation waters. Regional assessment of the volume and the distribution of potential sandstone reservoirs was made from a data base of 880 electrical well logs, from which a grid of 24 dip cross sections and 4 strike cross sections was constructed. Solution methane content in each of nine formations or divisions of formations was determined for each subdivision. The distribution of solution methane in the Gulf Coast was described on the basis of five reservoir models. Each model was characterized by depositional environment, reservoir continuity, porosity, permeability, and methane solubility.

  7. Venting formation fluids from deep-sea boreholes in a ridge flank setting: ODP Sites 1025 and 1026

    NASA Astrophysics Data System (ADS)

    Wheat, C. Geoffrey; Jannasch, Hans W.; Kastner, Miriam; Plant, Josh N.; Decarlo, Eric H.; Lebon, Geoff

    2004-08-01

    During ODP Leg 168, two of ten boreholes, ODP Holes 1025C and 1026B, were cased through the sediment section, penetrated basaltic crust that is overpressured, and sealed. In 1999 and 2000 the seals were removed, allowing crustal formation fluids to vent and be sampled. The composition of these fluids is compared to those of basal deep-sea pore waters, which have been the basis for estimating geochemical fluxes from low-temperature ridge flank hydrothermal systems. Estimates for the composition of the major ions in formation fluids based on basal pore waters are within 5% of the values measured in borehole fluids. Similar comparisons for minor and trace elements are not as good; some are reactive in the sediment section, resulting in large uncertainties in the pore water extrapolation, while others are influenced by a variety of contaminants, including steel, grease, drilling muds, and basal sediment. Evidence for contamination includes high dissolved and particulate concentrations of several metals (e.g., Fe, Cu, Co, Zn, and Pb) and measurable changes in concentration during the past four years in response to reaction with basal sediment. This new confidence in estimating the primary composition of formation fluids, coupled with advances in thermodynamic and kinetic models, reveals the possibility of anhydrite precipitation in ridge flank hydrothermal systems at temperatures of ˜70°C. Such new insights allow us to address the timing and conditions under which seawater-crustal reactions occur, leading to more accurate models of crustal evolution.

  8. New records of Primnoidae (Cnidaria: Octocorallia) in Brazilian deep waters

    NASA Astrophysics Data System (ADS)

    Arantes, Renata C. M.; Loiola, Livia L.

    2014-01-01

    The knowledge of octocorals occurring in Brazilian deep waters is still lacking, with only a few studies conducted so far, most of which focused on large-scale marine habitats characterization. Primnoidae are common and characteristic of seamounts and deepwater coral banks, often providing habitat for other marine species. Although primnoids occur in all ocean basins, only Primnoella and Plumarella species were recorded along the Brazilian coast before this study. Primnoid specimens were obtained through dredging and remotely operated vehicles (ROV) sampling, collected by research projects conducted off the Brazilian coast, between 15 and 34°S. Taxonomic assessment resulted in 5 new records of Primnoidae genera in Brazil: Calyptrophora, Candidella, Dasystenella, Narella and Thouarella. The occurrences of Narella-off Salvador and Vitória, and in Campos Basin (935-1700 m), and Calyptrophora-in Campos Basin (1059-1152 m), are herein reported for the first time in the South Atlantic. Calyptrophora microdentata was previously known in Lesser Antilles, New England and Corner Rise Seamounts, between 686 and 2310 m. Candidella imbricata geographical distribution includes Western and Eastern Atlantic (514-2063 m and 815-2139 m, respectively), being registered herein in Campos Basin, between 1059 and 1605 m. Dasystenella acanthina collected off Rio Grande do Sul state (810 m) and occurs also off Argentina and Southern Ocean, between 150 and 5087 m. Plumarella diadema, which type locality is off São Sebastião, Brazil, has its geographical range extended northwards, occurring in Campos Basin (650 m). Thouarella koellikeri previously known for Patagonia and Antartic Peninsula, is registered for the off Brazil for the first time, in Campos Basin and off São Sebastião (609-659 m). There is a lot of work yet to be done in terms of taxonomic knowledge of Brazilian deep-sea octocorals. Research projects focusing on the investigations, including ROV sampling, of other

  9. The Relationship of the Smectite-Illite Conversion to Pore Water Salinity Trends, Deep Water Offshore Niger Delta

    NASA Astrophysics Data System (ADS)

    Fitts, T. G.; Summa, L. L.

    2002-12-01

    Petroleum exploration in the deepwater Niger Delta has produced an abundance of physical property data and geochemical information in the section from 500 to 4000m below the seafloor. These have improved our understanding of the links between diagenetic processes and changes in pore fluid chemistry, and further suggest that smectite dehydration is not a major contributor to overpressure in the section. Literature data, coupled with new log, x-ray diffraction and surface area measurements, suggest that smectite and mixed-layer illite-smectite are major components of Miocene to Recent shales in key deep water wells. The smectite-illite transformation is generally complete by 2000m bml, corresponding to 80-90 degrees C. Such high percentages of hydrated clays result in sediments with low shallow overburden stresses, permeabilities and thermal conductivities. Because of the large contribution of smectite interlayer water to the total water content, diagenetic alteration of smectite more strongly affects density and pore fluid chemistry profiles here than in areas with less hydrated clay. Coincident with the conversion of smectite to illite, the total dissolved solids in the pore waters from several wells in the deepwater Niger Delta decrease from near seawater values at the sea floor to approximatly 10,000 ppm at 2000m bml. Pore fluid composition estimates are derived primarily from log calculation of water resistivity, with limited confirmation from pressure gradients in water legs, and uncontaminated MDT fluid samples. There are two models that could account for the observed decrease in salinity with depth: freshwater incursion via long-distance lateral fluid flow through continuous aquifers, and release of interlayer water from smectite during diagenesis. The available data suggest that release of interlayer water is the most likely explanation for the salinity observations from deep water Nigeria. Freshwater incursions are more likely on the shallow water shelf

  10. Geology of deep-water sandstones in the Mississippi Stanley Shale at Cossatot Falls, Arkansas

    SciTech Connect

    Coleman, J.L. Jr. )

    1993-09-01

    The Mississippian Stanley Shale crops out along the Cossatot River in the Ouachita Mountains of western Arkansas. Here, exposures of deep-water sandstones and shales, on recently established public lands, present a rare, three-dimensional look at sandstones of the usually obscured Stanley. Cossatot Falls, within the Cossatot River State Park Natural Area, is a series of class IV and V rapids developed on massive- to medium-bedded quartz sandstones on the northern flank of an asymmetric, thrust-faulted anticline. In western Arkansas, the Stanley Shale is a 10,000-ft (3200-m) succession of deep-water sandstone and shale. At Cossatot Falls, approximately 50 ft (155 m) of submarine-fan-channel sedimentary rocks are exposed during low-river stages. This section is composed primarily of sets of thinning-upward sandstone beds. With rare exceptions, the sandstones are turbidites, grading from massive, homogeneous, basal beds upward through festoon-cross-bedded thick beds, into rippled medium and thin beds. Sandstone sets are capped by thin shales and siltstones. Regional, north-northwestward paleocurrent indicators are substantiated by abundant, generally east-west ripple crests asymmetric to the north-northwest. Flute casts at the top of the sandstone sequence indicate an additional east-ward flow component. Based on regional, lithologic characteristics, the sandstones at Cossatot Falls appear to be within the Moyers Formation. The Moyers is the upper sandstone unit of the Stanley and is an oil and gas reservoir in the eastern Oklahoma Ouachita Mountains.

  11. Documentation of a deep percolation model for estimating ground-water recharge

    USGS Publications Warehouse

    Bauer, H.H.; Vaccaro, J.J.

    1987-01-01

    A deep percolation model, which operates on a daily basis, was developed to estimate long-term average groundwater recharge from precipitation. It has been designed primarily to simulate recharge in large areas with variable weather, soils, and land uses, but it can also be used at any scale. The physical and mathematical concepts of the deep percolation model, its subroutines and data requirements, and input data sequence and formats are documented. The physical processes simulated are soil moisture accumulation, evaporation from bare soil, plant transpiration, surface water runoff, snow accumulation and melt, and accumulation and evaporation of intercepted precipitation. The minimum data sets for the operation of the model are daily values of precipitation and maximum and minimum air temperature, soil thickness and available water capacity, soil texture, and land use. Long-term average annual precipitation, actual daily stream discharge, monthly estimates of base flow, Soil Conservation Service surface runoff curve numbers, land surface altitude-slope-aspect, and temperature lapse rates are optional. The program is written in the FORTRAN 77 language with no enhancements and should run on most computer systems without modifications. Documentation has been prepared so that program modifications may be made for inclusions of additional physical processes or deletion of ones not considered important. (Author 's abstract)

  12. North Atlantic Deep Water Formation: Information from Ice Cores

    NASA Technical Reports Server (NTRS)

    Oeschger, H.

    1984-01-01

    The main results of measurements of the CO2 concentration of air occluded in natural ice during periods of climatic change are presented, as well as other measured ice core parameters. Elements of an interpretation of the data in terms of mechanisms of changing environmental systems are briefly discussed.

  13. Biogeochemical malfunctioning in sediments beneath a deep-water fish farm.

    PubMed

    Valdemarsen, Thomas; Bannister, Raymond J; Hansen, Pia K; Holmer, Marianne; Ervik, Arne

    2012-11-01

    We investigated the environmental impact of a deep water fish farm (190 m). Despite deep water and low water currents, sediments underneath the farm were heavily enriched with organic matter, resulting in stimulated biogeochemical cycling. During the first 7 months of the production cycle benthic fluxes were stimulated >29 times for CO(2) and O(2) and >2000 times for NH(4)(+), when compared to the reference site. During the final 11 months, however, benthic fluxes decreased despite increasing sedimentation. Investigations of microbial mineralization revealed that the sediment metabolic capacity was exceeded, which resulted in inhibited microbial mineralization due to negative feed-backs from accumulation of various solutes in pore water. Conclusions are that (1) deep water sediments at 8 °C can metabolize fish farm waste corresponding to 407 and 29 mmol m(-2) d(-1) POC and TN, respectively, and (2) siting fish farms at deep water sites is not a universal solution for reducing benthic impacts.

  14. Deglacial changes in the strength of deep southern component water and sediment supply at the Argentine continental margin

    NASA Astrophysics Data System (ADS)

    Warratz, Grit; Henrich, Rüdiger; Voigt, Ines; Chiessi, Cristiano M.; Kuhn, Gerhard; Lantzsch, Hendrik

    2017-08-01

    The deep southern component water (SCW), comprising Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW), is a major component of the global oceanic circulation. It has been suggested that the deep Atlantic water mass structure changed significantly during the last glacial/interglacial cycle. However, deep SCW source-proximal records remain sparse. Here we present three coherent deep SCW paleocurrent records from the deep Argentine continental margin shedding light on deep water circulation and deep SCW flow strength in the Southwest Atlantic since the Last Glacial Maximum (LGM). Based on increased sortable silt values, we propose enhanced deep SCW flow strength from 14 to 10 cal ka B.P. relative to the early deglacial/LGM and the Holocene. We propose a direct influence of deep northern component water (NCW) on deep SCW flow strength due to vertical narrowing of deep SCW spreading, concurrent with a migration of the high-energetic LCDW/AABW interface occupying our core sites. We suggest a shoaled NCW until 13 cal ka B.P., thereby providing space for deep SCW spreading that resulted in reduced carbonate preservation at our core sites. Increased carbonate content from 13 cal ka B.P. indicates that the NCW expanded changing deep water properties at our core sites in the deep Southwest Atlantic. However, southern sourced terrigenous sediments continued to be deposited at our core sites, suggesting that deep SCW flow was uninterrupted along the Argentine continental margin since the LGM.

  15. Distribution, formation, and seasonal variability of Okhotsk Sea Mode Water

    NASA Astrophysics Data System (ADS)

    Gladyshev, Sergey; Talley, Lynne; Kantakov, Gennady; Khen, Gennady; Wakatsuchi, Masaaki

    2003-06-01

    Russian historical data and recently completed conductivity-temperature-depth surveys are used to examine the formation and spread in the deep Ohkotsk Sea of dense shelf water (DSW) produced in the Okhotsk Sea polynyas. Isopycnal analysis indicates that all of the main polynyas contribute to the ventilation at σθ < 26.80, including the Okhotsk Sea Mode Water (OSMW), which has densities σθ = 26.7-27.0. At densities greater than 26.9 σθ the northwest polynya is the only contributor to OSMW. (Although Shelikhov Bay polynyas produce the densest water with σθ > 27.1, vigorous tidal mixing leads to outflow of water with a density of only about 26.7 σθ). In the western Okhotsk Sea the East Sakhalin Current rapidly transports modified dense shelf water along the eastern Sakhalin slope to the Kuril Basin, where it is subject to further mixing because of the large anticyclonic eddies and tides. Most of the dense water flows off the shelves in spring. Their average flux does not exceed 0.2 Sv in summer and fall. The shelf water transport and water exchange with the North Pacific cause large seasonal variations of temperature at densities of 26.7-27.0 σθ (depths of 150-500 m) in the Kuril Basin, where the average temperature minimum occurs in April-May, and the average temperature maximum occurs in September, with a range of 0.2°-0.7°C. The average seasonal variations of salinity are quite small and do not exceed 0.05 psu. The Soya Water mixed by winter convection, penetrating to depths greater than 200 m, in the southern Kuril Basin also produces freezing water with density greater than 26.7 σθ. Using a simple isopycnal box model and seasonal observations, the OSMW production rate is seen to increase in summer up to 2.2 ± 1.7 Sv, mainly because of increased North Pacific inflow, and drops in winter to 0.2 ± 0.1 Sv. A compensating decrease in temperature in the Kuril Basin implies a DSW volume transport of 1.4 ± 1.1 Sv from February through May. The

  16. Assessment of Deep Water Archaeological Sites with Autonomous Underwater Vehicles

    NASA Astrophysics Data System (ADS)

    Foley, B. P.; Ferrini, V. L.; Bingham, B. S.; Camilli, R.; Delaporta, K.; Kourkoumelis, D.

    2006-12-01

    Deep submergence vehicle technology has recently enabled significant advances in the rapid assessment of marine archaeological sites. Precisely navigated vehicles equipped with high resolution digital cameras and high-frequency multibeam sonar systems can be used to assess not only the distribution of wreckage, but to quantify the size, distribution, and condition of individual artifacts contained within the wreck. This information is critical to deriving new knowledge of ancient civilizations based on shipwreck sites. The Woods Hole Oceanographic Institution in collaboration with the Hellenic Ministry of Culture and the Hellenic Centre for Marine Research is conducting an ongoing program to document ancient shipwrecks and refine underwater archaeological survey methods. The first project took place in 2005 near the Aegean island, Chios, when the team deployed an Autonomous Underwater Vehicle to investigate a 4th century BC wreck in 70 m water depth. Multiple low speed (20 cm/sec) digital imaging and acoustic mapping surveys were conducted at an altitude of 2.5 m yielded 200+% coverage of the wreck. Multibeam data provide centimeter resolution of the site's bathymetry, and a subset of 6000+ overlapping digital images were used to generate a continuous photomosaic of the entire wreck at sub-centimeter resolution. The full survey of the 20 m x 7 m wreck took approximately 18 hours. The second season in 2006 resulted in the survey of a historic period warship. The combination of digital imagery and sonar data reveal information about these wrecks that would otherwise be difficult to quantify. For instance, the orientation, location, number, and preservation state of amphora cargo elements observed in high-resolution imagery can be used to determine the vessel's origin and order of lading. Additionally, first-order archaeological questions can be answered: age of the wreck, cultural origin of the vessel, dimensions of the site, computation of three-dimensional cargo

  17. Parvibaculum indicum sp. nov., isolated from deep-sea water.

    PubMed

    Lai, Qiliang; Wang, Liping; Liu, Yuhui; Yuan, Jun; Sun, Fengqin; Shao, Zongze

    2011-02-01

    A taxonomic study was carried out on strain P31(T), which was isolated from a polycyclic aromatic hydrocarbon (PAH)-degrading consortium enriched with deep-sea water of the Indian Ocean. The isolate was Gram-reaction-negative, rod-shaped, motile by means of a polar flagellum and incapable of reducing nitrate to nitrite. Growth was observed at 0.5-8 % NaCl and at 10-41 °C. Strain P31(T) was unable to degrade Tween 80 or gelatin. The major respiratory quinone was ubiquinone 11 (Q-11). The dominant fatty acids were C(18 : 1)ω7c (39.79 %), 11-methyl C(18 : 1)ω7c (17.84 %), C(19 : 0) cyclo ω8c (12.05 %) and C(18 : 0) (6.09 %). The G+C content of the chromosomal DNA was 62.1 mol%. A phylogenetic tree based on 16S rRNA gene sequence analysis showed that strain P31(T) and Parvibaculum lavamentivorans DS-1(T) formed a distinct lineage in the family Phyllobacteriaceae; these two strains showed 95.7 % sequence similarity, while similarities between P31(T) and other members of the genus Parvibaculum were below 93 %. Based on the genotypic and phenotypic data, strain P31(T) represents a novel species of the genus Parvibaculum, for which the name Parvibaculum indicum sp. nov. is proposed. The type strain is P31(T) (=CCTCC AB 208230(T) =LMG 24712(T) =MCCC 1A01132(T)).

  18. Nitratireductor indicus sp. nov., isolated from deep-sea water.

    PubMed

    Lai, Qiliang; Yu, Zhiwei; Yuan, Jun; Sun, Fengqin; Shao, Zongze

    2011-02-01

    A taxonomic study was carried out on a novel bacterial strain, designated C115(T), isolated from a crude-oil-degrading consortium, enriched from deep-sea water of the Indian Ocean. Cells were Gram-negative short rods, mobile by means of a monopolar flagellum. Growth was observed at salinities of 0-7 % and at 10-43 °C. It was unable to degrade Tween 80 or gelatin. 16S rRNA gene sequence analysis showed that strain C115(T) was related most closely to Nitratireductor aquibiodomus NL21(T) (96.5 % similarity), Nitratireductor kimnyeongensis KY 101(T) (96.4 %) and Nitratireductor basaltis J3(T) (96.2 %). The predominant fatty acids were summed feature 8 (C(18 : 1)ω7c and/or C(18 : 1)ω6c, 81.8 %) and C(18 : 0) (7.0 %). The G+C content of the chromosomal DNA of strain C115(T) was 59 mol%. Based on its morphology, physiology and fatty acid composition together with 16S rRNA gene sequence comparisons, the novel strain most appropriately belongs to the genus Nitratireductor, but can be distinguished readily from recognized species of the genus. Strain C115(T) is therefore considered to represent a novel species of the genus Nitratireductor, for which the name Nitratireductor indicus sp. nov. is proposed. The type strain is C115(T) (=RC92-7(T) =CCTCC AB 209298(T) =LMG 25540(T) =MCCC 1A01260(T)).

  19. Deep-water riser fatigue monitoring systems based on acoustic telemetry

    NASA Astrophysics Data System (ADS)

    Li, Baojun; Wang, Haiyan; Shen, Xiaohong; Yan, Yongsheng; Yang, Fuzhou; Hua, Fei

    2014-12-01

    Marine risers play a key role in the deep and ultra-deep water oil and gas production. The vortex-induced vibration (VIV) of marine risers constitutes an important problem in deep water oil exploration and production. VIV will result in high rates of structural failure of marine riser due to fatigue damage accumulation and diminishes the riser fatigue life. In-service monitoring or full scale testing is essential to improve our understanding of VIV response and enhance our ability to predict fatigue damage. One marine riser fatigue acoustic telemetry scheme is proposed and an engineering prototype machine has been developed to monitor deep and ultra-deep water risers' fatigue and failure that can diminish the riser fatigue life and lead to economic losses and eco-catastrophe. Many breakthroughs and innovation have been achieved in the process of developing an engineering prototype machine. Sea trials were done on the 6th generation deep-water drilling platform HYSY-981 in the South China Sea. The inclination monitoring results show that the marine riser fatigue acoustic telemetry scheme is feasible and reliable and the engineering prototype machine meets the design criterion and can match the requirements of deep and ultra-deep water riser fatigue monitoring. The rich experience and field data gained in the sea trial which provide much technical support for optimization in the engineering prototype machine in the future.

  20. Enhanced hypolipidemic effect and safety of red mold dioscorea cultured in deep ocean water.

    PubMed

    Lee, Chun-Lin; Kung, Yi-Hsin; Wang, Jyh-Jye; Lung, Tzu-Ying; Pan, Tzu-Ming

    2011-08-10

    Red mold dioscorea (RMD) produced by Monascus sp. was proven to be a hypolipidemic functional food. Deep ocean water (DOW), that is, water obtained from over 200 m deep in the ocean, was found to promote the growth of fungus via its mineral richness. On the basis of the advantages, this study used 650 m DOW as the culture water to culture Monascus purpuresus NTU 568 and produce the DOW-RMD. The goal of this study is to compare the difference between DOW-RMD and reverse osmosis water-cultured RMD (ROW-RMD) on the hypolipidemic effect. Hyperlipidemic hamsters were fed a high-cholesterol diet and administered various doses of DOW-RMD or ROW-RMD for 8 weeks. After sacrifice, biochemical analyses in serum, liver, and feces were carried out. The results showed that DOW-RMD had a greater effect on lowering cholesterol levels and lipid peroxidation in serum and lipid plaque in heart aorta than ROW-RMD. However, DOW was likely to modulate the Monascus metabolite biosynthesis pathway toward the formation of hypolipidemic yellow pigments (such as monascin and ankaflavin) rather than red pigments and the mycotoxin citrinin. In addition, the DOW with higher Mg(2+) ion was proven to absorb into DOW-RMD; however, the accumulation of Mg(2+) ions should contribute a greater hypolipidemic effect to DOW-RMD. Comprehensively, the DOW-induced metabolism modulation and the ions of DOW were a benefit to the development of safe DOW-RMD with low citrinin levels and high hypolipidemic, antiatherosclerosis, and anti-fatty liver effects.

  1. Morphological divergence between three Arctic charr morphs – the significance of the deep-water environment

    PubMed Central

    Skoglund, Sigrid; Siwertsson, Anna; Amundsen, Per-Arne; Knudsen, Rune

    2015-01-01

    Morphological divergence was evident among three sympatric morphs of Arctic charr (Salvelinus alpinus (L.)) that are ecologically diverged along the shallow-, deep-water resource axis in a subarctic postglacial lake (Norway). The two deep-water (profundal) spawning morphs, a benthivore (PB-morph) and a piscivore (PP-morph), have evolved under identical abiotic conditions with constant low light and temperature levels in their deep-water habitat, and were morphologically most similar. However, they differed in important head traits (e.g., eye and mouth size) related to their different diet specializations. The small-sized PB-morph had a paedomorphic appearance with a blunt head shape, large eyes, and a deep body shape adapted to their profundal lifestyle feeding on submerged benthos from soft, deep-water sediments. The PP-morph had a robust head, large mouth with numerous teeth, and an elongated body shape strongly related to their piscivorous behavior. The littoral spawning omnivore morph (LO-morph) predominantly utilizes the shallow benthic–pelagic habitat and food resources. Compared to the deep-water morphs, the LO-morph had smaller head relative to body size. The LO-morph exhibited traits typical for both shallow-water benthic feeding (e.g., large body depths and small eyes) and planktivorous feeding in the pelagic habitat (e.g., streamlined body shape and small mouth). The development of morphological differences within the same deep-water habitat for the PB- and PP-morphs highlights the potential of biotic factors and ecological interactions to promote further divergence in the evolution of polymorphism in a tentative incipient speciation process. The diversity of deep-water charr in this study represents a novelty in the Arctic charr polymorphism as a truly deep-water piscivore morph has to our knowledge not been described elsewhere. PMID:26357540

  2. Numerically Simulating Carbonate Mineralization of Basalt with Injection of Carbon Dioxide into Deep Saline Formations

    SciTech Connect

    White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Bacon, Diana H.

    2006-07-08

    The principal mechanisms for the geologic sequestration of carbon dioxide in deep saline formations include geological structural trapping, hydrological entrapment of nonwetting fluids, aqueous phase dissolution and ionization, and geochemical sorption and mineralization. In sedimentary saline formations the dominant mechanisms are structural and dissolution trapping, with moderate to weak contributions from hydrological and geochemical trapping; where, hydrological trapping occurs during the imbibition of aqueous solution into pore spaces occupied by gaseous carbon dioxide, and geochemical trapping is controlled by generally slow reaction kinetics. In addition to being globally abundant and vast, deep basaltic lava formations offer mineralization kinetics that make geochemical trapping a dominate mechanism for trapping carbon dioxide in these formations. For several decades the United States Department of Energy has been investigating Columbia River basalt in the Pacific Northwest as part of its environmental programs and options for natural gas storage. Recently this nonpotable and extensively characterized basalt formation is being reconsidered as a potential reservoir for geologic sequestration of carbon dioxide. The reservoir has an estimated storage capacity of 100 giga tonnes of carbon dioxide and comprises layered basalt flows with sublayering that generally alternates between low permeability massive and high permeability breccia. Chemical analysis of the formation shows 10 wt% Fe, primarily in the +2 valence. The mineralization reaction that makes basalt formations attractive for carbon dioxide sequestration is that of calcium, magnesium, and iron silicates reacting with dissolved carbon dioxide, producing carbonate minerals and amorphous quartz. Preliminary estimates of the kinetics of the silicate-to-carbonate reactions have been determined experimentally and this research is continuing to determine effects of temperature, pressure, rock composition and

  3. The geological history of deep-sea colonization by echinoids: roles of surface productivity and deep-water ventilation

    PubMed Central

    Smith, Andrew B; Stockley, Bruce

    2005-01-01

    The origins and geological history of the modern fauna of deep-sea echinoids is explored using a combination of palaeontological and molecular data. We demonstrate that, whereas generalist omnivores have migrated into the deep sea in low numbers over the past 200 Myr, there was a short time-interval between approximately 75 and 55 Myr when the majority of specialist detritivore clades independently migrated off-shelf. This coincides with a marked increase in seasonality, continental run-off and surface water productivity, and suggests that increasing organic carbon delivery into ocean basins was an important controlling factor. Oceanic anoxic events, by contrast, appear to have played a subsidiary role in controlling deep-sea diversity. PMID:15888420

  4. Disparate acidification and calcium carbonate desaturation of deep and shallow waters of the Arctic Ocean.

    PubMed

    Luo, Yiming; Boudreau, Bernard P; Mucci, Alfonso

    2016-09-23

    The Arctic Ocean is acidifying from absorption of man-made CO2. Current predictive models of that acidification focus on surface waters, and their results argue that deep waters will acidify by downward penetration from the surface. Here we show, with an alternative model, the rapid, near simultaneous, acidification of both surface and deep waters, a prediction supported by current, but limited, saturation data. Whereas Arctic surface water responds directly by atmospheric CO2 uptake, deeper waters will be influenced strongly by intrusion of mid-depth, pre-acidified, Atlantic Ocean water. With unabated CO2 emissions, surface waters will become undersaturated with respect to aragonite by 2105 AD and could remain so for ∼600 years. In deep waters, the aragonite saturation horizon will rise, reaching the base of the surface mixed layer by 2140 AD and likely remaining there for over a millennium. The survival of aragonite-secreting organisms is consequently threatened on long timescales.

  5. Disparate acidification and calcium carbonate desaturation of deep and shallow waters of the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Luo, Yiming; Boudreau, Bernard P.; Mucci, Alfonso

    2016-09-01

    The Arctic Ocean is acidifying from absorption of man-made CO2. Current predictive models of that acidification focus on surface waters, and their results argue that deep waters will acidify by downward penetration from the surface. Here we show, with an alternative model, the rapid, near simultaneous, acidification of both surface and deep waters, a prediction supported by current, but limited, saturation data. Whereas Arctic surface water responds directly by atmospheric CO2 uptake, deeper waters will be influenced strongly by intrusion of mid-depth, pre-acidified, Atlantic Ocean water. With unabated CO2 emissions, surface waters will become undersaturated with respect to aragonite by 2105 AD and could remain so for ~600 years. In deep waters, the aragonite saturation horizon will rise, reaching the base of the surface mixed layer by 2140 AD and likely remaining there for over a millennium. The survival of aragonite-secreting organisms is consequently threatened on long timescales.

  6. Disparate acidification and calcium carbonate desaturation of deep and shallow waters of the Arctic Ocean

    PubMed Central

    Luo, Yiming; Boudreau, Bernard P.; Mucci, Alfonso

    2016-01-01

    The Arctic Ocean is acidifying from absorption of man-made CO2. Current predictive models of that acidification focus on surface waters, and their results argue that deep waters will acidify by downward penetration from the surface. Here we show, with an alternative model, the rapid, near simultaneous, acidification of both surface and deep waters, a prediction supported by current, but limited, saturation data. Whereas Arctic surface water responds directly by atmospheric CO2 uptake, deeper waters will be influenced strongly by intrusion of mid-depth, pre-acidified, Atlantic Ocean water. With unabated CO2 emissions, surface waters will become undersaturated with respect to aragonite by 2105 AD and could remain so for ∼600 years. In deep waters, the aragonite saturation horizon will rise, reaching the base of the surface mixed layer by 2140 AD and likely remaining there for over a millennium. The survival of aragonite-secreting organisms is consequently threatened on long timescales. PMID:27659188

  7. Growth response of a deep-water ferromanganese crust to evolution of the Neogene Indian Ocean

    USGS Publications Warehouse

    Banakar, V.K.; Hein, J.R.

    2000-01-01

    A deep-water ferromanganese crust from a Central Indian Ocean seamount dated previously by 10Be and 230Th(excess) was studied for compositional and textural variations that occurred throughout its growth history. The 10Be/9Be dated interval (upper 32 mm) yields an uniform growth rate of 2.8 ?? 0.1 mm/Ma [Frank, M., O'Nions, R.K., 1998. Sources of Pb for Indian Ocean ferromanganese crusts: a record of Himalayan erosion. Earth Planet. Sci. Lett., 158, pp. 121-130.] which gives an extrapolated age of ~ 26 Ma for the base of the crust at 72 mm and is comparable to the maximum age derived from the Co-model based growth rate estimates. This study shows that Fe-Mn oxyhydroxide precipitation did not occur from the time of emplacement of the seamount during the Eocene (~ 53 Ma) until the late Oligocene (~ 26 Ma). This paucity probably was the result of a nearly overlapping palaeo-CCD and palaeo-depth of crust formation, increased early Eocene productivity, instability and reworking of the surface rocks on the flanks of the seamount, and lack of oxic deep-water in the nascent Indian Ocean. Crust accretion began (older zone) with the formation of isolated cusps of Fe-Mn oxide during a time of high detritus influx, probably due to the early-Miocene intense erosion associated with maximum exhumation of the Himalayas (op. cit.). This cuspate textured zone extends from 72 mm to 42 mm representing the early-Miocene period. Intense polar cooling and increased mixing of deep and intermediate waters at the close of the Oligocene might have led to the increased oxygenation of the bottom-water in the basin. A considerable expansion in the vertical distance between the seafloor depth and the CCD during the early Miocene in addition to the influx of oxygenated bottom-water likely initiated Fe-Mn crust formation. Pillar structure characterises the younger zone, which extends from 40 mm to the surface of the crust, i.e., ~ 15 Ma to Present. This zone is characterised by > 25% higher

  8. North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

    DTIC Science & Technology

    2016-06-21

    the "Special Issue on Deep-water Ocean Acoustics" in the Journal of the Acoustical Society of America (Vol. 134, No . 4, Pt. 2 of 2 , October20 13...15. SUBJECT TERMS ocean acoustics, deep water acousti c propagati on 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF a. REPORT b. ABSTRACT c...the 2009- 2011 NPAL Philippine Sea experiments funded by ONR Grant NOOO 14- 08-1-0840, although some additional work on deep-water ocean acoustics is

  9. Impact of water mass mixing on the biogeochemistry and microbiology of the Northeast Atlantic Deep Water

    NASA Astrophysics Data System (ADS)

    Reinthaler, Thomas; Álvarez Salgado, Xosé Antón; Álvarez, Marta; van Aken, Hendrik M.; Herndl, Gerhard J.

    2013-12-01

    The extent to which water mass mixing contributes to the biological activity of the dark ocean is essentially unknown. Using a multiparameter water mass analysis, we examined the impact of water mass mixing on the nutrient distribution and microbial activity of the Northeast Atlantic Deep Water (NEADW) along an 8000 km long transect extending from 62°N to 5°S. Mixing of four water types (WT) and basin scale mineralization from the site where the WT where defined to the study area explained up to 95% of the variability in the distribution of inorganic nutrients and apparent oxygen utilization. Mixing-corrected average O2:N:P mineralization ratios of 127(±11):13.0(±0.7):1 in the core of the NEADW suggested preferential utilization of phosphorus compounds while dissolved organic carbon mineralization contributed a maximum of 20% to the oxygen demand of the NEADW. In conjunction with the calculated average mineralization ratios, our results indicate a major contribution of particulate organic matter to the biological activity in the NEADW. The variability in prokaryotic abundance, high nucleic acid containing cells, and prokaryotic heterotrophic production in the NEADW was explained by large scale (64-79%) and local mineralization processes (21-36%), consistent with the idea that deep-water prokaryotic communities are controlled by substrate supply. Overall, our results suggest a major impact of mixing on the distribution of inorganic nutrients and a weaker influence on the dissolved organic matter pool supporting prokaryotic activity in the NEADW.

  10. Impact of water mass mixing on the biogeochemistry and microbiology of the Northeast Atlantic Deep Water

    PubMed Central

    Reinthaler, Thomas; Salgado, Xosé Antón Álvarez; Álvarez, Marta; van Aken, Hendrik M.; Herndl, Gerhard J.

    2014-01-01

    The extent to which water mass mixing contributes to the biological activity of the dark ocean is essentially unknown. Using a multiparameter water mass analysis, we examined the impact of water mass mixing on the nutrient distribution and microbial activity of the Northeast Atlantic Deep Water (NEADW) along an 8000 km long transect extending from 62°N to 5°S. Mixing of four water types (WT) and basin scale mineralization from the site where the WT where defined to the study area explained up to 95% of the variability in the distribution of inorganic nutrients and apparent oxygen utilization. Mixing-corrected average O2:N:P mineralization ratios of 127(±11):13.0(±0.7):1 in the core of the NEADW suggested preferential utilization of phosphorus compounds while dissolved organic carbon mineralization contributed a maximum of 20% to the oxygen demand of the NEADW. In conjunction with the calculated average mineralization ratios, our results indicate a major contribution of particulate organic matter to the biological activity in the NEADW. The variability in prokaryotic abundance, high nucleic acid containing cells, and prokaryotic heterotrophic production in the NEADW was explained by large scale (64–79%) and local mineralization processes (21–36%), consistent with the idea that deep-water prokaryotic communities are controlled by substrate supply. Overall, our results suggest a major impact of mixing on the distribution of inorganic nutrients and a weaker influence on the dissolved organic matter pool supporting prokaryotic activity in the NEADW. PMID:24683294

  11. Transport of sludge-derived organic pollutants to deep-sea sediments at deep water dump site 106

    USGS Publications Warehouse

    Takada, H.; Farrington, J.W.; Bothner, Michael H.; Johnson, C.G.; Tripp, B.W.

    1994-01-01

    Linear alkylbenzenes (LABs), coprostanol and epi-coprostanol, were detected in sediment trap and bottom sediment samples at the Deep Water Dump Site 106 located 185 km off the coast of New Jersey, in water depths from 2400 to 2900 m. These findings clearly indicate that organic pollutants derived from dumped sludge are transported through the water column and have accumulated on the deep-sea floor. No significant difference in LABs isomeric composition was observed among sludge and samples, indicating little environmental biodegradation of these compounds. LABs and coprostanol have penetrated down to a depth of 6 cm in sediment, indicating the mixing of these compounds by biological and physical processes. Also, in artificially resuspended surface sediments, high concentrations of LABs and coprostanols were detected, implying that sewage-derived organic pollutants initially deposited on the deep-sea floor can be further dispersed by resuspension and transport processes. Small but significant amounts of coprostanol were detected in the sediment from a control site at which no LABs were detected. The coprostanol is probably derived from feces of marine mammals and sea birds and/or from microbial or geochemical transformations of cholesterol. Polcyclic aromatic hydrocarbons (PAHs) in sediment trap samples from the dump site were largely from the sewage sludge and had a mixed petroleum and pyrogenic composition. In contrast, PAHs in sediments in the dump site were mainly pyrogenic; contributed either from sewage sludge or from atmospheric transport to the overlying waters. & 1994 American Chemical Society.

  12. 75 FR 23189 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-03

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using Trawl Gear in the Gulf of Alaska... comprise the deep-water species fishery by vessels using trawl gear in the Gulf of Alaska (GOA). This... prohibiting directed fishing for the deep-water species fishery by vessels using trawl gear in the GOA....

  13. 77 FR 46338 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using Trawl Gear in the Gulf of Alaska... comprise the deep-water species fishery by vessels using trawl gear in the Gulf of Alaska (GOA). This..., NMFS is prohibiting directed fishing for the deep-water species fishery by vessels using trawl gear...

  14. 76 FR 23511 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using Trawl Gear in the Gulf of Alaska... comprise the deep-water species fishery by vessels using trawl gear in the Gulf of Alaska (GOA). This... prohibiting directed fishing for the deep-water species fishery by vessels using trawl gear in the GOA....

  15. 77 FR 24154 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-23

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Vessels Using Trawl Gear in the Gulf of Alaska... comprise the deep-water species fishery by vessels using trawl gear in the Gulf of Alaska (GOA). This... specified for the deep-water species fishery in the GOA has been reached. DATES: Effective 1200 hrs, Alaska...

  16. 76 FR 39790 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher Vessels in the Gulf of Alaska AGENCY... the deep-water species fishery for catcher vessels subject to sideboard limits established under the... Pacific halibut prohibited species catch (PSC) sideboard limit specified for the deep-water...

  17. 75 FR 38939 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher/Processor Rockfish Cooperatives in the Gulf... for species that comprise the deep-water species fishery by catcher/processor rockfish cooperatives... limit specified for the deep-water species fishery by catcher/processor rockfish cooperatives subject...

  18. 75 FR 38937 - Fisheries of the Economic Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Exclusive Zone Off Alaska; Deep-Water Species Fishery by Catcher Vessels in the Gulf of Alaska AGENCY... the deep-water species fishery for catcher vessels subject to sideboard limits established under the... Pacific halibut prohibited species catch (PSC) sideboard limit specified for the deep-water...

  19. Deep water exchanges between the South China Sea and the Pacific since the last glacial period

    NASA Astrophysics Data System (ADS)

    Wan, Sui; Jian, Zhimin

    2014-12-01

    Deep ocean circulation is widely considered as one of the important factors for increasing CO2 concentration and decreasing radiocarbon activity (Δ14C) of the atmosphere during the last deglaciation. The AMS 14C ages of benthic and planktonic foraminifers from 18 samples of Core MD05-2904 (water depth of 2066 m) in the northern South China Sea (SCS) and 15 samples of Core MD05-2896 (water depth of 1657 m) in the southern SCS were analyzed in this study for reconstructing the intrabasin deep oceanic processes and hence exploring the deep water exchanges between the SCS and the Pacific since the last glacial period. The results show that during the Holocene the average apparent ventilation age of deep water was younger in the southern SCS (~1350 years) than in the northern SCS (~1850 years) due to relatively strong vertical mixing and advection, consistent with modern observations. However, during the last glacial period and deglaciation the deep water was older in the southern SCS (~2050 years and ~1800 to 1200 years, respectively) than in the northern SCS (~1600 years and ~670 years, respectively), indicating reduced deep mixing and advection. Moreover, the northern SCS deep water was significantly younger during the last deglaciation than during the Holocene and the last glacial period, implying the existence of northern sourced newly formed and relatively young North Pacific deep water. Our records do not support the intrusion of anomalously 14C-depleted deep water to the middepth of the low-latitude western Pacific and the SCS during the "Mystery Interval" (17.5-14.5 kyr B.P.).

  20. A methodology for the geological and numerical modelling of CO2 storage in deep saline formations

    NASA Astrophysics Data System (ADS)

    Guandalini, R.; Moia, F.; Ciampa, G.; Cangiano, C.

    2009-04-01

    Several technological options have been proposed to stabilize and reduce the atmospheric concentrations of CO2 among which the most promising are the CCS technologies. The remedy proposed for large stationary CO2 sources as thermoelectric power plants is to separate the flue gas, capturing CO2 and to store it into deep subsurface geological formations. In order to support the identification of potential CO2 storage reservoirs in Italy, the project "Identification of Italian CO2 geological storage sites", financed by the Ministry of Economic Development with the Research Fund for the Italian Electrical System under the Contract Agreement established with the Ministry Decree of march 23, 2006, has been completed in 2008. The project involves all the aspects related to the selection of potential storage sites, each carried out in a proper task. The first task has been devoted to the data collection of more than 6800 wells, and their organization into a geological data base supported by GIS, of which 1911 contain information about the nature and the thickness of geological formations, the presence of fresh, saline or brackish water, brine, gas and oil, the underground temperature, the seismic velocity and electric resistance of geological materials from different logs, the permeability, porosity and geochemical characteristics. The goal of the second task was the set up of a numerical modelling integrated tool, that is the in order to allow the analysis of a potential site in terms of the storage capacity, both from solubility and mineral trapping points of view, in terms of risk assessment and long-term storage of CO2. This tool includes a fluid dynamic module, a chemical module and a module linking a geomechanical simulator. Acquirement of geological data, definition of simulation parameter, run control and final result analysis can be performed by a properly developed graphic user interface, fully integrated and calculation platform independent. The project is then

  1. Deep-water exchange between the Atlantic, Caribbean, and Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Sturges, Wilton

    The deep waters of the Caribbean Sea are renewed by sporadic flow over the two deep sills connecting with the open Atlantic. In turn, the deep waters of the Gulf of Mexico are renewed by flow from the northwest Caribbean over the sill in Yucatan Channel, between Mexico and Cuba. So we examine the obvious question: if all this renewal water is coming in, what is going out? The view that emerges is a three-layer mean deep flow in the Caribbean and the Gulf. There is strong vertical shear in the water above 800 m associated with the primary upperlayer flow. Surprisingly, this shear continues to at least 1400 m. In the three-layer scenario described here, the upper-most "deep layer" flows into the Gulf at depths of ˜800-1100 m as an extension of the upper-layer circulation. The deepest inflow is sporadic, just above sill depth. The third layer, containing the required mean return flow to achieve mass balance, is found between these two mean flows at depths of ˜1100 to ˜1900 m. There is little information about the horizontal pattern of this deep return flow. The transport in these deep flows into the Gulf and in the return flow is slightly less than 1 Sv. These conclusions are inferred from the computed mean vertical shear, conservation of potential vorticity in the deep layers, the observed salinity gradients, and the assumption that there can be no net flow between 800 and 2000 m. The deep return flow of water from the Gulf of Mexico, having salinity ˜34.96 psu, appears to flow from Yucatan Channel all the way back to Windward and Jungfern Passages, leaving the Caribbean above the entering deep renewal water.

  2. Effects of climate change on deep-water oxygen and winter mixing in a deep lake (Lake Geneva)

    NASA Astrophysics Data System (ADS)

    Schwefel, Robert; Alfred, Wüest; Damien, Bouffard

    2016-04-01

    Oxygen is the most important dissolved gas for lake ecosystems. Because low oxygen concentrations are an ongoing problem in many parts of the oceans and numerous lakes, oxygen depletion processes have been intensively studied over the last decades and were mainly attributed to high nutrient loads. Recently, climate-induced changes in stratification and mixing behavior were recognized as additional thread to hypolimnetic oxygen budgets in lakes and reservoirs [Matzinger et al., 2007; Zhang et al., 2015]. Observational data of Lake Geneva, a deep perialpine lake situated between France and Switzerland showed no decreasing trend in hypoxia over the last 43 years, despite an impressive reduction in nutrient input during this period. Instead, hypoxic conditions were predominantly controlled by deep mixing end of winter and in turn by winter temperatures. To test the sensitivity of Lake Geneva on future climate change and changes in water transparency, we simulated the hydrodynamics and temperature of Lake Geneva under varying conditions for atmospheric temperature and water clarity performed with the one-dimensional model SIMSTRAT [Goudsmit, 2002]. The results show, that the stratification in lakes is only weakly affected by changes in light absorption due to varying water quality. For conditions expected for the end of the century, a decrease in the annual mean deep convective mixing of up to 45 m is predicted. Also complete mixing events over the whole lake are less likely to occur. A change in the hypolimnetic oxygen concentration of up to 20% can thus be expected in the future. These results show, that changes in deep mixing have an equally strong impact as eutrophication on the deep-water oxygen development of oligomictic lakes and have to be considered in the prediction of the future development of lakes. References: Goudsmit, G. H., H. Burchard, F. Peeters, and A. Wüest (2002), Application of k-ɛ turbulence models to enclosed basins: The role of internal

  3. Seven hundred years of peat formation recorded throughout a deep floating mire profile from Central Italy

    NASA Astrophysics Data System (ADS)

    Lobianco, Daniela; D'Orazio, Valeria; Miano, Teodoro; Zaccone, Claudio

    2016-04-01

    Floating mires are defined by the occurrence of emergent vegetation rooted in highly organic buoyant mats that rise and fall with changes in water level. Islands floating and moving on a lake naturally were already described by Pliny the Elder in his Naturalis historia almost two millennia ago. Actually, he devoted a whole chapter of Naturalis historia to "Of Islands Ever Floating and Swimming", reporting how certain isles were always waving and never stood still. The status of "flotant" has been defined transitory; in fact, these small isles often disappear, in most of the cases because of a transition from floating island to firm land during decades is likely to happen. That is why most of the floating islands described by Pliny the Elder (e.g., Lacus Fundanus, Lacus Cutiliensis, Lacus Mutinensis, Lacus Statoniensis, Lacus Tarquiniensis, Lydia Calaminae, Lacus Vadimonis) do not exist anymore. In the present study, peat formation and organic matter evolution were investigated in order to understand how these peculiar environments form, and how stable actually they are. In fact, it is hoped that peat-forming floating mires could provide an exceptional tool for environmental studies, since much of their evolution, as well as the changes of the surrounding areas, is recorded in their peat deposits. A complete, 4-m deep peat core was collected in July 2012 from the floating island of Posta Fibreno, a relic mire in the Central Italy. This floating island has a diameter of ca. 30 m, a submerged thickness of about 3 m, and the vegetation is organized in concentric belts, from the Carex paniculata palisade to the Sphagnum centre. Here, some of the southernmost Italian populations of Sphagnum palustre occur. The 14C age dating of organic sediments isolated from the sample at 385 cm of depth revealed that the island formed ca. 700 yrs ago (620±30 yr BP). The top 100 cm, consisting almost exclusively of Sphagnum mosses, show a very low bulk density (avg., 0.03±0.01 g cm-3

  4. Bering Sea deep water ventilation over the last 2 Ma, evidence from foraminiferal assemblages and stable isotopes

    NASA Astrophysics Data System (ADS)

    Kender, S.; Ravelo, C.; Asahi, H.; Becker, J.; Hall, I.; Leng, M.; Kaminski, M.; Radi, T.; Aiello, I.

    2012-04-01

    We present benthic foraminiferal stable isotope and assemblage data from the Bering Sea continental slope (U1343, ~2000m water depth), in order to elucidate changes in productivity and deep water ventilation over the last ~2 Ma. The Bering Sea is the third largest marginal sea in the world, connecting the Pacific and Arctic Oceans, but there is still very little known of its palaeoceanographic past. Its open connections to the North Pacific make it an important location to monitor subarctic North Pacific palaeoceanography. Site U1343 is situated near the continental slope, and its high latitude location makes it sensitive to sea ice and glacial meltwater input, which caused large fluctuations in stratification, primary productivity and deep water properties through time. Although there is very little deep water forming in the Bering Sea today, potential intmediate and/or deep water formation in the past may also have affected water properties. High productivity in surface water adds to the nutrient content of the aged waters entering the Bering Sea at depth from the Pacific, causing oxygen levels in some locations to be significantly depleted and benthic foraminifera tolerant to low oxygen levels and high primary productivity to thrive. Changes in the proportions of the low oxygen and high productivity species (e.g. Bulimina, Globobulimina, Globocassidulina) show large fluctuations through time, with an overall increase from the beginning of the Mid-Pleistocene Transition (MPT) onwards (~1.2 Ma) indicating more prevalent episodes of low oxygen conditions persisted after this time. Bottom water δ13C(Uvigerina) exhibit more negative values before the MPT compared with eastern equatorial Pacific Site 849, suggesting the presence of aged deep water in the Bering Sea for at least the last 2 Ma. During the MPT bottom water δ13C becomes more negatively offset from the Pacific which, coupled with the presence of lower oxygen benthic foraminifera, suggests a lower oxygen

  5. Dunes versus ripples in deep-water, fine-grained sediments

    NASA Astrophysics Data System (ADS)

    Masalimova, L.; Lowe, D. R.

    2012-12-01

    The Lower Mount Messenger Formation (LMMF) is characterized by fine- to very fine-grained sediments. While the grain size doesn't change much within the formation, the sedimentary structures do. Perhaps the most striking difference between the channels in the upper part of the LMMF and the lobes in the lower part of the LMMF is the abundance of large-scale, climbing-dune cross-stratification in the lobes and of small-scale, climbing-ripple cross-lamination within channels. The sole presence of climbing dunes in fine-grained sandstones in deep-water lobe complex is surprising. Firstly, dunes are characteristic features largely in fluvial environments. Cross-stratification is not a widespread sedimentary structure in deep-water, part of the reason might be the difficulty in recognizing subtle stratification in weathered outcrop. The absence can be also explained by the fact that the flows might be insufficiently deep or there is never sufficient time for dune formation. Secondly, the hydraulics of the cross-stratification requires sand coarser than 0.2 mm (middle fine sand) to form dunes based on flume experiments. The cross-stratification mostly was documented in deep-water in coarse-grained sediments such as pebbles and gravels in southern Chile and in Quebec, medium to granule-grade sands in Oceanographer Canyon, and medium to coarse-grained sands in the Eocene Hecho Group, etc. Nevertheless, the dunes are documented in fine-grained systems such as Brushy Canyon Formation (the authors use "plow-and-fill" term instead of "dunes"). Thirdly, the cross-stratification is generally documented in confined setting such as channels and scours. But this study shows that the cross-stratification can be present in largely unconfined depositional setting of the LMMF. We postulate that the dunes found in the LMMF can be unusually high ripples from the hydrodynamic point of view. Considering the facts that (1) ripples are different from dunes in outcrop by size and the size of

  6. Deep Water Circulation during the Past 180 Thousand Years in the Northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Wei, K. Y.

    2016-12-01

    Some evidence appears to suggest that the North Pacific played a bigger role in forming deep waters during the end of the last ice age (particularly H1) than it does today (Okazaki et al., 2010; Rae et al., 2014). More recent data from the Bering Sea indicates that the relatively well-ventilated intermediate waters might be formed during the late Pleistocene but in a depth shallower than 1000 m. To understand whether the northern source deep-waters affected the deep circulation and its extent in the northwest Pacific in the late Pleistocene, we measured δ13C and δ18O of benthic foraminifera Uvigerina peregrina (300-425 µm) of OPD1210A (32o13.4'N, 158o15.6'E, water depth 2574 m) from the Shatsky Rise. By assembling data collected from the Northwest Pacific and comparing the integrated d13C time-series with others from the Southwest Pacific, North and South Atlantic, we concluded that the δ13C records of 2500 - 4000 m deep in western Pacific during the last 180 kyrs was composed by 60% NADW and 40% AABW modified with a remineralization constant (Lisiecki, 2010). The constant for the western equatorial and northwestern Pacific is -0.5‰ and for the southwestern Pacific is -0.2‰. The transportation of deep waters from the southwestern Pacific to the northern Pacific Basin was faster in glacial times than that during the interglacial times. We consider that the Pacific deep waters were affected mainly by the Circumpolar Deep Water (CDW) from Atlantic during the past 180 kyrs. The shifts of the deep ocean δ13C minima during glacial times were not caused by any additional freshly-formed water in the form of Glacial North Pacific Intermediate Water (GNPIW) in the North Pacific.

  7. An analysis of characteristics of variation of the Taiwan Warm Current Deep Water

    NASA Astrophysics Data System (ADS)

    Weng, Xuechuan; Wang, Congmin

    1985-06-01

    The Taiwan Warm Current Deep Water (or the East China Sea Upper Layer Water, or the East China Sea Subsurface Water) lying in the deep and bottom layers off the coast of Fujian-Zhejiang is one of the main watermasses in the continental shelf region of the western East China Sea. The hydrographical conditions and the fishery productions in this region are affected remarkably by the decline and growth of the Taiwan Warm Current Deep Water. Although the temperature, salinity and origin of the Taiwan Warm Current Deep Water have been investigated[3] by oceanographers the world over, there are up to now few papers published on its characteristics of ariations (seasonal and multiyear variations). Understanding of this problem will be helpful to further characterize this watermass. For this reason, in this paper, section 28°N representing the middle Taiwan Warm Current Deep Water and section 30°N representing the northern Taiwan Warm Current Deep Water are taken for examples, and the method of similar coefficient is used for analysis of this problem.

  8. Ancient Martian Deltas: Evidence for Shallow and Deep Standing Bodies of Water

    NASA Astrophysics Data System (ADS)

    Jew, C. L.; Kim, W.; Lim, Y.; Piliouras, A.

    2015-12-01

    Ancient deltas on Mars are indicative of a geologic history composed of complex fluvio-deltaic deposits. We focus on two morphologically different deltas preserved on Mars, one located in the Jezero crater and the other in the Shalbatana Valles canyon. The Jezero delta, formed during the Noachian age, is a large fluvial delta with strong channelization and a rigid shoreline resembling a terrestrial delta. In contrast, the Shalbatana Delta is a smaller scaled more briefly lived delta system, developed during the Hesperian, that is characterized by its smooth and simple planform. Evidence from previous studies on these Martian deltas such as the base level, mechanism to build sediment cohesion, estimated discharge, and time of formation offer support to ultimately discover why one delta drastically differs from the other. Based upon the observations from these two locations, we investigate through our physical experiments the conditions required to create these prograding deltas. We use carbonate precipitation in our experiments as a mechanism to increase bank stability, an alternative for any chemically driven precipitated deposits that potentially improve cohesion as vegetation does for terrestrial deltas. We found that there are differences in floodplain thickness, channelization, shoreline rugosity, and delta shape in the carbonate verse non-carbonate runs. Additionally, we conducted runs for isolating the influence that shallow and deep standing bodies of water have on prograding deltas. The experimental results suggested that the highly channelized delta (e.g., Jezero delta) rapidly prograded into a shallow body of water, covering a broader surface area and is dependent on a cohesive force for channel organization. On the contrary, Gilbert-type delta (e.g., Shalbatana delta) was best replicated when prograding into a deep standing body of water. Investigation using the experimental carbonate deltas suggests that cohesion results in better channelization (more

  9. Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

    DOEpatents

    King, Jr., Allen D.; King, Robert B.; Sailers, III, Earl L.

    1983-02-08

    A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

  10. Increasing presence of Arctic Ocean deep waters in the Greenland Sea

    NASA Astrophysics Data System (ADS)

    Somavilla Cabrillo, Raquel; Schauer, Ursula; Budeus, Gedeon

    2013-04-01

    Deep convection has been known to provide the coldest and freshest waters to the deep Greenland Sea, whose properties are balanced with the advection of warmer and saltier waters from the deep Arctic Ocean. However, during the last three decades, deep convection has come to a halt in the Greenland Sea. As previously reported and updated in this work through the analysis of the free available hydrographic data in the central Greenland Sea and in the Arctic Ocean from 1950 to 2010 (Pangaea and ICES data bases), as a consequence of this, two major hydrographic changes are observed: (1) the appearance and deepening of an intermediate temperature maximum and (2) a continuous warming and saltening of the deep Greenland Sea. The origin of both findings is found in the advection of Arctic Ocean deep waters from the Amerasian and Eurasian basins, respectively, into the central Greenland Sea. Associated to the first, a temperature increase of 0.35° C from 1993 to 2009 is observed at 1700 m. Below 2000 m, the temperature and salinity have increased at a mean rate of 0.136° C/decade and 0.01decade-1 in the last three decades. Overall, the stop of deep convection and the advection of Arctic Ocean deep waters result among the highest deep warming and saltening trends of the World Ocean in the Greenland Sea. In addition to the described update of the state of these changes, two new accomplishments are fulfilled in this study. First, in absence of deep convection, the continuous changing of the thermohaline properties of the deep Greenland Sea requires exchanges with adjacent ocean basins. This scenario enables us the estimation of the necessary transports from the deep Arctic to explain the observed changes. A transport of Eurasian Basin Deep Water of 0.31±0.04 Sv is obtained. Secondly, the warming and saltening of the deep Greenland Sea contributes, as any other ocean basin, to the World Ocean heat content and sea level rise. The estimation of these contributions shows larger

  11. Deep-water bedforms induced by refracting Internal Solitary Waves

    NASA Astrophysics Data System (ADS)

    Falcini, Federico; Droghei, Riccardo; Casalbore, Daniele; Martorelli, Eleonora; Mosetti, Renzo; Sannino, Gianmaria; Santoleri, Rosalia; Latino Chiocci, Francesco

    2017-04-01

    Subaqueous bedforms (or sand waves) are typically observed in those environments that are exposed to strong currents, characterized by a dominant unidirectional flow. However, sand-wave fields may be also observed in marine environments where no such current exists; the physical processes driving their formation are enigmatic or not well understood. We propose that internal solitary waves (ISWs), induced by tides, can produce an effective, unidirectional boundary flow filed that forms asymmetric sand waves. We test this idea by examining a sand-wave field off the Messina Strait, where we hypothesize that ISWs formed at the interface between intermediate and surface waters are refracted by topography. Hence, we argue that the deflected pattern (i.e., the depth-dependent orientation) of the sand-wave field is due to refraction of such ISWs. Combining field observations and numerical modelling, we show that ISWs can account for three key features: ISWs produce fluid velocities capable of mobilizing bottom sediments; the predicted refraction pattern resulting from the interaction of ISWs with bottom topography matches the observed deflection of the sand waves; and predicted migration rates of sand waves match empirical estimates. This work shows how ISWs may contribute to sculpting the structure of continental margins and it represents a promising link between the geological and oceanographic communities.

  12. Unique deep-water ecosystems off the southeastern United States

    USGS Publications Warehouse

    Ross, Steve W.

    2007-01-01

    If nothing else, research in deep-sea environments teaches us how little we know about such important and productive habitats. The relatively recent discovery of hydrothermal-vent and cold-seep ecosystems illustrates this paucity of knowledge, and the subsequent explosion of research on these systems is a good example of the impact such concentrated efforts can have on marine sciences (see the March 2007 special issue of Oceanography on InterRidge, and Levin et al., 2007). The recent surge of interest in deep-sea corals is another example of how focused research on a particular subject can result in new perspectives on continental slope biotopes. Although deep-sea corals have been known for over 200 years, they were viewed as somewhat of a novelty, and research on them was sporadic, typically geologic, and usually only documented their occurrences (e.g., Stetson et al., 1962; Neumann et al., 1977; Paull et al., 2000).

  13. Microbial ecology of deep-water mid-Atlantic canyons

    USGS Publications Warehouse

    Kellogg, Christina A.

    2011-01-01

    The research described in this fact sheet will be conducted from 2012 to 2014 as part of the U.S. Geological Survey's DISCOVRE (DIversity, Systematics, and COnnectivity of Vulnerable Reef Ecosystems) Program. This integrated, multidisciplinary effort will be investigating a variety of topics related to unique and fragile deep-sea ecosystems from the microscopic level to the ecosystem level. One goal is to improve understanding, at the microbiological scale, of the benthic communities (including corals) that reside in and around mid-Atlantic canyon habitats and their associated environments. Specific objectives include identifying and characterizing the microbial associates of deep-sea corals, characterizing the microbial biofilms on hard substrates to better determine their role in engineering the ecosystem, and adding a microbial dimension to benthic community structure and function assessments by characterizing micro-eukaryotes, bacteria, and archaea in deep-sea sediments.

  14. Accounting for water formation from hydrocarbon fuel combustion in life cycle analyses

    NASA Astrophysics Data System (ADS)

    Belmont, E. L.; Davidson, F. T.; Glazer, Y. R.; Beagle, E. A.; Webber, M. E.

    2017-09-01

    Hydrocarbon fuel production and utilization are considered water intensive processes due to the high volumes of water used in source development and fuel processing. At the same time, there is significant water formed during combustion. However, this water is not currently widely harvested at the site of production. Instead, it is added to the hydrologic cycle, often in a different location from the fuel production site. This study quantifies the water formed from combustion of these fuels and analyzes the magnitudes of formation in the context of other hydrologic sources and sinks in order to facilitate future assessments of water harvesting technology and/or atmospheric impacts of combustion. Annual water formation from stoichiometric combustion of hydrocarbon fuels, including natural gas, oil- and natural gas liquid-derived products, and coal, in the United States and worldwide are presented and compared with quantities of water sequestered, evaporated, and stored in the atmosphere. Water production factors in terms of mass and energy of fuel consumed, WPFm and WPFe, respectively, are defined for the comparison of fuels and incorporation into future life cycle analyses (LCAs). Results show that water formation from combustion has increased worldwide from 2005 to 2015, with the largest increase coming from growth in combustion of natural gas. Water formation from combustion of hydrocarbon fuels equals or exceeds water sequestered from the hydrologic cycle through deep well injection in the US annually. Overall, water formation is deemed significant enough to warrant consideration by LCAs of water intensity in fuel production and use, and should be included in future analyses.

  15. Past methane seepage and linked deep-water anoxia are logged in methane-derived carbonates

    NASA Astrophysics Data System (ADS)

    Stadnitskaia, A.; Liebetrau, V.; Eisenhauer, A.; Sinninghe Damsté, J. S.

    2012-04-01

    The precipitation of carbonate in methane saturated environments is a common phenomenon that is caused by the increase of alkalinity due to the microbial process of anaerobic oxidation of methane (AOM) accomplished by a consortium of sulfate reducing bacteria and methanotrophic archaea (Boetius et al., 2000). Since the formation of such carbonates is irrespective to climate changes and to the depth of the carbonate compensation, they represent unique archives of the time and duration of methane seepage, adjacent sedimentary/water column environments and associated bionetwork. The Nile Deep Sea Fan basin is known for the widespread occurrence of seabed methane/fluid seepage linked to mud volcanoes and pock marks. Massive accumulations of methane-derived carbonate pavements and up to one meter buildups were often encountered in the vicinity or even within mud volcano structures. Here we analyzed at high resolution the differences in stable carbon and oxygen isotope compositions and lipid biomarker composition, accompanied with U/Th dating of the topmost part of a ~1 m-high carbonate edifice sited at the margin of the Amon mud volcano. The uppermost part of the edifice has been dated at ~7.8 - 9.1 kyr B.P. This is synchronous with the increase of fresh-water fluxes in the Eastern Mediterranean resulting in density stratification of the water column (~ 10.5 - 5.0 14C kyr B.P.), with the formation of S1 sapropel (~9.7 - 5.7 14C kyr B.P.; De Lange et al., 2008), and with the Holocene warm climatic optimum (Rohling and Hilgen, 1991). Significant changes of ^13CCaCO3 values, from -32 to -9‰ (VPDB), indicate swings in methane flux, which affected rates of AOM and the consequent production of 13C-depleted HCO3-. Lipid biomarkers revealed the presence of methanotrophic archaea of the ANME-2 group due to the dominance of sn-2-hydroxyarchaeol over archaeol and the low abundance of tetraether lipids (Blumenberg et al., 2004). Ecologically these archaea are associated with

  16. Deep Water Ocean Acoustics (DWOA): The Philippine Sea, OBSANP, and THAAW Experiments

    DTIC Science & Technology

    2015-09-30

    and without the travel-time data showed significant changes to the temperature and salinity were made to fit the acoustic observations. The state...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Deep Water Ocean Acoustics (DWOA): The Philippine Sea...deep- water acoustic propagation and ambient noise has been collected in a wide variety of environments over the last few years with ONR support

  17. North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

    DTIC Science & Technology

    2012-09-30

    high power, rubidium oscillator that is turned on once a day to check the frequency of a less precise, but low power, Q-Tech Microcomputer...understanding of (i) the basic physics of low- frequency , broadband propagation in deep water, including the effects of oceanographic variability on signal...stability and coherence, (ii) the structure of the ambient noise field in deep water at low frequencies , and (iii) the extent to which acoustic

  18. Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters

    NASA Technical Reports Server (NTRS)

    Ward, B. B.; Kilpatrick, K. A.; Novelli, P. C.; Scranton, M. I.

    1987-01-01

    Measured biological oxidation rates of methane in near-surface waters of the Cariaco Basin are compared with the diffusional fluxes computed from concentration gradients of methane in the surface layer. Methane fluxes and oxidation rates were investigated in surface waters, at the oxic/anoxic interface, and in deep anoxic waters. It is shown that the surface-waters oxidation of methane is a mechanism which modulates the flux of methane from marine waters to the atmosphere.

  19. Ecogeochemistry potential in deep time biodiversity illustrated using a modern deep-water case study.

    PubMed

    Trueman, Clive N; Chung, Ming-Tsung; Shores, Diana

    2016-04-05

    The fossil record provides the only direct evidence of temporal trends in biodiversity over evolutionary timescales. Studies of biodiversity using the fossil record are, however, largely limited to discussions of taxonomic and/or morphological diversity. Behavioural and physiological traits that are likely to be under strong selection are largely obscured from the body fossil record. Similar problems exist in modern ecosystems where animals are difficult to access. In this review, we illustrate some of the common conceptual and methodological ground shared between those studying behavioural ecology in deep time and in inaccessible modern ecosystems. We discuss emerging ecogeochemical methods used to explore population connectivity and genetic drift, life-history traits and field metabolic rate and discuss some of the additional problems associated with applying these methods in deep time.

  20. Ecogeochemistry potential in deep time biodiversity illustrated using a modern deep-water case study

    PubMed Central

    Trueman, Clive N.; Shores, Diana

    2016-01-01

    The fossil record provides the only direct evidence of temporal trends in biodiversity over evolutionary timescales. Studies of biodiversity using the fossil record are, however, largely limited to discussions of taxonomic and/or morphological diversity. Behavioural and physiological traits that are likely to be under strong selection are largely obscured from the body fossil record. Similar problems exist in modern ecosystems where animals are difficult to access. In this review, we illustrate some of the common conceptual and methodological ground shared between those studying behavioural ecology in deep time and in inaccessible modern ecosystems. We discuss emerging ecogeochemical methods used to explore population connectivity and genetic drift, life-history traits and field metabolic rate and discuss some of the additional problems associated with applying these methods in deep time. PMID:26977063

  1. Deep Learning to Predict the Formation of Quinone Species in Drug Metabolism.

    PubMed

    Hughes, Tyler B; Swamidass, S Joshua

    2017-02-20

    Many adverse drug reactions are thought to be caused by electrophilically reactive drug metabolites that conjugate to nucleophilic sites within DNA and proteins, causing cancer or toxic immune responses. Quinone species, including quinone-imines, quinone-methides, and imine-methides, are electrophilic Michael acceptors that are often highly reactive and comprise over 40% of all known reactive metabolites. Quinone metabolites are created by cytochromes P450 and peroxidases. For example, cytochromes P450 oxidize acetaminophen to N-acetyl-p-benzoquinone imine, which is electrophilically reactive and covalently binds to nucleophilic sites within proteins. This reactive quinone metabolite elicits a toxic immune response when acetaminophen exceeds a safe dose. Using a deep learning approach, this study reports the first published method for predicting quinone formation: the formation of a quinone species by metabolic oxidation. We model both one- and two-step quinone formation, enabling accurate quinone formation predictions in nonobvious cases. We predict atom pairs that form quinones with an AUC accuracy of 97.6%, and we identify molecules that form quinones with 88.2% AUC. By modeling the formation of quinones, one of the most common types of reactive metabolites, our method provides a rapid screening tool for a key drug toxicity risk. The XenoSite quinone formation model is available at http://swami.wustl.edu/xenosite/p/quinone .

  2. Geochemical evidence for anoxic deep water in the Arabian Sea during the last glaciation

    SciTech Connect

    Sarkar, A.; Bhattacharya, S.K.; Sarin, M.M. )

    1993-03-01

    Various paleoceanographic studies have indicated that the deep ocean was probably depleted in dissolved oxygen during the last glacial period ([approximately]18 kyr B.P.; [delta][sup 18]O, stage 2) compared to present time. However, direct evidence of low oxygen content in the deep waters has been lacking. Here, the authors report geochemical evidence of near anoxic conditions in the deep Arabian Sea during the entire last glacial cycle ([delta][sup 18]O; stages 2, 3, and 4). Anoxia is inferred from the concomitant enrichment of organic carbon and authigenic uranium in the glacial sections of a core from the deep eastern Arabian Sea. The anoxic conditions during the last glacial period, probably caused by a change in deep water circulation, evidently enhanced preservation of organic matter and simultaneous removal of uranium from seawater. 57 refs., 3 figs., 2 tabs.

  3. Potential Osteoporosis Recovery by Deep Sea Water through Bone Regeneration in SAMP8 Mice

    PubMed Central

    Liu, Ming-Che; Wang, Ming-Fu; Chen, Wei-Hong; Tsai, Ching-Yu; Wu, Kuan-Hsien; Lin, Che-Tong; Shieh, Ying-Hua; Zeng, Rong; Deng, Win-Ping

    2013-01-01

    The aim of this study is to examine the therapeutic potential of deep sea water (DSW) on osteoporosis. Previously, we have established the ovariectomized senescence-accelerated mice (OVX-SAMP8) and demonstrated strong recovery of osteoporosis by stem cell and platelet-rich plasma (PRP). Deep sea water at hardness (HD) 1000 showed significant increase in proliferation of osteoblastic cell (MC3T3) by MTT assay. For in vivo animal study, bone mineral density (BMD) was strongly enhanced followed by the significantly increased trabecular numbers through micro-CT examination after a 4-month deep sea water treatment, and biochemistry analysis showed that serum alkaline phosphatase (ALP) activity was decreased. For stage-specific osteogenesis, bone marrow-derived stromal cells (BMSCs) were harvested and examined. Deep sea water-treated BMSCs showed stronger osteogenic differentiation such as BMP2, RUNX2, OPN, and OCN, and enhanced colony forming abilities, compared to the control group. Interestingly, most untreated OVX-SAMP8 mice died around 10 months; however, approximately 57% of DSW-treated groups lived up to 16.6 months, a life expectancy similar to the previously reported life expectancy for SAMR1 24 months. The results demonstrated the regenerative potentials of deep sea water on osteogenesis, showing that deep sea water could potentially be applied in osteoporosis therapy as a complementary and alternative medicine (CAM). PMID:24069046

  4. Joint OSNR monitoring and modulation format identification in digital coherent receivers using deep neural networks.

    PubMed

    Khan, Faisal Nadeem; Zhong, Kangping; Zhou, Xian; Al-Arashi, Waled Hussein; Yu, Changyuan; Lu, Chao; Lau, Alan Pak Tao

    2017-07-24

    We experimentally demonstrate the use of deep neural networks (DNNs) in combination with signals' amplitude histograms (AHs) for simultaneous optical signal-to-noise ratio (OSNR) monitoring and modulation format identification (MFI) in digital coherent receivers. The proposed technique automatically extracts OSNR and modulation format dependent features of AHs, obtained after constant modulus algorithm (CMA) equalization, and exploits them for the joint estimation of these parameters. Experimental results for 112 Gbps polarization-multiplexed (PM) quadrature phase-shift keying (QPSK), 112 Gbps PM 16 quadrature amplitude modulation (16-QAM), and 240 Gbps PM 64-QAM signals demonstrate OSNR monitoring with mean estimation errors of 1.2 dB, 0.4 dB, and 1 dB, respectively. Similarly, the results for MFI show 100% identification accuracy for all three modulation formats. The proposed technique applies deep machine learning algorithms inside standard digital coherent receiver and does not require any additional hardware. Therefore, it is attractive for cost-effective multi-parameter estimation in next-generation elastic optical networks (EONs).

  5. Reefs of the deep: the biology and geology of cold-water coral ecosystems.

    PubMed

    Roberts, J Murray; Wheeler, Andrew J; Freiwald, André

    2006-04-28

    Coral reefs are generally associated with shallow tropical seas; however, recent deep-ocean exploration using advanced acoustics and submersibles has revealed unexpectedly widespread and diverse coral ecosystems in deep waters on continental shelves, slopes, seamounts, and ridge systems around the world. Advances reviewed here include the use of corals as paleoclimatic archives and their biogeological functioning, biodiversity, and biogeography. Threats to these fragile, long-lived, and rich ecosystems are mounting: The impacts of deep-water trawling are already widespread, and effects of ocean acidification are potentially devastating.

  6. Multiple origins of deep-sea Asellota (Crustacea: Isopoda) from shallow waters revealed by molecular data

    PubMed Central

    Raupach, Michael J.; Mayer, Christoph; Malyutina, Marina; Wägele, Johann-Wolfgang

    2008-01-01

    The Asellota are a highly variable group of Isopoda with many species in freshwater and marine shallow-water environments. However, in the deep sea, they show their most impressive radiation with a broad range of astonishing morphological adaptations and bizarre body forms. Nevertheless, the evolution and phylogeny of the deep-sea Asellota are poorly known because of difficulties in scoring morphological characters. In this study, the molecular phylogeny of the Asellota is evaluated for 15 marine shallow-water species and 101 deep-sea species, using complete 18S and partial 28S rDNA gene sequences. Our molecular data support the monophyly of most deep-sea families and give evidence for a multiple colonization of the deep sea by at least four major lineages of asellote isopods. According to our molecular data, one of these lineages indicates an impressive radiation in the deep sea. Furthermore, the present study rejects the monophyly of the family Janiridae, a group of plesiomorphic shallow-water Asellota, and several shallow-water and deep-sea genera (Acanthaspidia, Ianthopsis, Haploniscus, Echinozone, Eurycope, Munnopsurus and Syneurycope). PMID:19033145

  7. Late Holocene intermediate water variability in the northeastern Atlantic as recorded by deep-sea corals

    NASA Astrophysics Data System (ADS)

    Copard, K.; Colin, C.; Henderson, G. M.; Scholten, J.; Douville, E.; Sicre, M.-A.; Frank, N.

    2012-01-01

    deep-water formation.

  8. Deep Circumflex Iliac Artery-Related Hemoperitoneum Formation After Surgical Drain Placement: Successful Transcatheter Embolization

    SciTech Connect

    Park, Sang Woo; Chang, Seong-Hwan Yun, Ik Jin; Lee, Hae Won

    2010-04-15

    A 53-year-old woman with liver cirrhosis and hepatocellular carcinoma underwent living donor liver transplantation. After transplantation, her hemoglobin and hematocrit levels decreased to 6.3 g/dl and 18.5%, respectively, during the course of 3 days. A contrast-enhanced abdominal computed axial tomography (CAT) scan showed a hemoperitoneum in the right perihepatic space with no evidence of abdominal wall hematoma or pseudoaneurysm formation. An angiogram of the deep circumflex iliac artery (DCIA) showed extravasation of contrast media along the surgical drain, which had been inserted during the transplantation procedure. Transcatheter embolization of the branches of the DCIA was successfully performed using N-butyl cyanoacrylate.

  9. Distribution of the Northern Water Mass Formation completing the Atlantic Meridional Overturning Circulation

    NASA Astrophysics Data System (ADS)

    R. Langehaug, H.; Rhines, P. B.; Eldevik, T.; Bitz, C. M.

    2010-12-01

    The transport of cold dense water that constitutes the lower limb of the Atlantic Meridional Overturning Circulation has been identified as a key indicator for climate change. The decadal water mass formation in the Subpolar North Atlantic and the Nordic Seas have been localized and quantified in a pre-industrial multi-century (700 years) simulation with the Bergen Climate Model (BCM2). The BCM2 has a well-represented Nordic Seas Overflow, and it is therefore an adequate model for quantitatively assessing the relative contributions from these dense overflows and from air-sea interaction driven water mass formation in the Subpolar North Atlantic. The assessment is done following the method introduced by Walin (1982); here the transformation in water mass outcrop areas is estimated from the winter heat and freshwater fluxes into the ocean. The results are compared and contrasted with a 1000 years run based on the 1990s from the Community Climate System Model (CCSM3). The deep-water pathways are traced by analysis of tracers (ideal age) and transport of mass, heat and salt on the theta-S plane (Figure 1), similar to what is applied to observations from the real ocean, in different sections downstream of the deep-water formation regions. Such consistent evaluation of model performance has largely not been pursued to date. In the BCM2 simulation open-ocean deep convection in the Greenland Sea does not appear as a source for the Nordic Seas Overflow. Rather the densification of the Atlantic Boundary Current in the Nordic Seas, especially west of Svalbard, seems to be important for the northern dense water formation. Further downstream, east of Newfoundland, the amount of Labrador Sea Water and Overflow Water originating in the Denmark Strait is of comparable size; 4 Sv and 5 Sv, respectively. Walin, G., 1982: On the relation between sea-surface heat flow and thermal circulation in the ocean. Tellus 34, 187-195. Figure 1: Volumetric TS-diagram of the water mass exchange

  10. An assessment on CO2 geosequestration in deep saline formations in the Taihsi Basin, central Taiwan

    NASA Astrophysics Data System (ADS)

    Cai, Mo-Si; Lin, Andrew T.; Fan, Jhen-Huei

    2015-04-01

    Geological storage of carbon dioxide (CO2) is to inject and store a large amount of anthropogenic CO2 in deep and sealed porous rocks in order to mitigate the aggravated threat of global climate changes. Borehole and reflection seismic data are used to understand the spatial distribution of suitable CO2 reservoirs and cap rocks in the Taihsi Basin, central Taiwan, where the level of seismicity is low. The Taihsi Basin was a rift basin during the Paleocene to Eocene, followed by a phase of post-rift subsidence during late Oligocene to late Miocene. The loading of the Taiwan mountain belt since late Miocene has turned the Taihsi Basin into a peripheral foreland basin, with strata gently dipping toward the mountain belts in the east. The coastal plain in central Taiwan (Changhua and Yunlin Counties) and its adjacent offshore areas are close to major CO2 emission sources and no active geological structures are found in these areas, making the study area a favorable CO2 storage site. Spatial distribution of formation thickness and depth for CO2 reservoirs and cap rocks indicates three CO2 storage systems existed in the study area. They are: (1) late Miocene to Pliocene Nanchuang Formation and Kueichulin Formation (reservoirs)-Chinshui Shale (seals) system (hereafter abbreviated as NK-C system), (2) early to middle Miocene Shihti Formation and Peiliao Formation (reservoirs)-Talu Shale (seals) system (SP-T system), (3) early Miocene Mushan Formation (reservoirs)-Piling Shale (seals) system (M-P system). The NK-C system contains multiple layers of porous sandstones from Nanchuang and Kueichulin formations, with total thickness around 210-280 m. In the vicinity of the northern bank of the Jhuoshuei River, reservoir top reaches a depth around 1850 m, with 60 m thick seal formation, the Chinshui Shale. However, the Chinshui Shale becomes sand-prone in the Changhua coastal and nearshore areas due to facies changes. The SP-T system consists of two porous sandstone layers from

  11. Direct evidence of deep water intrusions onto the continental shelf via surging internal tides

    NASA Astrophysics Data System (ADS)

    Nam, Sunghyun; Send, Uwe

    2011-05-01

    Near-bottom diurnal thermocline shoaling and diurnal baroclinic currents were observed from time series data of water temperature, salinity, pressure, and velocity collected from August 2006 to January 2007 in the nearshore zone off the Huntington Beach where the local inertial frequency is higher than the diurnal frequency (poleward of the diurnal critical latitude). During the stratified season, the deep offshore cold (dense) water, when shoaled into shallow water along the bottom, was often trapped for a few hours and dissipated in the nearshore region (water depth of 10-20 m) during the ebb phase of the diurnal surface tide. It appears that perturbations propagating onshore along the shoaled isopycnals can form an upslope surging front and an internal bolus. Our data allow the application of theoretical/lab criteria for internal hydraulic jumps, internal bolus formation, and internal wave breaking and all criteria are fulfilled during a part of the tidal shoaling cycle. Nonlinear advection associated with the internal boluses causes higher (close to ω-3) spectral falloff rate of near-bottom temperature with frequency ω than the canonical Garret-Munk spectra (ω-2) in the range of 0.1-1.0 cph, implying strong scattering of tidal energy toward smaller scales. We are able to directly calculate the offshore eddy heat flux by cold water intrusion onto the shelf resulting from this process. Similar impacts and implications are expected for the biogeochemical quantities, as well as for the role of subinertial internal waves on turbulent mixing in the immediate proximity of the generating region, i.e., sloping bottom.

  12. Implications of Cometary Water: Deep Impact, Stardust and Hayabusa

    NASA Technical Reports Server (NTRS)

    Sheldon, Robert B.; Hoover, Richard B.

    2006-01-01

    Three recent in situ spacecraft missions have explored comets or asteroids, producing data in conflict with the standard comet paradigm, the Whipple Dirty Snowball Model (DSM). We have developed an alternative Wet Comet Model (WCM) which proposes that comets undergo an irreversible phase change to a wet comet when they enter within Mars orbit. The WCM may explain some of the observational discrepancies seen by Deep Impact, Stardust and Hayabusa. In particular, it accurately predicted Deep Impact observation of organics, biominerals, and meltwater temperatures. Predictions concerning Stardust s returned cometary dust particles have yet to be falsified, but if comets are largely composed of the silicates seen by Stardust, there may be a cometary explanation for Itokawa s low density rubble-pile observed by Hayabusa.

  13. Implications of Cometary Water: Deep Impact, Stardust and Hayabusa

    NASA Technical Reports Server (NTRS)

    Sheldon, Robert B.; Hoover, Richard B.

    2006-01-01

    Three recent in situ spacecraft missions have explored comets or asteroids, producing data in conflict with the standard comet paradigm, the Whipple Dirty Snowball Model (DSM). We have developed an alternative Wet Comet Model (WCM) which proposes that comets undergo an irreversible phase change to a wet comet when they enter within Mars orbit. The WCM may explain some of the observational discrepancies seen by Deep Impact, Stardust and Hayabusa. In particular, it accurately predicted Deep Impact observation of organics, biominerals, and meltwater temperatures. Predictions concerning Stardust s returned cometary dust particles have yet to be falsified, but if comets are largely composed of the silicates seen by Stardust, there may be a cometary explanation for Itokawa s low density rubble-pile observed by Hayabusa.

  14. Optimal satellite formation reconfiguration using co-evolutionary particle swarm optimization in deep space

    NASA Astrophysics Data System (ADS)

    Huang, Haibin; Zhuang, Yufei

    2015-08-01

    This paper proposes a method that plans energy-optimal trajectories for multi-satellite formation reconfiguration in deep space environment. A novel co-evolutionary particle swarm optimization algorithm is stated to solve the nonlinear programming problem, so that the computational complexity of calculating the gradient information could be avoided. One swarm represents one satellite, and through communication with other swarms during the evolution, collisions between satellites can be avoided. In addition, a dynamic depth first search algorithm is proposed to solve the redundant search problem of a co-evolutionary particle swarm optimization method, with which the computation time can be shorten a lot. In order to make the actual trajectories optimal and collision-free with disturbance, a re-planning strategy is deduced for formation reconfiguration maneuver.

  15. Phosphate rock formation and marine phosphorus geochemistry: the deep time perspective.

    PubMed

    Filippelli, Gabriel M

    2011-08-01

    The role that phosphorite formation, the ultimate source rock for fertilizer phosphate reserves, plays in the marine phosphorus (P) cycle has long been debated. A shift has occurred from early models that evoked strikingly different oceanic P cycling during times of widespread phosphorite deposition to current thinking that phosphorite deposits may be lucky survivors of a series of inter-related tectonic, geochemical, sedimentological, and oceanic conditions. This paradigm shift has been facilitated by an awareness of the widespread nature of phosphogenesis-the formation of authigenic P-bearing minerals in marine sediments that contributes to phosphorite formation. This process occurs not just in continental margin sediments, but in deep sea oozes as well, and helps to clarify the driving forces behind phosphorite formation and links to marine P geochemistry. Two processes come into play to make phosphorite deposits: chemical dynamism and physical dynamism. Chemical dynamism involves the diagenetic release and subsequent concentration of P-bearing minerals particularly in horizons, controlled by a number of sedimentological and biogeochemical factors. Physical dynamism involves the reworking and sedimentary capping of P-rich sediments, which can either concentrate the relatively heavy and insoluble disseminated P-bearing minerals or provide an episodic change in sedimentology to concentrate chemically mobilized P. Both processes can result from along-margin current dynamics and/or sea level variations. Interestingly, net P accumulation rates are highest (i.e., the P removal pump is most efficient) when phosphorites are not forming. Both physical and chemical pathways involve processes not dominant in deep sea environments and in fact not often coincide in space and time even on continental margins, contributing to the rarity of high-quality phosphorite deposits and the limitation of phosphate rock reserves. This limitation is becoming critical, as the human demand

  16. Evaluation of formation water chemistry and scale prediction: Bakken Shale

    SciTech Connect

    Thyne, Geoffrey; Brady, Patrick

    2016-10-24

    Determination of in situ formation water chemistry is an essential component of reservoir management. This study details the use of thermodynamic computer models to calculate reservoir pH and restore produced water analyses for prediction of scale formation. Bakken produced water samples were restored to formation conditions and calculations of scale formation performed. In situ pH is controlled by feldspar-clay equilibria. Calcite scale is readily formed due to changes in pH during pressure drop from in situ to surface conditions. The formation of anhydrite and halite scale, which has been observed, was predicted only for the most saline samples. Finally, in addition, the formation of anhydrite and/or halite may be related to the localized conditions of increased salinity as water is partitioned into the gas phase during production.

  17. Evaluation of formation water chemistry and scale prediction: Bakken Shale

    DOE PAGES

    Thyne, Geoffrey; Brady, Patrick

    2016-10-24

    Determination of in situ formation water chemistry is an essential component of reservoir management. This study details the use of thermodynamic computer models to calculate reservoir pH and restore produced water analyses for prediction of scale formation. Bakken produced water samples were restored to formation conditions and calculations of scale formation performed. In situ pH is controlled by feldspar-clay equilibria. Calcite scale is readily formed due to changes in pH during pressure drop from in situ to surface conditions. The formation of anhydrite and halite scale, which has been observed, was predicted only for the most saline samples. Finally, inmore » addition, the formation of anhydrite and/or halite may be related to the localized conditions of increased salinity as water is partitioned into the gas phase during production.« less

  18. Water mass formation and circulation in the Persian Gulf and water exchange with the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Yao, Fengchao

    The Persian Gulf is a shallow, semi-enclosed marginal sea where the Persian Gulf Water (PGW), one of the most saline water masses in the world, is formed due to the arid climate. The PGW flushes out of the Persian Gulf as a deep outflow and induces a surface inflow of the Indian Ocean Surface Water (IOSW), driving an inverse-estuarine type water exchange through the Strait of Hormuz. In this dissertation, the circulation and water mass transformation processes in the Persian Gulf and the water exchange with the Indian Ocean through the Strait of Hormuz, in response to the atmospheric forcing, are studied using the HYbrid Coordinate Ocean Model (HYCOM). The model is driven by surface wind stress, heat and fresh water fluxes derived from two sources: the COADS (Comprehensive Ocean-Atmosphere Data Set) monthly climatology and high frequency (2-hourly) MM5 (The Fifth-Generation NCAR/Penn State Mesoscale Model) output. This study is motivated by the time series measurements in the Strait during December 1996 to March 1998 by Johns et al. (2003), which also serve as a major benchmark for evaluating the model results. The simulations with climatological forcing show that the IOSW propagates in two branches into the Gulf, one along the Iranian coast toward the northern gulf and the other one onto the southern banks driven by the Ekman drift by the prevailing northwesterly winds. These two branches of inflow form two cyclonic gyres in the northern and in the southern gulf respectively. Cold, saline deep waters are formed both in the northern gulf and in the southern gulf during the wintertime cooling period and their exports contribute seasonally to the outflow in the strait. After formation in winter, the dense water in the shallow southwestern gulf spills off into the strait and causes high-salinity pulses in the outflow in the strait, a phenomenon also present in the observations. The export of dense waters from the northern gulf persists throughout the year, with the

  19. Formation of Deep Sea Umber Deposits Linked to Microbial Metal Oxidation at the South Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Peng, Xiaotong; Ta, Kaiwen; Chen, Shun; Zhang, Lijuan; Xu, Hengchao

    2015-04-01

    Umber deposits are important metalliferous deposits, which occur in off-axis half-graben structures at ancient and modern ocean floor. The genesis of umber deposits has remained controversial for several decades. Recently, microbial Fe(II) oxidation associated with low-temperature diffuse venting has been identified as a key process for the formation of umber deposits, but the exact biochemical mechanisms involved to the precipitation of Mn oxides and co-precipitation of Fe oxyhydroxides and Mn oxides in umber deposits still remain unknown. Here, we used nano secondary ion mass spectrometer, synchrotron-based X-ray absorption spectroscopy, electron microscopy, and molecular techniques to demonstrate the coexistence of two types of metal-oxidizing bacteria within deep-sea hydrothermal umber deposits at the South Atlantic Ridge, where we found unique spheroids composed of biogenic Fe oxyhydroxides and Mn oxides in the deposits. Our data suggest that Fe oxyhydroxides and Mn oxides are metabolic by-products of lithotrophic Fe(II)-oxidizing bacteria and heterotrophic Mn(II)-oxidizing bacteria, respectively. The hydrothermal vents fuel lithotrophic Fe(II)-oxidizing bacteria, which constitute a trophic base that may support the activities of heterotrophic Mn(II)-oxidizing bacteria. The biological origin of umber deposits underscore the importance of geomicrobiologcial interaction in triggering the formation of deep-sea deposits, with important implications for the generation of submarine Mn deposits and crusts.

  20. Drop impact into a deep pool: vortex shedding and jet formation

    SciTech Connect

    Agbaglah, G.; Thoraval, M. -J.; Thoroddsen, S. T.; Zhang, L. V.; Fezzaa, K.; Deegan, R. D.

    2015-02-01

    One of the simplest splashing scenarios results from the impact of a single drop on a deep pool. The traditional understanding of this process is that the impact generates an axisymmetric sheet-like jet that later breaks up into secondary droplets. Recently it was shown that even this simplest of scenarios is more complicated than expected because multiple jets can be generated from a single impact event and there are transitions in the multiplicity of jets as the experimental parameters are varied. Here, we use experiments and numerical simulations of a single drop impacting on a deep pool to examine the transition from impacts that produce a single jet to those that produce two jets. Using high-speed X-ray imaging methods we show that vortex separation within the drop leads to the formation of a second jet long after the formation of the ejecta sheet. Using numerical simulations we develop a phase diagram for this transition and show that the capillary number is the most appropriate order parameter for the transition.

  1. Formation energies and energy levels of deep defects in narrow gap semiconductors

    SciTech Connect

    Patterson, J.D.; Li, W.

    1996-12-31

    The authors use a Green`s function technique for deep defect energy level calculations in mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total binding energy with an impurity cluster and with a perfect cluster. These alloys are among those that have been experimentally grown in microgravity aboard the Space Shuttle. To evaluate the quality of these crystals, it is necessary to characterize them, and one important aspect of this characterization is the study of deep defects which can limit carrier lifetime. Relaxation effects are calculated with molecular dynamics. The resulting energy shift can be greater for the interstitial case than the substitutional one. Relaxation in vacancies is also considered. The charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that caused by relaxation. However, different charged states for vacancies had little effect on the formation energy. For all cases the authors considered the concentration of Cd or Zn in the range appropriate for a band gap of 0.1 eV. The emphasis of their calculation is on chemical trends. Only limited comparison to experiment and other calculations is possible, but what there is supports the statement that their results are at least of the right order of magnitude.

  2. Hydrothermal fluid migration and brine pool formation in the Red Sea: the Atlantis II Deep

    NASA Astrophysics Data System (ADS)

    Schardt, Christian

    2016-01-01

    Numerical heat and fluid flow simulations of the Atlantis II Deep in the Red Sea were conducted to investigate the development, migration, and discharge of hydrothermal fluids into a submarine depression and determine the conditions necessary to form a brine pool. High-salinity fluids are predicted to form by leaching Miocene evaporates, migrate and convect within young oceanic crust, and discharge onto the seafloor. Predicted fluid discharge temperatures ( T max, 301 °C), discharge fluid velocities ( V max, 0.09 m/s), and salinities ( S max, 21 wt%) increase over time and reach values comparable to modern seafloor observations. Established convection patterns and discharge behavior are robust and are not greatly affected by geometry of rock property changes. Modeling results were used to calculate the minimum conditions for hydrothermal fluids from a developing hydrothermal system to mix with seawater, reverse buoyancy, and begin to form a brine pool in a submarine depression. Under conditions encountered on the seafloor ( T, 25-300 °C; S, 5-25 wt%), fluid mixtures predicted to pond on the seafloor range from late in the mixing process (99 %) at low temperatures ( T, 26 °C) to much earlier (36 % mixing) at higher temperatures ( T, 94 °C). A model of brine pool evolution is proposed that describes the processes and conditions necessary to initiate brine pool formation and compares formation conditions with accumulated ore material in the Atlantis II Deep and other locations.

  3. NDMA formation kinetics from three pharmaceuticals in four water matrices.

    PubMed

    Shen, Ruqiao; Andrews, Susan A

    2011-11-01

    N, N-nitrosodimethylamine (NDMA) is an emerging disinfection by-product (DBP) that has been widely detected in many drinking water systems and commonly associated with the chloramine disinfection process. Some amine-based pharmaceuticals have been demonstrated to form NDMA during chloramination, but studies regarding the reaction kinetics are largely lacking. This study investigates the NDMA formation kinetics from ranitidine, chlorphenamine, and doxylamine under practical chloramine disinfection conditions. The formation profile was monitored in both lab-grade water and real water matrices, and a statistical model is proposed to describe and predict the NDMA formation from selected pharmaceuticals in various water matrices. The results indicate the significant impact of water matrix components and reaction time on the NDMA formation from selected pharmaceuticals, and provide fresh insights on the estimation of ultimate NDMA formation potential from pharmaceutical precursors.

  4. Modeling Extremely Deep Convection over North America as a Source of Stratospheric Water Vapor

    NASA Astrophysics Data System (ADS)

    Leroy, S. S.; Clapp, C.; Smith, J. B.; Anderson, J. G.

    2015-12-01

    We have run the Advanced Research Weather Research and Forecasting Model (ARW) at scales that numerically resolve convection over a broad swath of the north central U.S. Our intentions were to simulate convective events that generated stratospheric water vapor plumes observed during the SEAC4RS mission, to quantify the amount of water vapor injected into the stratosphere by extremely deep convection, and to investigate ARW as a potential tool to forecast multi-decadal trends in extremely deep convection over North America. We have run ARW for five and a half days beginning at 12 UTC on 26 August 2013 on a 3-km horizontal grid with 50 vertical levels. We used MERRA for the initial conditions and boundary conditions because of its skill in reanalysis of water vapor. ARW was able to simulate many of the fundamental features of deep convection over North America, including specific events. We have shown that the convection simulated by ARW bears many of the features of mesoscale convective systems, including the flow of cold air over warm moist air, cold downdrafts and gust fronts, mid-level inflow, and wedges reminiscent of squall lines. The source of water vapor for the convection is low-level eastward transport into the ARW domain. Convection is initiated where local maxima in equivalent potential temperature of surface air form. Convection regularly penetrates to the level of neutral buoyancy of the surface air and can even influence the concentration of water vapor above. A few convective events inject water vapor above the 400 K potential temperature surface. Surprisingly, deep convective events can also desiccate the upper air, even in the stratosphere. There is clear evidence of convection generating ducted internal gravity waves that propagate upstream to trigger more deep convection. We will present a quantification of the amount of water vapor injected into the stratosphere by extremely deep convection, the causes of desiccation, and the mechanisms

  5. Pathways of upwelling deep waters to the surface of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Tamsitt, Veronica; Drake, Henri; Morrison, Adele; Talley, Lynne; Dufour, Carolina; Gray, Alison; Griffies, Stephen; Mazloff, Matthew; Sarmiento, Jorge; Wang, Jinbo; Weijer, Wilbert

    2017-04-01

    Upwelling of Atlantic, Indian and Pacific deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of anthropogenic carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. Here we go beyond the two-dimensional view of Southern Ocean upwelling, to show detailed Southern Ocean upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution ocean and climate models. The northern deep waters enter the Antarctic Circumpolar Current (ACC) via narrow southward currents along the boundaries of the three ocean basins, before spiraling southeastward and upward through the ACC. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the southern ACC boundary, with a spatially nonuniform distribution, regionalizing warm water supply to Antarctic ice shelves and the delivery of nutrient and carbon-rich water to the sea surface. The timescale for half of the deep water to upwell from 30°S to the mixed layer is on the order of 60-90 years, which has important implications for the timescale for signals to propagate through the deep ocean. In addition, we quantify the diabatic transformation along particle trajectories, to identify where diabatic processes are important along the upwelling pathways.

  6. Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

    SciTech Connect

    Zhang, W.; Xu, T.; Li, Y.

    2010-12-15

    The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} mineral trapping, the presence of Fe-bearing siliciclastic and/or carbonate is more favorable to the H{sub 2}S mineral trapping.

  7. First description of deep-water elasmobranch assemblages in the Exuma Sound, The Bahamas

    NASA Astrophysics Data System (ADS)

    Brooks, Edward J.; Brooks, Annabelle M. L.; Williams, Sean; Jordan, Lance K. B.; Abercrombie, Debra; Chapman, Demian D.; Howey-Jordan, Lucy A.; Grubbs, R. Dean

    2015-05-01

    Deep-sea chondrichthyans, like many deep-water fishes, are very poorly understood at the most fundamental biological, ecological and taxonomic levels. Our study represents the first ecological investigation of deep-water elasmobranch assemblages in The Bahamas, and the first assessment of species-specific resilience to capture for all of the species captured. Standardised deep-water longline surveys (n=69) were conducted September to December 2010 and 2011 between 472 m and 1024 m deep, resulting in the capture of 144 sharks from 8 different species. These included the Cuban dogfish, Squalus cubensis, the bigeye sixgill shark, Hexanchus nakamurai, the bluntnose sixgill shark, Hexanchus griseus, the smooth dogfish, Mustelus canis insularis, the roughskin dogfish, Centroscymnus owstoni, Springer's sawtail catshark, Galeus springeri and the false catshark, Pseudotriakis microdon. Preliminary genetic analysis indicated two or more species of gulper sharks, Centrophorus spp.; however, for the present study they were treated as a single species complex. Water depth and distance from the rocky structure of the Exuma Sound wall were inversely correlated with species richness, whereas seabed temperature was directly correlated with species richness. These variables also had a significant influence on the abundance and distribution of many species. Expanded depth ranges were established for S. cubensis and H. nakamurai, which, in the case of S. cubensis, is thought to be driven by thermal preferences. At-vessel mortality rates increased significantly with depth, and post-release mortality was thought to be high for some species, in part due to high post-release predation. This study highlights the importance of utilising strategic geographic locations that provide easy access to deep water, in combination with traditional expedition-based deep-ocean science, to accelerate the acquisition of fundamental ecological and biological insights into deep-sea elasmobranchs.

  8. Asynchronous warming and δ(18)O evolution of deep Atlantic water masses during the last deglaciation.

    PubMed

    Zhang, Jiaxu; Liu, Zhengyu; Brady, Esther C; Oppo, Delia W; Clark, Peter U; Jahn, Alexandra; Marcott, Shaun A; Lindsay, Keith

    2017-10-02

    The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ(18)O of benthic foraminiferal calcite (δ(18)Oc). Here, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ(18)O evolution. Model results suggest that, in response to North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ(18)Oc likely reflects early warming of the deep northern North Atlantic by ∼1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ(18)O, and call for caution when inferring water mass changes from δ(18)Oc records while assuming uniform changes in deep temperatures.

  9. Developing Deep Water Excercise Equipment for Low Back Pain (LBP) Patients: medical validation experiences.

    PubMed

    Jókai, Erika; Hárságyi, Ágnes

    2015-01-01

    Authors describe a joint work of practicing physicians and rehabilitation specialist engineers. In our work we wanted to prove the efficacy of deep-water physiotherapy among the hydrotherapy treatments in patients with degenerative chronic low back pain, by monitoring both objective and subjective parameters. On the other hand, we are also seeking the possibilities of developing a water exercise tool which can spare the shoulders, can be used in deep water and is suitable for helping the three-dimensional movements of the spine without burdening the upper limbs and shoulders.

  10. Parallel Estimation and Control Architectures for Deep-Space Formation Flying Spacecraft

    NASA Technical Reports Server (NTRS)

    Hadaegh, Fred Y.; Smith, Roy S.

    2006-01-01

    The formation flying of precisely controlled spacecraft in deep space can be used to implement optical instruments capable of imaging planets in other solar systems. The distance of the formation from Earth necessitates a significant level of autonomy and each spacecraft must base its actions on its estimates of the location and velocity of the other spacecraft. Precise coordination and control is the key requirement in such missions and the flow of information between spacecraft must be carefully designed. Doing this in an efficient and optimal manner requires novel techniques for the design of the on-board estimators. The use of standard Kalman filter-based designs can lead to unanticipated dynamics--which we refer to as disagreement dynamics--in the estimators' errors. We show how communication amongst the spacecraft can be designed in order to control all of the dynamics within the formation. We present several results relating the topology of the communication network to the resulting closed-loop control dynamics of the formation. The consequences for the design of the control, communication and coordination are discussed.

  11. Effects of electrode gap and electric potential on chlorine generation of electrolyzed deep ocean water.

    PubMed

    Hsu, Guoo-Shyng Wang; Hsu, Shun-Yao

    2016-07-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. A two-factor central composite design was adopted for studying the effects of electrode gap and electric potential on chlorine generation efficiency of electrolyzed deep ocean water. Deep ocean water was electrolyzed in a glass electrolyzing cell equipped with platinum-plated titanium anode and cathode. Results showed high electric efficiency at a low cell potential, and a high current density and high chlorine concentration at a high cell potential and low electrode gap. Current efficiency of the system was not significantly affected by electrode gap and electric potential. A small electrode gap reduced the required cell potential and resulted in high energy efficiency. The optimal choice of electrode gap and cell potential depends on the chlorine level of the electrolyzed deep ocean water to be produced, and a small electrode gap is preferred. Copyright © 2016. Published by Elsevier B.V.

  12. Piping coarse-grained sediment to a deep water fan through a shelf-edge delta bypass channel: Tank experiments

    NASA Astrophysics Data System (ADS)

    Kim, Yuri; Kim, Wonsuck; Cheong, Daekyo; Muto, Tetsuji; Pyles, David R.

    2013-12-01

    is now generally accepted that deltas that prograde to the shelf edge are able to transport coarse sediment to deep water either with or without sea level changes. However, it is still unclear how feeder rivers behave differently in the shelf-edge delta case to rivers found in a delta that progrades over the shelf. A series of nine shelf-edge delta experiments are presented to investigate the lateral mobility of the feeder channel at the shelf edge and the associated deep water depositional system under a range of sediment supply rates and shelf-front depths. In the experiments, constant sediment supply from an upstream point source under static sea level led the fluviodeltaic system to prograde over the shallow shelf surface and advance beyond the shelf edge into deep water. The feeder river of the fluviodeltaic system became a bypass system once the toe of the delta front reached the shelf edge. After the delta front was perched at the shelf edge, a submarine fan developed in deep water although remaining disconnected from the delta. In this bypass stage, no regional avulsion or lateral migration of the feeder river occurred and all sediment from the upstream source bypassed the river, delta front, and shelf-front slope. The duration of the bypass stage is proportional to shelf-front depth and inversely proportional to sediment discharge. The combined duration of the shelf-transit phase of the fluviodeltaic system and the bypass phase is the characteristic time scale for the continental margin to "anneal" transgression-inducing perturbation due to high-frequency and/or high-amplitude relative sea level rise. The sequential evolution in the experiment compares favorably to the Eocene Sobrarbe Formation, a shelf-edge delta in Spain, although natural variations are noted. This comparison justifies the application of concepts proposed herein to natural systems and provides insight into interpreting processes from ancient shelf-edge delta systems.

  13. Increased reservoir ages and poorly ventilated deep waters inferred in the glacial Eastern Equatorial Pacific

    PubMed Central

    de la Fuente, Maria; Skinner, Luke; Calvo, Eva; Pelejero, Carles; Cacho, Isabel

    2015-01-01

    Consistent evidence for a poorly ventilated deep Pacific Ocean that could have released its radiocarbon-depleted carbon stock to the atmosphere during the last deglaciation has long been sought. Such evidence remains lacking, in part due to a paucity of surface reservoir age reconstructions required for accurate deep-ocean ventilation age estimates. Here we combine new radiocarbon data from the Eastern Equatorial Pacific (EEP) with chronostratigraphic calendar age constraints to estimate shallow sub-surface reservoir age variability, and thus provide estimates of deep-ocean ventilation ages. Both shallow- and deep-water ventilation ages drop across the last deglaciation, consistent with similar reconstructions from the South Pacific and Southern Ocean. The observed regional fingerprint linking the Southern Ocean and the EEP is consistent with a dominant southern source for EEP thermocline waters and suggests relatively invariant ocean interior transport pathways but significantly reduced air–sea gas exchange in the glacial southern high latitudes. PMID:26137976

  14. Factors controlling Li concentration and isotopic composition in formation waters and host rocks of Marcellus Shale, Appalachian Basin

    USGS Publications Warehouse

    Phan, Thai T.; Capo, Rosemary C; Stewart, Brian W.; Macpherson, Gwen; Rowan, Elisabeth L.; Hammack, Richard W.

    2015-01-01

    In Greene Co., southwest Pennsylvania, the Upper Devonian sandstone formation waters have δ7Li values of + 14.6 ± 1.2 (2SD, n = 25), and are distinct from Marcellus Shale formation waters which have δ7Li of + 10.0 ± 0.8 (2SD, n = 12). These two formation waters also maintain distinctive 87Sr/86Sr ratios suggesting hydrologic separation between these units. Applying temperature-dependent illitilization model to Marcellus Shale, we found that Li concentration in clay minerals increased with Li concentration in pore fluid during diagenetic illite-smectite transition. Samples from north central PA show a much smaller range in both δ7Li and 87Sr/86Sr than in southwest Pennsylvania. Spatial variations in Li and δ7Li values show that Marcellus formation waters are not homogeneous across the Appalachian Basin. Marcellus formation waters in the northeastern Pennsylvania portion of the basin show a much smaller range in both δ7Li and 87Sr/86Sr, suggesting long term, cross-formational fluid migration in this region. Assessing the impact of potential mixing of fresh water with deep formation water requires establishment of a geochemical and isotopic baseline in the shallow, fresh water aquifers, and site specific characterization of formation water, followed by long-term monitoring, particularly in regions of future shale gas development.

  15. Deep Chandra Observations of HCG 16. I. Active Nuclei, Star Formation, and Galactic Winds

    NASA Astrophysics Data System (ADS)

    O'Sullivan, E.; Zezas, A.; Vrtilek, J. M.; Giacintucci, S.; Trevisan, M.; David, L. P.; Ponman, T. J.; Mamon, G. A.; Raychaudhury, S.

    2014-10-01

    We present new, deep Chandra X-ray and Giant Metrewave Radio Telescope 610 MHz observations of the spiral-galaxy-rich compact group HCG 16, which we use to examine nuclear activity, star formation, and high-luminosity X-ray binary populations in the major galaxies. We confirm the presence of obscured active nuclei in NGC 833 and NGC 835, and identify a previously unrecognized nuclear source in NGC 838. All three nuclei are variable on timescales of months to years, and for NGC 833 and NGC 835 this is most likely caused by changes in accretion rate. The deep Chandra observations allow us to detect for the first time an Fe Kα emission line in the spectrum of the Seyfert 2 nucleus of NGC 835. We find that NGC 838 and NGC 839 are both starburst-dominated systems, with only weak nuclear activity, in agreement with previous optical studies. We estimate the star formation rates in the two galaxies from their X-ray and radio emission, and compare these results with estimates from the infrared and ultraviolet bands to confirm that star formation in both galaxies is probably declining after galaxy-wide starbursts were triggered ~400-500 Myr ago. We examine the physical properties of their galactic superwinds, and find that both have temperatures of ~0.8 keV. We also examine the X-ray and radio properties of NGC 848, the fifth largest galaxy in the group, and show that it is dominated by emission from its starburst.

  16. The deep chlorophyll layer in Lake Ontario: Extent, mechanisms of formation, and abiotic predictors

    USGS Publications Warehouse

    Scofield, Anne E.; Watkins, James M.; Weidel, Brian C.; Luckey, Frederick J.; Rudstam, Lars G.

    2017-01-01

    Epilimnetic production has declined in Lake Ontario, but increased production in metalimnetic deep chlorophyll layers (DCLs) may compensate for these losses. We investigated the spatial and temporal extent of DCLs, the mechanisms driving DCL formation, and the use of physical variables for predicting the depth and concentration of the deep chlorophyll maximum (DCM) during April–September 2013. A DCL with DCM concentrations 2 to 3 times greater than those in the epilimnion was present when the euphotic depth extended below the epilimnion, which occurred primarily from late June through mid-August. In situ growth was important for DCL formation in June and July, but settling and photoadaptation likely also contributed to the later-season DCL. Supporting evidence includes: phytoplankton biovolume was 2.4 × greater in the DCL than in the epilimnion during July, the DCL phytoplankton community of July was different from that of May and the July epilimnion (p = 0.004), and there were concurrences of DCM with maxima in fine particle concentration and dissolved oxygen saturation. Higher nutrient levels in the metalimnion may also be a necessary condition for DCL formation because July metalimnetic concentrations were 1.5 × (nitrate) and 3.5 × (silica) greater than in the epilimnion. Thermal structure variables including epilimnion depth, thermocline depth, and thermocline steepness were useful for predicting DCM depth; the inclusion of euphotic depth only marginally improved these predictions. However, euphotic depth was critical for predicting DCM concentrations. The DCL is a productive and predictable feature of the Lake Ontario ecosystem during the stratified period.

  17. Spiraling pathways of global deep waters to the surface of the Southern Ocean.

    PubMed

    Tamsitt, Veronica; Drake, Henri F; Morrison, Adele K; Talley, Lynne D; Dufour, Carolina O; Gray, Alison R; Griffies, Stephen M; Mazloff, Matthew R; Sarmiento, Jorge L; Wang, Jinbo; Weijer, Wilbert

    2017-08-02

    Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60-90 years.Deep waters of the Atlantic, Pacific and Indian Oceans upwell in the Southern Oceanbut the exact pathways are not fully characterized. Here the authors present a three dimensional view showing a spiralling southward path, with enhanced upwelling by eddy-transport at topographic hotspots.

  18. The contribution of the Greenland and Barents Seas to the deep water of the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Swift, James H.; Takahashi, Taro; Livingston, Hugh D.

    1983-07-01

    The deep waters of the Arctic Ocean are traditionally held to be fed by an influx of Norwegian Sea Deep Water (NSDW) via the northward flowing West Spitsbergen Current. Discrete sample and CTD observations obtained from the Greenland-Spitsbergen Passage in August 1981 during the Transient Tracers in the Ocean (TTO) North Atlantic expedition showed a ≈ 100-m-thick layer of modified Greenland Sea Deep Water (GSDW: colder and fresher than NSDW) at 2500 m, spreading northward along the bottom of a deep, unimpeded channel, underneath the NSDW. Since the available data indicate that Arctic Ocean Deep Water (AODW) has a higher salinity than NSDW, mixing of NSDW and GSDW can not produce AODW. Therefore, other sources, such as the peripheral arctic shelf seas, must contribute dense saline water to the Arctic Ocean. Concentrations of 137Cs and 90Sr observed in AODW are greater than those observed in GSDW and NSDW. The concentrations of these radionuclides on the Barents Sea shelf are sufficiently high and in the correct relative proportions to support this proposition.

  19. North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

    DTIC Science & Technology

    2014-09-30

    capitalize on the three-dimensional character of the sound and noise fields. OBJECTIVES During 2009–2011 three experiments were conducted to study...Worcester et al., 2009). The DVLA consisted of two 1000-m subarrays: an axial subarray spanning the sound -channel axis and a deep subarray spanning... Octave Research Array (FORA). PhilSea10. The 2010–2011 NPAL Philippine Sea deep-water acoustic propagation experiment combined measurements of

  20. An advective mechanism for deep chlorophyll maxima formation in southern Drake Passage

    NASA Astrophysics Data System (ADS)

    Erickson, Zachary K.; Thompson, Andrew F.; Cassar, Nicolas; Sprintall, Janet; Mazloff, Matthew R.

    2016-10-01

    We observe surface and subsurface fluorescence-derived chlorophyll maxima in southern Drake Passage during austral summer. Backscatter measurements indicate that the deep chlorophyll maxima (DCMs) are also deep biomass maxima, and euphotic depth estimates show that they lie below the euphotic layer. Subsurface, offshore and near-surface, onshore features lie along the same isopycnal, suggesting advective generation of DCMs. Temperature measurements indicate a warming of surface waters throughout austral summer, capping the winter water (WW) layer and increasing off-shelf stratification in this isopycnal layer. The outcrop position of the WW isopycnal layer shifts onshore, into a surface phytoplankton bloom. A lateral potential vorticity (PV) gradient develops, such that a down-gradient PV flux is consistent with offshore, along-isopycnal tracer transport. Model results are consistent with this mechanism. Subduction of chlorophyll and biomass along isopycnals represents a biological term not observed by surface satellite measurements which may contribute significantly to the strength of the biological pump in this region.

  1. A HYCOM modeling study of the Persian Gulf: 2. Formation and export of Persian Gulf Water

    NASA Astrophysics Data System (ADS)

    Yao, Fengchao; Johns, William E.

    2010-11-01

    The circulation and water mass transformation processes in the Persian Gulf and the water exchange with the Indian Ocean through the Strait of Hormuz are studied using the Hybrid Coordinate Ocean Model (HYCOM). Model results suggest that intruding Indian Ocean Surface Water (IOSW) is transformed into hypersaline waters with salinity >41 practical salinity unit by the fresh water loss in the northern end of the gulf and in the southern shallow banks. During wintertime, intense heat loss from sea to air leads to the formation of cold and saline waters both in the northern gulf and in the southern gulf. Dense waters formed in the southern gulf have higher salinity and spill into the axial deep trough of the gulf as a sporadic bottom outflow in winter, which leads to high-salinity pulses in the strait as observed, whereas in summer their buoyancy is increased due to heating and they are exported as a warm yet salty intermediate depth flow through the strait. Dense waters formed in the northern gulf propagate toward the strait along the axial trough throughout the year. Correspondingly, there are two branches of seasonal overturning circulation in density classes: the northern branch peaking in August with strength of 0.13 Sv and the southern branch peaking in February and December with strength of 0.08 Sv. These two branches outflow together feed a seasonally varying deep outflow through the strait with an annual mean volume transport of 0.12 Sv.

  2. Deep-water renewal by turbidity currents in the Sulu Sea

    NASA Astrophysics Data System (ADS)

    Quadfasel, Detlef; Kudrass, Hermann; Frische, Andrea

    1990-11-01

    THE ventilation of the intermediate and deep layers of the ocean is governed by convection: dense water formed at the sea surface through air-sea interaction processes (mainly at high latitudes) sinks to great depths. Convection determines the heat, salt and dissolved-gas budgets of the ocean's interior and therefore exerts a significant influence on the Earth's climate. Convective processes can also be initiated by the flow of dense water over submarine sills separating ocean basins with water masses of different buoyancy. Here we report the observation of relatively light deep water in the overflow region near the sill in the northern part of the 5,000-m-deep Sulu Sea. Because of its buoyancy, this water could not have reached the sea floor of its own accord. Turbidity currents, induced by changes in water density that result from sediment influx, occur in this region at intervals of several decades, as indicated by the frequent deposition of graded sequences of silty mud on the abyssal plain. We suggest that such turbidity currents, combined with the effects of classical hydrological plume convection, are capable of bringing light water to large depths. In tropical regions, where normal oceanic convection is relatively weak, this mechanism may contribute significantly to the ventilation of deep basins.

  3. Deep-water kelp refugia as potential hotspots of tropical marine diversity and productivity.

    PubMed

    Graham, Michael H; Kinlan, Brian P; Druehl, Louis D; Garske, Lauren E; Banks, Stuart

    2007-10-16

    Classic marine ecological paradigms view kelp forests as inherently temperate-boreal phenomena replaced by coral reefs in tropical waters. These paradigms hinge on the notion that tropical surface waters are too warm and nutrient-depleted to support kelp productivity and survival. We present a synthetic oceanographic and ecophysiological model that accurately identifies all known kelp populations and, by using the same criteria, predicts the existence of >23,500 km(2) unexplored submerged (30- to 200-m depth) tropical kelp habitats. Predicted tropical kelp habitats were most probable in regions where bathymetry and upwelling resulted in mixed-layer shoaling above the depth of minimum annual irradiance dose for kelp survival. Using model predictions, we discovered extensive new deep-water Eisenia galapagensis populations in the Galápagos that increased in abundance with increasing depth to >60 m, complete with cold-water flora and fauna of temperate affinities. The predictability of deep-water kelp habitat and the discovery of expansive deep-water Galápagos kelp forests validate the extent of deep-water tropical kelp refugia, with potential implications for regional productivity and biodiversity, tropical food web ecology, and understanding of the resilience of tropical marine systems to climate change.

  4. Deep-water kelp refugia as potential hotspots of tropical marine diversity and productivity

    PubMed Central

    Graham, Michael H.; Kinlan, Brian P.; Druehl, Louis D.; Garske, Lauren E.; Banks, Stuart

    2007-01-01

    Classic marine ecological paradigms view kelp forests as inherently temperate-boreal phenomena replaced by coral reefs in tropical waters. These paradigms hinge on the notion that tropical surface waters are too warm and nutrient-depleted to support kelp productivity and survival. We present a synthetic oceanographic and ecophysiological model that accurately identifies all known kelp populations and, by using the same criteria, predicts the existence of >23,500 km2 unexplored submerged (30- to 200-m depth) tropical kelp habitats. Predicted tropical kelp habitats were most probable in regions where bathymetry and upwelling resulted in mixed-layer shoaling above the depth of minimum annual irradiance dose for kelp survival. Using model predictions, we discovered extensive new deep-water Eisenia galapagensis populations in the Galápagos that increased in abundance with increasing depth to >60 m, complete with cold-water flora and fauna of temperate affinities. The predictability of deep-water kelp habitat and the discovery of expansive deep-water Galápagos kelp forests validate the extent of deep-water tropical kelp refugia, with potential implications for regional productivity and biodiversity, tropical food web ecology, and understanding of the resilience of tropical marine systems to climate change. PMID:17913882

  5. The Structure of Sea Water and Gelatinous Water in the Deep Ocean

    NASA Astrophysics Data System (ADS)

    Peltzer, E. T.; Walz, P. M.; Wojciechowicz, M.; Brewer, P. G.

    2016-12-01

    Gelatinous life forms are common in the deep sea and are able to maintain a careful combination of body integrity and easy fluidity of motion over a wide range of T and P. They accomplish this in part by modifying the molecular structure of water. Both the transparent body of the organism (the mesoglea) and the structure of the immediate surrounding sea water were investigated by in situ laser Raman spectroscopy at depths from 300m to 2,800m. The structure of water is reasonably well known; the basic unit is a hydrogen bonded pentamer with defined stretching and bending modes. The spectrum of the bending band is separable into two components while the stretching band spectrum is composed of five components representing both intra- and inter-molecular vibrations. The effect of temperature on the various vibrational modes is complex. While the effect of pressure on the bending modes is small, but the effect of temperature and pressure on the stretching modes is significant and can be modeled as a van `t Hoff function. Our in situ experiments were conducted using MBARI's ROV Ventana and ROV Doc Ricketts. We collected cnidarians and ctenophores into a 6 L glass detritus sampler fitted with a metal grid plate. Once the animal was captured, we introduced argon gas through the lid of the sampler displacing the contained sea water and leaving a motionless sea water free specimen for spectroscopy. The laser beam was focused through the glass wall of the container and the focal point adjusted to be inside the gelatinous body. Our results very clearly show that:i) The gelatinous mass effectively excludes salts with zero sulfate ion being detected.ii) The water bending modes are absent from the gelatinous spectra.iii) The water stretching modes are highly modified from the typical 5 band liquid pentamer structure with only 3 vibrational modes observable. These results stand in marked contrast to the familiar household gelatin which is typically derived from bovine sources

  6. Application of Low cost Spirulina growth medium using Deep sea water

    NASA Astrophysics Data System (ADS)

    Lim, Dae-hack; Kim, Bong-ju; Lee, Sung-jae; Choi, Nag-chul; Park, Cheon-young

    2017-04-01

    Deep-sea water has a relatively constant temperature, abundant nutrients such as calcium, magnesium, nitrates, and phosphates, etc., and stable water quality, even though there might be some variations of their compositions according to collection places. Thus, deep-sea water would be a good substrate for algal growth and biomass production since it contains various nutrients, including a fluorescent red pigment, and β-carotene, etc. The aim of this study was to investigate the economics of a culture condition through comparative analysis to Spirulina platensis growth characteristic under various medium conditions for cost-effective production of Spirulina sp.. Growth experiments were performed with S. platensis under various culture medium conditions (deep sea water + SP medium). Growth tests for culture medium demonstrated that the deep sea water to SP medium ratio of 50:50(W/W) was effective in S. platensis with the maximum biomass (1.35g/L) and minimum medium making cost per production mass (133.28 KRW/g). Parameter estimation of bio-kinetics (maximum growth rate and yield) for low cost medium results showed that the maximum growth rate and yield of N, P, K were obtained under deep sea water to SP medium ratio of 50:50(W/W) of 0.057 1/day and 0.151, 0.076, 0.123, respectively. Acknowledgment : "This research was a part of the project titled 'Development of microalgae culture technique for cosmetic materials based on ocean deep sea water(20160297)', funded by the Ministry of Oceans and Fisheries, Korea."

  7. Effects of Deep Convection on Upper Tropospheric Outflow Ice Supersaturation and Cirrus Cloud Formation

    NASA Astrophysics Data System (ADS)

    DiGangi, J. P.; O'Brien, A.; Diao, M.; Beaton, S. P.; Zondlo, M. A.

    2013-12-01

    A barrier in constraining the Earth's radiative forcing budget stems from the large uncertainties associated with cloud formation and dynamics. Recent work* has shown that small scale dynamics play a significant role in controlling the relative humidity of the upper troposphere and, in turn, the microphysics of cirrus clouds. While there has been significant discussion of the long-term transport effects of ground level trace gases and aerosols, only recently have datasets become available which examine the effects of fast convective transport on the relatively pristine upper troposphere. During the NSF Deep Convective Clouds and Chemistry (DC3) Experiment in May-June 2012, multiple aircraft, each with a large suite of chemical, aerosol and, cloud physics payloads, were utilized to characterize both the inflow and outflow of deep convective storms over the continental US. We have used data from 10 storms during DC3 as case studies to illustrate the influence of trace gases and aerosols, transported by deep convection to the upper troposphere, on ice supersaturation regions and cirrus cloud formation. Ice supersaturation regions (ISSR), defined as regions with relative humidity greater than 100% at temperatures below -40°C, in the outflow region of each storm are identified using humidity data from the NSF/NCAR VCSEL hygrometer on the NSF G-V. The ISSR intensity of the outflow of a storm is defined as the aggregate mean of the maximum relative humidity encountered in each individual ISSR in this region, a quantity that is observed to increase with ISSR length scales. Coordinated sampling of the inflow region of each storm, determined from NEXRAD radar measurements and flight tracks combined with notes from the flight summaries, by the NASA DC-8 provide a characterization of the chemical and particulate composition at the base of the storm. Mineral and nitrate particulate in the storm inflow are observed to have strong positive correlations with the ISSR intensity in

  8. Enhanced Positive Water Vapor Feedback Associated with Tropical Deep Convection: New Evidence from Aura MLS

    NASA Technical Reports Server (NTRS)

    Su, Hui; Read, William G.; Jiang, Jonathan H.; Waters, Joe W.; Wu, Dong L.; Fetzer, Eric J.

    2006-01-01

    Recent simultaneous observations of upper tropospheric (UT) water vapor and cloud ice from the Microwave Limb Sounder (MLS) on the Aura satellite provide new evidence for tropical convective influence on UT water vapor and its associated greenhouse effect. The observations show that UT water vapor increases as cloud ice water content increases. They also show that, when sea surface temperature (SST) exceeds approx.300 K, UT cloud ice associated with tropical deep convection increases sharply with increasing SST. The moistening of the upper troposphere by deep convection leads to an enhanced positive water vapor feedback, about 3 times that implied solely by thermodynamics. Over tropical oceans when SST greater than approx.300 K, the 'convective UT water vapor feedback' inferred from the MLS observations contributes approximately 65% of the sensitivity of the clear-sky greenhouse parameter to SST.

  9. Enhanced Positive Water Vapor Feedback Associated with Tropical Deep Convection: New Evidence from Aura MLS

    NASA Technical Reports Server (NTRS)

    Su, Hui; Read, William G.; Jiang, Jonathan H.; Waters, Joe W.; Wu, Dong L.; Fetzer, Eric J.

    2006-01-01

    Recent simultaneous observations of upper tropospheric (UT) water vapor and cloud ice from the Microwave Limb Sounder (MLS) on the Aura satellite provide new evidence for tropical convective influence on UT water vapor and its associated greenhouse effect. The observations show that UT water vapor increases as cloud ice water content increases. They also show that, when sea surface temperature (SST) exceeds approx.300 K, UT cloud ice associated with tropical deep convection increases sharply with increasing SST. The moistening of the upper troposphere by deep convection leads to an enhanced positive water vapor feedback, about 3 times that implied solely by thermodynamics. Over tropical oceans when SST greater than approx.300 K, the 'convective UT water vapor feedback' inferred from the MLS observations contributes approximately 65% of the sensitivity of the clear-sky greenhouse parameter to SST.

  10. Simulation of Deep Water Renewal in Crater Lake, Oregon, USA under Current and Future Climate Conditions

    NASA Astrophysics Data System (ADS)

    Piccolroaz, S.; Wood, T. M.; Wherry, S.; Girdner, S.

    2015-12-01

    We applied a 1-dimensional lake model developed to simulate deep mixing related to thermobaric instabilities in temperate lakes to Crater Lake, a 590-m deep caldera lake in Oregon's Cascade Range known for its stunning deep blue color and extremely clear water, in order to determine the frequency of deep water renewal in future climate conditions. The lake model was calibrated with 6 years of water temperature profiles, and then simulated 10 years of validation data with an RMSE ranging from 0.81°C at 50 m depth to 0.04°C at 350-460 m depth. The simulated time series of heat content in the deep lake accurately captured extreme years characterized by weak and strong deep water renewal. The lake model uses wind speed and lake surface temperature (LST) as boundary conditions. LST projections under six climate scenarios from the CMIP5 intermodel comparison project (2 representative concentration pathways X 3 general circulation models) were evaluated with air2water, a simple lumped model that only requires daily values of downscaled air temperature. air2water was calibrated with data from 1993-2011, resulting in a RMSE between simulated and observed daily LST values of 0.68°C. All future climate scenarios project increased water temperature throughout the water column and a substantive reduction in the frequency of deepwater renewal events. The least extreme scenario (CNRM-CM5, RCP4.5) projects the frequency of deepwater renewal events to decrease from about 1 in 2 years in the present to about 1 in 3 years by 2100. The most extreme scenario (HadGEM2-ES, RCP8.5) projects the frequency of deepwater renewal events to be less than 1 in 7 years by 2100 and lake surface temperatures never cooling to less than 4°C after 2050. In all RCP4.5 simulations the temperature of the entire water column is greater than 4°C for increasing periods of time. In the RCP8.5 simulations, the temperature of the entire water column is greater than 4°C year round by the year 2060 (HadGEM2

  11. Potential for deep basin-centered gas accumulation in Travis Peak (Hosston) Formation, Gulf Coastal Basin

    USGS Publications Warehouse

    Bartberger, Charles E.; Dyman, Thaddeus S.; Condon, Steven M.

    2003-01-01

    The potential of Lower Cretaceous sandstones of the Travis Peak Formation in the northern Gulf Coast Basin to harbor a basin-centered gas accumulation was evaluated by examining (1) the depositional and diagenetic history and reservoir properties of Travis Peak sandstones, (2) the presence and quality of source rocks for generating gas, (3) the burial and thermal history of source rocks and time of gas generation and migration relative to tectonic development of Travis Peak traps, (4) gas and water recoveries from drill-stem and formation tests, (5) the distribution of abnormal pressures based on shut-in-pressure data, and (6) the presence or absence of gas-water contacts associated with gas accumulations in Travis Peak sandstones. The Travis Peak Formation (and correlative Hosston Formation) is a basinward-thickening wedge of terrigenous clastic sedimentary rocks that underlies the northern Gulf Coast Basin from eastern Texas across northern Louisiana to southern Mississippi. Clastic infl ux was focused in two main fl uvial-deltaic depocenters?one located in northeastern Texas and the other in southeastern Mississippi and northeastern Louisiana. Across the main hydrocarbon-productive trend in eastern Texas and northern Louisiana, the Travis Peak Formation is about 2,000 ft thick. Most Travis Peak hydrocarbon production in eastern Texas comes from drilling depths between 6,000 and 10,000 ft. Signifi cant decrease in porosity and permeability occurs through that depth interval. Above 8,000-ft drilling depth in eastern Texas, Travis Peak sandstone matrix permeabilities often are signifi cantly higher than the 0.1-millidarcy (mD) cutoff that characterizes tight-gas reservoirs. Below 8,000 ft, matrix permeability of Travis Peak sandstones is low because of pervasive quartz cementation, but abundant natural fractures impart signifi cant fracture permeability. Although pressure data within the middle and lower Travis Peak Formation are limited in eastern Texas

  12. The virial theorem for water waves and its application to deep-water wave breaking

    NASA Astrophysics Data System (ADS)

    Pizzo, Nicholas; Melville, W. Ken

    2014-11-01

    The connection between the geometry, kinematics and dynamics of steep and breaking waves is crucial for an improved understanding of air-sea interaction processes. In this study, we present a virial theorem for deep-water surface gravity waves, related to a conserved integral quantity originally derived by Benjamin and Olver (1982), and we apply this theorem to the study of properties of steep and breaking waves. Specifically, we relate the geometry and dynamics of these wave scenarios in an attempt to better understand the breakdown of equipartition between the kinetic and potential energy. The virial theorem will be studied both analytically and numerically, where in the latter case we make use of a variational description of water waves in a conformally mapped reference frame (Balk 1996) that we have developed for use in a numerical model. Particular attention will be given to the application of these findings to recent theoretical and laboratory studies in which it has been shown that the potential energy available to breaking waves plays a crucial role in setting the scales of post-breaking phenomena; for example, the breaking induced energy dissipation rate (Drazen et al. 2008) and the circulation generated by breaking (Pizzo and Melville 2013).

  13. Mapping Deep-Water Gas Emissions With Sidescan Sonar

    NASA Astrophysics Data System (ADS)

    Klaucke, Ingo; Weinrebe, Wilhelm; Sahling, Heiko; Bohrmann, Gerhard; Bürk, Dietmar

    2005-09-01

    Emissions of methane gas from cold seeps on the seafloor have a strong impact on a number of biogeochemical processes. These processes include the development of deep-sea benthic ecosystems via the process of anaerobic oxidation of methane [Boetius et al., 2000] or the precipitation of carbonates [Ritger et al., 1987]. The fluxes of other chemical species associated with methane emissions may even influence the chemical composition of seawater [Aloisi et al., 2004]. Such gas emissions may have been much more intensive in the past with a strong impact onglobal climate [Dickens, 1999], as suggested bycarbon isotope data. Many international and national research projects, such as the METRO collaborative project (Methane and Methane Hydrates Within the Black Sea: Structural Analyses, Quantification and Impact of a Dynamic Methane Reservoir), part of the German research and development program Geotechnologien, focus on these cold seep sites and stimulate interdisciplinary work between a variety of scientific groups.

  14. A deep seated movement in a marly-arenaceous formation: analysis of slope deformation and pore pressure influence

    NASA Astrophysics Data System (ADS)

    Assefa, S.; Graziani, A.; Lembo-Fazio, A.

    2015-09-01

    The case history of a deep-seated slope movement in a complex rock formation (Marly-Arenaceous Formation) is analyzed. The movement, monitored for more than 20 years, was recognized after the discovery of intense cracking in the concrete lining of a hydraulic tunnel running across the slope. The time history of displacements shows that the ongoing deformation process is essentially a stationary creep phenomenon, also influenced by transient variations in pore pressure distribution. The slip surface is formed by a tectonized clay gouge layer and the mobilized shear strength is close to residual. The slope has been modelled (UDEC code) as a complex blocky structure defined by several joint sets: bedding joints, inclined and sub-vertical discontinuities. Different geometries of the slip surface, reasonably varied within the range of hypotheses compatible with field evidences, have limited influence on the limit friction angle of the slip surface. Joint patterns have influence on the deformation mode and minor impact on the mobilized friction angle. The model response is less sensitive to the water level at the slope toe as compared to the rise of groundwater table.

  15. Volumetrics of CO{sub 2} Storage in Deep Saline Formations

    SciTech Connect

    Steele-MacInnis, Matthew; Capobianco, Ryan M; Dilmore, Robert; Goodman, Angela; Guthrie, George; Rimstidt, J Donald; Bodnar, Robert J

    2013-01-01

    Concern about the role of greenhouse gases in global climate change has generated interest in sequestering CO{sub 2} from fossil-fuel combustion in deep saline formations. Pore space in these formations is initially filled with brine, and space to accommodate injected CO{sub 2} must be generated by displacing brine, and to a lesser extent by compression of brine and rock. The formation volume required to store a given mass of CO{sub 2} depends on the storage mechanism. We compare the equilibrium volumetric requirements of three end-member processes: CO{sub 2} stored as a supercritical fluid (structural or stratigraphic trapping); CO{sub 2} dissolved in pre-existing brine (solubility trapping); and CO{sub 2} solubility enhanced by dissolution of calcite. For typical storage conditions, storing CO{sub 2} by solubility trapping reduces the volume required to store the same amount of CO{sub 2} by structural or stratigraphic trapping by about 50%. Accessibility of CO{sub 2} to brine determines which storage mechanism (structural/stratigraphic versus solubility) dominates at a given time, which is a critical factor in evaluating CO{sub 2} volumetric requirements and long-term storage security.

  16. Star formation properties of Hickson Compact Groups based on deep Hα imaging

    NASA Astrophysics Data System (ADS)

    Eigenthaler, Paul; Ploeckinger, Sylvia; Verdugo, Miguel; Ziegler, Bodo

    2015-08-01

    We present deep Hα imaging of seven Hickson Compact Groups (HCGs) using the 4.1-m Southern Astrophysics Research (SOAR) Telescope. The high spatial resolution of the observations allows us to study both the integrated star formation properties of the main galaxies as well as the 2D distribution of star-forming knots in the faint tidal arms that form during interactions between the individual galaxies. We derive star formation rates and stellar masses for group members and discuss their position relative to the main sequence of star-forming galaxies. Despite the existence of tidal features within the galaxy groups, we do not find any indication for enhanced star formation in the selected sample of HCGs. We study azimuthally averaged Hα profiles of the galaxy discs and compare them with the g' and r' surface brightness profiles. We do not find any truncated galaxy discs but reveal that more massive galaxies show a higher light concentration in Hα than less massive ones. We also see that galaxies that show a high light concentration in r', show a systematic higher light concentration in Hα. Tidal dwarf galaxy (TDG) candidates have been previously detected in R-band images for two groups in our sample but we find that most of them are likely background objects as they do not show any emission in Hα. We present a new TDG candidate at the tip of the tidal tail in HCG 91.

  17. Tracking CO2 Plume in Deep Saline Formations Utilizing a Time-lapse Pressure Tomography Approach

    NASA Astrophysics Data System (ADS)

    Hu, L.; Bayer, P.; Brauchler, R.

    2015-12-01

    CO2 storage in deep saline formations is considered as an attractive option to cut down greenhouse gas emissions. Among the major challenges is the development of efficient technologies for controlling and monitoring the evolution of CO2 plumes during and after injection in the underground. As an alternative to the most commonly used geophysical approaches for subsurface characterization, we propose a pressure-based tomographical approach to track CO2 plume history. By taking into account the direct relationship between saturation and flow properties, pressure tomography has the potential not only to detect a plume but also to estimate the saturation of CO2. The experimental set-up of pressure tomography involves injection of brine or CO2 at variable depths (sources). We use a time-lapse approach, considering first the CO2-free formation, and then the multi-phase CO2-brine system. By applying a rapid eikonal-based inversion technique, pressure fluctuations at observation locations (receivers) are utilized to reconstruct the spatial distribution of the apparent single-phase and mixed-phase diffusivity. Evolution of the plume shape is then delineated by comparison of diffusivity tomograms derived from different times. Finally, an integrated value of CO2 saturation within the plume is obtained by means of a single-phase proxy. Applicability of this novel approach is evaluated in different virtual formations. The time-lapse pressure tomographic investigation revealed that knowledge about the spatial heterogeneity of permeability has a remarkable impact on proper characterization of plume shape.

  18. STAR FORMATION IN THE CHANDRA DEEP FIELD SOUTH: OBSERVATIONS CONFRONT SIMULATIONS

    SciTech Connect

    Damen, Maaike; Franx, Marijn; Foerster Schreiber, Natascha M.; Labbe, Ivo; Toft, Sune; Van Dokkum, Pieter G.; Wuyts, Stijn

    2009-11-01

    We investigate the star formation history of the universe using FIREWORKS, a multiwavelength survey of the Chandra Deep Field South. We study the evolution of the specific star formation rate (sSFR) with redshift in different mass bins from z = 0 to z approx 3. We find that the sSFR increases with redshift for all masses. The logarithmic increase of the sSFR with redshift is nearly independent of mass, but this cannot yet be verified at the lowest-mass bins at z>0.8, due to incompleteness. We convert the sSFRs to a dimensionless growth rate to facilitate a comparison with a semianalytic galaxy formation model that was implemented on the Millennium Simulation. The model predicts that the growth rates and sSFRs increase similarly with redshift for all masses, consistent with the observations. However, we find that for all masses, the inferred observed growth rates increase more rapidly with redshift than the model predictions. We discuss several possible causes for this discrepancy, ranging from field-to-field variance, conversions to SFR, and shape of the initial mass function. We find that none of these can solve the discrepancy completely. We conclude that the models need to be adapted to produce the steep increase in growth rate between redshift z = 0 and z = 1.

  19. Volumetrics of CO{sub 2} Storage in Deep Saline Formations

    SciTech Connect

    Steele-MacInnis, Matthew; Capobianco, Ryan M; Dilmore, Robert; Goodman, Angela; Guthrie, George; Rimstidt, J Donald; Bodnar, Robert J

    2013-01-01

    Concern about the role of greenhouse gases in global climate change has generated interest in sequestering CO{sub 2} from fossil-fuel combustion in deep saline formations. Pore space in these formations is initially filled with brine, and space to accommodate injected CO{sub 2} must be generated by displacing brine, and to a lesser extent by compression of brine and rock. The formation volume required to store a given mass of CO{sub 2} depends on the storage mechanism. We compare the equilibrium volumetric requirements of three end-member processes: CO{sub 2} stored as a supercritical fluid (structural or stratigraphic trapping); CO{sub 2} dissolved in pre-existing brine (solubility trapping); and CO{sub 2} solubility enhanced by dissolution of calcite. For typical storage conditions, storing CO{sub 2} by solubility trapping reduces the volume required to store the same amount of CO{sub 2} by structural or stratigraphic trapping by about 50%. Accessibility of CO{sub 2} to brine determines which storage mechanism (structural/stratigraphic versus solubility) dominates at a given time, which is a critical factor in evaluating CO{sub 2} volumetric requirements and long-term storage security.

  20. Deep-water Circulation: Processes & Products (16-18 June 2010, Baiona): introduction and future challenges

    NASA Astrophysics Data System (ADS)

    Hernández-Molina, Francisco Javier; Stow, Dorrik A. V.; Llave, Estefanía; Rebesco, Michele; Ercilla, Gemma; van Rooij, David; Mena, Anxo; Vázquez, Juan-Tomás; Voelker, Antje H. L.

    2011-12-01

    Deep-water circulation is a critical part of the global conveyor belt that regulates Earth's climate. The bottom (contour)-current component of this circulation is of key significance in shaping the deep seafloor through erosion, transport, and deposition. As a result, there exists a high variety of large-scale erosional and depositional features (drifts) that together form more complex contourite depositional systems on continental slopes and rises as well as in ocean basins, generated by different water masses flowing at different depths and at different speeds either in the same or in opposite directions. Yet, the nature of these deep-water processes and the deposited contourites is still poorly understood in detail. Their ultimate decoding will undoubtedly yield information of fundamental importance to the earth and ocean sciences. The international congress Deep-water Circulation: Processes & Products was held from 16-18 June 2010 in Baiona, Spain, hosted by the University of Vigo. Volume 31(5/6) of Geo-Marine Letters is a special double issue containing 17 selected contributions from the congress, guest edited by F.J. Hernández-Molina, D.A.V. Stow, E. Llave, M. Rebesco, G. Ercilla, D. Van Rooij, A. Mena, J.-T. Vázquez and A.H.L. Voelker. The papers and discussions at the congress and the articles in this special issue provide a truly multidisciplinary perspective of interest to both academic and industrial participants, contributing to the advancement of knowledge on deep-water bottom circulation and related processes, as well as contourite sedimentation. The multidisciplinary contributions (including geomorphology, tectonics, stratigraphy, sedimentology, paleoceanography, physical oceanography, and deep-water ecology) have demonstrated that advances in paleoceanographic reconstructions and our understanding of the ocean's role in the global climate system depend largely on the feedbacks among disciplines. New insights into the link between the biota of

  1. Vibrational analysis and formation mechanism of typical deep eutectic solvents: An experimental and theoretical study.

    PubMed

    Zhu, Siwen; Li, Hongping; Zhu, Wenshuai; Jiang, Wei; Wang, Chao; Wu, Peiwen; Zhang, Qi; Li, Huaming

    2016-07-01

    Deep eutectic solvents (DESs), as ionic liquid analogues for green solvents, have gained increasing attentions in chemistry. In this work, three typical kinds of DESs (ChCl/Gly, ChCl/AcOH and ChCl/Urea) were successfully synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and Raman. Then comprehensive and systematical analyses were performed by the methods of density functional theory (DFT). Two methods (B3LYP/6-311++G(2d,p) and dispersion-corrected B3LYP-D3/6-311++G(2d,p)) were employed to investigate the structures, vibrational frequencies and assign their ownership of vibrational modes for the DESs, respectively. Nearly all the experimental characteristic peaks of IR and Raman were identified according to the calculated results. By linear fitting of the combined calculated vs experimental vibration frequencies, it can be found that both of the two methods are excellent to reproduce the experimental results. Besides, hydrogen bonds were proved to exist in DESs by IR spectrum, structure analysis and RDG analysis. This work was aimed at predicting and understanding the vibrational spectra of the three typical DESs based on DFT methods. Moreover, by comparing experimental and theoretical results, it provides us a deep understanding of the formation mechanisms of DESs. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Circumpolar Deep Water transport and current structure at the Amundsen Sea shelf break

    NASA Astrophysics Data System (ADS)

    Assmann, Karen M.; Wåhlin, Anna K.; Heywood, Karen J.; Jenkins, Adrian; Kim, Tae Wan; Lee, Sang Hoon

    2017-04-01

    The West Antarctic Ice Sheet has been losing mass at an increasing rate over the past decades. Ocean heat transport to the ice-ocean interface has been identified as an important contributor to this mass loss and the role it plays in ice sheet stability makes it crucial to understand its drivers in order to make accurate future projections of global sea level. While processes closer to the ice-ocean interface modulate this heat transport, its ultimate source is located in the deep basin off the continental shelf as a core of relatively warm, salty water underlying a colder, fresher shallow surface layer. To reach the marine terminating glaciers and the base of floating ice shelves, this warm, salty water mass must cross the bathymetric obstacle of the shelf break. Glacial troughs that intersect the Amundsen shelf break and deepen southwards towards the ice shelf fronts have been shown to play an important role in transporting warm, salty Circumpolar Deep Water (CDW) towards the ice shelves. North of the shelf break, circulation in the Amundsen Sea occupies an intermediate regime between the eastward Antarctic Circumpolar Current that impinges on the shelf break in the Bellingshausen Sea and the westward southern limb of the Ross Gyre that follows the shelf break in the Ross Sea. Hydrographic and mooring observations and numerical model results at the mouth of the central shelf break trough leading to Pine Island and Thwaites Glaciers show a westward wind-driven shelf break current overlying an eastward undercurrent that turns onto the shelf in the trough. It is thought that the existence of the latter feature facilitates the on-shelf transport of CDW. A less clearly defined shelf break depression further west acts as the main pathway for CDW to Dotson and eastern Getz Ice shelves. Model results indicate that a similar eastward undercurrent exists here driving the on-shelf transport of CDW. Two moorings on the upper slope east of the trough entrance show a

  3. High resolution sequence stratigraphy of Miocene deep-water clastic outcrops, Taranaki coast, New Zealand

    SciTech Connect

    King, P.R.; Browne, G.H.; Slatt, R.M.

    1995-08-01

    Approximately 700m of deep water clastic deposits of Mt. Messenger Formation are superbly exposed along the Taranaki coast of North Island, New Zealand. Biostratigraphy indicates the interval was deposited during the time span 10.5-9.2m.y. in water depths grading upward from lower bathyal to middle-upper bathyal. This interval is considered part of a 3rd order depositional sequence deposited under conditions of fluctuating relative sea-level, concomitant with high sedimentation rates. Several 4th order depositional sequences, reflecting successive sea-level falls, are recognized within the interval. Sequence boundaries display a range of erosive morphologies from metre-wide canyons to scours several hundred metres across. All components of a generic lowstand systems tract--basin floor fan, channel-levee complex and progading complex--are present in logical and temporal order. They are repetitive through the interval, with the relatively shallower-water components becoming more prevalent upward. Basin floor fan lithologies are mainly m-thick, massive and convolute-bedded sandstones that alternate with cm- and dm-thick massive, horizontally-stratified and ripple-laminated sandstones and bioturbated mudstones. Channel-levee deposits consist of interleaving packages of thin-bedded, climbing-rippled and parallel-laminated sandstones and millstones; infrequent channels are filled with sandstones and mudstones, and sometimes lined with conglomerate. Thin beds of parallel to convoluted mudstone comprise prograding complex deposits. Similar lowstand systems tracts can be recognized and correlated on subsurface seismic reflection profiles and wireline logs. Such correlation has been aided by a continuous outcrop gamma-ray fog obtained over most of the measured interval. In the adjacent Taranaki peninsula, basin floor fan and channel-levee deposits comprise hydrocarbon reservoir intervals. Outcrop and subsurface reservior sandstones exhibit similar permeabilities.

  4. Significance of water fluxes in a deep arid-region vadose zone to waste disposal strategies

    SciTech Connect

    Johnejack, K.R.; Blout, D.O.; Sully, M.J.; Emer, D.F.; Hammermeister, D.P.; Dever, L.G.; O`Neill, L.J.; Tyler, S.W.; Chapman, J.

    1994-03-01

    Recently collected subsurface site characterization data have led to the development of a conceptual model of water movement beneath the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site (NTS) that differs significantly from the conceptual model of water movement inherent in Resource Conservation and Recovery Act (RCRA) regulations. At the Area 5 RWMS, water fluxes in approximately the upper 75 m (250 ft) of the vadose zone point in the upward direction (rather than downward) which effectively isolates this region from the deep (approximately 250 m (820 ft)) uppermost aquifer. Standard RCRA approaches for detection and containment (groundwater monitoring and double liners/leachate collection/leak detection systems) are not able to fulfill their intended function in this rather unique hydrogeologic environment. In order to better fulfill the waste detection and containment intentions of RCRA for mixed waste disposal at the Area 5 RWMS, the Department of Energy, Nevada Operations Office (DOE/NV) is preparing a single petition for both a waiver from groundwater monitoring and an exemption from double liners with leachate collection/leak detection. DOE/NV proposes in this petition that the containment function of liners and leachate collection is better accomplished by the natural hydrogeologic processes operating in the upper vadose zone; and the detection function of groundwater monitoring and the leak detection system in liners is better fulfilled by an alternative vadose zone monitoring system. In addition, an alternative point of compliance is proposed that will aid in early detection, as well as limit the extent of potential contamination before detection. Finally, special cell design features and operation practices will be implemented to limit leachate formation, especially while the cell is open to the atmosphere during waste emplacement.

  5. Unusual Deep Water sponge assemblage in South China—Witness of the end-Ordovician mass extinction

    NASA Astrophysics Data System (ADS)

    Li, Lixia; Feng, Hongzhen; Janussen, Dorte; Reitner, Joachim

    2015-11-01

    There are few sponges known from the end-Ordovician to early-Silurian strata all over the world, and no records of sponge fossils have been found yet in China during this interval. Here we report a unique sponge assemblage spanning the interval of the end-Ordovician mass extinction from the Kaochiapien Formation (Upper Ordovician-Lower Silurian) in South China. This assemblage contains a variety of well-preserved siliceous sponges, including both Burgess Shale-type and modern type taxa. It is clear that this assemblage developed in deep water, low energy ecosystem with less competitors and more vacant niches. Its explosion may be related to the euxinic and anoxic condition as well as the noticeable transgression during the end-Ordovician mass extinction. The excellent preservation of this assemblage is probably due to the rapid burial by mud turbidites. This unusual sponge assemblage provides a link between the Burgess Shale-type deep water sponges and the modern forms. It gives an excellent insight into the deep sea palaeoecology and the macroevolution of Phanerozoic sponges, and opens a new window to investigate the marine ecosystem before and after the end-Ordovician mass extinction. It also offers potential to search for exceptional fossil biota across the Ordovician-Silurian boundary interval in China.

  6. Unusual Deep Water sponge assemblage in South China—Witness of the end-Ordovician mass extinction

    PubMed Central

    Li, Lixia; Feng, Hongzhen; Janussen, Dorte; Reitner, Joachim

    2015-01-01

    There are few sponges known from the end-Ordovician to early-Silurian strata all over the world, and no records of sponge fossils have been found yet in China during this interval. Here we report a unique sponge assemblage spanning the interval of the end-Ordovician mass extinction from the Kaochiapien Formation (Upper Ordovician-Lower Silurian) in South China. This assemblage contains a variety of well-preserved siliceous sponges, including both Burgess Shale-type and modern type taxa. It is clear that this assemblage developed in deep water, low energy ecosystem with less competitors and more vacant niches. Its explosion may be related to the euxinic and anoxic condition as well as the noticeable transgression during the end-Ordovician mass extinction. The excellent preservation of this assemblage is probably due to the rapid burial by mud turbidites. This unusual sponge assemblage provides a link between the Burgess Shale-type deep water sponges and the modern forms. It gives an excellent insight into the deep sea palaeoecology and the macroevolution of Phanerozoic sponges, and opens a new window to investigate the marine ecosystem before and after the end-Ordovician mass extinction. It also offers potential to search for exceptional fossil biota across the Ordovician-Silurian boundary interval in China. PMID:26538179

  7. Unusual Deep Water sponge assemblage in South China-Witness of the end-Ordovician mass extinction.

    PubMed

    Li, Lixia; Feng, Hongzhen; Janussen, Dorte; Reitner, Joachim

    2015-11-05

    There are few sponges known from the end-Ordovician to early-Silurian strata all over the world, and no records of sponge fossils have been found yet in China during this interval. Here we report a unique sponge assemblage spanning the interval of the end-Ordovician mass extinction from the Kaochiapien Formation (Upper Ordovician-Lower Silurian) in South China. This assemblage contains a variety of well-preserved siliceous sponges, including both Burgess Shale-type and modern type taxa. It is clear that this assemblage developed in deep water, low energy ecosystem with less competitors and more vacant niches. Its explosion may be related to the euxinic and anoxic condition as well as the noticeable transgression during the end-Ordovician mass extinction. The excellent preservation of this assemblage is probably due to the rapid burial by mud turbidites. This unusual sponge assemblage provides a link between the Burgess Shale-type deep water sponges and the modern forms. It gives an excellent insight into the deep sea palaeoecology and the macroevolution of Phanerozoic sponges, and opens a new window to investigate the marine ecosystem before and after the end-Ordovician mass extinction. It also offers potential to search for exceptional fossil biota across the Ordovician-Silurian boundary interval in China.

  8. Features of a taut leg mooring system for deep water

    SciTech Connect

    Loevstad, T.; Namork, J.; Nilsen, A.U.

    1995-12-31

    As oil exploration and production is moving into greater water depths there is a need for cost effective stationkeeping systems. To date all floating production units have used conventional catenary mooring systems consisting of chain or a chain/wire combination. For greater water depths the use of a catenary mooring system (CMS) will result in very long lines and a large additional vertical load on the platform. The objective of the present work has been to develop cost effective stationkeeping systems for floating production units in 500--1,500 m water depth. The work is based on a case study of a large steel floater (semi). A conceptual design of a taut mooring system (TMS) has been developed. This investigation has focused on the dynamic behavior of the TMS in order to document acceptable dynamic performance. A taut mooring system based on a polyester fiber rope offers an alternative. For a water depth of 1,200 m the line length is reduced from 3,100 m to 2,030 m and the footprint is reduced from 2,800 m to 1,700 m by using a taut mooring system instead of a catenary system. In addition, a taut mooring system using polyester ropes is significantly more cost effective than a conventional catenary mooring system at large water depths. As an overall conclusion the investigation has confirmed satisfactory behavior of the proposed TMS concept.

  9. Prokaryotic phylogenetic diversity of Hungarian deep subsurface geothermal well waters.

    PubMed

    Németh, Andrea; Szirányi, Barbara; Krett, Gergely; Janurik, Endre; Kosáros, Tünde; Pekár, Ferenc; Márialigeti, Károly; Borsodi, Andrea K

    2014-09-01

    Geothermal wells characterized by thermal waters warmer than 30°C can be found in more than 65% of the area of Hungary. The examined thermal wells located nearby Szarvas are used for heating industrial and agricultural facilities because of their relatively high hydrocarbon content. The aim of this study was to reveal the prokaryotic community structure of the water of SZR18, K87 and SZR21 geothermal wells using molecular cloning methods and Denaturing Gradient Gel Electrophoresis (DGGE). Water samples from the outflow pipes were collected in 2012 and 2013. The phylogenetic distribution of archaeal molecular clones was very similar in each sample, the most abundant groups belonged to the genera Methanosaeta, Methanothermobacter and Thermofilum. In contrast, the distribution of bacterial molecular clones was very diverse. Many of them showed the closest sequence similarities to uncultured clone sequences from similar thermal environments. From the water of the SZR18 well, phylotypes closely related to genera Fictibacillus and Alicyclobacillus (Firmicutes) were only revealed, while the bacterial diversity of the K87 well water was much higher. Here, the members of the phyla Thermodesulfobacteria, Proteobacteria, Nitrospira, Chlorobi, OP1 and OPB7 were also detected besides Firmicutes.

  10. Reducing production of taste and odor by deep-living cyanobacteria in drinking water reservoirs by regulation of water level.

    PubMed

    Su, Ming; Jia, Dongmin; Yu, Jianwei; Vogt, Rolf D; Wang, Jingshi; An, Wei; Yang, Min

    2017-01-01

    Abatement and control of algae, producing toxins and creating taste & odor (T&O) in drinking water sources, is a major challenge for water supply. In this study we proposed a strategy based on water level regulation for the control of odor-producing cyanobacteria in source water. Miyun Reservoir, the main surface water source for Beijing, has been suffering from 2-methylisoborneol (2-MIB) induced T&O problems caused by deep-living Planktothrix sp. since 2002. The biomass of deep-living Planktothrix in Miyun Reservoir was found to be mainly governed by the water depth above its sediment habitat. An algorithm for water level regulation aiming to minimize the risk for T&O in different types of reservoirs is proposed. The study demonstrates that risk for T&O can be minimized by increasing the water level in Miyun Reservoir. The high-risk area can be reduced by about 2.91% (0.61% to 5.76%) of surface area for each meter increase in the water level, when the water level is lower than 145m. More specifically, the water level needs to be raised to higher than 147.7ma.s.l. from 131.0m in order to obtain an acceptable risk level (ARL) of 10%. This management strategy to abate T&O problems is simpler and cheaper to implement compared to traditional physical, chemical and biological techniques. Moreover, it has no apparent negative impact on water quality and aquatic organisms.

  11. Halocline water formation in the Barents Sea

    NASA Technical Reports Server (NTRS)

    Steele, Michael; Morison, James H.; Curtin, Thomas B.

    1995-01-01

    Hydrographic data from the first phase of the Coordinated Eastern Arctic Experiment (CEAREX) are analyzed. The data consist of temperature and salinity measurements made by a ship-based conductivity-temperature-depth (CTD) instrument and by a drifting SALARGOS buoy. These data were collected in the autumn and early winter of 1988-1989 in the northern Barents Sea, mostly in ice-covered conditions and then across the marginal ice zone (MIZ). The data show that relatively warm, salty water of Atlantic origin is modified by air cooling and ice melting to produce lighter water that has properties identical to (lower) halocline water found in the Arctic Ocean. This occurs mostly at the MIZ and to a lesser degree within the ice pack itself. At the MIZ the halocline water subjects underneath the lighter meltwater that resides directly under the ice pack; geostrophic velocity calculations indicate that it then turns eastward and flows toward the Kara Sea, in keeping with previous chemical tracer analyses. A rough calculation reveals that the amount of halocline water formed in this way in the Barents Sea and Fram Strait is 30-50% of that formed by ice growth in eastern Arctic polynyas.

  12. Halocline water formation in the Barents Sea

    NASA Technical Reports Server (NTRS)

    Steele, Michael; Morison, James H.; Curtin, Thomas B.

    1995-01-01

    Hydrographic data from the first phase of the Coordinated Eastern Arctic Experiment (CEAREX) are analyzed. The data consist of temperature and salinity measurements made by a ship-based conductivity-temperature-depth (CTD) instrument and by a drifting SALARGOS buoy. These data were collected in the autumn and early winter of 1988-1989 in the northern Barents Sea, mostly in ice-covered conditions and then across the marginal ice zone (MIZ). The data show that relatively warm, salty water of Atlantic origin is modified by air cooling and ice melting to produce lighter water that has properties identical to (lower) halocline water found in the Arctic Ocean. This occurs mostly at the MIZ and to a lesser degree within the ice pack itself. At the MIZ the halocline water subjects underneath the lighter meltwater that resides directly under the ice pack; geostrophic velocity calculations indicate that it then turns eastward and flows toward the Kara Sea, in keeping with previous chemical tracer analyses. A rough calculation reveals that the amount of halocline water formed in this way in the Barents Sea and Fram Strait is 30-50% of that formed by ice growth in eastern Arctic polynyas.

  13. Deep water dissolution in Marine Isotope Stage 3 from the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, B.

    2015-12-01

    The production, transport, deposition, and dissolution of carbonate profoundly implicate the global carbon cycle affect the inventory and distribution of dissolved organic carbon (DIC) and alkalinity (ALK), which drive atmospheric CO2 change on glacial-interglacial timescale. the process may provide significant clues for improved understanding of the mechanisms that control the global climate system. In this study, we calculate and analyze the foraminiferal dissolution index (FDX) and the fragmentation ratios of planktonic foraminifera over 60-25 ka based on samples from 17924 and ODP 1144 in the northeastern South China Sea (SCS) to reconstruct the deep water carbonate dissolution during Marine Isotope Stage 3 (MIS 3). Result shows that the dissolution of carbonate increases gradually at 17924 but keeps stable at ODP 1144. The changes of FDX coincidence with that of fragmentation ratios at 17924 and ODP 1144 suggest both indexes can be used as reliable dissolving proxies of planktonic foraminifera. Comparing FDX and fragmentation ratios at both sites, we find the FDX and fragmentation ratios at 17924 are higher than those at 1144, indicating that carbonate dissolution is intenser in 17924 core during MIS 3. The increasing total percentage of both N. dutertrei and G. bulloides during MIS 3 reveals the rising primary productivity that may lead to deep water [CO32-] decrease. The slow down of thermohaline circulation may increase deep water residence time and accelerate carbonate dissolution. In addition, the covering of ice caps, iron supply and increased surface-water stratification also contribute to atmosphere CO2 depletion and [CO32-] decrease in deep water. In the meanwhile, regression result from colder temperature increases the input of ALK and DIC to the deep ocean and deepens the carbonate saturation depth, which makes the deep water [CO32-] rise. In ODP Site 1144, the decrease in [CO32-] caused by more CO2 restored in deep water is equal to the increase in

  14. Reduced deep soil water uptake through forest conversion to pasture in Amazonia

    SciTech Connect

    Jipp, P.H.; Nepstad, D.C. Woods Hole Research Center, MA )

    1993-06-01

    Forests of eastern Amazonia are being replaced by pastures and secondary forests. We measured soil water storage and flux in adjacent forest and pasture ecosystems using Time Domain Reflectometry sensors installed in the walls of deep (9-m) shafts. The forest withdrew 597+/-25 mm of soil water stored below 1 m depth during the 1991 dry season (Jun-Dec), 1.7 times more than the pasture. Uptake from the bottom of the forest soil profile continued even after rainfall resumed in early 1992. The hydrologic impacts of tropical deforestation may be most severe for evergreen forests with deep rooting zones in areas of seasonal drought.

  15. Deciduous and Evergreen Trees Rely on Deep Water Throughout the Year in a Subtropical Seasonal Forest

    NASA Astrophysics Data System (ADS)

    Ellsworth, P.

    2010-12-01

    In subtropical and tropical seasonal forests, trees have adapted to low shallow soil water availability during the dry season by modifying root density, rooting depth, and leaf phenology. Here we test the well known hypothesis that water uptake in deciduous trees is restricted to the shallow soil layer, which prevents them from sustaining transpiring leaves during the dry season. Evergreens, on the other hand, access perennially available deep water sources, allowing them to maintain their transpiring leaves during the dry season. To determine where in the soil profile deciduous and evergreen trees take up water, we used stable isotope analysis to measure water source use of two deciduous and three evergreen species for a period of 13 months. In addition, to test the possibility that leaflessness could alter the isotopic composition of stem water, we measured the isotopic variation in stem water caused by artificial defoliation of an evergreen species. Deciduous and evergreen trees took up water from the same depths in both the wet and dry seasons. Deciduous and evergreen trees used approximately 51% deep water (50-150cm) throughout the year, while soil from 0-20cm was the least important water source with 24 and 6% of water uptake for wet and dry seasons, respectively. Low use of shallow water (0-20cm) in the wet season was due to inconstant water availability. Though the top 20cm of soil is the location of most nutrients, the soil’s limited water availability requires plants to have access to a more reliable deep water source to meet both their dry and wet season transpirational demands. This apparent spatial uncoupling in water and nutrient uptake denotes separate resource allocation for nutrient and water acquisition. Deciduous trees showed isotopic enrichment of stem water compared to evergreen plants only during the period that deciduous trees were leafless. We explain this as isotopic enrichment of fixed pool of stem water by evaporation as our defoliation

  16. The Geomechanics of CO2 Storage in Deep Sedimentary Formations

    SciTech Connect

    Rutqvist, Jonny

    2012-01-12

    This study provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO2 storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO2 repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO2 storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large

  17. Deep-water longline fishing has reduced impact on Vulnerable Marine Ecosystems.

    PubMed

    Pham, Christopher K; Diogo, Hugo; Menezes, Gui; Porteiro, Filipe; Braga-Henriques, Andreia; Vandeperre, Frederic; Morato, Telmo

    2014-04-29

    Bottom trawl fishing threatens deep-sea ecosystems, modifying the seafloor morphology and its physical properties, with dramatic consequences on benthic communities. Therefore, the future of deep-sea fishing relies on alternative techniques that maintain the health of deep-sea ecosystems and tolerate appropriate human uses of the marine environment. In this study, we demonstrate that deep-sea bottom longline fishing has little impact on vulnerable marine ecosystems, reducing bycatch of cold-water corals and limiting additional damage to benthic communities. We found that slow-growing vulnerable species are still common in areas subject to more than 20 years of longlining activity and estimate that one deep-sea bottom trawl will have a similar impact to 296-1,719 longlines, depending on the morphological complexity of the impacted species. Given the pronounced differences in the magnitude of disturbances coupled with its selectivity and low fuel consumption, we suggest that regulated deep-sea longlining can be an alternative to deep-sea bottom trawling.

  18. Deep-water longline fishing has reduced impact on Vulnerable Marine Ecosystems

    PubMed Central

    Pham, Christopher K.; Diogo, Hugo; Menezes, Gui; Porteiro, Filipe; Braga-Henriques, Andreia; Vandeperre, Frederic; Morato, Telmo

    2014-01-01

    Bottom trawl fishing threatens deep-sea ecosystems, modifying the seafloor morphology and its physical properties, with dramatic consequences on benthic communities. Therefore, the future of deep-sea fishing relies on alternative techniques that maintain the health of deep-sea ecosystems and tolerate appropriate human uses of the marine environment. In this study, we demonstrate that deep-sea bottom longline fishing has little impact on vulnerable marine ecosystems, reducing bycatch of cold-water corals and limiting additional damage to benthic communities. We found that slow-growing vulnerable species are still common in areas subject to more than 20 years of longlining activity and estimate that one deep-sea bottom trawl will have a similar impact to 296–1,719 longlines, depending on the morphological complexity of the impacted species. Given the pronounced differences in the magnitude of disturbances coupled with its selectivity and low fuel consumption, we suggest that regulated deep-sea longlining can be an alternative to deep-sea bottom trawling. PMID:24776718

  19. Geology as destiny: cold waters run deep in western Oregon.

    Treesearch

    Sally. Duncan

    2002-01-01

    The summer of 2001 brought the second-worst drought on record in Oregon, resulting in historically low streamflows and reservoir levels, stressed aquatic ecosystems, and even dramatic confrontations between irrigators and federal resource agencies in the Klamath basin. These events underscore the critical and growing importance of water availability and allocation in...

  20. Factors influencing big-bubble formation during deep anterior lamellar keratoplasty in keratoconus.

    PubMed

    Feizi, Sepehr; Javadi, Mohammad Ali; Daryabari, Seyed-Hashem

    2016-05-01

    To investigate recipient and operative factors that can influence the rate of achieving a bare Descemet's membrane (DM) during deep anterior lamellar keratoplasty (DALK) for keratoconus. In this retrospective comparative study, a total of 290 (153 right) consecutive eyes from 257 (179 male) keratoconus-affected patients who underwent DALK with the big-bubble technique were enrolled. Univariate analyses and multiple logistic regressions were used to investigate factors including patient age and sex, family history of keratoconus, history of contact lens wear or vernal keratoconjunctivitis, the presence of Vogt's striae or superficial stromal opacities, keratometric readings, corneal diameter, central and peripheral corneal thickness, anterior chamber depth, vitreous length, and trephination size, which could predict achievement of a bare DM. The surgery was completed as a DALK in 289 of 290 eyes, and a bare DM was successfully achieved in 229 (79.2%) eyes. The recipient sex and trephination size significantly influenced the success rate of big-bubble formation. Females had decreased odds of achieving a bare DM by 0.44 times (p=0.02). For each 0.1 mm increase in the trephination size, the odds of a successful big-bubble formation increased by 1.36 times (p=0.03). Other investigated factors did not significantly influence the rate of achieving a bare DM. The rate of successful big-bubble formation was 79.2% in keratoconus. Among the different factors, recipient sex and trephination size significantly influenced this rate. Females had a lower probability of big-bubble formation, and a large trephination size was associated with an increase in the probability of achieving a bare DM. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. About transformation of the deep-water methane bubbles into hydrate powder and hydrate foam

    NASA Astrophysics Data System (ADS)

    Egorov, A. V.; Nigmatulin, R. I.; Rozhkov, A. N.; Sagalevich, A. M.; Chernyaev, E. S.

    2012-04-01

    During the Russian Academy of Sciences "MIRI na Baikale, 2008-2010" expedition, deep-water experiments with the bubbles of methane seeping from the bottom at depths 405, 860 and 1400 meters were carried out. These depths correspond to gas hydrate stability zone. Bubbles were caught by the trap which was looked like an inverted glass. It was found that the behavior of bubbles in a trap depends on the depth. At depth of 405 meters formation of hydrates was not observed. Having got to a trap at the depth of 860 meters, bubbles became covered by solid hydrate envelope, kept the initial form, and after a time period collapsed in a number of hydrate fragments which showed all properties of a granular matter. No visible changes in the hydrate granular matter were observed in the course of lifting it to a depth of 380 meters. Shallower, the decomposition of the hydrate granular matter into methane gas was observed. In the experiments at depth of 1400 meters the caught bubbles, becoming covered by hydrate envelope formed solid hydrate foam in the trap. At lifting this foam structure was deformed slightly but simultaneously a free gas left the foam and filled the trap. The volume of free gas in the trap at lifting varied according to the Boyle-Mariotte law.

  2. Preparation and assessment of a candidate reference sample of Lake Baikal deep water

    NASA Astrophysics Data System (ADS)

    Suturin, A. N.; Paradina, L. F.; Epov, V. N.; Semenov, A. R.; Lozhkin, V. I.; Petrov, L. L.

    2003-02-01

    The possibility of the creation of a multi-element reference sample of Lake Baikal deep-water composition is justified. This is a new type of reference sample composed of natural water with a wide range of macro- and microelements. This candidate reference sample has a matrix composition consisting of hydrocarbonate and calcium water, a composition that is typical of many rivers and lakes of the world, as well as rain water. The creation of a candidate reference sample of Lake Baikal water is possible due to the stable water composition at a depth of 500 m, and to the use of water sampling technology which results in the preservation of the initial composition of water and its absolute sterility. Trial batches of Baikal water collected annually and stored in special polyethylenetereftalate bottles for a period of 9 years remained stable and homogenous for most elements. Preliminary data for a range of elements and compounds are presented.

  3. Clean subglacial access: prospects for future deep hot-water drilling

    PubMed Central

    Pearce, David; Hodgson, Dominic A.; Smith, Andrew M.; Rose, Mike; Ross, Neil; Mowlem, Matt; Parnell, John

    2016-01-01

    Accessing and sampling subglacial environments deep beneath the Antarctic Ice Sheet presents several challenges to existing drilling technologies. With over half of the ice sheet believed to be resting on a wet bed, drilling down to this environment must conform to international agreements on environmental stewardship and protection, making clean hot-water drilling the most viable option. Such a drill, and its water recovery system, must be capable of accessing significantly greater ice depths than previous hot-water drills, and remain fully operational after connecting with the basal hydrological system. The Subglacial Lake Ellsworth (SLE) project developed a comprehensive plan for deep (greater than 3000 m) subglacial lake research, involving the design and development of a clean deep-ice hot-water drill. However, during fieldwork in December 2012 drilling was halted after a succession of equipment issues culminated in a failure to link with a subsurface cavity and abandonment of the access holes. The lessons learned from this experience are presented here. Combining knowledge gained from these lessons with experience from other hot-water drilling programmes, and recent field testing, we describe the most viable technical options and operational procedures for future clean entry into SLE and other deep subglacial access targets. PMID:26667913

  4. Lagrangian pathways of deep water upwelling in the Southern Ocean State Estimate

    NASA Astrophysics Data System (ADS)

    Tamsitt, V. M.; Talley, L. D.; Mazloff, M. R.; Wang, J.

    2016-02-01

    Pathways of upwelling of deep waters in the Southern Ocean are investigated using Lagrangian particle trajectories advected offline in the 1/6th°, data-assimilating Southern Ocean State Estimate (sose.ucsd.edu). A total of 18 million particles released at 1000 m - 3500 m at 30° S in each basin were tracked for 60 years by looping velocities from the latest 2005-2010 SOSE iteration. 5% of particles upwelled to 500 m or shallower by the end of the simulation with 37%, 42% and 21% from the Atlantic, Indian and Pacific basins, respectively. Trajectories indicate that particles in the neutral density range 26.7-28.1 from all basins enter the Antarctic Circumpolar Current (ACC), follow the fronts of the ACC, and tend to upwell to the surface ocean toward the southern edge of the ACC and south of the ACC. We analyze differences in upwelling pathways between North Atlantic Deep Water and Indian and Pacific deep waters and explore the role of topography in the upwelling of these deep water masses. These upwelling pathways are important to understanding the 3-dimensional structure of the Southern Ocean overturning circulation and the supply of carbon and nutrient-rich waters to the surface of the Southern Ocean.

  5. Clean subglacial access: prospects for future deep hot-water drilling.

    PubMed

    Makinson, Keith; Pearce, David; Hodgson, Dominic A; Bentley, Michael J; Smith, Andrew M; Tranter, Martyn; Rose, Mike; Ross, Neil; Mowlem, Matt; Parnell, John; Siegert, Martin J

    2016-01-28

    Accessing and sampling subglacial environments deep beneath the Antarctic Ice Sheet presents several challenges to existing drilling technologies. With over half of the ice sheet believed to be resting on a wet bed, drilling down to this environment must conform to international agreements on environmental stewardship and protection, making clean hot-water drilling the most viable option. Such a drill, and its water recovery system, must be capable of accessing significantly greater ice depths than previous hot-water drills, and remain fully operational after connecting with the basal hydrological system. The Subglacial Lake Ellsworth (SLE) project developed a comprehensive plan for deep (greater than 3000 m) subglacial lake research, involving the design and development of a clean deep-ice hot-water drill. However, during fieldwork in December 2012 drilling was halted after a succession of equipment issues culminated in a failure to link with a subsurface cavity and abandonment of the access holes. The lessons learned from this experience are presented here. Combining knowledge gained from these lessons with experience from other hot-water drilling programmes, and recent field testing, we describe the most viable technical options and operational procedures for future clean entry into SLE and other deep subglacial access targets.

  6. Evidence for the bioerosion of deep-water corals by echinoids in the Northeast Atlantic

    NASA Astrophysics Data System (ADS)

    Stevenson, Angela; Rocha, Carlos

    2013-01-01

    In situ video observations of echinoids interacting with deep-sea coral are common in the deep-sea, but paradoxically the deep-sea literature is devoid of reports of bioerosion by extant echinoids. Here we present evidence of contemporary bioerosion of cold-water coral by four species of deep-sea echinoids, Gracilechinus elegans, Gracilechinus alexandri, Cidaris cidaris, and Araeosoma fenestratum, showing that they actively predate on the living framework of reef building corals, Lophelia pertusa and Madrepora oculata, in the NE Atlantic. Echinoid specimens were collected in six canyons located in the Bay of Biscay, France and two canyons on the north side of the Porcupine Bank and Goban Spur, Ireland. A total of 44 live specimens from the four taxa (9 of G. elegans, 4 of G. alexandri, 21 of C. cidaris and 10 of A. fenestratum) showed recent ingestion of the coral infrastructure. Upon dissection, live coral skeleton was observed encased in a thick mucus layer within the gastrointestinal tract of G. elegans and G. alexandri while both live and dead coral fragments were found in C. cidaris and A. fenestratum. Echinoid bioerosion limits the growth of shallow-water reefs. Our observations suggest that echinoids may also play an important role in the ecology of deep-water coral reefs.

  7. Distinctive Microbial Community Structure in Highly Stratified Deep-Sea Brine Water Columns

    PubMed Central

    Bougouffa, S.; Yang, J. K.; Lee, O. O.; Wang, Y.; Batang, Z.; Al-Suwailem, A.

    2013-01-01

    Atlantis II and Discovery are two hydrothermal and hypersaline deep-sea pools in the Red Sea rift that are characterized by strong thermohalo-stratification and temperatures steadily peaking near the bottom. We conducted comprehensive vertical profiling of the microbial populations in both pools and highlighted the influential environmental factors. Pyrosequencing of the 16S rRNA genes revealed shifts in community structures vis-à-vis depth. High diversity and low abundance were features of the deepest convective layers despite the low cell density. Surprisingly, the brine interfaces had significantly higher cell counts than the overlying deep-sea water, yet they were lowest in diversity. Vertical stratification of the bacterial populations was apparent as we moved from the Alphaproteobacteria-dominated deep sea to the Planctomycetaceae- or Deferribacteres-dominated interfaces to the Gammaproteobacteria-dominated brine layers. Archaeal marine group I was dominant in the deep-sea water and interfaces, while several euryarchaeotic groups increased in the brine. Across sites, microbial phylotypes and abundances varied substantially in the brine interface of Discovery compared with Atlantis II, despite the near-identical populations in the overlying deep-sea waters. The lowest convective layers harbored interestingly similar microbial communities, even though temperature and heavy metal concentrations were very different. Multivariate analysis indicated that temperature and salinity were the major influences shaping the communities. The harsh conditions and the low-abundance phylotypes could explain the observed correlation in the brine pools. PMID:23542623

  8. Deep water bottom current evolution in the northern South China Sea during the last 150 kyr: Evidence from sedimentary sortable silt and magnetic fabric

    NASA Astrophysics Data System (ADS)

    Li, Niu; Yang, Xiaoqiang; Peng, Jie; Zhou, Qixian; Su, Zhihua

    2017-04-01

    Deep water bottom current (DWBC) plays a central role in global climate. Relative to the Atlantic, the evolution of Pacific deepwater circulation is still unclear. Luzon Strait with a sill depth of about 2600 m serves as the only important deep connection between the South China Sea (SCS) and the Pacific, providing a unique opportunity to monitor the western Pacific deep water circulation. We present a magnetic and grain size analysis of two sediment cores (PC111 and PC83) located in Xisha Trough, northern SCS in order to reconstruct past changes of DWBC during the last 150 kyrs. Variations in the mean size of sortable silt and the magnetic grain size was interpreted to indicate past changes of DWBC, which suggest abrupt, millennial-scale increasing DWBC strength corresponding to Heinrich Stadials (HS1, HS2, HS3, HS4. HS5, HS6, HS7, HS8, HS9, HS10, HS11) for past 150 kyr, times of weak North Atlantic Deep Water formation. The direction of DWBC reconstructed from the anisotropy of magnetic susceptibility (AMS) is mostly N-S direction in core PC111 from 30 to 0 ka and NW-SE direction in core PC83 from 50 to 0 ka, which are parallel to the local topography. The good relationship between DWBC strength and the relative positive value of the planktonic foraminifera δ18O suggests the evolution of DWBC in northern SCS, sourced probably from North Pacific Deep Water, closely linking to the global climate.

  9. Gas hydrates (clathrates) causing pore-water freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins

    USGS Publications Warehouse

    Hesse, R.; Harrison, W.E.

    1981-01-01

    The occurrence of gas hydrates in deep-water sections of the continental margins predicted from anomalous acoustic reflectors on seismic profiles has been confirmed by recent deep-sea drilling results. On the Pacific continental slope off Guatemala gas hydrates were brought up for the first time from two holes (497, 498A) drilled during Leg 67 of the DSDP in water depths of 2360 and 5500 m, respectively. The hydrates occur in organic matter-rich Pleistocene to Miocene terrigenous sediments. In the hydrate-bearing zone a marked decrease in interstitial water chlorinities was observed starting at about 10-20 m subbottom depth. Pore waters at the bottom of the holes (near 400 m subbottom) have as little as half the chlorinity of seawater (i.e. 9???). Similar, but less pronounced, trends were observed during previous legs of the DSDP in other hydrate-prone segments of the continental margins where recharge of fresh water from the continent can be excluded (e.g. Leg 11). The crystallization of hydrates, like ice, excludes salt ions from the crystal structure. During burial the dissolved salts are separated from the solids. Subsidence results in a downward motion of the solids (including hydrates) relative to the pore fluids. Thawing of hydrates during recovery releases fresh water which is remixed with the pore fluid not involved in hydrate formation. The volume of the latter decreases downhole thus causing downward decreasing salinity (chlorinity). Hydrate formation is responsible for oxygen isotope fractionation with 18O-enrichment in the hydrate explaining increasingly more positive ??18O values in the pore fluids recovered (after hydrate dissociation) with depth. ?? 1981.

  10. Methods of measuring water levels in deep wells

    USGS Publications Warehouse

    Garber, M.S.; Koopman, F. C.

    1968-01-01

    Accurate measurement of water levels deeper than 1,000 feet in wells requires specialized equipment. Corrections for stretch and thermal expansion of measuring tapes must be considered, and other measuring devices must be calibrated periodically. Bore-hole deviation corrections also must be made. Devices for recording fluctuation of fluid level usually require mechanical modification for use at these depths. A multichannel recording device utilizing pressure transducers has been constructed. This device was originally designed to record aquifer response to nearby underground nuclear explosions but can also be used for recording data from multi-well pumping tests. Bottom-hole recording devices designed for oil-field use have been utilized in a limited manner. These devices were generally found to lack the precision required, in ground-water investigations at the Nevada Test Site but may be applicable in other areas. A newly developed bottom-hole recording pressure gauge of improved accuracy has been used with satisfactory results.

  11. America’s Water Future and Deep Energy

    DTIC Science & Technology

    2012-03-21

    returned to the surface as flow-back and produced wastewater . The fifth step is wastewater treatment and waste disposal. Wastewaters are stored on...USDW. The sources of contamination of USDW are attributed to accident, lack of wastewater treatment , and by hydraulic fractures extending beyond the...introducing harmful HF wastewater to surface or ground waters. Second, a lack of adequate wastewater treatment introduces HF chemicals into USDW

  12. Gulf Coast Deep Water Port Facilities Study. Environmental Assessment.

    DTIC Science & Technology

    1973-04-01

    both minimize dredging (under the current assumptions) and to facilitate possible future expansion to accommodate ships of deeper draft. Artr dtim -~zA...by percolating water which becomes a weak acid as it penetrates the residual soil mantling the bed rock. Because of variability in bed rock...composition and soil conditions, the soil layer developed on bed rock in Karst terrains is extremely variable in thickness and structural competence. Core

  13. Adriatic water masses, their rates of formation and transport through the Otranto Strait

    NASA Astrophysics Data System (ADS)

    Vilibić, Ivica; Orlić, Mirko

    2002-08-01

    The paper examines dense water formation in the South Adriatic by analysing temperature, salinity and dissolved oxygen data collected during six along-Adriatic cruises carried out from the Jabuka Pit to the Otranto Strait. The least-squares tracer analysis method is applied to distinguish the fractions of the four characteristic deep, dense water masses of the Adriatic Sea. Two types of dense water generation are considered: (1) shelf type occurring during cold and dry winters in the North Adriatic and resulting in the North Adriatic dense water (NAdDW) which partially transforms to the Middle Adriatic dense water (MAdDW) on its way along the Italian shelf to the Bari Canyon, where it interacts with topography, violently mixes and sinks; and (2) deep-convection type occurring in the centre of the South Adriatic Pit, generating dense water which reaches down to 800 m, fills the bottom and enters the Ionian Sea through the Otranto Strait. Both processes are visible in the July 1976 data, as the previous winter was cold (February) and relatively dry over the whole Adriatic basin. Both types of processes can influence the bottom layer of the Otranto Strait, where the fraction of shelf-type dense water generated in the North and Middle Adriatic was occasionally observed along with the fraction of water generated by deep convection in the South Adriatic. During the non-generative period, the cyclonic South Adriatic Gyre moved more to the northwest in general, as the Levantine intermediate water (LIW) occupied southeastern part of the South Adriatic Pit. However, such behaviour was not observed in January 1980, when LIW filled much of the Adriatic, thus diminishing density gradients in the South Adriatic. By applying a simple box model of water masses, it is estimated that the decay time of the Adriatic water masses equals 26 months, whereas transport of the Adriatic deep water (ADW) in the Otranto Strait amounted to 0.34 Sv during summer 1975. In the winter 1974/75 the

  14. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan

    PubMed Central

    Shao, Kwang-Tsao; Lin, Jack; Yeh, Hsin-Ming; Lee, Mao-Yin; Chen, Lee-Sea; Lin, Hen-Wei

    2014-01-01

    Abstract The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the “Database of Taiwan’s Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/)” as part of the “Fish Database of Taiwan,” can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity. PMID:25610339

  15. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan.

    PubMed

    Shao, Kwang-Tsao; Lin, Jack; Yeh, Hsin-Ming; Lee, Mao-Yin; Chen, Lee-Sea; Lin, Hen-Wei

    2014-01-01

    The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the "Database of Taiwan's Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/)" as part of the "Fish Database of Taiwan," can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity.

  16. Subtask 2.17 - CO{sub 2} Storage Efficiency in Deep Saline Formations

    SciTech Connect

    Gorecki, Charles; Liu, Guoxiang; Braunberger, Jason; Klenner, Robert; Ayash, Scott; Dotzenrod, Neil; Steadman, Edward; Harju, John

    2014-02-01

    As the field of carbon capture and storage (CCS) continues to advance, and large-scale implementation of geologic carbon dioxide (CO{sub 2}) storage progresses, it will be important to understand the potential of geologic formations to store meaningful amounts of CO{sub 2}. Geologic CO{sub 2} storage in deep saline formations (DSFs) has been suggested as one of the best potential methods for reducing anthropogenic CO{sub 2} emission to the atmosphere, and as such, updated storage resource estimation methods will continue to be an important component for the widespread deployment of CCS around the world. While there have been several methodologies suggested in the literature, most of these methods are based on a volumetric calculation of the pore volume of the DSF multiplied by a storage efficiency term and do not consider the effect of site-specific dynamic factors such as injection rate, injection pattern, timing of injection, pressure interference between injection locations, and overall formation pressure buildup. These volumetric methods may be excellent for comparing the potential between particular formations or basins, but they have not been validated through real-world experience or full-formation injection simulations. Several studies have also suggested that the dynamic components of geologic storage may play the most important role in storing CO{sub 2} in DSFs but until now have not directly compared CO{sub 2} storage resource estimates made with volumetric methodologies to estimates made using dynamic CO{sub 2} storage methodologies. In this study, two DSFs, in geographically separate areas with geologically diverse properties, were evaluated with both volumetric and dynamic CO{sub 2} storage resource estimation methodologies to compare the results and determine the applicability of both approaches. In the end, it was determined that the dynamic CO{sub 2} storage resource potential is timedependent and it asymptotically approaches the volumetric CO

  17. Methanosarcina subterranea sp. nov., a methanogenic archaeon isolated from a deep subsurface diatomaceous shale formation.

    PubMed

    Shimizu, Satoru; Ueno, Akio; Naganuma, Takeshi; Kaneko, Katsuhiko

    2015-04-01

    A methanogenic archaeon, strain HC-2(T), was isolated from a deep diatomaceous shale formation. The strain grew on methanol, monomethylamine, dimethylamine, trimethylamine and dimethylsulphide, but not on acetate, H2/CO2, formate, 2-propanol, 2-butanol or cyclopentanol. Cells were Gram-stain-negative, non-motile, and coccus-like, 0.9-1.4 µm in diameter, and occurred singly, in pairs, or as aggregates. The strain grew at 10-40 °C (optimum 35 °C), pH 5.9-7.4 (optimum pH 6.6-6.8) and in 0-0.6 M NaCl (optimum 0.1-0.2 M). The genomic DNA G+C content was 41.5 mol% and the 16S rRNA gene sequence was closely related to those of Methanosarcina lacustris DSM 13486(T) (99.1%) and Methanosarcina siciliae DSM 3028(T) (98.3%). Values for DNA-DNA hybridization with these strains were less than 30%. The phenotypic and phylogenetic features of HC-2(T) indicate that it represents a novel species of the genus Methanosarcina , for which the name Methanosarcina subterranea sp. nov. is proposed. The type strain is HC-2(T) ( = DSM 22503(T) = JCM 15540(T) = NBRC 102578(T)). © 2015 IUMS.

  18. Influence of deep-frying using various commercial oils on acrylamide formation in French fries.

    PubMed

    Zhang, Hao; Zhang, Hui; Cheng, Lilin; Wang, Li; Qian, Haifeng

    2015-01-01

    This study investigated the effect of different types of commercial oils (rice bran oil, shortening oil, high-oleic rapeseed oil, low-erucic acid rapeseed oil, blend oil A and blend oil B) and frying cycles on acrylamide formation during the preparation of French fries by deep-frying. Frying was carried out in intermittent mode (two batches each for 12 min without any time lag) and repeated for 600 frying cycles. Results indicated that the French fries that were fried in oils having lower heat transfer coefficients contained lower acrylamide concentrations (913 µg kg(-1)), whereas those fried with oils having higher heat transfer coefficients contained higher acrylamide concentrations (1219 µg kg(-1)). Unlike the peroxide value, acrylamide levels in French fries did not change significantly with an increase in the number of frying cycles when tested for 600 frying cycles for every type of oil. This study clearly indicates that the contribution of frying oils to the formation of acrylamide should not be neglected due to their different heat transfer coefficients. On the other hand, continuous use of frying oil does not lead to a higher acrylamide concentration in French fries.

  19. Symbiont-driven sulfur crystal formation in a thiotrophic symbiosis from deep-sea hydrocarbon seeps

    PubMed Central

    Eichinger, Irmgard; Schmitz-Esser, Stephan; Schmid, Markus; Fisher, Charles R; Bright, Monika

    2014-01-01

    The siboglinid tubeworm Sclerolinum contortum symbiosis inhabits sulfidic sediments at deep-sea hydrocarbon seeps in the Gulf of Mexico. A single symbiont phylotype in the symbiont-housing organ is inferred from phylogenetic analyses of the 16S ribosomal ribonucleic acid (16S rRNA) gene and fluorescent in situ hybridization. The phylotype we studied here, and a previous study from an arctic hydrocarbon seep population, reveal identical 16S rRNA symbiont gene sequences. While sulfide is apparently the energy source for the symbionts (and ultimately the gutless host), both partners also have to cope with its toxicity. This study demonstrates abundant large sulfur crystals restricted to the trophosome area. Based on Raman microspectroscopy and energy dispersive X-ray analysis, these crystals have the same S8 sulfur configuration as the recently described small sulfur vesicles formed in the symbionts. The crystals reside adjacent to the symbionts in the trophosome. This suggests that their formation is either extra- or intracellular in symbionts. We propose that formation of these crystals provides both energy-storage compounds for the symbionts and serves the symbiosis by removing excess toxic sulfide from host tissues. This symbiont-mediated sulfide detoxification may have been crucial for the establishment of thiotrophic symbiosis and continues to remain an important function of the symbionts. PMID:24992535

  20. Methanoculleus horonobensis sp. nov., a methanogenic archaeon isolated from a deep diatomaceous shale formation.

    PubMed

    Shimizu, Satoru; Ueno, Akio; Tamamura, Shuji; Naganuma, Takeshi; Kaneko, Katsuhiko

    2013-11-01

    A methanogenic organism from the domain Archaea, designated strain T10(T), was isolated from groundwater sampled from a deep diatomaceous shale formation located in Horonobe, Hokkaido, Japan. The strain utilized H2/CO2 and formate as substrates for methanogenesis. Cells were strictly anaerobic, Gram-negative-staining, flagellated, irregular coccoids, 0.7-1.6 µm in diameter, and occurred singly. The strain grew at 25-45 °C (optimum 37-42 °C), at pH 5.8-8.2 (optimum pH 6.7-6.8) and in the presence of 0-1.3 M NaCl (optimum 0.1-0.2 M NaCl). The G+C content of the genomic DNA was 62.9 mol%. 16S rRNA gene sequencing revealed that, although the strain is a member of the genus Methanoculleus, it clearly differed from all described species of this genus (95.5-98.3 % sequence similarity). Values for DNA-DNA hybridization with type strains of closely related Methanoculleus species were less than 50 %. Phenotypic and phylogenetic features of strain T10(T) clearly indicate that it represents a novel species of the genus Methanoculleus, for which the name Methanoculleus horonobensis sp. nov. is proposed. The type strain is T10(T) ( = DSM 21626(T) = JCM 15517(T)).

  1. Intermediate to deep water hydrographic changes of the Japan Sea over the past 10 Myr, inferred from radiolarian data (IODP Exp. 346, Site U1425)

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Kenji M.; Itaki, Takuya; Tada, Ryuji; Kurokawa, Shunsuke

    2017-04-01

    The Japan Sea is a back-arc basin opened under a continental rifting during the Early to Middle Miocene (ca. 25-13 Ma). This area is characterized by active tectonism, which drastically modified the Japan Sea paleogeography such as the sill depth of its key straits. In modern condition, the Japan Sea is connected to adjacent marginal seas and the Pacific Ocean by four straits shallower than 130 m. These straits are the Tsushima Strait connecting to the East China Sea, the Tsugaru Strait connecting to the Pacific, and the Soya and Mamiya Straits connecting to the Sea of Okhotsk. Therefore, the intermediate and deep water of the Japan Sea is isolated, leading the formation of a unique and regional deep sea water, known as the Japan Sea Proper Water. However, past studies show that during the late Miocene and Pliocene, only the Tsugaru Strait connecting to the North Pacific was opened. This strait was deeper during Plio-Miocene and have likely enable inflow of deep to intermediate water of the North Pacific in the Japan Sea. Radiolarians are one of the planktic micro-organisms group bearing siliceous skeletons. Their species comprise shallow to deep water dwellers, sensitive to changes in sea water physical/ecological properties forced by climate changes. Their fossils are known for be well preserved in the deep-sea sediments of the North Pacific. Therefore, in this study we propose to monitor changes in intermediate to deep water hydrography of the Japan Sea since the late Miocene, using radiolarian as an environmental proxy. In 2013 the IODP Expedition 346 retrieved sediment cores at different sites in the Japan Sea. In this study, we have analyzed 139 core sediments samples collected at Site U1425. This site is situated in the middle of the Yamato Bank. We selected this site because the past 10 Myr could be recovered continuously without hiatuses. Changes in radiolarian assemblages reveal that the oceanographic setting of the Japan Sea changed drastically at ca. 2

  2. Habitat, Fauna, and Conservation of Florida's Deep-Water Coral Reefs

    NASA Astrophysics Data System (ADS)

    Reed, J. K.; Pomponi, S. A.; Messing, C. G.; Brooke, S.

    2008-05-01

    Various types of deep-water coral habitats are common off the southeastern United States from the Blake Plateau through the Straits of Florida to the eastern Gulf of Mexico. Expeditions in the past decade with the Johnson-Sea- Link manned submersibles, ROVs, and AUVs have discovered, mapped and compiled data on the status, distribution, habitat, and biodiversity for many of these relatively unknown deep-sea coral ecosystems. We have discovered over three hundred, high relief (15-152-m tall) coral mounds (depth 700-800 m) along the length of eastern Florida (700 km). The north Florida sites are rocky lithoherms, whereas the southern sites are primarily classic coral bioherms, capped with dense 1-2 m tall thickets of Lophelia pertusa and Enallopsammia profunda. Off southeastern Florida, the Miami Terrace escarpment (depth 300-600 m) extends nearly 150 km as a steep, rocky slope of Miocene-age phosphoritic limestone, which provides habitat for a rich biodiversity of fish and benthic invertebrates. Off the Florida Keys, the Pourtalès Terrace (depth 200- 460 m) has extensive high-relief bioherms and numerous deep-water sinkholes to depths of 250-610 m and diameters up to 800 m. The dominant, deep-water, colonial scleractinian corals in this region include Oculina varicosa, L. pertusa, E. profunda, Madrepora oculata, and Solenosmilia variabilis. Other coral species include hydrozoans (Stylasteridae), bamboo octocorals (Isididae), numerous other gorgonians, and black corals (Antipatharia). These structure-forming taxa provide habitat and living space for a relatively unknown but biologically rich and diverse community of crustaceans, mollusks, echinoderms, polychaete and sipunculan worms, and associated fishes. We have identified 142 taxa of benthic macro-invertebrates, including 66 Porifera and 57 Cnidaria. Nearly 100 species of fish have been identified to date in association with these deep-water coral habitats. Paull et al. (2000) estimated that over 40

  3. Modification of deep waters in Marguerite Bay, western Antarctic Peninsula, caused by topographic overflows

    NASA Astrophysics Data System (ADS)

    Venables, Hugh J.; Meredith, Michael P.; Brearley, J. Alexander

    2017-05-01

    Circumpolar Deep Water (CDW) intrudes from the mid-layers of the Antarctic Circumpolar Current onto the shelf of the western Antarctic Peninsula, providing a source of heat and nutrients to the regional ocean. It is well known that CDW is modified as it flows across the shelf, but the mechanisms responsible for this are not fully known. Here, data from underwater gliders with high spatial resolution are used to demonstrate the importance of detailed bathymetry in inducing multiple local mixing events. Clear evidence for overflows is observed in the glider data as water flows along a deep channel with multiple transverse ridges. The ridges block the densest waters, with overflowing water descending several hundred metres to fill subsequent basins. This vertical flow leads to entrainment of overlying colder and fresher water in localised mixing events. Initially this process leads to an increase in bottom temperatures due to the temperature maximum waters descending to greater depths. After several ridges, however, the mixing is sufficient to remove the temperature maximum completely and the entrainment of colder thermocline waters to depth reduces the bottom temperature, to approximately the same as in the source region of Marguerite Trough. Similarly, it is shown that deep waters of Palmer Deep are warmer than at the same depth at the shelf break. The exact details of the transformations observed are heavily dependent on the local bathymetry and water column structure, but glacially-carved troughs and shallow sills are a common feature of the bathymetry of polar shelves, and these types of processes may be a factor in determining the hydrographic conditions close to the coast across a wider area.

  4. Polychaete Annelid (segmented worms) Species Composition in the Deep Gulf of Mexico following the Deep Water Horizon (DWH) Oil Spill

    NASA Astrophysics Data System (ADS)

    QU, F.; Rowe, G.

    2012-12-01

    Sediments 5 to 9 km from the Deep Water Horizon (DWH) Oil Spill site were sampled using a 0.2 m2 box corer 5 months after the event to assess the effects of the oil spill on polychaete annelid (segmented worms) community structure. Numbers of species, abundance, and biodiversity indices were all significantly lower than pre-spill values from similar depths in the eastern Gulf of Mexico (GoM). All of the five dominant species were different. Non-selective deposit feeders and selective deposit feeders were still the most frequent feeding guilds, but their abundances decreased significantly after the event. A large number of carnivorous Sigalionidae may be a response to an accumulation of PAHs on the sediment. Multivariate analyses (CLUSTER and multidimensional scaling (MDS)) illustrate the differences between assemblages near the DWH and those from prior studies in similar deep GoM habitats. In sum, the polychaete populations appeared to be at an early stage of succession in the recovery from the spill or they could be a resident assemblage that is the natural characteristic infauna in or adjacent to natural seeps of fossil hydrocarbons.

  5. Rapid reductions in North Atlantic Deep Water during the peak of the last interglacial period.

    PubMed

    Galaasen, Eirik Vinje; Ninnemann, Ulysses S; Irvalı, Nil; Kleiven, Helga Kikki F; Rosenthal, Yair; Kissel, Catherine; Hodell, David A

    2014-03-07

    Deep ocean circulation has been considered relatively stable during interglacial periods, yet little is known about its behavior on submillennial time scales. Using a subcentennially resolved epibenthic foraminiferal δ(13)C record, we show that the influence of North Atlantic Deep Water (NADW) was strong at the onset of the last interglacial period and was then interrupted by several prominent centennial-scale reductions. These NADW transients occurred during periods of increased ice rafting and southward expansions of polar water influence, suggesting that a buoyancy threshold for convective instability was triggered by freshwater and circum-Arctic cryosphere changes. The deep Atlantic chemical changes were similar in magnitude to those associated with glaciations, implying that the canonical view of a relatively stable interglacial circulation may not hold for conditions warmer and fresher than at present.

  6. The interplay between eddies, deep convection and sinking of dense water in an idealized model study of the Labrador Sea

    NASA Astrophysics Data System (ADS)

    Georgiou, Sotiria; van der Boog, Carine G.; Brüggemann, Nils; Pietrzak, Julie; Katsman, Caroline A.

    2017-04-01

    The Atlantic Meridional Overturning Circulation (AMOC) is of paramount importance for climate. Open ocean convection in the Labrador Sea plays a major role in the functioning of the AMOC. Historically, the connection between the formation of dense water in the interior of the Labrador Sea and its sinking was thought to be direct. However, recent studies indicate that this connection may not be straightforward and that the eddies play an important role. In particular, eddies transfer heat between the boundary current and the cooling region by lateral turbulent buoyancy fluxes. The aim of this study is to address the impact of the eddies on deep convection and sinking in the North Atlantic with a focus on the Labrador Sea where strong mesoscale activity occurs. For that, an idealized eddy-resolving configuration (MITgcm) is employed for the Labrador Sea region. The model output demonstrates a good agreement with observations and provides an excellent platform to examine the interplay between eddies, ocean convection and sinking of dense water masses in the Labrador Sea. The sensitivity of the characteristics of the deep convection and the sinking of the dense water with respect to surface fluxes and lateral heat fluxes is examined. It is shown that the presence of eddies limits the mixed layer deepening, reduces the convection volume and affects the magnitude and location of the sinking. In addition, it is shown that the sinking of dense water occurs near the boundaries and it is investigated to which extent it is governed by the alongshore density differences. To estimate the influence of climate change, we perform sensitivity simulations with altered surface fluxes according to future projections. Our results are relevant to the general understanding of the dynamics that are involved in the deep convection and the sinking in the Labrador Sea, especially in a changing environment.

  7. Physical properties of the Atlantic - Arctic water exchange formation. Modelling and analysis

    NASA Astrophysics Data System (ADS)

    Moshonkin, Sergey; Gusev, Anatoly; Bagno, Alexey; Zalesny, Vladimir

    2016-04-01

    Physical mechanisms of water exchange between North Atlantic (NA) and Arctic Oceans (AO) in 1958-2009 are analyzed using results of numerical experiments with the eddy-permitting ocean circulation model INMOM (Institute of Numerical Mathematics Ocean Model). Changes of heat and salt transports by West Spitsbergen and East Greenland currents caused by atmospheric forcing produce the baroclinic modes of velocity anomalies in the layer 0-300m, stabilizing ocean response on the atmospheric forcing, which stimulates keeping water exchange between NA and AO at the certain climatological level. We revealed the quick response of dense water outflow by near-bottom current in the deep NA layers through the Denmark Strait at monthly timescale on the North Atlantic oscillation (NAO) index change, as well as the response at the scale 39 months. The quick response on NAO is broken in 1969-1978, which is caused by the Great Salinity Anomaly. Transverse oscillations of the Norwegian current front have the great influence on the formation of the intermediate dense waters of Greenland and Norwegian Seas (GNS). Dense water outflow to the NA deep layers through the Faroe Channels with the time lag of 1 year respond to the transverse oscillations of the front. The mass transport of by near-bottom current through Faroe Channels to the NA can be used as the integral index of formation and discharge of new high-density water portions generated due to mixing of salt warm Atlantic waters and freshened cold Arctic waters in GNS. The research was supported by the Council on the Russian Federation President Grants (grant № MK-3241.2015.5)

  8. Insight into the microbial community structure of a Norwegian deep-water coral reef environment

    NASA Astrophysics Data System (ADS)

    Jensen, Sigmund; Neufeld, Josh D.; Birkeland, Nils-Kåre; Hovland, Martin; Murrell, J. Colin

    2008-11-01

    Deep-water coral reefs support rich biological communities below the photic zone of fjords and continental shelves around the world. In this environment, life is enclosed within cold permanent darkness, in stark contrast to life in tropical coral reefs. We collected samples of water, sediment and a Desmacidon sp. sponge from a deep-water coral reef off the coast of Norway, and characterised bacterial communities with focus on primary producers in the dark. Following DNA extraction, PCR amplification and 16S rRNA gene library sequencing, bioinformatic analyses demonstrated significant differences between bacterial communities associated with the three samples. The finding that 50% of the clones showed <90% identity to cultured bacteria reflects the novel and uncharacterised diversity associated with these deep-water coral reefs. A total of 13 bacterial phyla were identified. Acidobacteria dominated the sponge library and Proteobacteria dominated the bacterioplankton and sediment libraries. Phylogenetic analysis revealed a possible new clade of sponge-associated Acidobacteria, which includes representatives from the Desmacidon sp. (Norway), Rhopaloeides odorabile (Australia) and Discodermia dissoluta (Curacao). Furthermore, the targeted recovery of a particulate methane monooxygenase ( pmoA) gene from the Desmacidon sp. DNA extract suggests that as yet uncultivated type I methanotrophs may mediate methane oxidation in this deep-water coral reef. Methanotrophs were not identified in the 16S rRNA gene libraries, but the presence of a high number (8%) of clones related to sulfide-, nitrite- and iodide-oxidising bacteria suggests chemosynthesis to be involved with maintenance of the deep-water coral reef ecosystem.

  9. Reservoir compartmentalization of deep-water Intra Qua Iboe sand (Pliocene), Edop field, offshore Nigeria

    SciTech Connect

    Hermance, W.E.; Olaifa, J.O.; Shanmugam, G.

    1995-08-01

    An integration of 3-D seismic and sedimentological information provides a basis for recognizing and mapping individual flow units within the Intra Qua Iboe (IQI) reservoir (Pliocene), Edop Field, offshore Nigeria. Core examination show the following depositional facies: A-Sandy slump/mass flow, B-Muddy slump/mass flow, C. Bottom current reworking. D-Non-channelized turbidity currents, E. Channelized (coalesced) turbidity currents. F-Channelized (isolated) turbidity currents, G-Pelagic/hemipelagic, H-Levee, I-Reworked slope, J-Wave dominated, and K-Tide dominated facies. With the exception of facies J and K, all these facies are of deep-water affinity. The IQI was deposited on an upper slope environment in close proximity to the shelf edge. Through time, as the shelf edge migrated scaward, deposition began with a channel dominated deep-water system (IQI 1 and 2) and progressed through a slump/debris flow dominated deep-water system (IQI 3, the principle reservoir) to a tide and wave dominated shallow-water system (IQI 4). Compositional and textural similarities between the deep-water facies result in similar log motifs. Furthermore, these depositional facies are not readily apparent as distinct seismic facies. Deep-water facies A, D, E, and F are reservoir facies, whereas facies B, C, G, H, and I are non-reservoir facies. However, Facies G is useful as a seismically mappable event throughout the study area. Mapping of these non-reservoir events provides the framework for understanding gross reservoir architecture. This study has resulted in seven defined reservoir units within the IQI, which serves as the architectural framework for ongoing reservoir characterization.

  10. Dissolved inorganic carbon isotopic composition of the Gulf of Mexico deep-water masses.

    NASA Astrophysics Data System (ADS)

    Quintanilla-Terminel, J. G.; Herguera, J. C.; Ferreira-Bartrina, V.; Hernández-Ayón, J. M.; Camacho-Ibar, V.

    2014-12-01

    This study provides new data for the establishment of a carbon biogeochemical dynamics baseline in the deep Gulf of Mexico (GM) based on carbon isotopes in dissolved inorganic carbon. Water samples from 40 deep-water stations south of 25˚N were collected during XIXIMI-2 cruise, July 2011, aboard BO/Justo Sierra. Vertical profiles of temperature, salinity and dissolved oxygen (DO) were further measured in each station. In the Stable Isotopes Laboratory at CICESE we determined the carbon isotopic composition of the dissolved inorganic carbon (DIC) (δ13CDIC). Remarkably, density, DO and δ13CCID profiles showed a clear difference between the Loop current and the deep-waters of the GM south of 25˚N. We found the following average δ13CCID values in the Loop current and in the deep-waters of the Gulf: subtropical underwater (SUW): 0.73±0.06‰ and 0.86±0.04‰; 18 degree water (18W): 0.76 ± 0.08‰ and 0.58± 0.06‰; North Atlantic central water (NACW): 0.77 ± 0.05‰ and 0.71 ± 0.09‰; South Atlantic central water (SACW): 0.80 ± 0.08‰ and 0.77 ± 0.07‰; Antartic intermediate water (AAIW): 1.00 ± 0.06‰ and 0.90 ± 0.08‰; North Atlantic deep water (NADW): 1.03 ± 0.06‰ and 1.01 ± 0.10‰. We will discuss how the biological component, δ13CCID-BIO, of subsurface water masses match very closely the apparent oxygen utilization relation described by Kroopnick, 1985, with the exception of SUW, and as a consequence the 18W is probably the water mass most affected by organic carbon remineralization processes in the GM south of 25˚N. We further show how these waters seem to store a larger proportion of anthropogenic carbon than the deeper water masses.

  11. Unsteady evolution of localized unidirectional deep-water wave groups.

    PubMed

    Cousins, Will; Sapsis, Themistoklis P

    2015-06-01

    We study the evolution of localized wave groups in unidirectional water wave envelope equations [the nonlinear Schrödinger (NLSE) and the modified NLSE (MNLSE)]. These localizations of energy can lead to disastrous extreme responses (rogue waves). We analytically quantify the role of such spatial localization, introducing a technique to reduce the underlying partial differential equation dynamics to a simple ordinary differential equation for the wave packet amplitude. We use this reduced model to show how the scale-invariant symmetries of the NLSE break down when the additional terms in the MNLSE are included, inducing a critical scale for the occurrence of extreme waves.

  12. Unsteady evolution of localized unidirectional deep-water wave groups

    NASA Astrophysics Data System (ADS)

    Cousins, Will; Sapsis, Themistoklis P.

    2015-06-01

    We study the evolution of localized wave groups in unidirectional water wave envelope equations [the nonlinear Schrödinger (NLSE) and the modified NLSE (MNLSE)]. These localizations of energy can lead to disastrous extreme responses (rogue waves). We analytically quantify the role of such spatial localization, introducing a technique to reduce the underlying partial differential equation dynamics to a simple ordinary differential equation for the wave packet amplitude. We use this reduced model to show how the scale-invariant symmetries of the NLSE break down when the additional terms in the MNLSE are included, inducing a critical scale for the occurrence of extreme waves.

  13. Deep-Water Resedimented Carbonate Exploration Play Types: Controls and Models

    NASA Astrophysics Data System (ADS)

    Minzoni, M.; Janson, X.; Kerans, C.; Playton, T.; Winefield, P.; Burgess, P. M.

    2016-12-01

    Deepwater resedimented deposits have been described in both modern and ancient carbonate sequences, many with good reservoir potential, for example the giant Cretaceous Poza Rica field in Mexico ( 40 MMBoe), the Mississippian Tangiz field in Kazakhstan, and several fields in the U.S. Permian basin (several Tcf gas). Nevertheless, carbonate slope and basin systems remain poorly understood when compared to their siliciclastic counterparts. Legacy published and unpublished work, combined with a global database of surface and sub-surface examples of resedimented carbonates, has highlighted that downslope resedimentation of carbonate material is in large part controlled by the evolution of the parent platform margin, which in turn is best characterized in terms of various controlling processes such as the carbonate factory type, tectonic setting, eustatic variations, and prevailing wind direction and ocean current patterns. Two generic play types emerge: (i) attached carbonate slope play -developed immediately adjacent to the parent carbonate platform and dominated by rock fall and platform collapse deposits or in situ boundstone; and (ii) detached carbonate slope play - deposited further from the platform margin via channelized turbidity currents and other mass-flow processes. High-rising, steep, bypass platform margins with collapse scars and grain-dominated factories have the highest potential to generate channelized and detached deep-water reservoirs with high initial porosity and permeability. Best reservoirs are aragonitic grainstones transported from the platform into the adjacent basin, and undergoing dissolution in submarine undersaturated water with early formation of secondary porosity to further enhance reservoir properties. Any exploration model aiming at identifying potential resedimented carbonate plays should be based on carbonate platform configurations and factory types favorable for re-sedimentation of large sedimentary bodies and preservation or

  14. Water potential and starvation stress in deep subsurface microorganisms

    SciTech Connect

    Kieft, T.L.; Rosacker, L.L.; Willcox, D.; Franklin, A.J.

    1990-12-31

    Nine intact core samples, collected aseptically from depths of 10--436 m near the Savannah River Plant in South Carolina, were tested for water potential, microbial numbers, and microbial activity. Although all samples were collected from below the water table, two samples (a Pee Dee clay from 238 m and a Middendorf clay from 324 m) showed unsaturated conditions ({minus}2.7 and {minus}2.1 MPa, respectively). Both of these samples had very low numbers of culturable cells, low microbial biomass (ATP assay), and low microbial activities (measured as respiration), suggesting that low metric waterpotentials in these strata are limiting factors to microorganisms. An Acinetobacter sp. isolated from the 324 m depth was found to maintain viability under starvation conditions in sterilized aquifer material, even when subjected to severe desiccation ({minus}22 MPa). A Pseudomonas sp., with the ability to oxidize thiosulfate to sulfate, was isolated from the 378 m Middendorf clay sample. This organism survived nutrient deprivation reasonably well; however, the presence of thiosulfate appeared to interfere with its normal ability to maintain viability by endogenous metabolism. Cells cultured in the presence of thiosulfate did not undergo dwarfing and cell viability declines. These are two examples of indigenous subsurface microorganisms, each with different adaptations for long-term survival under conditions of desiccation and/or starvation.

  15. Water potential and starvation stress in deep subsurface microorganisms

    SciTech Connect

    Kieft, T.L.; Rosacker, L.L.; Willcox, D.; Franklin, A.J.

    1990-01-01

    Nine intact core samples, collected aseptically from depths of 10--436 m near the Savannah River Plant in South Carolina, were tested for water potential, microbial numbers, and microbial activity. Although all samples were collected from below the water table, two samples (a Pee Dee clay from 238 m and a Middendorf clay from 324 m) showed unsaturated conditions ({minus}2.7 and {minus}2.1 MPa, respectively). Both of these samples had very low numbers of culturable cells, low microbial biomass (ATP assay), and low microbial activities (measured as respiration), suggesting that low metric waterpotentials in these strata are limiting factors to microorganisms. An Acinetobacter sp. isolated from the 324 m depth was found to maintain viability under starvation conditions in sterilized aquifer material, even when subjected to severe desiccation ({minus}22 MPa). A Pseudomonas sp., with the ability to oxidize thiosulfate to sulfate, was isolated from the 378 m Middendorf clay sample. This organism survived nutrient deprivation reasonably well; however, the presence of thiosulfate appeared to interfere with its normal ability to maintain viability by endogenous metabolism. Cells cultured in the presence of thiosulfate did not undergo dwarfing and cell viability declines. These are two examples of indigenous subsurface microorganisms, each with different adaptations for long-term survival under conditions of desiccation and/or starvation.

  16. Classification of human activity on water through micro-Dopplers using deep convolutional neural networks

    NASA Astrophysics Data System (ADS)

    Kim, Youngwook; Moon, Taesup

    2016-05-01

    Detecting humans and classifying their activities on the water has significant applications for surveillance, border patrols, and rescue operations. When humans are illuminated by radar signal, they produce micro-Doppler signatures due to moving limbs. There has been a number of research into recognizing humans on land by their unique micro-Doppler signatures, but there is scant research into detecting humans on water. In this study, we investigate the micro-Doppler signatures of humans on water, including a swimming person, a swimming person pulling a floating object, and a rowing person in a small boat. The measured swimming styles were free stroke, backstroke, and breaststroke. Each activity was observed to have a unique micro-Doppler signature. Human activities were classified based on their micro-Doppler signatures. For the classification, we propose to apply deep convolutional neural networks (DCNN), a powerful deep learning technique. Rather than using conventional supervised learning that relies on handcrafted features, we present an alternative deep learning approach. We apply the DCNN, one of the most successful deep learning algorithms for image recognition, directly to a raw micro-Doppler spectrogram of humans on the water. Without extracting any explicit features from the micro-Dopplers, the DCNN can learn the necessary features and build classification boundaries using the training data. We show that the DCNN can achieve accuracy of more than 87.8% for activity classification using 5- fold cross validation.

  17. Laboratory Studies of Steep and Breaking Deep Water Waves in a Convergent Channel

    DTIC Science & Technology

    1985-08-21

    Area Code) (202)767-2904 22c. OFFICE SYMBOL Code 5841 DD FORM 1473, 34 MAR 33 APR edition nay be used until exhausted. All other editions are...of deep-water waves," J. Fluid Mech., Vol. 115, 165-185. M. Miche, June 1954, " Undulatory movements of the sea in constant or decreasing

  18. Identifying pathways for sanitary sewer pathogens to reach deep water supply wells in Madison, Wisconsin

    USDA-ARS?s Scientific Manuscript database

    Previous work conducted by the Wisconsin Geological and Natural History Survey indicated that human enteric viruses from leaking sewers are present in several municipal wells in Madison, WI. These wells are the drinking water source for the City of Madison, are typically 700 to 900 feet deep, and pe...

  19. Mechanical stratigraphy of deep-water sandstones: insights from a multisciplinary field and laboratory study

    NASA Astrophysics Data System (ADS)

    Agosta, Fabrizio; di Celma, Claudio; Tondi, Emanuele; Corradetti, Amerigo; Cantalamessa, Gino

    2010-05-01

    Turbidite sandstones found in deep-water fold-and-thrust belts are increasingly exploited as hydrocarbon reservoirs. Within these rocks, the fluid flow is profoundly affected by the complex interaction between primary sedimentological and stratigraphic attributes (i.e, facies, layering, reservoir quality, stacking patterns, bed connectivity and lateral extent) and fracture characteristics (i.e., length, spacing, distribution, orientation, connectivity). Unfortunately, most of these features are at, or below, the resolution of conventional seismic datasets and, for this reason, their identification and localization represent one of the fundamental challenges facing exploration, appraisal and production of the sandstone reservoirs. In this respect, whereas considerable effort has been afforded to a characterization of the sedimentological and stratigraphic aspects of sandstones, detailed analysis of fractures in this type of successions has received significantly less attention. In this work, we combine field and laboratory analyses to assess the possible mechanical control exerted by the rock properties (grain size, intergranualr porosity, and Young modulus), as well as the influence of bed thickness, on joint density in turbidite sandstones. Joints are mode-I fractures occurring parallel to the greatest principle stress axis, which solve opening displacement and do not show evidence of shearing and enhance the values of total porosity forming preferential hydraulic conduits for fluid flow. Within layered rocks, commonly, joints form perpendicular to bedding due to overburden or exhumation. The empirical relation between joint spacing and bed thickness, documented in the field by many authors, has been mechanically related to the stress perturbation taking place around joints during their formation. Furthermore, close correlations between joint density and rock properties have been already established. In this present contribution, we focus on the bed

  20. Comparison of ground-water quality in samples from selected shallow and deep wells in the central Oklahoma aquifer, 2003-2005

    USGS Publications Warehouse

    Becker, Carol J.

    2006-01-01

    The aquifer units of the Central Oklahoma aquifer underlie about 2,890 square miles of central Oklahoma and are used extensively to supply water for municipal, domestic, industrial, and agricultural needs. The Central Oklahoma aquifer also is commonly referred to as the Garber-Wellington aquifer because the Garber Sandstone and Wellington Formation yield the greatest quantities of usable water for domestic and high-capacity wells. The major water-quality concerns for the Central Oklahoma aquifer described by the U.S. Geological Survey National Water Quality Assessment Program (1987 to 1992) were elevated concentrations of nitrate nitrogen in shallow water and the occurrence of arsenic, chromium, and selenium in parts of the aquifer. The quality of water from deep public-water supply wells in the Central Oklahoma aquifer is monitored by the State of Oklahoma. The chemical quality of water from shallow domestic wells is not monitored, and, therefore, there is a concern that well owners may be unknowingly ingesting water with nitrate nitrogen, arsenic, chromium, selenium, and other chemical constituents at concentrations that are considered harmful. As a result of this concern, the Oklahoma Department of Environmental Quality and the U.S. Geological Survey collaborated on a study to sample water during June 2003 through August 2005 from 23 shallow wells (less than 200 feet in depth) and 28 deep wells (200 feet or greater in depth) completed in the bedrock aquifer units of the Central Oklahoma aquifer. The objectives of the study were to describe the chemical quality of water from shallow and deep wells and to determine if the differences in constituent concentrations are statistically significant. Water from shallow wells had significantly higher concentrations of calcium, magnesium, bicarbonate, sulfate, chloride, and nitrate nitrogen than water from deep wells. There were no significant differences between concentrations of dissolved solids, sodium, and fluoride in

  1. Deep water velocities and particle displacements induced by acoustic-gravity waves from submarine earthquakes

    NASA Astrophysics Data System (ADS)

    Oliveira, T. C. A.; Kadri, U.

    2016-02-01

    An uplift of the ocean bottom caused by a submarine earthquake can generate Acoustic-Gravity Waves (AGW), progressive compression-type waves that travel at near the speed of sound in water. The role of AGW for oceans hydrodynamics has recently became a topic of increasing scientific interest. Kadri [Deep ocean water transport by acoustic-gravity waves, J.Geo. Res. Oceans, 119, (2014)] showed theoretically that AGW can contribute to deep ocean currents and circulation. We analyze and simulate the fundamental AGW modes generated by a submarine earthquake. We consider the first five AGW modes and show that they may all induce comparable temporal variations in water particle velocities at different depths in regions far from the epicenter. Results of temporal variations of horizontal and vertical fluid parcel velocities induced by AGW confirm chaotic flow trajectories at different water depths. A realistic example based on the 2004 Indian Ocean earthquake shows that vertical water particle displacements of O(10-2 ) m can be generated at 1 Km depth in a 4 km water depth ocean. We show that the velocity field depends on the presence of the leading AGW modes. Each AGW mode becomes evanescent at a critical time, at which energy is transferred to the next higher modes. Consequently, the main pattern of the velocity field changes as the leading mode change. As an example, for a reference point located at 1000 Km from the epicenter, the first five AGW become evanescent after 1.6, 4.6, 7.7, 10.8 and 13.8 hours, respectively. Our analysis and simulations shed light on the spatio-temporal evolution of the deep water velocities and particle displacements induced by AGW that radiate during submarine earthquakes. Thus, this work is a contribution to understand the role of high moment magnitude submarine earthquakes in deep water mixing mechanism.

  2. Challenge to the model of lake charr evolution: Shallow- and deep-water morphs exist within a small postglacial lake

    USGS Publications Warehouse

    Chavarie, Louise; Muir, Andrew M.; Zimmerman, Mara S.; Baillie, Shauna M.; Hansen, Michael J.; Nate, Nancy A.; Yule, Daniel L.; Middel, Trevor; Bentzen, Paul; Krueger, Charles C.

    2016-01-01

    All examples of lake charr (Salvelinus namaycush) diversity occur within the largest, deepest lakes of North America (i.e. > 2000 km2). We report here Rush Lake (1.3 km2) as the first example of a small lake with two lake charr morphs (lean and huronicus). Morphology, diet, life history, and genetics were examined to demonstrate the existence of morphs and determine the potential influence of evolutionary processes that led to their formation or maintenance. Results showed that the huronicus morph, caught in deep-water, had a deeper body, smaller head and jaws, higher eye position, greater buoyancy, and deeper peduncle than the shallow-water lean morph. Huronicus grew slower to a smaller adult size, and had an older mean age than the lean morph. Genetic comparisons showed low genetic divergence between morphs, indicating incomplete reproductive isolation. Phenotypic plasticity and differences in habitat use between deep and shallow waters associated with variation in foraging opportunities seems to have been sufficient to maintain the two morphs, demonstrating their important roles in resource polymorphism. Rush Lake expands previous explanations for lake charr intraspecific diversity, from large to small lakes and from reproductive isolation to the presence of gene flow associated with strong ecological drivers.

  3. Formation of disinfection byproducts in typical Chinese drinking water.

    PubMed

    Liu, Wenbo; Zhao, Yanmei; Chow, Christopher W K; Wang, Dongsheng

    2011-01-01

    Eight typical drinking water supplies in China were selected in this study. Both source and tap water were used to investigate the occurrence of chlorinated disinfection byproducts (DBPs), and seasonal variation in the concentrations of trihalomethanes (THMs) of seven water sources was compared. The results showed that the pollution level for source water in China, as shown by DBP formation potential, was low. The most encountered DBPs were chloroform, dichloroacetic acid, trichloroacetic acid, and chlorodibromoacetic acid. The concentration of every THMs and haloacetic acid (HAA) compound was under the limit of standards for drinking water quality. The highest total THMs concentrations were detected in spring.

  4. Observations of open-ocean deep convection in the northwestern Mediterranean Sea: Seasonal and interannual variability of mixing and deep water masses for the 2007-2013 Period

    NASA Astrophysics Data System (ADS)

    Houpert, L.; Durrieu de Madron, X.; Testor, P.; Bosse, A.; D'Ortenzio, F.; Bouin, M. N.; Dausse, D.; Le Goff, H.; Kunesch, S.; Labaste, M.; Coppola, L.; Mortier, L.; Raimbault, P.

    2016-11-01

    We present here a unique oceanographic and meteorological data set focus on the deep convection processes. Our results are essentially based on in situ data (mooring, research vessel, glider, and profiling float) collected from a multiplatform and integrated monitoring system (MOOSE: Mediterranean Ocean Observing System on Environment), which monitored continuously the northwestern Mediterranean Sea since 2007, and in particular high-frequency potential temperature, salinity, and current measurements from the mooring LION located within the convection region. From 2009 to 2013, the mixed layer depth reaches the seabed, at a depth of 2330m, in February. Then, the violent vertical mixing of the whole water column lasts between 9 and 12 days setting up the characteristics of the newly formed deep water. Each deep convection winter formed a new warmer and saltier "vintage" of deep water. These sudden inputs of salt and heat in the deep ocean are responsible for trends in salinity (3.3 ± 0.2 × 10-3/yr) and potential temperature (3.2 ± 0.5 × 10-3 C/yr) observed from 2009 to 2013 for the 600-2300 m layer. For the first time, the overlapping of the three "phases" of deep convection can be observed, with secondary vertical mixing events (2-4 days) after the beginning of the restratification phase, and the restratification/spreading phase still active at the beginning of the following deep convection event.

  5. Spontaneous Formation of Water Droplets at Oil-Solid Interfaces

    PubMed Central

    Yang, Zhongqiang; Abbott, Nicholas L.

    2010-01-01

    We report observations of spontaneous formation of micrometer-sized water droplets within micrometer-thick films of a range of different oils (isotropic and nematic 4-cyano-4’-pentylbiphenyl (5CB), and silicone, olive and corn oil) that are supported on glass substrates treated with octadecyltrichlorosilane (OTS) and immersed under water. Confocal imaging was used to determine that the water droplets nucleate and grow at the interface between the oils and OTS-treated glass with a contact angle of ~130°. A simple thermodynamic model based on macroscopic interfacial energetic arguments consistent with the contact angle of 130°, however, fails to account for the spontaneous formation of the water droplets. ζ-potential measurements performed with OTS-treated glass (− 59.0 ± 16.4 mV) and hydrophobic monolayers formed on gold films (2.0 ± 0.7 mV), when combined with the observed absence of droplet formation under films of oil supported on the latter surfaces, suggest that the charge of the oil-solid interface promotes partitioning of water to the interfacial region. The hydrophobic nature of the OTS-treated glass promotes dewetting of water accumulated in the interfacial region into droplets (a thin film of water is seen to form on bare glass). The inhibitory effect on droplet formation of both salt (NaCl) and sucrose (0.1mM to 500mM) added to the aqueous phase was similar, indicating that both solutes lower the chemical potential of the bulk water (osmotic effect) sufficiently to prevent partitioning of the water to the interface between the oil and supporting substrates. These results suggest that charged, hydrophobic surfaces can provide routes to spontaneous formation of surface-supported, water-in-oil emulsions. PMID:20712383

  6. The Network Concept of Creativity and Deep Thinking: Applications to Social Opinion Formation and Talent Support

    ERIC Educational Resources Information Center

    Csermely, Peter

    2017-01-01

    Our century has unprecedented new challenges, which need creative solutions and deep thinking. Contemplative, deep thinking became an "endangered species" in our rushing world of Tweets, elevator pitches, and fast decisions. Here, we describe how important aspects of both creativity and deep thinking can be understood as network…

  7. Rapid vertical mixing rates in deep waters of the Andaman Basin.

    PubMed

    Dutta, Koushik; Bhushan, Ravi; Somayajulu, B L K

    2007-10-01

    The Andaman Basin is an enclosed region in the northeastern Indian Ocean with its deep water below approximately 1800 m almost isolated with respect to horizontal ventilation by the Andaman-Nicobar Islands separating it from the Bay of Bengal. The physical and chemical properties including radiocarbon ((14)C) measured at two stations of the Andaman Basin show negligible variation with depth in the waters below 1300 m, indicating a well-mixed water mass. This study attempts to derive the mixing rates for deep waters of the Andaman Basin. Model calculations based on (14)C profile measurements indicate rapid vertical mixing (vertical advection velocity, w>200 m year(-1)) in waters deeper than 1800 m of the basin. For a basin with deep water thickness of 1000 m below 1800 m, deduced mixing rate of >200 m year(-1) translates to mixing time of <5 years. As shown for other regions, the possible mechanism responsible for such high vertical mixing rates could be the internal waves generated from tidal currents flowing through rough topography. In addition, Andaman Basin is underlain with a young crust and is known for its high heat flow, which also could contribute to the high vertical mixing.

  8. Use of deep water lagoons for reducing sewage toxicity prior to wastewater treatment

    SciTech Connect

    Shaw, J.R.; Zuiderveen, J.A.; Belcher, B.; McGinley, P.; Birge, W.J.

    1994-12-31

    Investigations were conducted to determine the effectiveness of deep lagoons as a means of wastewater pretreatment. A lagoon system associated with a wastewater treatment plant (WWTP) was selected for study and parameters identified for monitoring included toxicity, metals, total suspended solids (TSS) and ammonia. This system included two lagoons, with 7--15 day hydraulic retention times, fed sequentially with untreated water. Toxicity and other parameters were measured for raw influent water, the two lagoon outfalls, and the final WWTP effluent. In seven-day chronic tests with Ceriodaphnia dubia, the NOEC of influent water was as low as 20%, and 100% mortality occurred at 40%. Outfall from the first deep water lagoon showed reduced toxicity. The NOEC was > 50% but complete mortality occurred in undiluted effluent. Further reduction in toxicity occurred in the second lagoon. Its undiluted effluent had no effect on survival, but did markedly reduce fecundity. The final effluent discharged from the treatment plant affected neither survival nor fecundity. Results of this investigation support the use of deep water lagoons as an effective and economical means of pretreating wastewater. This approach offers promise for municipal waters, industrial effluents and stormwater runoff.

  9. When People Push Water Deep Under Ground, It Can Cause Repeating Ground Shakes

    NASA Astrophysics Data System (ADS)

    Brudzinski, M.; Skoumal, R.; Currie, B.

    2016-12-01

    We look for ground shakes that repeat many times using a fast computer. We can do this when people put out a box that senses ground waves and stores all of them in computer memory. When a ground shake happens, we take the wave form from the ground shake, and use the fast computer to look for any matching wave forms in all of the ground waves stored in memory. Repeating ground shakes can happen when people push water deep down into the ground, which makes it easier for rocks to slip past each other. Sometimes people really push water down deep to break tight rocks and get more stuff stored inside that we use for power. The left over water from breaking rocks is not clean so it often gets pushed down even deeper, far away from the water people drink. In 99 out of 100 cases, pushing the water deep down under ground does not cause ground shakes we can see, even with a computer. Even fewer cases can be felt by people. In the cases where the water causes ground shakes, very small repeating ground shakes often happen early on. We can use a fast computer to find these repeating ground shakes to help us know if larger ground shakes might happen.

  10. Arsenic migration to deep groundwater in Bangladesh influenced by adsorption and water demand

    PubMed Central

    Radloff, K.A.; Zheng, Y.; Michael, H.A.; Stute, M.; Bostick, B. C.; Mihajlov, I.; Bounds, M.; Huq, M. R.; Choudhury, I.; Rahman, M.W.; Schlosser, P.; Ahmed, K. M.; van Geen, A.

    2011-01-01

    Drinking shallow groundwater with naturally elevated concentrations of arsenic is causing widespread disease in many parts of South and Southeast Asia. In the Bengal Basin, growing reliance on deep (>150 m) groundwater has lowered exposure. In the most affected districts of Bangladesh, shallow groundwater concentrations average 100 to 370 μg L−1, while deep groundwater is typically < 10 μg L−1. Groundwater flow simulations have suggested that, even when deep pumping is restricted to domestic use, deep groundwater in some areas of the Bengal Basin is at risk of contamination. However, these simulations have neglected the impedance of As migration by adsorption to aquifer sediments. Here we quantify for the first time As sorption on deeper sediments in situ by replicating the intrusion of shallow groundwater through injection of 1,000 L of deep groundwater modified with 200 μg L−1 of As into a deeper aquifer. Arsenic concentrations in the injected water were reduced by 70% due to adsorption within a single day. Basin-scale modelling indicates that while As adsorption extends the sustainable use of deep groundwater, some areas remain vulnerable; these areas can be prioritized for management and monitoring. PMID:22308168

  11. Lytic viral infection of bacterioplankton in deep waters of the western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Li, Y.; Luo, T.; Sun, J.; Cai, L.; Liang, Y.; Jiao, N.; Zhang, R.

    2014-05-01

    As the most abundant biological entities in the ocean, viruses influence host mortality and nutrient recycling mainly through lytic infection. Yet, the ecological characteristics of virioplankton and viral impacts on host mortality and biogeochemical cycling in the deep sea are largely unknown. In the present study, viral abundance and lytic infection were investigated throughout the water column in the western Pacific Ocean. Both the prokaryotic and viral abundance and production showed a significantly decreasing trend from epipelagic to meso- and bathypelagic waters. Viral abundance decreased from 0.36-1.05 × 1010 particles L-1 to 0.43-0.80 × 109 particles L-1, while the virus : prokaryote ratio varied from 7.21 to 16.23 to 2.45-23.40, at the surface and 2000 m, respectively. Lytic viral production rates in surface and 2000 m waters were, on average, 1.03 × 1010 L-1 day-1 and 5.74 × 108 L-1 day-1. Relatively high percentages of prokaryotic cells lysed by viruses at 1000 and 2000 m were observed, suggesting a significant contribution of viruses to prokaryotic mortality in the deep ocean. The carbon released by viral lysis in deep western Pacific Ocean waters was from 0.03 to 2.32 μg C L-1 day-1. Our findings demonstrated a highly dynamic and active viral population in these deep waters and suggested that virioplankton play an important role in the microbial loop and subsequently biogeochemical cycling in deep oceans.

  12. An evaluation of water quality in private drinking water wells near natural gas extraction sites in the Barnett Shale formation.

    PubMed

    Fontenot, Brian E; Hunt, Laura R; Hildenbrand, Zacariah L; Carlton, Doug D; Oka, Hyppolite; Walton, Jayme L; Hopkins, Dan; Osorio, Alexandra; Bjorndal, Bryan; Hu, Qinhong H; Schug, Kevin A

    2013-09-03

    Natural gas has become a leading source of alternative energy with the advent of techniques to economically extract gas reserves from deep shale formations. Here, we present an assessment of private well water quality in aquifers overlying the Barnett Shale formation of North Texas. We evaluated samples from 100 private drinking water wells using analytical chemistry techniques. Analyses revealed that arsenic, selenium, strontium and total dissolved solids (TDS) exceeded the Environmental Protection Agency's Drinking Water Maximum Contaminant Limit (MCL) in some samples from private water wells located within 3 km of active natural gas wells. Lower levels of arsenic, selenium, strontium, and barium were detected at reference sites outside the Barnett Shale region as well as sites within the Barnett Shale region located more than 3 km from active natural gas wells. Methanol and ethanol were also detected in 29% of samples. Samples exceeding MCL levels were randomly distributed within areas of active natural gas extraction, and the spatial patterns in our data suggest that elevated constituent levels could be due to a variety of factors including mobilization of natural constituents, hydrogeochemical changes from lowering of the water table, or industrial accidents such as faulty gas well casings.

  13. Partial reactivation of a huge deep-seated ancient rock slide: recognition, formation mechanism, and stability

    NASA Astrophysics Data System (ADS)

    Tang, Minggao; Xu, Qiang; Li, Yusheng; Huang, Runqiu; Rengers, Niek; Zhu, Xing

    2016-08-01

    About 18 years ago, a large-scale discontinuous layer in properties and colour was found in the new Fengjie town at the shore of the Three Gorges Reservoir area in China. There are many resettled residents and buildings on the sloping area, the safety of which is potentially affected by this layer, so it has become the focus of attention. Before this study started there were two viewpoints regarding the origin of this layer. One was that is was from a huge ancient slide and the other was that is was from a fault graben. In order to find out how it was formed and to be able to carry out a stability analysis of the slope the authors have carried out a research program, including geological field investigations and mapping, a deep drilling hole, a geotechnical centrifuge model test, and a simulation analysis. The results of the research led to the conclusion that the layer is the sliding plane of a huge deep-seated ancient rock slide, which we called the Sanmashan landslide. An important argument for the conclusion is the recognition of a regional compressive tectonic stress field in this area, which cannot lead to the formation of a fault graben because it needs a tensional tectonic stress field. Moreover, numerous unique geological features, sliding marks, and other relics of the ancient slide have been discovered in the field. The formation process of the ancient slide could be repeated in a large geotechnical centrifuge model test. The test shows that a deformation and failure process of "creep-crack-cut" has occurred. The type of the ancient slide can be classified as a "successive rotational rock slide". Finally, the role of seepage in the stability of the Sanmashan landslide has been analysed. Our final conclusions are that, during rainfall and filling-drawdown cycles in the Three Gorges Reservoir, the Sanmashan landslide as a whole is dormant and stable and the secondary landslides in the toe area of the slope are presently stable but can be reactivated. This

  14. Developmental plasticity of shell morphology of quagga mussels from shallow and deep-water habitats of the Great Lakes

    Treesearch

    Suzanne Peyer; John C. Hermanson; Carol Eunmi Lee

    2010-01-01

    The invasive zebra mussel (Dreissena polymorpha) has quickly colonized shallow-water habitats in the North American Great Lakes since the 1980s but the quagga mussel (Dreissena bugensis) is becoming dominant in both shallow and deep-water habitats. While quagga mussel shell morphology differs between shallow and deep habitats, functional causes and consequences of such...

  15. Distribution of Quercus agrifolia mycorrhizae deep within weathered bedrock: a potential mechanism for transport of stored water

    Treesearch

    M. Bornyasz; R. Graham; M. Allen

    2002-01-01

    In southwestern California, Quercus agrifolia distribution closely matches regions of granitic regolith. High annual evapotranspiration demand and inherent shallow soil conditions lead to a dependence on a deep rooting system and an ability to access water from deep within the regolith. Most of the plant available water in weathered granitic rock is...

  16. The Mediterranean deep-water kelp Laminaria rodriguezii is an endangered species in the Adriatic Sea.

    PubMed

    Žuljević, Ante; Peters, Akira F; Nikolić, Vedran; Antolić, Boris; Despalatović, Marija; Cvitković, Ivan; Isajlović, Igor; Mihanović, Hrvoje; Matijević, Slavica; Shewring, Dawn M; Canese, Simonepietro; Katsaros, Christos; Küpper, Frithjof C

    Deep-water kelps are little-known large brown algae occurring close to the lower limit of photosynthetic life in the sea. This study compares historical and recent records of the deep-water Mediterranean kelp Laminaria rodriguezii in the Adriatic Sea. Historical records include data from herbarium collections and trawling fishery expeditions in the mid-twentieth century, while recent data comprise records of the last 17 years from MEDITS expeditions, ROV surveys of historical kelp locations, benthic surveys and records by fishermen. Altogether, these findings demonstrate that the Adriatic population of L. rodriguezii has suffered a decline of more than 85 % of its historical range and is now present only around the small offshore island of Palagruža. Bottom trawling activities are presumably responsible for the disappearance elsewhere. We propose to classify L. rodriguezii as "Endangered" in the Adriatic Sea under IUCN criteria B1ab(i,iii,iv), ver 3.1. Oceanographic characteristics of the habitat suggest that besides high water transparency, presence of North Adriatic Dense Water with both strong currents and stable low temperatures of around 14 °C are essential oceanographic factors for the development of L. rodriguezii in the Central Adriatic. The origin of cold water thus differs from that at upwelling sites permitting populations of tropical deep-water kelps. The phylogenetic position of L. rodriguezii is so far unknown. DNA sequences from nuclear and cytoplasmic markers of two thalli from Croatia and the western Mediterranean confirmed that L. rodriguezii is a member of the Laminariaceae and most closely related to L. ochroleuca, L. pallida and the Brazilian deep-water kelp L. abyssalis.

  17. GOODS-Herschel: ultra-deep XMM-Newton observations reveal AGN/star-formation connection

    NASA Astrophysics Data System (ADS)

    Rovilos, E.; Comastri, A.; Gilli, R.; Georgantopoulos, I.; Ranalli, P.; Vignali, C.; Lusso, E.; Cappelluti, N.; Zamorani, G.; Elbaz, D.; Dickinson, M.; Hwang, H. S.; Charmandaris, V.; Ivison, R. J.; Merloni, A.; Daddi, E.; Carrera, F. J.; Brandt, W. N.; Mullaney, J. R.; Scott, D.; Alexander, D. M.; Del Moro, A.; Morrison, G.; Murphy, E. J.; Altieri, B.; Aussel, H.; Dannerbauer, H.; Kartaltepe, J.; Leiton, R.; Magdis, G.; Magnelli, B.; Popesso, P.; Valtchanov, I.

    2012-10-01

    Models of galaxy evolution assume some connection between the AGN and star formation activity in galaxies. We use the multi-wavelength information of the CDFS to assess this issue. We select the AGNs from the 3 Ms XMM-Newton survey and measure the star-formation rates of their hosts using data that probe rest-frame wavelengths longward of 20 μm, predominantly from deep 100 μm and 160 μm Herschel observations, but also from Spitzer-MIPS-70 μm. Star-formation rates are obtained from spectral energy distribution fits, identifying and subtracting an AGN component. Our sample consists of sources in the z ≈ 0.5-4 redshift range, with star-formation rates SFR ≈ 101-103 M⊙ yr-1 and stellar masses M⋆ ≈ 1010-1011.5 M⊙. We divide the star-formation rates by the stellar masses of the hosts to derive specific star-formation rates (sSFR) and find evidence for a positive correlation between the AGN activity (proxied by the X-ray luminosity) and the sSFR for themost active systems with X-ray luminosities exceeding Lx ≃ 1043 erg s-1 and redshifts z ≳ 1. We do not find evidence for such a correlation for lower luminosity systems or those at lower redshifts, consistent with previous studies. We do not find any correlation between the SFR (or the sSFR) and the X-ray absorption derived from high-quality XMM-Newton spectra either, showing that the absorption is likely to be linked to the nuclear region rather than the host, while the star-formation is not nuclear. Comparing the sSFR of the hosts to the characteristic sSFR of star-forming galaxies at the same redshift (the so-called "main sequence") we find that the AGNs reside mostly in main-sequence and starburst hosts, reflecting the AGN-sSFR connection; however the infrared selection might bias this result. Limiting our analysis to the highest X-ray luminosity AGNs (X-ray QSOs with Lx > 1044 erg s-1), we find that the highest-redshift QSOs (with z ≳ 2) reside predominantly in starburst hosts, with an average s

  18. WASI-2D: A software tool for regionally optimized analysis of imaging spectrometer data from deep and shallow waters

    NASA Astrophysics Data System (ADS)

    Gege, Peter

    2014-01-01

    An image processing software has been developed which allows quantitative analysis of multi- and hyperspectral data from oceanic, coastal and inland waters. It has been implemented into the Water Colour Simulator WASI, which is a tool for the simulation and analysis of optical properties and light field parameters of deep and shallow waters. The new module WASI-2D can import atmospherically corrected images from airborne sensors and satellite instruments in various data formats and units like remote sensing reflectance or radiance. It can be easily adapted by the user to different sensors and to optical properties of the studied area. Data analysis is done by inverse modelling using established analytical models. The bio-optical model of the water column accounts for gelbstoff (coloured dissolved organic matter, CDOM), detritus, and mixtures of up to 6 phytoplankton classes and 2 spectrally different types of suspended matter. The reflectance of the sea floor is treated as sum of up to 6 substrate types. An analytic model of downwelling irradiance allows wavelength dependent modelling of sun glint and sky glint at the water surface. The provided database covers the spectral range from 350 to 1000 nm in 1 nm intervals. It can be exchanged easily to represent the optical properties of water constituents, bottom types and the atmosphere of the studied area.

  19. Reactivity of Iron-bearing Minerals in Deep Saline Formations subjected to Carbon Injection

    NASA Astrophysics Data System (ADS)

    Schoonen, M. A.; Sklute, E. C.; Strongin, D. R.; Dyar, M. D.

    2013-12-01

    Deep saline aquifers are being considered as repositories for captured CO2. Here the influence of co-injected hydrogen sulfide and sulfur dioxide on the reactivity of hematite-bearing sandstones was evaluated as a function of salt content and water/rock ratio. The reactivity of the Triassic Moenkopi red sandstone under scCO2-dominated conditions (supercritical fluid around the point of injection) and water-dominated conditions (aqueous phase influenced by the injection of scCO2) was studied. Flow-through experiments were used to simulate scCO2-dominated conditions. Crushed sandstone packed in a column was exposed to a co-mingled stream of supercritical CO2 and an aqueous H2S or SO2 solution (75°C). Batch experiments to simulate water-dominated conditions were conducted in small autoclaves that were loaded with crushed sandstone, a small amount of water, and dry ice before to 75°C. The role of water/rock ratio was explored by conducting experiments at a water/rock ratio of 4.3/1 and 1.4/1. The reacted sandstones were recovered at the conclusion of each type of experiment and analyzed for changes in mineralogical composition using X-ray Diffraction. Selected reaction products were also studied using Mössbauer spectroscopy, FTIR, and Visible Near Infrared (VNIR) spectroscopy. The results of the flow through experiments, simulating scCO2-dominated conditions, showed no changes in the iron mineralogy of the sand, regardless of whether pure scCO2 or scCO2 co-mingled with SO2 or H2S was used. By contrast, batch experiments, simulating water-dominated conditions, showed significant changes in iron mineralogy. The presence of sulfide led to the conversion of the hematite component in the sandstone to pyrite at all salt concentrations (0-6M NaCl). In experiments with sulfide and sulfite, siderite and pyrite formed, but siderite was favored at higher salinity and lower water/rock ratio. Availability of water at the mineral surface might be a critical factor in the

  20. Deep water challenges: Oil industry moves off continental shelf; meets new oceanographic data-gathering challenges

    SciTech Connect

    Mardell, G.; Flynn, J.

    1995-08-01

    While offshore oil industry activities move from the continental shelves to the continental slope and even onto the abyssal plains of the deep oceans, new oceanographic problems arise - from riser-deforming internal waves to ocean-floor avalanches. As well as soliton-induced currents, other subsurface flows need to be monitored to provide data in support of wide ranging underwater activities, including exploration drilling, deployment of subsea systems, diver and ROV operations, and pipe design, lay and inspection. This article examines some of the work carried out over the past year or so with data-gathering deep water moorings.

  1. Deep-focus earthquakes and recycling of water into the earth's mantle

    NASA Technical Reports Server (NTRS)

    Meade, Charles; Jeanloz, Raymond

    1991-01-01

    For more than 50 years, observations of earthquakes to depths of 100 to 650 kilometers inside earth have been enigmatic: at these depths, rocks are expected to deform by ductile flow rather than brittle fracturing or frictional sliding on fault surfaces. Laboratory experiments and detailed calculations of the pressures and temperatures in seismically active subduction zones indicate that this deep-focus seismicity could originate from dehydration and high-pressure structural instabilities occurring in the hydrated part of the lithosphere that sinks into the upper mantle. Thus, seismologists may be mapping the recirculation of water from the oceans back into the deep interior of the planet.

  2. Deep-focus earthquakes and recycling of water into the earth's mantle

    NASA Technical Reports Server (NTRS)

    Meade, Charles; Jeanloz, Raymond

    1991-01-01

    For more than 50 years, observations of earthquakes to depths of 100 to 650 kilometers inside earth have been enigmatic: at these depths, rocks are expected to deform by ductile flow rather than brittle fracturing or frictional sliding on fault surfaces. Laboratory experiments and detailed calculations of the pressures and temperatures in seismically active subduction zones indicate that this deep-focus seismicity could originate from dehydration and high-pressure structural instabilities occurring in the hydrated part of the lithosphere that sinks into the upper mantle. Thus, seismologists may be mapping the recirculation of water from the oceans back into the deep interior of the planet.

  3. Abrupt changes in the southern extent of North Atlantic Deep Water during Dansgaard-Oeschger events

    NASA Astrophysics Data System (ADS)

    Gottschalk, Julia; Skinner, Luke C.; Misra, Sambuddha; Waelbroeck, Claire; Menviel, Laurie; Timmermann, Axel

    2015-12-01

    The glacial climate system transitioned rapidly between cold (stadial) and warm (interstadial) conditions in the Northern Hemisphere. This variability, referred to as Dansgaard-Oeschger variability, is widely believed to arise from perturbations of the Atlantic Meridional Overturning Circulation. Evidence for such changes during the longer Heinrich stadials has been identified, but direct evidence for overturning circulation changes during Dansgaard-Oeschger events has proven elusive. Here we reconstruct bottom water [CO32-] variability from B/Ca ratios of benthic foraminifera and indicators of sedimentary dissolution, and use these reconstructions to infer the flow of northern-sourced deep water to the deep central sub-Antarctic Atlantic Ocean. We find that nearly every Dansgaard-Oeschger interstadial is accompanied by a rapid incursion of North Atlantic Deep Water into the deep South Atlantic. Based on these results and transient climate model simulations, we conclude that North Atlantic stadial-interstadial climate variability was associated with significant Atlantic overturning circulation changes that were rapidly transmitted across the Atlantic. However, by demonstrating the persistent role of Atlantic overturning circulation changes in past abrupt climate variability, our reconstructions of carbonate chemistry further indicate that the carbon cycle response to abrupt climate change was not a simple function of North Atlantic overturning.

  4. Formation of organic chloramines during water disinfection: chlorination versus chloramination.

    PubMed

    Lee, Wontae; Westerhoff, Paul

    2009-05-01

    Many of the available studies on formation of organic chloramines during chlorination or chloramination have involved model organic nitrogen compounds (e.g., amino acids), but not naturally occurring organic nitrogen in water. This study assessed organic chloramine formation during chlorination and chloramination of 16 natural organic matter (NOM) solutions and 16 surface waters which contained dissolved organic nitrogen (DON). Chlorination rapidly formed organic chloramines within 10 min, whereas chloramination formed organic chloramination much more slowly, reaching the maximum concentration between 2 and 120 h after the addition of monochloramine into the solutions containing DON. The average organic chloramine formation upon addition of free chlorine and monochloramine into the NOM solutions were 0.78 mg-Cl(2)/mg-DON at 10 min and 0.16 mg-Cl(2)/mg-DON at 24h, respectively. Organic chloramine formation upon chlorination and chloramination increased as the dissolved organic carbon/dissolved organic nitrogen (DOC/DON) ratio decreased (i.e., DON contents increased). Chlorination of molecular weight (10,000 Da) fractionated water showed that molecular weight of DON would not impact the amount of organic chloramines produced. Comparison of three different disinfection schemes at water treatment plants (free chlorine, preformed monochloramine, and chlorine/ammonia additions) indicated organic chloramine formation could lead to a possible overestimation of disinfection capacity in many chloraminated water systems that add chlorine followed by an ammonia addition to form monochloramine.

  5. Movements of a deep-water fish: establishing marine fisheries management boundaries in coastal Arctic waters.

    PubMed

    Hussey, Nigel E; Hedges, Kevin J; Barkley, Amanda N; Treble, Margaret A; Peklova, Iva; Webber, Dale M; Ferguson, Steven H; Yurkowski, David J; Kessel, Steven T; Bedard, Jeannette M; Fisk, Aaron T

    2017-04-01

    in 2014. The community fishery can now develop an open-water fishery in addition to the winter fishery to exploit the TAC, which will ensure the longevity of the fishery under projected climate-change scenarios. Telemetry shows great promise as a tool for understanding deep-water species and for directly informing fisheries management of these ecosystems that are inherently complex to study. © 2016 by the Ecological Society of America.

  6. Deep-water octocorals (Cnidaria: Octocorallia) from Brazil: Family Chrysogorgiidae Verrill, 1883.

    PubMed

    Cordeiro, Ralf T S; Castro, Clovis B; Pérez, Carlos D

    2015-12-15

    Current knowledge about the Brazilian deep-water octocoral fauna remains scarce, fragmented, and mostly based on unpublished, regional scale surveys. The present work provides the first comprehensive study of the family Chrysogorgidae Verrill, 1883 in Brazil, based on morphological analysis of specimens collected in the last decade and those currently placed in museums. Members of this family are common mainly at great depths and remarkable for the iridescent aspect of their colonies. In Brazil, to the present, only four species were reported: Chrysogorgia elegans (Verrill, 1883), Chrysogorgia multiflora Deichmann, 1936, Stephanogorgia rattoi Castro, Medeiros & Loiola, 2010 and Trichogorgia brasiliensis Castro, Medeiros & Loiola, 2010-the last two are shallow-water species. In this study, three new deep-water species are described, Chrysogorgia tuberculata, Chrysogorgia upsilonia and Radicipes kopelatos, and a new record to Brazil is reported, Chrysogorgia fewkesii Verrill, 1883, as well as latitudinal expansions in distributions of Chrysogorgia elegans and Chrysogorgia multiflora are presented.

  7. Protist Community Grazing on Prokaryotic Prey in Deep Ocean Water Masses

    PubMed Central

    Cobban, Alec; Kujawinski, Elizabeth B.; Edgcomb, Virginia P.

    2015-01-01

    Oceanic protist grazing at mesopelagic and bathypelagic depths, and their subsequent effects on trophic links between eukaryotes and prokaryotes, are not well constrained. Recent studies show evidence of higher than expected grazing activity by protists down to mesopelagic depths. This study provides the first exploration of protist grazing in the bathypelagic North Atlantic Deep Water (NADW). Grazing was measured throughout the water column at three stations in the South Atlantic using fluorescently-labeled prey analogues. Grazing in the deep Antarctic Intermediate water (AAIW) and NADW at all three stations removed 3.79% ± 1.72% to 31.14% ± 8.24% of the standing prokaryote stock. These results imply that protist grazing may be a significant source of labile organic carbon at certain meso- and bathypelagic depths. PMID:25894547

  8. Protist Community Grazing on Prokaryotic Prey in Deep Ocean Water Masses.

    PubMed

    Rocke, Emma; Pachiadaki, Maria G; Cobban, Alec; Kujawinski, Elizabeth B; Edgcomb, Virginia P

    2015-01-01

    Oceanic protist grazing at mesopelagic and bathypelagic depths, and their subsequent effects on trophic links between eukaryotes and prokaryotes, are not well constrained. Recent studies show evidence of higher than expected grazing activity by protists down to mesopelagic depths. This study provides the first exploration of protist grazing in the bathypelagic North Atlantic Deep Water (NADW). Grazing was measured throughout the water column at three stations in the South Atlantic using fluorescently-labeled prey analogues. Grazing in the deep Antarctic Intermediate water (AAIW) and NADW at all three stations removed 3.79% ± 1.72% to 31.14% ± 8.24% of the standing prokaryote stock. These results imply that protist grazing may be a significant source of labile organic carbon at certain meso- and bathypelagic depths.

  9. Isotope analysis of water trapped in fluid inclusions in deep sea corals

    NASA Astrophysics Data System (ADS)

    Vonhof, Hubert; Reijmer, John; Feenstra, Eline; Mienis, Furu

    2015-04-01

    Extant Lophelia pertusa deep sea coral specimens from the Loachev mound region in the North Atlantic Ocean contain water filled fluid inclusions in their skeleton. This fluid inclusion water was extracted with a crushing device, and its hydrogen and oxygen isotope ratios analysed. The resulting data span a wide range of isotope values which are remarkably different from the seawater isotope composition of the sites studied. Comparison with food source isotope signatures suggests that coral inclusion water contains a high, but variable proportion of metabolic water. The isotope composition of the inclusion water appears to vary with the position on the deep see coral reef, and shows a correlation with the stable isotope composition of the coral aragonite. This correlation seems to suggest that growth rate and other ecological factors play an important role in determining the isotope composition of fluids trapped in the coral skeleton, which can potentially be developed as a proxy for non-equilibrium isotope fractionation observed in the aragonite skeleton of many of the common deep sea coral species.

  10. Pattern formation during water infiltration in soil increases the resilience of water-stressed ecosystems

    NASA Astrophysics Data System (ADS)

    Cueto-Felgueroso, L.; Juanes, R.

    2010-12-01

    Feedbacks between climate, soil and vegetation transform the structure of arid and semiarid ecosystems, altering the water and nutrient cycles and shaping the patterns of biodiversity and human development at regional and global scales. When rainfall water infiltrates into dry soil, a hydrodynamic instability leads to the onset of columnar preferential flow paths, through which most of the soil is by-passed by the inflowing water. Here we show that the interplay between evaporation and transpiration from shallowly-rooted plants leads to patterns of preferential flow that persist over many rainfall cycles. Fingered flow allows water to quickly traverse the shallow root zone, effectively reducing evapotranspiration losses from the topsoil, and allowing the presence of subsoil water and deep drainage fluxes in arid regions. Subsoil water is available to deeply rooted plants, and recharges groundwater resources at rates that are much higher than those previously estimated using simplified models of infiltration. Deep drainage due to fingering in arid regions stresses the ecological significance of deep roots, and suggests that current models of vegetation cover may underestimate root biomass and terrestrial carbon sinks. The proposed mechanism may be essential to explain the structure and resilience of water-stressed ecosystems, and moderates their response to climate variability.

  11. Methods of reducing the water permeability of water and oil producing subterranean formations

    SciTech Connect

    Dalrymple, E.D.

    1992-09-15

    This patent describes a method of reducing the water produced from a subterranean formation penetrated by a wellbore without appreciably reducing the oil produced therefrom, it comprises: pumping a hydrocarbon solution of a hydrocarbon carrier liquid and a treating agent into the formation by way of the wellbore, and then discontinuing the pumping and returning the formation to production.

  12. Active Ankle Movements Prevent Formation of Lower-Extremity Deep Venous Thrombosis After Orthopedic Surgery

    PubMed Central

    Li, Ye; Guan, Xiang-Hong; Wang, Rui; Li, Bin; Ning, Bo; Su, Wei; Sun, Tao; Li, Hong-Yan

    2016-01-01

    Background The aim of this study was to assess the preventive value of active ankle movements in the formation of lower-extremity deep venous thrombosis (DVT), attempting to develop a new method for rehabilitation nursing after orthopedic surgery. Material/Methods We randomly assigned 193 patients undergoing orthopedic surgery in the lower limbs into a case group (n=96) and a control group (n=97). The control group received routine nursing while the case group performed active ankle movements in addition to receiving routine nursing. Maximum venous outflow (MVO), maximum venous capacity (MVC), and blood rheology were measured and the incidence of DVT was recorded. Results On the 11th and 14th days of the experiment, the case group had significantly higher MVO and MVC than the control group (all P<0.05). The whole-blood viscosity at high shear rate and the plasma viscosity were significantly lower in the case group than in the control group on the 14th day (both P<0.05). During the experiment, a significantly higher overall DVT incidence was recorded in the control group (8 with asymptomatic DVT) compared with the case group (1 with asymptomatic DVT) (P=0.034). During follow-up, the case group presented a significantly lower DVT incidence (1 with symptomatic DVT and 4 with asymptomatic DVT) than in the control group (5 with symptomatic DVT and 10 with asymptomatic DVT) (P=0.031). Conclusions Through increasing MVO and MVC and reducing blood rheology, active ankle movements may prevent the formation of lower-extremity DVT after orthopedic surgery. PMID:27600467

  13. Lytic viral infection of bacterioplankton in deep waters of the western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Li, Y.; Luo, T.; Sun, J.; Cai, L.; Jiao, N.; Zhang, R.

    2013-12-01

    As the most abundant biological entities in the ocean, viruses can influence host mortality and nutrients recycling mainly through lytic infection. Yet ecological characteristics of virioplankton and viral impacts on host mortality and biogeochemical cycling in the deep sea are largely unknown. In present study, viral abundance and lytic infection was investigated throughout the water column in the western Pacific Ocean. Both the prokaryotic and viral abundance and production showed a significantly decreasing trend from epipelagic to meso- and bathypelagic waters. Viral abundance decreased from 0.36-1.05 × 1010 particles L-1 to 0.43-0.80 × 109 particles L-1, while the virus : prokaryote ratio varied from 7.21-16.23 to 2.45-23.40, at surface and 2000 m depth, respectively. The lytic viral production rates in surface and 2000 m waters were, averagely, 1.03 × 1010 L-1 day-1 and 5.74 × 108 L-1 day-1, respectively. Relatively high percentages of prokaryotic cells lysed by virus in 1000 m and 2000 m were observed, suggesting a significant contribution of viruses to prokaryotic mortality in deep ocean. The carbon released by viral lysis in deep western Pacific Ocean waters was from 0.03 to 2.32 μg C L-1 day-1. Our findings demonstrated a highly dynamic and active viral population in the deep western Pacific Ocean and suggested that virioplankton play an important role in the microbial loop and subsequently biogeochemical cycling in deep oceans.

  14. Neodymium isotopic composition of intermediate and deep waters in the glacial southwest Pacific

    NASA Astrophysics Data System (ADS)

    Noble, Taryn L.; Piotrowski, Alexander M.; McCave, I. Nick

    2013-12-01

    Neodymium (Nd) isotopes, tracers of deep water mass source and mixing, were measured on sedimentary planktic foraminifera with authigenic coatings from a depth-transect of cores (1400-4800 m) from Chatham Rise in the southwest Pacific, over the past 30 ka. We observe deglacial variations in the Nd isotopic composition, which showed an average glacial composition of ɛNd=-5.0 (1σ; ±0.3n=4) for cores sites below 3200 mbsl. No significant deglacial variation was observed in the Nd isotopic composition of intermediate depth waters (1400 mbsl), in contrast with benthic foraminifera δC13 data. The deglacial ɛNd shift of CDW in the southwest Pacific is consistent with changes observed in the deep South Atlantic and Equatorial Indian Ocean, but ɛNd values are offset by ˜1ɛNd-unit to more radiogenic values throughout the deglacial records, likely due to admixture of a Nd isotope signal which was modified in the Southern Ocean or Pacific, perhaps by boundary exchange. However, this modification did not overprint the deglacial Nd isotope change. The consistent deglacial evolution of ɛNd in the South Atlantic, Equatorial Indian and southwest Pacific CDW, is evidence for the connection of CDW during the glacial, and propagation of diminished North Atlantic Deep Water export to the glacial Southern Ocean. In contrast, spatial heterogeneities in the benthic foraminifera δC13 of CDW have been observed in the Atlantic, Indian and Pacific basins of the deep glacial Southern Ocean. The Nd isotope data implies a well-connected deep Southern Ocean, which transported waters from the Atlantic to the Indian and Pacific oceans, during the glacial. This suggests that basin-scale variability in the glacial δC13 composition of CDW was unrelated to circulation changes.

  15. Exceptional dense water formation on the Adriatic shelf in the winter of 2012

    NASA Astrophysics Data System (ADS)

    Mihanović, H.; Vilibić, I.; Carniel, S.; Tudor, M.; Russo, A.; Bergamasco, A.; Bubić, N.; Ljubešić, Z.; Viličić, D.; Boldrin, A.; Malačič, V.; Celio, M.; Comici, C.; Raicich, F.

    2012-12-01

    We document dense water formation (DWF) throughout the Adriatic shelf and coastal area in January/February 2012, resulting in record-breaking densities observed during and after the event. The unprecedented dense water generation was preconditioned by a dry and warm year which resulted in a significant reduction of coastal freshwaters, superimposed on a long-term basin-wide salinity increase. The final event that triggered the DWF was an extended period of cold weather with strong and severe winds. Record-breaking potential density anomalies (above 30 kg m-3) were measured at several DWF sites. Accumulated surface net heat and water losses in some coastal regions exceeded 1.5 GJ m-2 and 250 kg m-2 over 21 days, respectively. Excessiveness, importance of shelf-type DWF, effects on the thermohaline circulation and deep aquatic systems, and connection with climate change are discussed.

  16. A method for simulating transient ground-water recharge in deep water-table settings in central Florida by using a simple water-balance/transfer-function model

    USGS Publications Warehouse

    O'Reilly, Andrew M.

    2004-01-01

    A relatively simple method is needed that provides estimates of transient ground-water recharge in deep water-table settings that can be incorporated into other hydrologic models. Deep water-table settings are areas where the water table is below the reach of plant roots and virtually all water that is not lost to surface runoff, evaporation at land surface, or evapotranspiration in the root zone eventually becomes ground-water recharge. Areas in central Florida with a deep water table generally are high recharge areas; consequently, simulation of recharge in these areas is of particular interest to water-resource managers. Yet the complexities of meteorological variations and unsaturated flow processes make it difficult to estimate short-term recharge rates, thereby confounding calibration and predictive use of transient hydrologic models. A simple water-balance/transfer-function (WBTF) model was developed for simulating transient ground-water recharge in deep water-table settings. The WBTF model represents a one-dimensional column from the top of the vegetative canopy to the water table and consists of two components: (1) a water-balance module that simulates the water storage capacity of the vegetative canopy and root zone; and (2) a transfer-function module that simulates the traveltime of water as it percolates from the bottom of the root zone to the water table. Data requirements include two time series for the period of interest?precipitation (or precipitation minus surface runoff, if surface runoff is not negligible) and evapotranspiration?and values for five parameters that represent water storage capacity or soil-drainage characteristics. A limiting assumption of the WBTF model is that the percolation of water below the root zone is a linear process. That is, percolating water is assumed to have the same traveltime characteristics, experiencing the same delay and attenuation, as it moves through the unsaturated zone. This assumption is more accurate if

  17. Impact of switching crop type on water and solute fluxes in deep vadose zone

    NASA Astrophysics Data System (ADS)

    Turkeltaub, T.; Kurtzman, D.; Russak, E. E.; Dahan, O.

    2015-12-01

    Switching crop type and consequently changing irrigation and fertilization regimes lead to alterations in deep percolation and solute concentrations of pore water. Herein, observations from the deep vadose zone and model simulations demonstrate the changes in water, chloride, and nitrate fluxes under a commercial greenhouse following the change from tomato to lettuce cropping. The site, located above a phreatic aquifer, was monitored for 5 years. A vadose-zone monitoring system was implemented under the greenhouse and provided continuous data on both temporal variations in water content and chemical composition of the pore water at multiple depths in the deep vadose zone (up to 20 m). Following crop switching, a significant reduction in chloride concentration and dramatic increase in nitrate were observed across the unsaturated zone. The changes in chemical composition of the vadose-zone pore water appeared as sequential breakthroughs across the unsaturated zone, initiating at land surface and propagating down toward the water table. Today, 3 years after switching the crops, penetration of the impact exceeds 10 m depth. Variations in the isotopic composition of nitrate (18O and 15N) in water samples obtained from the entire vadose zone clearly support a fast leaching process and mobilization of solutes across the unsaturated zone following the change in crop type. Water flow and chloride transport models were calibrated to observations acquired during an enhanced infiltration experiment. Forward simulation runs were performed with the calibrated models, constrained to tomato and lettuce cultivation regimes as surface boundary conditions. Predicted chloride and nitrate concentrations were in agreement with the observed concentrations. The simulated water drainage and nitrogen leaching implied that the observed changes are an outcome of recommended agricultural management practices.

  18. Table-driven configuration and formatting of telemetry data in the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Manning, Evan

    1994-01-01

    With a restructured software architecture for telemetry system control and data processing, the NASA/Deep Space Network (DSN) has substantially improved its ability to accommodate a wide variety of spacecraft in an era of 'better, faster, cheaper'. In the new architecture, the permanent software implements all capabilities needed by any system user, and text tables specify how these capabilities are to be used for each spacecraft. Most changes can now be made rapidly, outside of the traditional software development cycle. The system can be updated to support a new spacecraft through table changes rather than software changes, reducing the implementation, test, and delivery cycle for such a change from three months to three weeks. The mechanical separation of the text table files from the program software, with tables only loaded into memory when that mission is being supported, dramatically reduces the level of regression testing required. The format of each table is a different compromise between ease of human interpretation, efficiency of computer interpretation, and flexibility.

  19. On the validity of the double integrator approximation in deep space formation flying

    NASA Technical Reports Server (NTRS)

    Kang, B. H.; Hadaegh, F. Y.; Scharf, D. P.

    2002-01-01

    Free-flying models are commonly used f o r path planning and open loop control design (i. e., guidance design) and translational feedback control design (i. e., control design) for deep space precision formation flying. The free flying model, essentially a double integrator, results from discarding small terms in the relative spacecraft equations of motion. While the magnitude of these discarded terms may be small, one must show that their dynamic effects are small as compared to the precision performance requirements. We do so by deriving a theoretical method for bounding the difference between the solution of a nonlinear truth model of the relative translational spacecraft dynamics and a Simplified linear time-invariant model. Presently, the method incorporates feedforward and static output feedback control. The method is applied to a Terrestrial Planet Finder- based example. Using only feedforward control (guidance) the free-flying model and a Hill- Clohessy- Wiltshire Equations-based model are shown to be accurate to 1 c m for up to 4 and 30 hours, respectively. Also shown is that the simplest free-flying model may not be sufficient for low-gain feedback control design-closed-loop tracking errors can be as large as 8 meters.

  20. Three new records of deep-water goniasterids (Echinodermata: Asteroidea: Goniasteridae) from China seas

    NASA Astrophysics Data System (ADS)

    Xiao, Ning; Liao, Yulin

    2013-09-01

    In this paper, three deep-water species of the family Goniasteridae, Ceramaster misakiensis (Goto, 1914), Nymphaster arthrocnemis Fisher, 1913 and Pontioceramus grandis Fisher, 1911, are recorded for the first time from Chinese waters based on collections deposited in the Marine Biological Museum, Chinese Academy of Sciences. The specimens examined were collected during the period 1956 to 1978 from the East China and South China Seas at depths of 184 to 472 m. Diagnosis, detailed figures, and the geographic distributions are provided. A revised list of Goniasteridae recorded from Chinese waters is proposed.

  1. Deep Hubble Space Telescope Imaging of IC 1613. II. The Star Formation History

    NASA Astrophysics Data System (ADS)

    Skillman, Evan D.; Tolstoy, Eline; Cole, Andrew A.; Dolphin, Andrew E.; Saha, Abhijit; Gallagher, J. S.; Dohm-Palmer, R. C.; Mateo, Mario

    2003-10-01

    We have taken deep images of an outlying field in the Local Group dwarf irregular galaxy IC 1613 with the WFPC2 aboard the Hubble Space Telescope in the standard broadband F555W (V, 8 orbits) and F814W (I, 16 orbits) filters. The photometry reaches to V=27.7 (MV=+3.4) and I=27.1 (MI=+2.8) at the 50% completeness level, the deepest to date for an isolated dwarf irregular galaxy. We analyze the resulting color-magnitude diagram (CMD) and compare it with CMDs created from theoretical stellar models using three different methods to derive a star formation history (SFH) as well as constrain the chemical evolution for IC 1613. All three methods find an enhanced star formation rate (SFR), at roughly the same magnitude (factor of 3), over roughly the same period (from 3 to 6 Gyr ago). Additionally, all three methods were driven to similar age-metallicity relationships (AMR) that show an increase from [Fe/H]~-1.3 at earliest times to [Fe/H]~-0.7 at present. Good agreement is found between the AMR which is derived from the CMD analysis and that which can be inferred from the derived SFH at all but the earliest ages. The agreement between the three models and the self-consistency of the derived chemical enrichment history support the reality of the derived SFH of IC 1613 and, more generally, are supportive of the practice of constructing galaxy SFHs from CMDs. A comparison of the newly observed outer field with an earlier studied central field of IC 1613 shows that the SFR in the outer field has been significantly depressed during the last Gyr. This implies that the optical scale length of the galaxy has been decreasing with time and that comparison of galaxies at intermediate redshift with present-day galaxies should take this effect into account. Comparing the CMD of the outer field of IC 1613 with CMDs of Milky Way dSph companions, we find strong similarities between IC 1613 and the more distant dSph companions (Carina, Fornax, Leo I, and Leo II) in that all are dominated

  2. How Temperature and Water levels affect Polar Mesospheric Cloud Formation

    NASA Astrophysics Data System (ADS)

    Smith, L. L.; Randall, C. E.; Harvey, V.

    2012-12-01

    Using the Cloud Imaging and Particle Size (CIPS) instrument data, which is part of the Aeronomy in the Mesosphere (AIM) mission, we compare the albedo and ice water content measurements of CIPS with the Navy Operation Global Atmospheric Prediction System - Advanced Level Phyiscs and High Altitude (NOGAPS-ALPHA) temperature and water vapor data in order to derive a greater understanding of cloud formation and physics. We particularly focus on data from June 2007 and July 2007 in this case study because of particular cloud structures and formations during this time period for future studies.

  3. A Multiscale Approach for the Understanding of Water Film Formation

    SciTech Connect

    Baolin Deng; Bing Hua; Young Gan; Zhen Chen; Thornton, Edward

    2006-04-05

    Reductive immobilization of toxic and radioactive metals by gaseous hydrogen sulfide is a promising technology for in-situ remediation of soils and groundwater (Fig. 1 & 2). Rate of chromium(VI) reduction by gaseous hydrogen sulfide in the vadose zone soil is controlled by gas phase humidity and soil particle size (Fig. 3). It is believed that water film formation on solid surfaces is needed for effective contaminant reduction and immobilization (Fig. 4). Molecular Dynamics (MD) Simulation is used to understand the mechanism of water film formation.

  4. Distribution and sources of pre-anthropogenic lead isotopes in deep ocean water from Fe-Mn crusts

    USGS Publications Warehouse

    Von Blanckenburg, F.; O'Nions, R. K.; Hein, J.R.

    1996-01-01

    The lead isotope composition of ocean water is not well constrained due to contamination by anthropogenic lead. Here the global distribution of lead isotopes in deep ocean water is presented as derived from dated (ca. 100 ka) surface layers of hydrogenetic Fe-Mn crusts. The results indicate that the radiogenic lead in North Atlantic deep water is probably supplied from the continents by river particulates, and that lead in Pacific deep water is similar to that characteristic of island and continental volcanic arcs. Despite a short residence time in deep water (80-100 a), the isotopes of lead appear to be exceedingly well mixed in the Pacific basin. There is no evidence for the import of North Atlantic deep water-derived lead into the Pacific ocean, nor into the North Indian Ocean. This implies that the short residence time of lead in deep water prohibits advection over such long distances. Consequently, any climate-induced changes in deep-water flow are not expected to result in major changes in the seawater Pb-isotope record of the Pacific Ocean.

  5. Biomarkers in the stratified water column of the Landsort Deep (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Berndmeyer, C.; Thiel, V.; Schmale, O.; Wasmund, N.; Blumenberg, M.

    2014-06-01

    The water column of the Landsort Deep, central Baltic Sea, is stratified into an oxic, suboxic and anoxic zone. This stratification controls the distributions of individual microbial communities and biogeochemical processes. In summer 2011, particulate organic matter was filtered from these zones using an in~situ pump. Lipid biomarkers were extracted from the filters to establish water column profiles of individual hydrocarbons, alcohols, phospholipid fatty acids, and bacteriohopanepolyols (BHPs). As a reference, a cyanobacterial bloom sampled in summer 2012 in the central Baltic Sea Gotland Deep was analyzed for BHPs. The biomarker data from the surface layer of the oxic zone showed major inputs from different cyanobacteria and eukaryotes such as dinoflagellates and ciliates, while the underlying cold winter water layer was characterized by a low diversity and abundance of organisms, with copepods as a major group. The suboxic zone supported bacterivorous ciliates, type I aerobic methanotrophic bacteria, sulfate reducing bacteria, and, most likely, methanogenic archaea. In the anoxic zone, sulfate reducers and archaea were the dominating microorganisms as indicated by the presence of distinctive branched fatty acids, archaeol and PMI derivatives, respectively. Our study of in situ biomarkers in the Landsort Deep thus provided an integrated insight into the distribution of relevant players and the related biogeochemical processes in stratified water columns of marginal seas.

  6. Biomarkers in the stratified water column of the Landsort Deep (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Berndmeyer, C.; Thiel, V.; Schmale, O.; Wasmund, N.; Blumenberg, M.

    2014-12-01

    The water column of the Landsort Deep, central Baltic Sea, is stratified into an oxic, suboxic, and anoxic zone. This stratification controls the distributions of individual microbial communities and biogeochemical processes. In summer 2011, particulate organic matter was filtered from these zones using an in situ pump. Lipid biomarkers were extracted from the filters to establish water-column profiles of individual hydrocarbons, alcohols, phospholipid f