Science.gov

Sample records for atlantic ocean supplementary

  1. Dust Cloud, Mid Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of a dust cloud from a Sahara Desert, North Africa dust storm was taken over the Mid Atlantic Ocean, some 1700 miles from the African coast (24.5N, 45.0W). Dust, sand and other particulate matter from arid regions is frequently stirred up by fast blowing desert winds and carried aloft to high altitudes where it may be transported great distances, sometimes as much as half way around the world.

  2. Dust Cloud, Mid Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of a dust cloud from a Sahara Desert, North Africa dust storm was taken over the Mid Atlantic Ocean, some 1700 miles from the African coast (24.5N, 45.0W). Dust, sand and other particulate matter from arid regions is frequently stirred up by fast blowing desert winds and carried aloft to high altitudes where it may be transported great distances, sometimes as much as half way around the world.

  3. Hydrogen in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Walter, S.; Kock, A.; Steinhoff, T.; Röckmann, T.

    2009-04-01

    Although hydrogen (H2) is considered as one of the most important future energy carriers, little is known about the global biogeochemical cycle of this trace gas (Rhee et al. 2006). In order to assess the potential impact of expected increasing H2 concentrations to the atmosphere a fundamental understanding of the global H2 cycle is indispensable (Tromp et al. 2003, Warwick et al. 2004). Oceans are one source of atmospheric H2, produced by biological processes such as fermentation and N2-fixation and abiotic photochemical processes (Punshon and Moore 2008 and references herein). Further information can be obtained by studying the isotope composition of H2. However, the isotopic ratio of oceanic released H2 is unknown and has so far only been estimated from thermodynamic equilibrium. We investigated the atmospheric D/H isotopic ratio of H2 in the Atlantic Ocean. First results of atmospheric H2 isotope ratios from the West African coast of Mauritania and from a meridional transect over the Atlantic Ocean will be presented. Samples were taken onboard the German research vessel "Poseidon" in February 2007 associated to SOPRAN and during the cruise Ant XXIV-4 with the German research vessel "Polarstern" in April 2008 between Punta Arenas (Chile) and Bremerhaven (Germany). Literature Punshon, S. and R.M. Moore; Aerobic hydrogen production and dinitrogen fixation in the marine cyanobacterium Trichodesmium erythraeum IMS101; Limnol. Oceanogr., 53(6), 2749-2753, 2008. Rhee, T.S., C.A.M. Brenninkmeijer, and T. Röckmann; The overwhelming role of soils in the global atmospheric hydrogen cycle, Atmos. Chem. Phys., 6, 1611-1625, 2006. Tromp, T.K., Shi, R.-L., Allen, M., Eiler, J.M., and Y. L. Yung1; Potential Environmental Impact of a Hydrogen Economy on the Stratosphere, Science, 300, 1740-1742, 2003. Warwick, N.J., Bekki, S., Nisbet, E.G., and J.A. Pyle; Impact of a hydrogen economy on the stratosphere and troposphere studied in a 2-D model; Geo.Res.Lett., 31, L05107, doi:10

  4. 76 FR 31235 - Safety Zone; Ocean City Air Show, Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ... establish a temporary safety zone on the Atlantic Ocean in the vicinity of Ocean City, MD to support the Ocean City Air Show. This action is necessary to provide for the safety of life on navigable waters... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Ocean City Air Show, Atlantic Ocean,...

  5. 75 FR 18778 - Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... to support the Ocean City Air Show. This action is intended to restrict vessel traffic movement on the Atlantic Ocean to protect mariners and the public from the hazards associated with air show events... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Ocean City Air Show 2010, Atlantic Ocean...

  6. Atmospheric Blocking and Atlantic Multidecadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by affecting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially 1996 to 2010). It also describes much longer time scale Atlantic multidecadal ocean variability (AMV), including the extreme pre-greenhouse-gas northern warming of the 1930s to 1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat exchange, both of which contribute to the warm phase of AMV.

  7. Atmospheric blocking and Atlantic multidecadal ocean variability.

    PubMed

    Häkkinen, Sirpa; Rhines, Peter B; Worthen, Denise L

    2011-11-04

    Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by affecting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially 1996 to 2010). It also describes much longer time scale Atlantic multidecadal ocean variability (AMV), including the extreme pre-greenhouse-gas northern warming of the 1930s to 1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat exchange, both of which contribute to the warm phase of AMV.

  8. Atmospheric Blocking and Atlantic Multidecadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by affecting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially 1996 to 2010). It also describes much longer time scale Atlantic multidecadal ocean variability (AMV), including the extreme pre-greenhouse-gas northern warming of the 1930s to 1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat exchange, both of which contribute to the warm phase of AMV.

  9. Atlantic and Indian Oceans Pollution in Africa

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  10. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized fishery...

  11. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized fishery...

  12. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized fishery...

  13. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized fishery...

  14. Atlantic and indian oceans pollution in africa

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  15. Silver in the far North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Rivera-Duarte, I.; Flegal, A. R.; Sañudo-Wilhelmy, S. A.; Véron, A. J.

    Total (unfiltered) silver concentrations in higher latitudes of the North Atlantic (52-68°N) are reported for the second Intergovernmental Oceanographic Commission (IOC) Global Investigation of Pollutants in the Marine Environment (GIPME) baseline survey of 1993. These silver concentrations (0.69-7.2 pM) are oceanographically consistent with those (0.24-9.6 pM) previously reported for lower latitudes in the eastern North and South Atlantic ( Flegal et al., 1995). However, surface (⩽200 m) water concentrations of silver (0.69-4.6 pM) in the northern North Atlantic waters are, on average, ten-fold larger than those (0.25 pM) considered natural background concentrations in surface waters of the central Atlantic. In contrast, variations in deep far North Atlantic silver concentrations are associated with discrete water masses. Consequently, the cycling of silver in the far North Atlantic appears to be predominantly controlled by external inputs and the advection of distinct water masses, in contrast to the nutrient-like biogeochemical cycling of silver observed in the central Atlantic and Pacific oceans.

  16. Anisotropic tomography of the Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Silveira, G.; Stutzmann, E.

    2003-04-01

    We present a regional tri-dimensional model of the Atlantic Ocean with anisotropy. The model, derived from Rayleigh and Love phase velocity measurements, is defined from the Moho down to 300 km depth with a lateral resolution of about 500 km and is presented in terms of average isotropic S-wave velocity, azimuthal anisotropy and transverse isotropy. The cratons beneath North America, Brazil and Africa are clearly associated with fast S-wave velocity anomalies. The Mid Atlantic Ridge is a shallow structure in the North Atlantic corresponding to a negative velocity anomaly down to about 150 km depth. In contrast, the ridge negative signature is visible in the South Atlantic down to the deepest depth inverted, that is 300~km depth. This difference is probably related to the presence of hot-spots along or close to the ridge axis in the South Atlantic and may indicate a different mechanism for the ridge between the North and South Atlantic. Negative velocity anomalies are clearly associated with hot-spots from the surface down to at least 300km depth, they are much broader that the supposed size of the hot-spots and seem to be connected along a North-South direction. Down to 100 km depth, a fast S-wave velocity anomaly is extenting from Africa into the Atlantic Ocean within the zone defined as the Africa superswell area. This result indicates that the hot material rising from below does not reach the surface in this area but may be pushing the lithosphere upward. In most parts of the Atlantic, the azimuthal anisotropy directions remain stable with increasing depth. Close to the ridge, the fast S-wave velocity direction is roughly parallel to the sea floor spreading direction. The hot-spot anisotropy signature is striking beneath Bermuda, Cape Verde and Fernando Noronha islands where the fast S-wave velocity direction seems to diverge radially from the hot-spots. The Atlantic average radial anisotropy is similar to that of the PREM model, that is positive down to about

  17. Anisotropic tomography of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Silveira, Graça.; Stutzmann, Eléonore

    2002-10-01

    We present the first regional three-dimensional model of the Atlantic Ocean with anisotropy. The model, derived from Rayleigh and Love wave phase velocity measurements, is defined from the Moho down to 300 km depth with a lateral resolution of about 500 km and is presented in terms of average isotropic S-wave velocity, azimuthal anisotropy and transverse isotropy. The cratons beneath North America, Brazil and Africa are clearly associated with fast S-wave velocity anomalies. The mid-Atlantic ridge (MAR) is a shallow structure in the north Atlantic corresponding to a negative velocity anomaly down to about 150 km depth. In contrast, the ridge negative signature is visible in the south Atlantic down to the deepest depth inverted, that is 300 km depth. This difference is probably related to the presence of hot-spots along or close to the ridge axis in the south Atlantic and may indicate a different mechanism for the ridge between the north and south Atlantic. Negative velocity anomalies are clearly associated with hot-spots from the surface down to at least 300 km depth, they are much broader than the supposed size of the hot-spots and seem to be connected along a north-south direction. Down to 100 km depth, a fast S-wave velocity anomaly is extenting from Africa into the Atlantic Ocean within the zone defined as the Africa superswell area. This result indicates that the hot material rising from below does not reach the surface in this area but may be pushing the lithosphere upward. In most parts of the Atlantic, the azimuthal anisotropy directions remain stable with increasing depth. Close to the ridge, the fast S-wave velocity direction is roughly parallel to the sea floor spreading direction. The hot-spot anisotropy signature is striking beneath Bermuda, Cape Verde and Fernando Noronha islands where the fast S-wave velocity direction seems to diverge radially from the hot-spots. The Atlantic average radial anisotropy is similar to that of the PREM model, that is

  18. 77 FR 22523 - Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... action is necessary to provide for the safety of life on navigable waters during the 2012 Ocean City Air... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast...

  19. Tenarife Island, Canary Island Archipelago, Atlantic Ocean

    NASA Image and Video Library

    1991-08-11

    Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

  20. NOAA Research Vessel Explores Atlantic Ocean Seamounts

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2014-10-01

    Mike Ford, a biological oceanographer with the National Oceanic and Atmospheric Administration (NOAA), sat rapt in front of a bank of high-definition monitors. They provided live video and data feeds from a tethered pair of instrument-laden remotely operated vehicles (ROVs) that were descending 4692 meters on their deepest dive ever. Their target: an unnamed and unexplored New England seamount discovered in the North Atlantic last year.

  1. A Latitudinal Metabolome of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Johnson, W.; Kido Soule, M. C.; Longnecker, K.; Kujawinski, E. B.

    2016-02-01

    Microbial consortia function via the exchange and transformation of small organic molecules or metabolites. These metabolites make up a pool of rapidly cycling organic matter in the ocean that is challenging to characterize due to its low concentrations. We seek to determine the distribution of these molecules and the factors that shape their abundance and flux. Through measurements of the abundance of a core set of metabolites, including nucleic acids, amino acids, sugars, vitamins, and signaling molecules, we gain a real-time snapshot of microbial activity. We used a targeted metabolomics technique to profile metabolite abundance in particulate and dissolved organic matter extracts collected from a 14,000 km transect running from 38˚S to 55˚N in the Western Atlantic Ocean. This extensive dataset is the first of its kind in the Atlantic Ocean and allows us to explore connections among metabolites as well as latitudinal trends in metabolite abundance. We found changes in the intracellular abundance of certain metabolites between low and high nutrient regions and a wide distribution of certain dissolved vitamins in the surface ocean. These measurements give us baseline data on the distribution of these metabolites and allow us to extend our understanding of microbial community activity in different regions of the ocean.

  2. Dissipation effects in North Atlantic Ocean modeling

    NASA Astrophysics Data System (ADS)

    Dietrich, D. E.; Mehra, A.; Haney, R. L.; Bowman, M. J.; Tseng, Y. H.

    2004-03-01

    Numerical experiments varying lateral viscosity and diffusivity between 20 and 150 m2/s in a North Atlantic Ocean (NAO) model having 4th-order accurate numerics, in which the dense deep current system (DCS) from the northern seas and Arctic Ocean is simulated directly show that Gulf Stream (GS) separation is strongly affected by the dissipation of the DCS. This is true even though the separation is highly inertial with large Reynolds number for GS separation flow scales. We show that realistic NAO modeling requires less than 150 m2/s viscosity and diffusivity in order to maintain the DCS material current with enough intensity to get realistic GS separation near Cape Hatteras (CH). This also demands accurate, low dissipation numerics, because of the long transit time (1-10 years) of DCS material from its northern seas and Arctic Ocean source regions to the Cape Hatteras region and the small lateral and vertical scales of DCS.

  3. 33 CFR 165.T05-0494 - Safety Zone, Atlantic Ocean; Ocean City, NJ.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Safety Zone, Atlantic Ocean; Ocean City, NJ. 165.T05-0494 Section 165.T05-0494 Navigation and Navigable Waters COAST GUARD... § 165.T05-0494 Safety Zone, Atlantic Ocean; Ocean City, NJ. (a) Location. The following area is a safety...

  4. Large Tabular Iceberg, South Atlantic Ocean

    NASA Image and Video Library

    1991-09-18

    This large tabular iceberg, broken off from the Antarctic Ice Sheet, was spotted in the South Atlantic Ocean (57.0S, 57.0W) southeast of the tip of South America as it was slowly being moved north and east by wind, current and tidal influences. This type of iceberg, never to be seen in the northern hemisphere, is typical for Antarctica. Although some such icebergs are as large as 100 km in length, this one measures about 35 by 69 km.

  5. Oceanic origin of southeast tropical Atlantic biases

    NASA Astrophysics Data System (ADS)

    Xu, Zhao; Li, Mingkui; Patricola, Christina M.; Chang, Ping

    2014-12-01

    Most coupled general circulation models suffer from a prominent warm sea surface temperature bias in the southeast tropical Atlantic Ocean off the coast of Africa. The origin of the bias is not understood and remains highly controversial. Previous studies suggest that the origin of the bias stems from systematic errors of atmospheric models in simulating surface heat flux and coastal wind, or poorly simulated coastal upwelling. In this study, we show, using different reanalysis and observational data sets combined with a set of eddy-resolving regional ocean model simulations, that systematic errors in ocean models also make a significant contribution to the bias problem. In particular (1) the strong warm bias at the Angola-Benguela front that is maintained by the local wind and the convergence of Angola and Benguela Currents is caused by an overshooting of the Angola Current in ocean models and (2) the alongshore warm bias to the south of the front is caused by ocean model deficiencies in simulating the sharp thermocline along the Angola coast, which is linked to biases in the equatorial thermocline, and the complex circulation system within the Benguela upwelling zone.

  6. Oceanic Origin of Tropical Atlantic SST Biases

    NASA Astrophysics Data System (ADS)

    Chang, P.; Xu, Z.; Li, M.; Patricola, C. M.

    2012-12-01

    Most coupled general circulation models (CGCMs) suffer from a prominent warm sea surface temperature (SST) bias in the southeastern tropical Atlantic Ocean off the coast of Africa. The origin of the bias is not understood and remains highly controversial. Previous studies suggest that the origin of the bias stems from systematic errors of atmospheric models in simulating surface heat flux and coastal wind, or poorly simulated coastal upwelling. In this study, we show, using different reanalysis and observational data sets combined with a set of eddy-resolving regional ocean model simulations, that systematic errors in ocean models also make a significant contribution to the bias problem. In particular, (1) the strong warm bias at the Angola Benguela front that is maintained by the local wind and the convergence of Angola and Benguela Current is caused by an overshooting of the Angola Current in ocean models and (2) the alongshore warm bias to the south of the front is caused by ocean model deficiencies in simulating the sharp thermocline along the equator, the strong thermal gradient beneath the Angola current, and the complex circulation system within the Benguela upwelling zone.

  7. Hurricane Gonzalo in the Atlantic Ocean

    NASA Image and Video Library

    2017-09-28

    On Oct. 16 at 17:45 UTC NASA's Terra satellite captured this image of Hurricane Gonzalo in the Atlantic Ocean. Image Credit: NASA Goddard MODIS Rapid Response Team-- NASA and NOAA satellites have been providing continuous coverage of Hurricane Gonzalo as it moves toward Bermuda. NASA's Terra satellite saw thunderstorms wrapped tightly around the center with large bands of thunderstorms wrapping into it. NOAA's GOES-East satellite provided and "eye-opening" view of Gonzalo, still a Category 4 hurricane on Oct. 16. A hurricane warning is in effect for Bermuda and that means that hurricane conditions are expected within the warning area, meaning the entire island. Read more: www.nasa.gov/content/goddard/gonzalo-atlantic-ocean/index... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  8. Phytoplankton bloom in the North Atlantic Ocean

    NASA Image and Video Library

    2017-09-27

    On July 23, 2013 the deep blue waters of the central North Atlantic Ocean provided a background for a spectacular bloom of phytoplankton. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this true-color image of the event at 16:25 UTC (12:25 p.m. EDT) that same day. Phytoplankton are tiny single-celled photosynthetic organisms that live suspended in a watery environment. They are primary producers in the ocean, forming the base of the marine food chain, and, like terrestrial plants, take up carbon dioxide, make carbohydrates from energy from light, and release oxygen. Phytoplankton live in the ocean year round, but are usually not visible. When light, nutrients and water temperature are just right, however, a colony can explode into growth, creating huge blooms that stain the ocean for miles. While each organism lives only a short time, the high reproductive means that a bloom can last for days or weeks. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  9. North Atlantic Finite Element Ocean Modeling

    NASA Astrophysics Data System (ADS)

    Veluthedathekuzhiyil, Praveen

    This thesis presents a modified version of the Finite Element Ocean Model (FEOM) developed at Alfred Wegener Institute for Polar and Marine Research (AWI) for the North Atlantic Ocean. A reasonable North Atlantic Ocean simulation is obtained against the observational data sets in a Control simulation (CS) where the surface boundary conditions are relaxed to a climatology. The vertical mixing in the model was tuned to represent convection in the model, also the horizontal mixing and diffusion coefficients to represent the changes in the resolution of the model’s unstructured grid. In addition, the open boundaries in the model are treated with a sponge layer where tracers are relaxed to climatology. The model is then further modified to accept the atmospheric flux forcing at the surface boundary with an added net heat flux correction and freshwater forcing from major rivers that are flowing into the North Atlantic Ocean. The impact of this boundary condition on the simulation results is then analyzed and shows many improvements albeit the drift in tracer properties around the Gulf Stream region remains as that of the CS case. However a comparison of the vertical sections at Cape Desolation and Cape Farewell with the available observational data sets shows many improvements in this simulation compared to that of the CS case. But the freshwater content in the Labrador Sea interior shows a continued drift as that of the CS case with an improvement towards the 10th model year. A detailed analysis of the boundary currents around the Labrador Sea shows the weak offshore transport of freshwater from the West Greenland Current (WGC) as one of the causes. To further improve the model and reasonably represent the boundary currents and associated sub-grid scale eddies in the model, a modified sub-grid scale parameterization based on Gent and McWilliams, (1990) is adopted. The sensitivity of using various approaches in the thickness diffusion parameter ( Kgm) for this

  10. Space Radar Image of North Atlantic Ocean

    NASA Image and Video Library

    1999-04-15

    This is a radar image showing surface features on the open ocean in the northeast Atlantic Ocean. There is no land mass in this image. The purple line in the lower left of the image is the stern wake of a ship. The ship creating the wake is the bright white spot on the middle, left side of the image. The ship's wake is about 28 kilometers (17 miles) long in this image and investigators believe that is because the ship may be discharging oil. The oil makes the wake last longer and causes it to stand out in this radar image. A fairly sharp boundary or front extends from the lower left to the upper right corner of the image and separates two distinct water masses that have different temperatures. The different water temperature affects the wind patterns on the ocean. In this image, the light green area depicts rougher water with more wind, while the purple area is calmer water with less wind. The dark patches are smooth areas of low wind, probably related to clouds along the front, and the bright green patches are likely due to ice crystals in the clouds that scatter the radar waves. The overall "fuzzy" look of this image is caused by long ocean waves, also called swells. Ocean radar imagery allows the fine detail of ocean features and interactions to be seen, such as the wake, swell, ocean front and cloud effects, which can then be used to enhance the understanding of ocean dynamics on smaller and smaller scales. The image is centered at 42.8 degrees north latitude, 26.2 degrees west longitude and shows an area approximately 35 kilometers by 65 kilometers (22 by 40 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, horizontally received; blue is L-band vertically transmitted, vertically received. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR

  11. Space Radar Image of North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image showing surface features on the open ocean in the northeast Atlantic Ocean. There is no land mass in this image. The purple line in the lower left of the image is the stern wake of a ship. The ship creating the wake is the bright white spot on the middle, left side of the image. The ship's wake is about 28 kilometers (17 miles) long in this image and investigators believe that is because the ship may be discharging oil. The oil makes the wake last longer and causes it to stand out in this radar image. A fairly sharp boundary or front extends from the lower left to the upper right corner of the image and separates two distinct water masses that have different temperatures. The different water temperature affects the wind patterns on the ocean. In this image, the light green area depicts rougher water with more wind, while the purple area is calmer water with less wind. The dark patches are smooth areas of low wind, probably related to clouds along the front, and the bright green patches are likely due to ice crystals in the clouds that scatter the radar waves. The overall 'fuzzy' look of this image is caused by long ocean waves, also called swells. Ocean radar imagery allows the fine detail of ocean features and interactions to be seen, such as the wake, swell, ocean front and cloud effects, which can then be used to enhance the understanding of ocean dynamics on smaller and smaller scales. The image is centered at 42.8 degrees north latitude, 26.2 degrees west longitude and shows an area approximately 35 kilometers by 65 kilometers (22 by 40 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, horizontally received; blue is L-band vertically transmitted, vertically received. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR

  12. Southwest Atlantic Ocean Marathon Expedition, Leg 8.

    DTIC Science & Technology

    1986-07-01

    1150.1 2.649 2.770 84 37 27 407 82 778 27.400 7 9 12.210 78 6 1450.2 .2 1171.0 1160 0 2612 2.733 S4 379 27 413 2. 031 27 406 73, 12.214 79654. 1400.2 16.2...AD-R?2 192 SOUTHWEST ATLANTIC OCEAN MARATHON EXPEDITION LEG 9 (U) 1/5MASHINGTON UNIV SEATTLE DEPT OF OC ANOGRAPHY G 1 RODEN ET AL. JUL 86 NISSt4- 84 ...S 41 0.8 W AWS.0 1004.0 22.0o 240 16.1 15.6 30 OCT 84 8 37 40.3 S 41 0.6 W 5035.0 106.8 30.0 o350 17.0 13.8 ~ so OCT 84 9 38 0.4 S 42 0.5 W 5064.0

  13. Plankton respiration in the Eastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Robinson, Carol; Serret, Pablo; Tilstone, Gavin; Teira, Eva; Zubkov, Mikhail V.; Rees, Andrew P.; Woodward, E. Malcolm S.

    2002-05-01

    Concurrent measurements of dark community respiration (DCR), gross production (GP), size fractionated primary production ( 14C PP), nitrogen uptake, nutrients, chlorophyll a concentration, and heterotrophic and autotrophic bacterial abundance were collected from the upper 200 m of a latitudinal (32°S-48°N) transect in the Eastern Atlantic Ocean during May/June 1998. The mean mixed layer respiration rate was 2.5±2.1 mmol O 2 m -3 d -1 ( n=119) for the whole transect, 2.2±1.1 mmol O 2 m -3 d -1 ( n=32) in areas where chlorophyll a was <0.5 mg m -3 and 1.5±0.7 mmol O 2 m -3 d -1 ( n=10) where chlorophyll a was <0.2 mg m -3. These values lie within the range of published data collected in comparable waters, they co-vary with indicators of heterotrophic and autotrophic biomass (heterotrophic bacterial abundance, chlorophyll a concentration, beam attenuation and particulate organic carbon concentration) and they can be reconciled with accepted estimates of total respiratory activity. The mean and median respiratory quotient (RQ), calculated as the ratio of dissolved inorganic carbon production to dissolved oxygen consumption, was 0.8 ( n=11). At the time of the study, plankton community respiration exceeded GP in the picoautotroph dominated oligotrophic regions (Eastern Tropical Atlantic [15.5°S-14.2°N] and North Atlantic Subtropical Gyre [21.5-42.5°N]), which amounted to 50% of the stations sampled along the 12,100 km transect. These regions also exhibited high heterotrophic: autotrophic biomass ratios, higher turnover rates of phytoplankton than of bacteria and low f ratios. However, the carbon supply mechanisms required to sustain the rates of respiration higher than GP could not be fully quantified. Future research should aim to determine the temporal balance of respiration and GP together with substrate supply mechanisms in these ocean regions.

  14. NAO and extreme ocean states in the Northeast Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gleeson, Emily; Gallagher, Sarah; Clancy, Colm; Dias, Frédéric

    2017-02-01

    Large scale atmospheric oscillations are known to have an influence on waves in the North Atlantic. In quantifying how the wave and wind climate of this region may change towards the end of the century due to climate change, it is useful to investigate the influence of large scale oscillations using indices such as the North Atlantic Oscillation (NAO: fluctuations in the difference between the Icelandic low pressure system and the Azore high pressure system). In this study a statistical analysis of the station-based NAO index was carried out using an ensemble of EC-Earth global climate simulations, where EC-Earth is a European-developed atmosphere ocean sea-ice coupled climate model. The NAO index was compared to observations and to projected changes in the index by the end of the century under the RCP4.5 and RCP8.5 forcing scenarios. In addition, an ensemble of EC-Earth driven WAVEWATCH III wave model projections over the North Atlantic was analysed to determine the correlations between the NAO and significant wave height (Hs) and the NAO and extreme ocean states. For the most part, no statistically significant differences were found between the distributions of observed and modelled station-based NAO or in projected distributions of the NAO. Means and extremes of Hs are projected to decrease on average by the end of this century. The 95th percentile of Hs is strongly positively correlated to the NAO. Projections of Hs extremes are location dependent and in fact, under the influence of positive NAO the 20-year return levels of Hs were found to be amplified in some regions. However, it is important to note that the projected decreases in the 95th percentile of Hs off the west coast of Ireland are not statistically significant in one of the RCP4.5 and one of the RCP8.5 simulations (me41, me83) which indicates that there is still uncertainty in the projections of higher percentiles.

  15. North Atlantic forcing of tropical Indian Ocean climate.

    PubMed

    Mohtadi, Mahyar; Prange, Matthias; Oppo, Delia W; De Pol-Holz, Ricardo; Merkel, Ute; Zhang, Xiao; Steinke, Stephan; Lückge, Andreas

    2014-05-01

    The response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells, but the dearth of high-resolution records outside the monsoon realm in the Indian Ocean precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian Ocean. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian Ocean for the past 45,000 years, combined with climate model simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian Ocean hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian Ocean realm and wet and warm conditions in the southern realm during North Atlantic cold spells.

  16. Interannual atmospheric variability forced by the deep equatorial Atlantic Ocean.

    PubMed

    Brandt, Peter; Funk, Andreas; Hormann, Verena; Dengler, Marcus; Greatbatch, Richard J; Toole, John M

    2011-05-26

    Climate variability in the tropical Atlantic Ocean is determined by large-scale ocean-atmosphere interactions, which particularly affect deep atmospheric convection over the ocean and surrounding continents. Apart from influences from the Pacific El Niño/Southern Oscillation and the North Atlantic Oscillation, the tropical Atlantic variability is thought to be dominated by two distinct ocean-atmosphere coupled modes of variability that are characterized by meridional and zonal sea-surface-temperature gradients and are mainly active on decadal and interannual timescales, respectively. Here we report evidence that the intrinsic ocean dynamics of the deep equatorial Atlantic can also affect sea surface temperature, wind and rainfall in the tropical Atlantic region and constitutes a 4.5-yr climate cycle. Specifically, vertically alternating deep zonal jets of short vertical wavelength with a period of about 4.5 yr and amplitudes of more than 10 cm s(-1) are observed, in the deep Atlantic, to propagate their energy upwards, towards the surface. They are linked, at the sea surface, to equatorial zonal current anomalies and eastern Atlantic temperature anomalies that have amplitudes of about 6 cm s(-1) and 0.4 °C, respectively, and are associated with distinct wind and rainfall patterns. Although deep jets are also observed in the Pacific and Indian oceans, only the Atlantic deep jets seem to oscillate on interannual timescales. Our knowledge of the persistence and regularity of these jets is limited by the availability of high-quality data. Despite this caveat, the oscillatory behaviour can still be used to improve predictions of sea surface temperature in the tropical Atlantic. Deep-jet generation and upward energy transmission through the Equatorial Undercurrent warrant further theoretical study.

  17. AtlantOS - Optimizing and Enhancing the Integrated Atlantic Ocean Observing System

    NASA Astrophysics Data System (ADS)

    Reitz, Anja; Visbeck, Martin; AtlantOS Consortium, the

    2016-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements of heterogeneous international, national and regional design to support science and a wide range of information products. Thus there is tremendous opportunity to develop the systems towards a fully integrated Atlantic Ocean Observing System consistent with the recently developed 'Framework of Ocean Observing'. The vision of AtlantOS is to improve and innovate Atlantic observing by using the Framework of Ocean Observing to obtain an international, more sustainable, more efficient, more integrated, and fit-for-purpose system. Hence, the AtlantOS initiative will have a long-lasting and sustainable contribution to the societal, economic and scientific benefit arising from this integrated approach. This will be delivered by improving the value for money, extent, completeness, quality and ease of access to Atlantic Ocean data required by industries, product supplying agencies, scientist and citizens. The overarching target of the AtlantOS initiative is to deliver an advanced framework for the development of an integrated Atlantic Ocean Observing System that goes beyond the state-of -the-art, and leaves a legacy of sustainability after the life of the project. The legacy will derive from the following aims: i) to improve international collaboration in the design, implementation and benefit sharing of ocean observing, ii) to promote engagement and innovation in all aspects of ocean observing, iii) to facilitate free and open access to ocean data and information, iv) to enable and disseminate methods of achieving quality and authority of ocean information, v) to strengthen the Global Ocean Observing System (GOOS) and to sustain observing systems that are critical for the Copernicus Marine Environment Monitoring Service and its applications and vi) to contribute to the aims of the Galway Statement on Atlantic

  18. Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean.

    PubMed

    Cunningham, Stuart A; Roberts, Christopher D; Frajka-Williams, Eleanor; Johns, William E; Hobbs, Will; Palmer, Matthew D; Rayner, Darren; Smeed, David A; McCarthy, Gerard

    2013-12-16

    [1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales.

  19. Changes in North Atlantic nitrogen fixation controlled by ocean circulation.

    PubMed

    Straub, Marietta; Sigman, Daniel M; Ren, Haojia; Martínez-García, Alfredo; Meckler, A Nele; Hain, Mathis P; Haug, Gerald H

    2013-09-12

    In the ocean, the chemical forms of nitrogen that are readily available for biological use (known collectively as 'fixed' nitrogen) fuel the global phytoplankton productivity that exports carbon to the deep ocean. Accordingly, variation in the oceanic fixed nitrogen reservoir has been proposed as a cause of glacial-interglacial changes in atmospheric carbon dioxide concentration. Marine nitrogen fixation, which produces most of the ocean's fixed nitrogen, is thought to be affected by multiple factors, including ocean temperature and the availability of iron and phosphorus. Here we reconstruct changes in North Atlantic nitrogen fixation over the past 160,000 years from the shell-bound nitrogen isotope ratio ((15)N/(14)N) of planktonic foraminifera in Caribbean Sea sediments. The observed changes cannot be explained by reconstructed changes in temperature, the supply of (iron-bearing) dust or water column denitrification. We identify a strong, roughly 23,000-year cycle in nitrogen fixation and suggest that it is a response to orbitally driven changes in equatorial Atlantic upwelling, which imports 'excess' phosphorus (phosphorus in stoichiometric excess of fixed nitrogen) into the tropical North Atlantic surface. In addition, we find that nitrogen fixation was reduced during glacial stages 6 and 4, when North Atlantic Deep Water had shoaled to become glacial North Atlantic intermediate water, which isolated the Atlantic thermocline from excess phosphorus-rich mid-depth waters that today enter from the Southern Ocean. Although modern studies have yielded diverse views of the controls on nitrogen fixation, our palaeobiogeochemical data suggest that excess phosphorus is the master variable in the North Atlantic Ocean and indicate that the variations in its supply over the most recent glacial cycle were dominated by the response of regional ocean circulation to the orbital cycles.

  20. 78 FR 34879 - Special Local Regulations for Marine Events, Atlantic City Offshore Race, Atlantic Ocean...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    .... The marine event formerly originated on the third Sunday in July, but now is on the fourth Sunday in... Sunday in July on the waters of the Atlantic Ocean at Atlantic City, New Jersey. The regulation listing.... The date listed in the Table has the marine event on the third Sunday in July. However, this temporary...

  1. /sup 14/C distribution in the Atlantic Ocean

    SciTech Connect

    Stuiver, M.

    1980-05-20

    The amount of /sup 14/C produced by nuclear bomb testing that entered the Atlantic Ocean by late 1972 was 1.71 x 10/sup -8/ ..mu..mol/cm/sup 2/ of ocean surface area for the west Atlantic (36/sup 0/S-45/sup 0/N) and 1.18 x 10/sup -8/ ..mu..mol/cm/sup 2/ for the east Atlantic (50/sup 0/S-28/sup 0/N) Geochemical Ocean Sections Study stations. There are strong latitudinal differences in the integrated amount of bomb /sup 14/C content in Atlantic waters. Bomb-produced /sup 14/C is mostly encountered near the center of the large mid-latitude gyres, whereas the equatorial region has a lower /sup 14/C inventory. The average ocean wide vertical distribution of bomb /sup 14/C in the Atlantic can be explained by a vertical eddy diffusion coefficient of 4.0 cm/sup 2//s in the surface mixed layer plus thermocline gyre reservoirs. The average /sup 14/C activity per unit area measured in the Atlantic yields an atmosphere-ocean CO/sub 2/ exchange rate of 23 mol/m/sup 2/ yr, which is equivalent with an atmospheric CO/sub 2/ residence time of 6.8 years.

  2. Open ocean dead zones in the tropical North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Karstensen, J.; Fiedler, B.; Schütte, F.; Brandt, P.; Körtzinger, A.; Fischer, G.; Zantopp, R.; Hahn, J.; Visbeck, M.; Wallace, D.

    2015-04-01

    Here we present first observations, from instrumentation installed on moorings and a float, of unexpectedly low (<2 μmol kg-1) oxygen environments in the open waters of the tropical North Atlantic, a region where oxygen concentration does normally not fall much below 40 μmol kg-1. The low-oxygen zones are created at shallow depth, just below the mixed layer, in the euphotic zone of cyclonic eddies and anticyclonic-modewater eddies. Both types of eddies are prone to high surface productivity. Net respiration rates for the eddies are found to be 3 to 5 times higher when compared with surrounding waters. Oxygen is lowest in the centre of the eddies, in a depth range where the swirl velocity, defining the transition between eddy and surroundings, has its maximum. It is assumed that the strong velocity at the outer rim of the eddies hampers the transport of properties across the eddies boundary and as such isolates their cores. This is supported by a remarkably stable hydrographic structure of the eddies core over periods of several months. The eddies propagate westward, at about 4 to 5 km day-1, from their generation region off the West African coast into the open ocean. High productivity and accompanying respiration, paired with sluggish exchange across the eddy boundary, create the "dead zone" inside the eddies, so far only reported for coastal areas or lakes. We observe a direct impact of the open ocean dead zones on the marine ecosystem as such that the diurnal vertical migration of zooplankton is suppressed inside the eddies.

  3. Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa; Rhines, Peter B.; Worthlen, Denise L.

    2011-01-01

    Based on the 20th century atmospheric reanalysis, winters with more frequent blocking, in a band of blocked latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability. Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by impacting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially, 1996-2010). It also describes much longer-timescale Atlantic multidecadal ocean variability (AMV), including the extreme, pre-greenhouse-gas, northern warming of the 1930s-1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat-exchange, both of which contribute to the warm phase of AMV.

  4. The distribution of dissolved iron in the West Atlantic Ocean.

    PubMed

    Rijkenberg, Micha J A; Middag, Rob; Laan, Patrick; Gerringa, Loes J A; van Aken, Hendrik M; Schoemann, Véronique; de Jong, Jeroen T M; de Baar, Hein J W

    2014-01-01

    Iron (Fe) is an essential trace element for marine life. Extremely low Fe concentrations limit primary production and nitrogen fixation in large parts of the oceans and consequently influence ocean ecosystem functioning. The importance of Fe for ocean ecosystems makes Fe one of the core chemical trace elements in the international GEOTRACES program. Despite the recognized importance of Fe, our present knowledge of its supply and biogeochemical cycle has been limited by mostly fragmentary datasets. Here, we present highly accurate dissolved Fe (DFe) values measured at an unprecedented high intensity (1407 samples) along the longest full ocean depth transect (17,500 kilometers) covering the entire western Atlantic Ocean. DFe measurements along this transect unveiled details about the supply and cycling of Fe. External sources of Fe identified included off-shelf and river supply, hydrothermal vents and aeolian dust. Nevertheless, vertical processes such as the recycling of Fe resulting from the remineralization of sinking organic matter and the removal of Fe by scavenging still dominated the distribution of DFe. In the northern West Atlantic Ocean, Fe recycling and lateral transport from the eastern tropical North Atlantic Oxygen Minimum Zone (OMZ) dominated the DFe-distribution. Finally, our measurements showed that the North Atlantic Deep Water (NADW), the major driver of the so-called ocean conveyor belt, contains excess DFe relative to phosphate after full biological utilization and is therefore an important source of Fe for biological production in the global ocean.

  5. The Distribution of Dissolved Iron in the West Atlantic Ocean

    PubMed Central

    Rijkenberg, Micha J. A.; Middag, Rob; Laan, Patrick; Gerringa, Loes J. A.; van Aken, Hendrik M.; Schoemann, Véronique; de Jong, Jeroen T. M.; de Baar, Hein J. W.

    2014-01-01

    Iron (Fe) is an essential trace element for marine life. Extremely low Fe concentrations limit primary production and nitrogen fixation in large parts of the oceans and consequently influence ocean ecosystem functioning. The importance of Fe for ocean ecosystems makes Fe one of the core chemical trace elements in the international GEOTRACES program. Despite the recognized importance of Fe, our present knowledge of its supply and biogeochemical cycle has been limited by mostly fragmentary datasets. Here, we present highly accurate dissolved Fe (DFe) values measured at an unprecedented high intensity (1407 samples) along the longest full ocean depth transect (17500 kilometers) covering the entire western Atlantic Ocean. DFe measurements along this transect unveiled details about the supply and cycling of Fe. External sources of Fe identified included off-shelf and river supply, hydrothermal vents and aeolian dust. Nevertheless, vertical processes such as the recycling of Fe resulting from the remineralization of sinking organic matter and the removal of Fe by scavenging still dominated the distribution of DFe. In the northern West Atlantic Ocean, Fe recycling and lateral transport from the eastern tropical North Atlantic Oxygen Minimum Zone (OMZ) dominated the DFe-distribution. Finally, our measurements showed that the North Atlantic Deep Water (NADW), the major driver of the so-called ocean conveyor belt, contains excess DFe relative to phosphate after full biological utilization and is therefore an important source of Fe for biological production in the global ocean. PMID:24978190

  6. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Northwest Atlantic Ocean fishery. 600.520 Section 600.520 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND...—(1) Allocations. Foreign vessels may engage in fishing only in accordance with applicable...

  7. Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Atmospheric blocking over the northern North Atlantic involves isolation of large regions of air from the westerly circulation for 5-14 days or more. From a recent 20th century atmospheric reanalysis (1,2) winters with more frequent blocking persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability (AMV). Ocean circulation is forced by wind-stress curl and related air/sea heat exchange, and we find that their space-time structure is associated with dominant blocking patterns: weaker ocean gyres and weaker heat exchange contribute to the warm phase of AMV. Increased blocking activity extending from Greenland to British Isles is evident when winter blocking days of the cold years (1900-1929) are subtracted from those of the warm years (1939-1968).

  8. Cloud Streets over the Atlantic Ocean

    NASA Image and Video Library

    2017-09-27

    In the midst of a cold snap that sent temperatures 20–40°F (11–22°C) below normal across much of the United States, the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite captured this image of cloud streets over the Atlantic Ocean on January 7, 2014. Cloud streets—long parallel bands of cumulus clouds—form when cold air blows over warmer waters and a warmer air layer (or temperature inversion) rests over the top of both. The comparatively warm water gives up heat and moisture to the cold air above, and columns of heated air called thermals naturally rise through the atmosphere. The temperature inversion acts like a lid, so when the rising thermals hit it, they roll over and loop back on themselves, creating parallel cylinders of rotating air. As this happens, the moisture cools and condenses into flat-bottomed, fluffy-topped cumulus clouds that line up parallel to the direction of the prevailing wind. On January 7, the winds were predominantly out of the northwest. Cloud streets can stretch for hundreds of kilometers if the land or water surface underneath is uniform. Sea surface temperature need to be at least 40°F (22°C) warmer than the air for cloud streets to form. More info: earthobservatory.nasa.gov/NaturalHazards/view.php?id=82800 NASA Earth Observatory image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC. Caption by Adam Voiland. Instrument: Terra - MODIS Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  9. Atlantic Ocean CARINA data: overview and salinity adjustments

    SciTech Connect

    Tanhua, T.; Steinfeldt, R.; Key, Robert; Brown, P.; Gruber, N.; Wanninkhof, R.; Perez, F.F.; Kortzinger, A.; Velo, A.; Schuster, U.; Van Heuven, S.; Bullister, J.L.; Stendardo, I.; Hoppema, M.; Olsen, Are; Kozyr, Alexander; Pierrot, D.; Schirnick, C.; Wallace, D.W.R.

    2010-01-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30 S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control) for salinity for this data set. Procedures of quality control including crossover analysis between stations and inversion analysis of all crossover data are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally was well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, oceanic carbon inventories

  10. Atlantic Ocean CARINA data: overview and salinity adjustments

    NASA Astrophysics Data System (ADS)

    Tanhua, T.; Steinfeldt, R.; Key, R. M.; Brown, P.; Gruber, N.; Wanninkhof, R.; Perez, F.; Körtzinger, A.; Velo, A.; Schuster, U.; van Heuven, S.; Bullister, J. L.; Stendardo, I.; Hoppema, M.; Olsen, A.; Kozyr, A.; Pierrot, D.; Schirnick, C.; Wallace, D. W. R.

    2010-02-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control) for salinity for this data set. Procedures of quality control - including crossover analysis between stations and inversion analysis of all crossover data - are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, oceanic carbon

  11. Toxic Trichodesmium bloom occurrence in the southwestern South Atlantic Ocean.

    PubMed

    Sacilotto Detoni, Amália Maria; Costa, Luiza Dy Fonseca; Pacheco, Lucas Abrão; Yunes, João Sarkis

    2016-02-01

    Harmful Trichodesmium blooms have been reported on the continental slope of the southwestern South Atlantic Ocean; we sampled six such blooms. The highest saxitoxin concentration was observed where the number of colonies was proportionally greater relative to the total density of trichomes. Trichodesmium blooms are harmful to shrimp larvae and may lead to plankton community mortality. This study is the first record of neurotoxic blooms in the open waters of the South Atlantic. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. An updated anthropogenic CO2 inventory in the Atlantic Ocean

    SciTech Connect

    Lee, K.; Choi, S.-D.; Park, G.-H.; Peng, T.-H.; Key, Robert; Sabine, Chris; Feely, R. A.; Bullister, J.L.; Millero, F. J.; Kozyr, Alexander

    2003-01-01

    This paper presents a comprehensive analysis of the basin-wide inventory of anthropogenic CO2 in the Atlantic Ocean based on high-quality inorganic carbon, alkalinity, chlorofluorocarbon, and nutrient data collected during the World Ocean Circulation Experiment (WOCE) Hydrographic Program, the Joint Global Ocean Flux Study (JGOFS), and the Ocean-Atmosphere Carbon Exchange Study (OACES) surveys of the Atlantic Ocean between 1990 and 1998. Anthropogenic CO2 was separated from the large pool of dissolved inorganic carbon using an extended version of the DC* method originally developed by Gruber et al. [1996]. The extension of the method includes the use of an optimum multiparameter analysis to determine the relative contributions from various source water types to the sample on an isopycnal surface. Total inventories of anthropogenic CO2 in the Atlantic Ocean are highest in the subtropical regions at 20 40, whereas anthropogenic CO2 penetrates the deepest in high-latitude regions (>40N). The deeper penetration at high northern latitudes is largely due to the formation of deep water that feeds the Deep Western Boundary Current, which transports anthropogenic CO2 into the interior. In contrast, waters south of 50S in the Southern Ocean contain little anthropogenic CO2. Analysis of the data collected during the 1990 1998 period yielded a total anthropogenic CO2 inventory of 28.4 4.7 Pg C in the North Atlantic (equator-70N) and of 18.5 3.9 Pg C in the South Atlantic (equator-70S). These estimated basin-wide inventories of anthropogenic CO2 are in good agreement with previous estimates obtained by Gruber [1998], after accounting for the difference in observational periods. Our calculation of the anthropogenic CO2 inventory in the Atlantic Ocean, in conjunction with the inventories calculated previously for the Indian Ocean [Sabine et al., 1999] and for the Pacific Ocean [Sabine et al., 2002], yields a global anthropogenic CO2 inventory of 112 17 Pg C that has accumulated

  13. Atlantic Ocean CARINA data: overview and salinity adjustments

    NASA Astrophysics Data System (ADS)

    Tanhua, T.; Steinfeldt, R.; Key, R. M.; Brown, P.; Gruber, N.; Wanninkhof, R.; Perez, F.; Körtzinger, A.; Velo, A.; Schuster, U.; van Heuven, S.; Bullister, J. L.; Stendardo, I.; Hoppema, M.; Olsen, A.; Kozyr, A.; Pierrot, D.; Schirnick, C.; Wallace, D. W. R.

    2009-08-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. Arctic, Atlantic and Southern Ocean. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report details of the secondary QC for salinity for this data set. Procedures of quality control - including crossover analysis between stations and inversion analysis of all crossover data - are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal accuracy of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s (Key et al., 2004), and is now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

  14. Interactions between sea surface temperature over the South Atlantic Ocean and the South Atlantic Convergence Zone

    NASA Astrophysics Data System (ADS)

    Chaves, Rosane Rodrigues; Nobre, Paulo

    2004-02-01

    Interactions between the sea surface temperature (SST) over the South Atlantic Ocean (40°S-Equador) and the South Atlantic Convergence Zone (SACZ) were studied through numerical experiments with an atmospheric general circulation model (AGCM) and an ocean general circulation model (OGCM). The AGCM experiments showed that warm SST anomalies over the South Atlantic tend to intensify the SACZ and shift it northward, while cool SST anomalies over the South Atlantic tend to weaken the SACZ. The OGCM experiments, on the other hand, showed that the intensification of the SACZ contributes to cool the underlying ocean through the reduction of incident shortwave solar radiation, causing the appearance of cold SST anomalies or the weakening of pre-existing warm SST anomalies. The most important finding in this work was the predominance of the cloud/shortwave - SST negative thermodynamic feedback between the atmosphere and the ocean over the southwest tropical Atlantic, this is one order of magnitude larger than the dynamic feedback associated with Ekman pumping. The latter was verified only during strong SACZ events. The results suggest that negative SST anomalies often observed underlying the SACZ represent an ocean response to atmospheric forcing.

  15. Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    de Souza, Gregory F.; Reynolds, Ben C.; Rickli, Jörg; Frank, Martin; Saito, Mak A.; Gerringa, Loes J. A.; Bourdon, Bernard

    2012-06-01

    The fractionation of silicon (Si) stable isotopes by biological activity in the surface ocean makes the stable isotope composition of silicon (δ30Si) dissolved in seawater a sensitive tracer of the oceanic biogeochemical Si cycle. We present a high-precision dataset that characterizes the δ30Si distribution in the deep Atlantic Ocean from Denmark Strait to Drake Passage, documenting strong meridional and smaller, but resolvable, vertical δ30Si gradients. We show that these gradients are related to the two sources of deep and bottom waters in the Atlantic Ocean: waters of North Atlantic and Nordic origin carry a high δ30Si signature of ≥+1.7‰ into the deep Atlantic, while Antarctic Bottom Water transports Si with a low δ30Si value of around +1.2‰. The deep Atlantic δ30Si distribution is thus governed by the quasi-conservative mixing of Si from these two isotopically distinct sources. This disparity in Si isotope composition between the North Atlantic and Southern Ocean is in marked contrast to the homogeneity of the stable nitrogen isotope composition of deep ocean nitrate (δ15N-NO3). We infer that the meridional δ30Si gradient derives from the transport of the high δ30Si signature of Southern Ocean intermediate/mode waters into the North Atlantic by the upper return path of the meridional overturning circulation (MOC). The basin-scale deep Atlantic δ30Si gradient thus owes its existence to the interaction of the physical circulation with biological nutrient uptake at high southern latitudes, which fractionates Si isotopes between the abyssal and intermediate/mode waters formed in the Southern Ocean.

  16. Chloromethane and dichloromethane in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kolusu, Seshagiri Rao; Schlünzen, K. Heinke; Grawe, David; Seifert, Richard

    2017-02-01

    Chloromethane and dichloromethane were measured in the air of marine environment and in seawater during a cruise from the Port of Spain to Rio de Janeiro in the tropical Atlantic Ocean in April and May of 2009. Variation of chloromethane and dichloromethane concentrations was analysed as a function of latitude. There is no correlation observed between chloromethane and dichloromethane concentrations in the seawater suggest that they may not have a common oceanic source. In addition, a relation of concentrations, fluxes and sea surface temperature were studied to determine a dependency of concentrations and fluxes on sea surface temperature. Sea surface temperature does not show any significant effect on dichloromethane concentrations in surface seawater. Chloromethane and dichloromethane are supersaturated in the seawater during the cruise. This implies that the tropical Atlantic Ocean emits chloromethane and dichloromethane into the atmosphere. The tropical Atlantic Ocean mean fluxes of chloromethane and dichloromethane during the cruise were 150 nmol m-2 d-1 and 81 nmol m-2 d-1, respectively. The backward trajectory analysis revealed that the tropical Atlantic Ocean and African coast were primary and secondary source regions for chloromethane and dichloromethane respectively, during the Meteor cruise.

  17. The Atlantic Multidecadal Oscillation without a role for ocean circulation.

    PubMed

    Clement, Amy; Bellomo, Katinka; Murphy, Lisa N; Cane, Mark A; Mauritsen, Thorsten; Rädel, Gaby; Stevens, Bjorn

    2015-10-16

    The Atlantic Multidecadal Oscillation (AMO) is a major mode of climate variability with important societal impacts. Most previous explanations identify the driver of the AMO as the ocean circulation, specifically the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot be the driver. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the characteristics of the AMO in the current generation of climate models. These results suggest that the AMO is the response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling playing a role in the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response to, not a cause of, the AMO. Copyright © 2015, American Association for the Advancement of Science.

  18. The Atlantic Multidecadal Oscillation without a role for ocean circulation

    NASA Astrophysics Data System (ADS)

    Clement, Amy; Bellomo, Katinka; Murphy, Lisa N.; Cane, Mark A.; Mauritsen, Thorsten; Rädel, Gaby; Stevens, Bjorn

    2015-10-01

    The Atlantic Multidecadal Oscillation (AMO) is a major mode of climate variability with important societal impacts. Most previous explanations identify the driver of the AMO as the ocean circulation, specifically the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot be the driver. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the characteristics of the AMO in the current generation of climate models. These results suggest that the AMO is the response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling playing a role in the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response to, not a cause of, the AMO.

  19. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded by...

  20. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of the...

  1. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port of...

  2. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port of...

  3. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of the...

  4. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port of...

  5. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port of...

  6. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of the...

  7. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded by...

  8. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of the...

  9. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded by...

  10. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded by...

  11. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded by...

  12. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of the...

  13. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port of...

  14. Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Bates, N. R.; Best, M. H. P.; Neely, K.; Garley, R.; Dickson, A. G.; Johnson, R. J.

    2012-01-01

    Fossil fuel use, cement manufacture and land-use changes are the primary sources of anthropogenic carbon dioxide (CO2) to the atmosphere, with the ocean absorbing 30 %. Ocean uptake and chemical equilibration of anthropogenic CO2with seawater results in a gradual reduction in seawater pH and saturation states (Ω) for calcium carbonate (CaCO3) minerals in a process termed ocean acidification. Assessing the present and future impact of ocean acidification on marine ecosystems requires detection of the multi-decadal rate of change across ocean basins and at ocean time-series sites. Here, we show the longest continuous record of ocean CO2 changes and ocean acidification in the North Atlantic subtropical gyre near Bermuda from 1983-2011. Dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2) increased in surface seawater by ~40 μmol kg-1 and ~50 μatm (~20 %), respectively. Increasing Revelle factor (β) values imply that the capacity of North Atlantic surface waters to absorb CO2 has also diminished. As indicators of ocean acidification, seawater pH decreased by ~0.05 (0.0017 yr-1) and Ω values by ~7-8 %. Such data provide critically needed multi-decadal information for assessing the North Atlantic Ocean CO2sink and the pH changes that determine marine ecosystem responses to ocean acidification.

  15. Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Bates, N. R.; Best, M. H. P.; Neely, K.; Garley, R.; Dickson, A. G.; Johnson, R. J.

    2012-07-01

    Fossil fuel use, cement manufacture and land-use changes are the primary sources of anthropogenic carbon dioxide (CO2) to the atmosphere, with the ocean absorbing approximately 30% (Sabine et al., 2004). Ocean uptake and chemical equilibration of anthropogenic CO2 with seawater results in a gradual reduction in seawater pH and saturation states (Ω) for calcium carbonate (CaCO3) minerals in a process termed ocean acidification. Assessing the present and future impact of ocean acidification on marine ecosystems requires detection of the multi-decadal rate of change across ocean basins and at ocean time-series sites. Here, we show the longest continuous record of ocean CO2 changes and ocean acidification in the North Atlantic subtropical gyre near Bermuda from 1983-2011. Dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2) increased in surface seawater by ~40 μmol kg-1 and ~50 μatm (~20%), respectively. Increasing Revelle factor (β) values imply that the capacity of North Atlantic surface waters to absorb CO2 has also diminished. As indicators of ocean acidification, seawater pH decreased by ~0.05 (0.0017 yr-1) and ω values by ~7-8%. Such data provide critically needed multi-decadal information for assessing the North Atlantic Ocean CO2 sink and the pH changes that determine marine ecosystem responses to ocean acidification.

  16. Dynamics of upwelling annual cycle in the equatorial Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Wang, Li-Chiao; Jin, Fei-Fei; Wu, Chau-Ron; Hsu, Huang-Hsiung

    2017-04-01

    The annual upwelling is an important component of the equatorial Atlantic annual cycle. A simple theory is proposed using the framework of Zebiak-Cane (ZC) ocean model for insights into the dynamics of the upwelling annual cycle. It is demonstrated that in the Atlantic equatorial region this upwelling is dominated by Ekman processing in the west, whereas in the east it is primarily owing to shoaling and deepening of the thermocline resulting from equatorial mass meridional recharge/discharge and zonal redistribution processes associated with wind-driven equatorial ocean waves. This wind-driven wave upwelling plays an important role in the development of the annual cycle in the sea surface temperature of the cold tongue in the eastern equatorial Atlantic.

  17. Cloud formation over Western Atlantic Ocean north of South America

    NASA Image and Video Library

    1962-10-03

    S62-06606 (3 Oct. 1962) --- Cloud formation over Western Atlantic Ocean north of South America taken during the fourth orbit pass of the Mercury-Atlas 8 (MA-8) mission by astronaut Walter M. Schirra Jr. with a hand-held camera. Photo credit: NASA

  18. Brazil, Atlantic Ocean, Africa, Sahara & Antarctica seen from Apollo 4

    NASA Image and Video Library

    1967-11-09

    AS04-01-410 (9 Nov. 1967) --- Coastal Brazil, Atlantic Ocean, West Africa, Sahara, Antarctica, looking west, as photographed from the Apollo 4 (Spacecraft 017/Saturn 501) unmanned, Earth-orbital space mission. This picture was taken when the Spacecraft 017 and Saturn S-IVB (third) stage were orbiting Earth at an altitude of 9,745 nautical miles.

  19. Eight centuries of north atlantic ocean atmosphere variability

    PubMed

    Black; Peterson; Overpeck; Kaplan; Evans; Kashgarian

    1999-11-26

    Climate in the tropical North Atlantic is controlled largely by variations in the strength of the trade winds, the position of the Intertropical Convergence Zone, and sea surface temperatures. A high-resolution study of Caribbean sediments provides a subdecadally resolved record of tropical upwelling and trade wind variability spanning the past 825 years. These results confirm the importance of a decadal (12- to 13-year) mode of Atlantic variability believed to be driven by coupled tropical ocean-atmosphere dynamics. Although a well-defined interdecadal mode of variability does not appear to be characteristic of the tropical Atlantic, there is evidence that century-scale variability is substantial. The tropical Atlantic may also have been involved in a major shift in Northern Hemisphere climate variability that took place about 700 years ago.

  20. CARINA TCO2 data in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Pierrot, D.; Brown, P.; van Heuven, S.; Tanhua, T.; Schuster, U.; Wanninkhof, R.; Key, R. M.

    2010-07-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged in a new data base: the CARINA (CARbon IN the Atlantic) Project. These data have gone through rigorous quality control (QC) procedures so as to improve the quality and consistency of the data as much as possible. Secondary quality control, which involved objective study of data in order to quantify systematic differences in the reported values, was performed for the pertinent parameters in the CARINA data base. Systematic biases in the data have been tentatively corrected in the data products. The products are three merged data files with measured, adjusted and interpolated data of all cruises for each of the three CARINA regions (Arctic Mediterranean Seas, Atlantic and Southern Ocean). Ninety-eight cruises were conducted in the "Atlantic" defined as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we report the details of the secondary QC which was done on the total dissolved inorganic carbon (TCO2) data and the adjustments that were applied to yield the final data product in the Atlantic. Procedures of quality control - including crossover analysis between stations and inversion analysis of all crossover data - are briefly described. Adjustments were applied to TCO2 measurements for 17 of the cruises in the Atlantic Ocean region. With these adjustments, the CARINA data base is consistent both internally as well as with GLODAP data, an oceanographic data set based on the WOCE Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, regional oceanic carbon inventories, uptake rates and model validation.

  1. CARINA TCO2 data in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Pierrot, D.; Brown, P.; van Heuven, S.; Tanhua, T.; Schuster, U.; Wanninkhof, R.; Key, R. M.

    2010-01-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic, Atlantic and Southern Ocean have been retrieved and merged in a new data base: the CARINA (CARbon IN the Atlantic) Project. These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. Secondary quality control, which involved objective study of data in order to quantify systematic differences in the reported values, was performed for the pertinent parameters in the CARINA data base. Systematic biases in the data have been corrected in the data products. The products are three merged data files with measured, adjusted and interpolated data of all cruises for each of the three CARINA regions (Arctic, Atlantic and Southern Ocean). Ninety-eight cruises were conducted in the "Atlantic" defined as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we report the details of the secondary QC which was done on the total dissolved inorganic carbon (TCO2) data and the adjustments that were applied to yield the final data product in the Atlantic. Procedures of quality control - including crossover analysis between stations and inversion analysis of all crossover data - are briefly described. Adjustments were applied to TCO2 measurements for 17 of the cruises in the Atlantic Ocean region. With these adjustments, the CARINA data base is consistent both internally as well as with GLODAP data, an oceanographic data set based on the WOCE Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, regional oceanic carbon inventories, uptake rates and model validation.

  2. Layered basic complex in oceanic crust, romanche fracture, equatorial atlantic ocean.

    PubMed

    Melson, W G; Thompson, G

    1970-05-15

    A layered, basic igneous intrusion, analogous in mineralogy and texture to certain large, continental layered complexes, is exposed in the Romanche Fracture, equatorial Atlantic Ocean. Crustal intrusion of large masses of basic magmas with their subsequent gravity differentiation is probably one of a number of major processes involved in the formation of new oceanic crust during sea-floor spreading.

  3. Eocene Temperature Evolution of the Tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cramwinckel, M.; Kocken, I.; Agnini, C.; Huber, M.; van der Ploeg, R.; Frieling, J.; Bijl, P.; Peterse, F.; Roehl, U.; Bohaty, S. M.; Schouten, S.; Sluijs, A.

    2016-12-01

    The transition from the early Eocene ( 50 Ma) hothouse towards the Oligocene ( 33 Ma) icehouse was interrupted by the Middle Eocene Climatic Optimum (MECO) ( 40 Ma), a 500,000-year long episode of deep sea and Southern Ocean warming. It remains unclear whether this transient warming event was global, and whether it was caused by changes in atmospheric greenhouse gas concentrations or confined to high latitudes resulting from ocean circulation change. Here we show, based on biomarker paleothermometry applied at Ocean Drilling Program Site 959, offshore Ghana, that sea surface temperatures in the eastern equatorial Atlantic Ocean declined by 7°C over the middle-late Eocene, in agreement with temperature trends documented in the southern high latitudes. In the equatorial Atlantic, this long-term trend was punctuated by 2.5°C warming during the MECO. At the zenith of MECO warmth, changes in dinoflagellate cyst assemblages and laminated sediments at Site 959 point to open ocean hyperstratification and seafloor deoxygenation, respectively. Remarkably, the data reveal that the magnitude of temperature change in the tropics was approximately half that in the Southern Ocean. This suggests that the generally ice free Eocene yielded limited but significant polar amplification of climate change. Crucially, general circulation model (GCM) simulations reveal that the recorded tropical and deep ocean temperature trends are best explained by greenhouse gas forcing, controlling both middle-late Eocene cooling and the superimposed MECO warming.

  4. Impact of the salt leakage through the Indian-Atlantic ocean gateway on the Atlantic MOC

    NASA Astrophysics Data System (ADS)

    Marino, G.; Zahn, R.; Ziveri, P.; Ziegler, M.; Hall, I. R.; Elderfield, H.

    2012-04-01

    Freshwater perturbation in the northern North Atlantic exerts a strong influence on the stability of the Atlantic meridional overturning circulation (AMOC) with potentially severe impacts on the regional and global climates. The occurrence of ice rafted detritus (IRD) in the glacial sediments of the North Atlantic testifies to past episodes of Laurentide ice sheet surging that also coincided with AMOC curtailments and prominent climate deterioration in the Northeast Atlantic and Western Europe. The equally abrupt warming shifts observed in Greenland ice core and North Atlantic sediment core records that characterize the end of each IRD event have been related to the rapid resumption of AMOC and its associated heat transport. The hysteresis response, under glacial boundary conditions, of the AMOC to freshwater forcing suggests that a reduction in this forcing may have been sufficient to trigger the rapid AMOC resumptions revealed by several palaeoceanographic records. But recent modelling studies allude to the potential importance of a salt surplus, originating in the Indian Ocean and transported to the South Atlantic via the Agulhas leakage, that may have acted as a positive feedback on the AMOC strengthening. This possibility, however, has yet to be adequately tested with palaeoproxy reconstructions. We present a suite of multi-centennial-scale palaeoceanographic records spanning a full glacial cycle from the Southwest African margin and Agulhas Plateau that have been generated as part of the EU Marie Curie GATEWAYS project. The sediment cores are positioned such that they monitor the leakage of Agulhas water into the Atlantic and the Agulhas Return Current that straddles the South Atlantic subtropical front on its way to the Indian Ocean. Paired Mg/Ca-δ18O analyses on the planktonic foraminifera Globigerinoides ruber and Globigerina bulloides reveal millennial-scale surface ocean temperature and salinity changes at the core sites that reflect recurrent

  5. CARINA (Carbon dioxide in the Atlantic Ocean) Data from CDIAC

    DOE Data Explorer

    The idea for CARINA developed at a workshop (CO2 in the northern North Atlantic) that was held at the HANSE-Wissenschaftskolleg (HANSE Institute for Advanced Study) in Delmenhorst, Germany from June 9 to 11, 1999. While the main scientific focus is the North Atlantic, some data from the South Atlantic have been included in the project, along with data from the Arctic Ocean. Data sets go back to 1972, and more than 100 are currently available. The data are also being used in conjunction with other projects and research groups, such as the Atlantic Ocean Carbon Synthesis Group. See the inventory of data at http://store.pangaea.de/Projects/CARBOOCEAN/carina/data_inventory.htm See a detailed table of information on the cruises at http://cdiac.ornl.gov/oceans/CARINA/Carina_table.html and also provides access to data files. The CARBOOCEAN data portal provides a specialized interface for CARINA data, a reference list for historic carbon data, and password protected access to the "Data Underway Warehouse.".

  6. Multidecadal variability and climate shift in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Seidov, Dan; Mishonov, Alexey; Reagan, James; Parsons, Rost

    2017-05-01

    Decadal variability of ocean heat content (OHC) and temperature trends over 60 years in the North Atlantic Ocean were analyzed using a new high-resolution ocean climatology based on quality-controlled historic in situ observations. Two 30 year ocean climates of 1955-1984 and 1985-2012 were compared to evaluate the climate shift in this region. The spatial distribution of the OHC climate shift is highly inhomogeneous, with the climate shift being the strongest southeast of the Gulf Stream Extension. This may be caused by the Atlantic Meridional Overturning Circulation slowdown in conjunction with heaving of warm subtropical water. The 30 year climate shift shows higher OHC gain in the Gulf Stream region than reported in shorter timescale estimates. The OHC change is generally coherent with the Atlantic Multidecadal Oscillation index. This coherence suggests that quasi-cyclicity of the OHC may exist, with a period of 60 to 80 years, superimposed on the slow basin-wide warming trend.

  7. Quantification of dissolved iron sources to the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Conway, Tim M.; John, Seth G.

    2014-07-01

    Dissolved iron is an essential micronutrient for marine phytoplankton, and its availability controls patterns of primary productivity and carbon cycling throughout the oceans. The relative importance of different sources of iron to the oceans is not well known, however, and flux estimates from atmospheric dust, hydrothermal vents and oceanic sediments vary by orders of magnitude. Here we present a high-resolution transect of dissolved stable iron isotope ratios (δ56Fe) and iron concentrations ([Fe]) along a section of the North Atlantic Ocean. The different iron sources can be identified by their unique δ56Fe signatures, which persist throughout the water column. This allows us to calculate the relative contribution from dust, hydrothermal venting and reductive and non-reductive sedimentary release to the dissolved phase. We find that Saharan dust aerosol is the dominant source of dissolved iron along the section, contributing 71-87 per cent of dissolved iron. Additional sources of iron are non-reductive release from oxygenated sediments on the North American margin (10-19 per cent), reductive sedimentary dissolution on the African margin (1-4 per cent) and hydrothermal venting at the Mid-Atlantic Ridge (2-6 per cent). Our data also indicate that hydrothermal vents in the North Atlantic are a source of isotopically light iron, which travels thousands of kilometres from vent sites, potentially influencing surface productivity. Changes in the relative importance of the different iron sources through time may affect interactions between the carbon cycle and climate.

  8. Modeling Mesoscale Eddies in the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Chao, Yi

    1999-01-01

    Ocean modeling plays an important role in understanding the current climatic conditions and predicting the future climate change. Modeling the ocean at eddy-permitting and/or eddy resolving resolutions (1/3 degree or higher) has a two-fold objective. One part is to represent the ocean as realistically as possible, because mesoscale eddies have an impact on the large-scale circulation. The second objective is to learn how to represent effects of mesoscale eddies without explicitly resolving them. This is particularly important for climate models which cannot be run at eddy-resolving resolutions because of the computational constraints. At JPL, a 1/6 degree latitude by 1/6 degree longitude with 37 vertical levels Atlantic Ocean model has been developed. The model is based on the Parallel Ocean Program (POP) developed at Los Alamos National Laboratory (LANL). Using the 256-processor Cray T3D, we have conducted a 40-year integration of this Atlantic eddy-resolving ocean model. A regional analysis demonstrate that many observed features associated with the Caribbean Sea eddies can be realistically simulated by this model. Analysis of this Atlantic eddy-resolving ocean model further suggests that these Caribbean Sea eddies are connected with eddies formed outside the Caribbean Sea at the confluence of the North Brazil Current (NBC) and the North Equatorial Countercurrent. The diagram of the model simulated surface current shows that the Caribbean eddies ultimately originate in the NBC retroflection region, traveling more than a year from the North Brazil coast through the Lesser Antilles into the Caribbean Sea and eventually into the Gulf of Mexico. Additional information is contained in the original.

  9. Decadal acidification in the water masses of the Atlantic Ocean.

    PubMed

    Ríos, Aida F; Resplandy, Laure; García-Ibáñez, Maribel I; Fajar, Noelia M; Velo, Anton; Padin, Xose A; Wanninkhof, Rik; Steinfeldt, Reiner; Rosón, Gabriel; Pérez, Fiz F

    2015-08-11

    Global ocean acidification is caused primarily by the ocean's uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50 °S-36 °N) for the Atlantic Ocean over two decades (1993-2013). Changes in pH associated with the uptake of anthropogenic CO2 (ΔpHCant) and with variations caused by biological activity and ocean circulation (ΔpHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (∆pH) were observed in central, mode, and intermediate waters, with a maximum ΔpH value in South Atlantic Central Waters of -0.042 ± 0.003. The ΔpH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between -0.0015 and -0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative ΔpHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic.

  10. Deglacial Atlantic Radiocarbon: A Southern Ocean Perspective

    NASA Astrophysics Data System (ADS)

    Robinson, L. F.; Burke, A.; Adkins, J. F.; Chen, T.; Spooner, P.

    2014-12-01

    It is widely accepted that the Southern Ocean is an important component of the climate system, acting as a key site for carbon and heat exchange between the atmosphere and oceans. The deglaciation with its associated millenial climate changes is a key time period for testing the mechanisms behind these exchanges. Ascertaining the precise timing of these events is a challenge given complications from variable and largely unconstrained reservoir ages, dissolution of carbonate hard parts and sediment redistribution by strong currents. Nevertheless improvements to our understanding of Southern Ocean dynamics in the past requires accurately-dated proxy records that can be embedded in GCM models. Radiocarbon measured in deep-sea corals offers just such an archive and proxy. Using the skeletons of deep-sea corals we are now able to reconstruct aspects of the history of three distinct water masses in the Drake Passage on a precise timescale, allowing direct comparison to U-series dated speleothem terrestrial records and polar ice cores. We present here a new deglacial radiocarbon record from the Drake Passage which more than doubles the resolution of published records. We focus on the deglacial, as well as providing insights from the contrasting period leading up to the LGM. Together with new data from far-field sites we interpret our results as evidence for a Southern Ocean control on atmospheric carbon dioxide and radiocarbon evolution during the deglaciation, and a northern hemisphere control during the run up to the LGM.

  11. Organic pollutants and ocean fronts across the Atlantic Ocean: A review

    NASA Astrophysics Data System (ADS)

    Lohmann, Rainer; Belkin, Igor M.

    2014-11-01

    Little is known about the effect of ocean fronts on pollutants dynamics, particularly organic pollutants. Since fronts are associated with convergent currents and productive fishing grounds, any possible convergence of pollutants at fronts would raise concerns. The focus here is on relatively persistent organic pollutants, POPs, as non-persistent organic pollutants are rarely found in the open ocean. Results from recent cruises in the Atlantic Ocean are examined for POP distributions across ocean fronts in (i) the Canary Current; (ii) the Gulf Stream; and (iii) the Amazon and Rio de la Plata Plumes. Few studies achieved a spatial resolution of 10-20 km, while most had 100-300 km between adjacent stations. The majority of the well-resolved studies measured perfluorinated compounds (PFCs), which seem particularly well suited for frontal resolution. In the NE Atlantic, concentrations of PFCs sharply decreased between SW Europe and NW Africa upon crossing the Canary Current Front at 24-27°N. In the Western Atlantic, the PFC concentrations sharply increased upon entering the Amazon River Plume and Rio de la Plata Plume. In the NW Atlantic, concentrations of several pollutants such as polycyclic aromatic hydrocarbons are very high in Rhode Island Sound, decreasing to below detection limit in the open ocean. The more persistent and already phased-out polychlorinated biphenyls (PCBs) displayed elevated concentrations in the Gulf Stream and Rhode Island Sound, thereby highlighting the importance of ocean fronts, along-front currents, and cross-frontal transport for the dispersal of PCBs.

  12. Basin-scale estimates of oceanic primary production by remote sensing - The North Atlantic

    NASA Technical Reports Server (NTRS)

    Platt, Trevor; Caverhill, Carla; Sathyendranath, Shubha

    1991-01-01

    The monthly averaged CZCS data for 1979 are used to estimate annual primary production at ocean basin scales in the North Atlantic. The principal supplementary data used were 873 vertical profiles of chlorophyll and 248 sets of parameters derived from photosynthesis-light experiments. Four different procedures were tested for calculation of primary production. The spectral model with nonuniform biomass was considered as the benchmark for comparison against the other three models. The less complete models gave results that differed by as much as 50 percent from the benchmark. Vertically uniform models tended to underestimate primary production by about 20 percent compared to the nonuniform models. At horizontal scale, the differences between spectral and nonspectral models were negligible. The linear correlation between biomass and estimated production was poor outside the tropics, suggesting caution against the indiscriminate use of biomass as a proxy variable for primary production.

  13. 77 FR 11387 - Safety Zone; Lauderdale Air Show, Atlantic Ocean, Fort Lauderdale, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lauderdale Air Show, Atlantic Ocean, Fort... establishing a temporary safety zone on the waters of the Atlantic Ocean in the vicinity of Fort Lauderdale... Lauderdale Air Show will include numerous aircraft engaging in aerobatic maneuvers over the Atlantic...

  14. Deglacial pulses of deep-ocean silicate into the subtropical North Atlantic Ocean.

    PubMed

    Meckler, A N; Sigman, D M; Gibson, K A; François, R; Martínez-García, A; Jaccard, S L; Röhl, U; Peterson, L C; Tiedemann, R; Haug, G H

    2013-03-28

    Growing evidence suggests that the low atmospheric CO2 concentration of the ice ages resulted from enhanced storage of CO2 in the ocean interior, largely as a result of changes in the Southern Ocean. Early in the most recent deglaciation, a reduction in North Atlantic overturning circulation seems to have driven CO2 release from the Southern Ocean, but the mechanism connecting the North Atlantic and the Southern Ocean remains unclear. Biogenic opal export in the low-latitude ocean relies on silicate from the underlying thermocline, the concentration of which is affected by the circulation of the ocean interior. Here we report a record of biogenic opal export from a coastal upwelling system off the coast of northwest Africa that shows pronounced opal maxima during each glacial termination over the past 550,000 years. These opal peaks are consistent with a strong deglacial reduction in the formation of silicate-poor glacial North Atlantic intermediate water (GNAIW). The loss of GNAIW allowed mixing with underlying silicate-rich deep water to increase the silicate supply to the surface ocean. An increase in westerly-wind-driven upwelling in the Southern Ocean in response to the North Atlantic change has been proposed to drive the deglacial rise in atmospheric CO2 (refs 3, 4). However, such a circulation change would have accelerated the formation of Antarctic intermediate water and sub-Antarctic mode water, which today have as little silicate as North Atlantic Deep Water and would have thus maintained low silicate concentrations in the Atlantic thermocline. The deglacial opal maxima reported here suggest an alternative mechanism for the deglacial CO2 release. Just as the reduction in GNAIW led to upward silicate transport, it should also have allowed the downward mixing of warm, low-density surface water to reach into the deep ocean. The resulting decrease in the density of the deep Atlantic relative to the Southern Ocean surface promoted Antarctic overturning

  15. Diverse Manifestations of Convective Upwelling Beneath the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    White, Nicky; Parnell-Turner, Ross

    2013-04-01

    The Icelandic Plume dominates the North Atlantic Ocean. Residual depth anomalies of oceanic lithosphere, long wavelength gravity anomalies, and seismic tomographic models show that this large upwelling reaches from Baffin Bay to Western Norway, and from offshore Newfoundland to Spitzbergen. At continental margins, there is excellent evidence for present-day dynamic support of crust beneath Scotland and Western Norway. It is generally agreed that the Icelandic Plume started at 62 Ma. In recent years, a quantitative understanding of the temporal evolution of this upwelling has begun to emerge. The best evidence occurs in the oceanic basins north and south of Iceland. Since the mid-oceanic ridge straddles the plume, it acts as a linear sampler of transient activity over the last 40-50 Ma. A pair of seismic reflection flowlines acquired in 2010 have enabled us to determine the detailed history of transient activity. The implications of this history are profound. Waxing and waning of convective upwelling beneath this important oceanic gateway appears to have modulated the overflow of the ancient precursor to North Atlantic Deep Water (NADW). The growth of contourite drifts which plaster deep-water margins can also be directly linked to changing vertical motions at this gateway. Finally, there is increasing evidence that the otherwise uniform thermal subsidence of sedimentary basins, which fringe both sides of the North Atlantic Ocean, has been periodically interrupted by transient uplift events which generated ephemeral landscapes. These geologic manifestations of convective activity should lead to improved insights into the fluid dynamics of the mantle.

  16. Deep ocean early warning signals of an Atlantic MOC collapse

    NASA Astrophysics Data System (ADS)

    Feng, Qing Yi; Viebahn, Jan P.; Dijkstra, Henk A.

    2014-08-01

    A future collapse of the Atlantic Meridional Overturning Circulation (MOC) has been identified as one of the most dangerous tipping points in the climate system. It is therefore crucial to develop early warning indicators for such a potential collapse based on relatively short time series. So far, attempts to use indicators based on critical slowdown have been marginally successful. Based on complex climate network reconstruction, we here present a promising new indicator for the MOC collapse that efficiently monitors spatial changes in deep ocean circulation. Through our analysis of the performance of this indicator, we formulate optimal locations of measurement of the MOC to provide early warning signals of a collapse. Our results imply that an increase in spatial resolution of the Atlantic MOC observations (i.e., at more sections) can improve early detection, because the spatial coherence in the deep ocean arising near the transition is better captured.

  17. Measurements of Ocean Derived Aerosol Over the North Atlantic

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Quinn, P.; Frossard, A. A.; Russell, L. M.; Hakala, J. P.; Kieber, D. J.; Keene, W. C.

    2012-12-01

    Breaking waves on the ocean surface inject sea spray particles into the atmosphere which can act as CCN. Characterization of particles freshly emitted from the ocean surface requires a sampling method that is able to isolate those particles and prevent them from interacting with ambient gases and particles. Here we report measurements of particles directly emitted from the ocean using a newly developed in-situ particle generator (Sea Sweep). The Sea Sweep was deployed alongside RV Ronald H. Brown in the North Atlantic during August of 2012 in two contrasting regions; one in the eutrophic waters on Georges Bank and one in the oligotrophic waters near Bermuda. Bubbles were generated 0.75 m below the ocean surface with stainless steel frits and swept into a hood/vacuum hose to feed a suite of aerosol instrumentation on board the ship. The measured aerosol properties from the two regions will be compared.

  18. Trace metal accumulation in carbonate biominerals of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Demina, L. L.; Oskina, N. S.; Galkin, S. V.

    2016-01-01

    New data on trace metal (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) distribution in carbonate biominerals formed in geochemically different oceanic environments are discussed. Calcite shells of shelf and deepwater hydrothermal vent mussels as well as planktic foraminifers and pteropods from the central Atlantic Ocean have been studied. The variability in concentrations of most trace elements between different groups of calcifying organisms are usually within one order of magnitude, except for Fe and Mn, the elevated contents of which in microfossils are caused by post-sedimentation interaction. Different groups of calcifying organisms demonstrate a biogeochemical uniformity in trace metal accumulation during the biomineralization processes.

  19. Decadal acidification in the water masses of the Atlantic Ocean

    PubMed Central

    Ríos, Aida F.; Resplandy, Laure; García-Ibáñez, Maribel I.; Fajar, Noelia M.; Velo, Anton; Padin, Xose A.; Wanninkhof, Rik; Steinfeldt, Reiner; Rosón, Gabriel; Pérez, Fiz F.

    2015-01-01

    Global ocean acidification is caused primarily by the ocean’s uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50°S–36°N) for the Atlantic Ocean over two decades (1993–2013). Changes in pH associated with the uptake of anthropogenic CO2 (ΔpHCant) and with variations caused by biological activity and ocean circulation (ΔpHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (∆pH) were observed in central, mode, and intermediate waters, with a maximum ΔpH value in South Atlantic Central Waters of −0.042 ± 0.003. The ΔpH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between −0.0015 and −0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative ΔpHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic. PMID:26216947

  20. New lysianassoid amphipods from the north eastern atlantic ocean.

    PubMed

    Kaim-Malka, R A

    2014-06-25

    Two new lysianassoid amphipod species, Ambasia anophthalma n. sp. and Bathyamaryllis biscayensis n. sp., are described based on adult females collected in the North Eastern Atlantic Ocean (Bay of Biscay) by an autonomous bait system deployed on the sea bottom at a depth of 1460-1550 m. These two species are characterized by the absence of eyes (blind species). They belong to genera which include very few species.

  1. Organic matter in eolian dusts over the Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Simoneit, B. R. T.

    1977-01-01

    The elemental and mineralogical composition and the microfossil and detritus content of particulate fallout from the lower troposphere over the Atlantic Ocean have been extensively documented in earlier work, and it was possible to ascribe terrigenous source areas to such fallout. A brief review of the organic geochemistry of eolian dusts is also presented here. The lipids of eolian dusts sampled from the air mass over the eastern Atlantic from about 35 deg N to 30 deg S were analyzed here. These lipids consisted mainly of normal alkanes, carboxylic acids and alcohols. The n-alkanes were found to range from n-C23 to n-C35 with high CPI values and maximizing at n-C27 in the North Atlantic, at n-C29 in the equatorial Atlantic and at n-C31 in the South Atlantic. The n-fatty acids had mostly bimodal distributions, ranging from n-C12 to n-C30 (high CPI), with maxima at n-C16 and in the northern samples at n-C24 and in the southern samples at n-C26. The n-alcohols ranged from n-C12 to n-C32, with high CPI values and maxima mainly at n-C28. The compositions of these lipids indicated that their terrigenous sources were comprised mainly of higher plant vegetation and desiccated lacustrine mud flats on the African continent.

  2. Organic matter in eolian dusts over the Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Simoneit, B. R. T.

    1977-01-01

    The elemental and mineralogical composition and the microfossil and detritus content of particulate fallout from the lower troposphere over the Atlantic Ocean have been extensively documented in earlier work, and it was possible to ascribe terrigenous source areas to such fallout. A brief review of the organic geochemistry of eolian dusts is also presented here. The lipids of eolian dusts sampled from the air mass over the eastern Atlantic from about 35 deg N to 30 deg S were analyzed here. These lipids consisted mainly of normal alkanes, carboxylic acids and alcohols. The n-alkanes were found to range from n-C23 to n-C35 with high CPI values and maximizing at n-C27 in the North Atlantic, at n-C29 in the equatorial Atlantic and at n-C31 in the South Atlantic. The n-fatty acids had mostly bimodal distributions, ranging from n-C12 to n-C30 (high CPI), with maxima at n-C16 and in the northern samples at n-C24 and in the southern samples at n-C26. The n-alcohols ranged from n-C12 to n-C32, with high CPI values and maxima mainly at n-C28. The compositions of these lipids indicated that their terrigenous sources were comprised mainly of higher plant vegetation and desiccated lacustrine mud flats on the African continent.

  3. Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa M.; Rhines, P. B.; Worthen, D. L.

    2012-01-01

    Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system.

  4. Potential Impact of North Atlantic Climate Variability on Ocean Biogeochemical Processes

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Muhling, B.; Lee, S. K.; Muller-Karger, F. E.; Enfield, D. B.; Lamkin, J. T.; Roffer, M. A.

    2016-02-01

    Previous studies have shown that upper ocean circulations largely determine primary production in the euphotic layers, here the global ocean model with biogeochemistry (GFDL's Modular Ocean Model with TOPAZ biogeochemistry) forced with the ERA-Interim is used to simulate the natural variability of biogeochemical processes in global ocean during 1979-present. Preliminary results show that the surface chlorophyll is overall underestimated in MOM-TOPAZ, but its spatial pattern is fairly realistic. Relatively high chlorophyll variability is shown in the subpolar North Atlantic, northeastern tropical Atlantic, and equatorial Atlantic. Further analysis suggests that the chlorophyll variability in the North Atlantic Ocean is affected by long-term climate variability. For the subpolar North Atlantic region, the chlorophyll variability is light-limited and is significantly correlated with North Atlantic Oscillation. A dipole pattern of chlorophyll variability is found between the northeastern tropical Atlantic and equatorial Atlantic. For the northeastern North Atlantic, the chlorophyll variability is significantly correlated with Atlantic Meridional Mode (AMM) and Atlantic Multidecadal Oscillation (AMO). During the negative phase of AMM and AMO, the increased trade wind in the northeast North Atlantic can lead to increased upwelling of nutrients. In the equatorial Atlantic region, the chlorophyll variability is largely link to Atlantic-Niño and associated equatorial upwelling of nutrients. The potential impact of climate variability on the distribution of pelagic fishes (i.e. yellowfin tuna) are discussed.

  5. Supplementary report on the ground-water supplies of the Atlantic City region

    USGS Publications Warehouse

    Barksdale, Henry C.; Sundstrom, Raymond W.; Brunstein, Maurice S.

    1936-01-01

    At present more potable water is taken from the Atlantic City 800-foot sand than from any other source of supply for the region. This sand is the sole source for some of the smaller communities on the barrier beaches. The original static head of the water in it at Atlantic City was between 20 and 25 feet above sea level. The head has been lowered more than 50 feet over much of the region,  and in parts of Atlantic City it has been lowered considerably more than 100 feet. A consideration of the principles governing the relation between salt water and fresh water in water-bearing sands indicates that the 800-foot sand probably contained salt water at a distance of 5 or 10 miles out from Atlantic City before any water was pumped from it. The evidence collected in this investigation indicates that the cone of depression created by the pumping from this sand in the Atlantic City region has probably extended inland to the intake area of the sand, the nearest part of which is probably about 40 miles from Atlantic City. If this is so, the conclusion is almost inescapable that it has also extended oceanward for a distance considerably greater than the 5 or 10 miles to the original zone of contact between the fresh and salt waters, and that salt water is probably being drawn toward the Atlantic City region through this sand. The time of its arrival will depend primarily upon the rate of pumping in the region and upon how much of the fresh water that originally lay between the region and the zone of contact must be removed before the salt water can reach the region. It may arrive in the near future if it advances in the form of a narrow tongue. On the other hand, if it advances along a broader front; so that more of the intervening fresh water must be pumped out of the formation, its arrival may be delayed for some time.

  6. The Low-Frequency Variability of the Tropical Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa; Mo, Kingtse C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Upper ocean temperature variability in the tropical Atlantic is examined from the Comprehensive Ocean Atmosphere Data Set (COADS) as well as from an ocean model simulation forced by COADS anomalies appended to a monthly climatology. Our findings are as follows: Only the sea surface temperatures (SST) in the northern tropics are driven by heat fluxes, while the southern tropical variability arises from wind driven ocean circulation changes. The subsurface temperatures in the northern and southern tropics are found to have a strong linkage to buoyancy forcing changes in the northern North Atlantic. Evidence for Kelvin-like boundary wave propagation from the high latitudes is presented from the model simulation. This extratropical influence is associated with wintertime North Atlantic Oscillation (NAO) forcing and manifests itself in the northern and southern tropical temperature anomalies of the same sign at depth of 100-200 meters as result of a Rossby wave propagation away from the eastern boundary in the wake of the boundary wave passage. The most apparent association of the southern tropical sea surface temperature anomalies (STA) arises with the anomalous cross-equatorial winds which can be related to both NAO and the remote influence from the Pacific equatorial region. These teleconnections are seasonal so that the NAO impact on the tropical SST is the largest it mid-winter but in spring and early summer the Pacific remote influence competes with NAO. However, NAO appears to have a more substantial role than the Pacific influence at low frequencies during the last 50 years. The dynamic origin of STA is indirectly confirmed from the SST-heat flux relationship using ocean model experiments which remove either anomalous wind stress forcing or atmospheric forcing anomalies contributing to heat exchange.

  7. Using Ocean Exploration in the Atlantic Canyons to Advance Conversations about Transatlantic Ocean Literacy

    NASA Astrophysics Data System (ADS)

    Keener, P.; Tuddenham, P. T.; Bishop, T.

    2016-02-01

    The National Oceanic and Atmospheric Administration (NOAA) Ship Okeanos Explorer spent the 2013 field season exploring a wide variety of seafloor features and biological communities in and between largely unexplored canyons in the Northeast Atlantic Ocean, revealing hot spots for biodiversity and providing new information about how these canyons change over time. During the expeditions, an interdisciplinary team of scientists from dozens of institutions and multiple sectors together with ocean educators and the public were able to observe via telepresence the deep Atlantic using NOAA's new remotely-operated vehicle Deep Discoverer. In a collaboration between the NOAA Office of Ocean Exploration and Research and The College of Exploration, along with partners in Canada and the European Union (EU), key exploration findings from the NOAA Ship Okeanos Explorer 2013 field season were designed into an online workshop in which 640 educators, scientists, government representatives, policy makers, and other interested stakeholders representing 40 states within the U.S. and 29 countries participated. The five-week long online offering, titled Deepwater Explorations in the North Atlantic Onboard the NOAA Ship Okeanos Explorer…Online Conversations to Advance Transatlantic Ocean Literacy, built upon the telepresence experience and served as a foundation for extending conversations begun approximately a year earlier on transatlantic ocean literacy, as called for in The Galway Statement. Scientific experts from the U.S., Canada, and the EU provided keynote addresses on deep-sea corals, methane seeps, deep-water canyons, seamounts, and biological diversity in this important area of our "shared Atlantic Ocean." This session will socialize key findings of the workshop based on an evaluation conducted at the conclusion of the workshop and offers insight into how online learning communities can advance ocean literacy and scientific understanding in support of The Galway Statement.

  8. The sources of deep ocean infragravity waves observed in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Crawford, Wayne; Ballu, Valerie; Bertin, Xavier; Karpytchev, Mikhail

    2015-07-01

    Infragravity waves are long-period (25-250 s) ocean surface gravity waves generated in coastal zones through wave-wave interactions or oscillation of the breaking point. Most of the infragravity wave energy is trapped or dissipated near coastlines, but a small percentage escapes into the open oceans. The source of deep ocean infragravity waves is debated, specifically whether they come mostly from regions with strong source waves or from sites with particular morphologies/orientations. We correlate measurements of infragravity waves in the deep North Atlantic Ocean with infragravity wave generation parameters throughout the Atlantic Ocean to find the dominant sources of deep ocean infragravity wave energy in the North Atlantic Ocean. The deep ocean infragravity wave data are from a 5 year deployment of absolute pressure gauges west of the Azores islands (37°N, 35°W) and shorter data sets from seafloor tsunami gauges (DART buoys). Two main sources are identified: one off of the west coast of southern Europe and northern Africa (25°N-40°N) in northern hemisphere winter and the other off the west coast of equatorial Africa (the Gulf of Guinea) in southern hemisphere winter. These regions have relatively weak source waves and weak infragravity wave propagation paths to the main measurement site, indicating that that the site morphology/orientation dominates the creation of deep ocean infragravity waves. Both regions have also been identified as potential sources of global seismological noise, suggesting that the same mechanisms may be behind the generation of deep ocean infragravity waves and global seismological noise in the frequency band from 0.001 to 0.04 Hz.

  9. Monitoring the North Atlantic using ocean colour data

    NASA Astrophysics Data System (ADS)

    Fuentes-Yaco, C.; Caverhill, C.; Maass, H.; Porter, C.; White, GN, III

    2016-04-01

    The Remote Sensing Unit (RSU) at the Bedford Institute of Oceanography (BIO) has been monitoring the North Atlantic using ocean colour products for decades. Optical sensors used include CZCS, POLDER, SeaWiFS, MODIS/Aqua and MERIS. The monitoring area is defined by the Atlantic Zone Monitoring Program (AZMP) but certain products extend into Arctic waters, and all-Canadian waters which include the Pacific coast. RSU provides Level 3 images for various products in several formats and a range of temporal and spatial resolutions. Basic statistics for pre-defined areas of interest are compiled for each product. Climatologies and anomaly maps are also routinely produced, and custom products are delivered by request. RSU is involved in the generation of Level 4 products, such as characterizing the phenology of spring and fall phytoplankton blooms, computing primary production, using ocean colour to aid in EBSA (Ecologically and Biologically Significant Area) definition and developing habitat suitability maps. Upcoming operational products include maps of diatom distribution, biogeochemical province boundaries, and products from sensors such as VIIRS (Visible Infrared Imaging Radiometer Suite), OLCI (Ocean Land Colour Instrument), and PACE (Pre-Aerosol, Clouds and ocean Ecosystem) hyperspectral microsatellite mission.

  10. Near-Inertial and Thermal Upper Ocean Response to Atmospheric Forcing in the North Atlantic Ocean

    DTIC Science & Technology

    2010-06-01

    water is then subducted as the ocean restratifies during spring, and advected throughout the subtropical gyre by the large scale wind driven circulation...Luther, and W. C. Patzert, 1992: The heat budget in the north atlantic subtropical frontal zone . J. Geophys. Res., 97 (C11), 17 947–17 959. 131 Price, J

  11. Oceanic Situational Awareness over the North Atlantic Corridor

    NASA Technical Reports Server (NTRS)

    Welch, Bryan; Greenfield, Israel

    2005-01-01

    Air traffic control (ATC) mandated, aircraft separations over the oceans impose a limitation on traffic capacity for a given corridor, given the projected traffic growth over the oceanic domain. The separations result from a lack of acceptable situational awareness over oceans where radar position updates are not available. This study considers the use of Automatic Dependent Surveillance (ADS) data transmitted over a commercial satellite communications system as an approach to provide ATC with the needed situational awareness and thusly allow for reduced aircraft separations. This study uses Federal Aviation Administration data from a single day for the North Atlantic Corridor to analyze traffic loading to be used as a benchmark against which to compare several approaches for coordinating data transmissions from the aircraft to the satellites.

  12. Quantification of dissolved iron sources to the North Atlantic Ocean.

    PubMed

    Conway, Tim M; John, Seth G

    2014-07-10

    Dissolved iron is an essential micronutrient for marine phytoplankton, and its availability controls patterns of primary productivity and carbon cycling throughout the oceans. The relative importance of different sources of iron to the oceans is not well known, however, and flux estimates from atmospheric dust, hydrothermal vents and oceanic sediments vary by orders of magnitude. Here we present a high-resolution transect of dissolved stable iron isotope ratios (δ(56)Fe) and iron concentrations ([Fe]) along a section of the North Atlantic Ocean. The different iron sources can be identified by their unique δ(56)Fe signatures, which persist throughout the water column. This allows us to calculate the relative contribution from dust, hydrothermal venting and reductive and non-reductive sedimentary release to the dissolved phase. We find that Saharan dust aerosol is the dominant source of dissolved iron along the section, contributing 71-87 per cent of dissolved iron. Additional sources of iron are non-reductive release from oxygenated sediments on the North American margin (10-19 per cent), reductive sedimentary dissolution on the African margin (1-4 per cent) and hydrothermal venting at the Mid-Atlantic Ridge (2-6 per cent). Our data also indicate that hydrothermal vents in the North Atlantic are a source of isotopically light iron, which travels thousands of kilometres from vent sites, potentially influencing surface productivity. Changes in the relative importance of the different iron sources through time may affect interactions between the carbon cycle and climate.

  13. Fennerosquilla heptacantha (Crustacea: Stomatopoda: Squillidae) in South Atlantic Ocean.

    PubMed

    Lucatelli, Débora

    2015-10-07

    Fennerosquilla is a monotypic genus that belongs to the family Squillidae, which has the highest generic diversity within Stomatopoda. This genus has been recorded in the north Atlantic Ocean, the Gulf of Mexico and Caribbean Sea, between 105 and 458 m depth. The present specimen was collected during the project "Avaliação da Biota Bentônica e Planctônica na porção offshore das Bacias Potiguar e Ceará", in 2011, from the continental slope region of Brazil. In this expedition Fennerosquilla heptacantha was found at 178-193 m depth, and represents the first record of the species in the south Atlantic Ocean (Rio Grande do Norte State, northeastern Brazil), expanding the southern limit distribution. The specimen is the largest recorded, measuring 149 mm total length. The pigmentation zone on median region of telson and all diagnostic characters are still preserved and agree with the original description. Fennerosquilla heptacantha has a disjunct deep water distribution (more than 100 m) in the tropical western Atlantic, mostly along the continental slope.

  14. Atlantic Southern Ocean productivity: Fertilization from above or below?

    NASA Astrophysics Data System (ADS)

    Meskhidze, Nicholas; Nenes, Athanasios; Chameides, William L.; Luo, Chao; Mahowald, Natalie

    2007-06-01

    Primary productivity and the associated uptake of atmospheric carbon dioxide in the Southern Ocean (SO) is thought to be generally limited by bioavailable iron (Fe). Two sources of Fe for the surface waters of the SO have been proposed: (1) oceanic input of nutrient-rich (i.e., Fe) waters from upwelling and lateral flows from continental margins; and (2) atmospheric input from the deposition of mineral dust emanating from the arid regions of South America and Australia. In this work, analysis of weekly remotely sensed sea surface temperature (SST), ocean chlorophyll a content [Chl a] and model-derived atmospheric dust-Fe fluxes are used to identify the predominant source of Fe during phytoplankton blooms in the surface waters of the south Atlantic Ocean between 40°S and 60°S. The results of our study suggest that oceanic source through upwelling of nutrient-rich waters due to mesoscale frontal dynamics is the major source of bioavailable Fe controlling biological activity in this region. This result is consistent with the idea that acidification of aeolian dust prior to its deposition to the ocean may be required to solubilize the large fraction of mineral-iron and make it bioavailable.

  15. An alternative early opening scenario for the Central Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Labails, Cinthia; Olivet, Jean-Louis; Aslanian, Daniel; Roest, Walter R.

    2010-09-01

    The opening of the Central Atlantic Ocean basin that separated North America from northwest Africa is well documented and assumed to have started during the Late Jurassic. However, the early evolution and the initial breakup history of Pangaea are still debated: most of the existing models are based on one or multiple ridge jumps at the Middle Jurassic leaving the oldest crust on the American side, between the East Coast Magnetic Anomaly (ECMA) and the Blake Spur Magnetic Anomaly (BSMA). According to these hypotheses, the BSMA represents the limit of the initial basin and the footprint subsequent to the ridge jump. Consequently, the evolution of the northwest African margin is widely different from the northeast American margin. However, this setting is in contradiction with the existing observations. In this paper, we propose an alternative scenario for the continental breakup and the Mesozoic spreading history of the Central Atlantic Ocean. The new model is based on an analysis of geophysical data (including new seismic lines, an interpretation of the newly compiled magnetic data, and satellite derived gravimetry) and recently published results which demonstrate that the opening of the Central Atlantic Ocean started already during the Late Sinemurian (190 Ma), based on a new identification of the African conjugate to the ECMA and on the extent of salt provinces off Morocco and Nova Scotia. The identification of an African conjugate magnetic anomaly to BSMA, the African Blake Spur Magnetic Anomaly (ABSMA), together with the significant change in basement topography, are in good agreement with that initial reconstruction. The early opening history for the Central Atlantic Ocean is described in four distinct phases. During the first 20 Myr after the initial breakup (190-170 Ma, from Late Sinemurian to early Bajocian), oceanic accretion was extremely slow (˜ 0.8 cm/y). At the time of Blake Spur (170 Ma, early Bajocian), a drastic change occurred both in the relative

  16. Latitudinal distribution of prokaryotic picoplankton populations in the Atlantic Ocean.

    PubMed

    Schattenhofer, Martha; Fuchs, Bernhard M; Amann, Rudolf; Zubkov, Mikhail V; Tarran, Glen A; Pernthaler, Jakob

    2009-08-01

    Members of the prokaryotic picoplankton are the main drivers of the biogeochemical cycles over large areas of the world's oceans. In order to ascertain changes in picoplankton composition in the euphotic and twilight zones at an ocean basin scale we determined the distribution of 11 marine bacterial and archaeal phyla in three different water layers along a transect across the Atlantic Ocean from South Africa (32.9 degrees S) to the UK (46.4 degrees N) during boreal spring. Depth profiles down to 500 m at 65 stations were analysed by catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and automated epifluorescence microscopy. There was no obvious overall difference in microbial community composition between the surface water layer and the deep chlorophyll maximum (DCM) layer. There were, however, significant differences between the two photic water layers and the mesopelagic zone. SAR11 (35 +/- 9%) and Prochlorococcus (12 +/- 8%) together dominated the surface waters, whereas SAR11 and Crenarchaeota of the marine group I formed equal proportions of the picoplankton community below the DCM (both approximately 15%). However, due to their small cell sizes Crenarchaeota contributed distinctly less to total microbial biomass than SAR11 in this mesopelagic water layer. Bacteria from the uncultured Chloroflexi-related clade SAR202 occurred preferentially below the DCM (4-6%). Distinct latitudinal distribution patterns were found both in the photic zone and in the mesopelagic waters: in the photic zone, SAR11 was more abundant in the Northern Atlantic Ocean (up to 45%) than in the Southern Atlantic gyre (approximately 25%), the biomass of Prochlorococcus peaked in the tropical Atlantic Ocean, and Bacteroidetes and Gammaproteobacteria bloomed in the nutrient-rich northern temperate waters and in the Benguela upwelling. In mesopelagic waters, higher proportions of SAR202 were present in both central gyre regions, whereas Crenarchaeota were clearly

  17. The Cretaceous opening of the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Granot, Roi; Dyment, Jérôme

    2015-03-01

    The separation of South America from Africa during the Cretaceous is poorly understood due to the long period of stable polarity of the geomagnetic field, the Cretaceous Normal Superchron (CNS, lasted between ∼121 and 83.6 Myr ago). We present a new identification of magnetic anomalies located within the southern South Atlantic magnetic quiet zones that have arisen due to past variations in the strength of the dipolar geomagnetic field. Using these anomalies, together with fracture zone locations, we calculate the first set of magnetic anomalies-based finite rotation parameters for South America and Africa during that period. The kinematic solutions are generally consistent with fracture zone traces and magnetic anomalies outside the area used to construct them. The rotations indicate that seafloor spreading rates increased steadily throughout most of the Cretaceous and decreased sharply at around 80 Myr ago. A change in plate motion took place in the middle of the superchron, roughly 100 Myr ago, around the time of the final breakup (i.e., separation of continental-oceanic boundary in the Equatorial Atlantic). Prominent misfit between the calculated synthetic flowlines (older than Anomaly Q1) and the fracture zones straddling the African Plate in the central South Atlantic could only be explained by a combination of seafloor asymmetry and internal dextral motion (<100 km) within South America, west of the Rio Grande fracture zone. This process has lasted until ∼92 Myr ago after which both Africa and South America (south of the equator) behaved rigidly. The clearing of the continental-oceanic boundaries within the Equatorial Atlantic Gateway was probably completed by ∼95 Myr ago. The clearing was followed by a progressive widening and deepening of the passageway, leading to the emergence of north-south flow of intermediate and deep-water which might have triggered the global cooling of bottom water and the end for the Cretaceous greenhouse period.

  18. FERROMANGANESE CRUST RESOURCES IN THE PACIFIC AND ATLANTIC OCEANS.

    USGS Publications Warehouse

    Commeau, R.F.; Clark, A.; Johnson, Chad; Manheim, F. T.; Aruscavage, P. J.; Lane, C.M.

    1984-01-01

    Ferromanganese crusts on raised areas of the ocean floor have joined abyssal manganese nodules and hydrothermal sulfides as potential marine resources. Significant volumes of cobalt-rich (about 1% Co) crusts have been identified to date within the US Exclusive Economic Zone (EEZ) in the Central Pacific: in the NW Hawaiian Ridge and Seamount region and in the seamounts in the Johnston Island and Palmyra Island regions. Large volumes of lower grade crusts, slabs, and nodules are also present in shallow ( greater than 1000 m) waters on the Blake plateau, off Florida-South Carolina in the Atlantic Ocean. Data on ferromanganese crusts have been increased by recent German and USGS cruises, but are still sparse, and other regions having crust potential are under current investigation. The authors discuss economic potentials for cobalt-rich crusts in the Central Pacific and Western North Atlantic oceans, with special reference to US EEZ areas. Additional research is needed before more quantitative resource estimates can be made.

  19. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and photographers get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  20. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and spectators get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  1. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and photographers get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  2. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and spectators get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  3. Sea Level Variation at the North Atlantic Ocean from Altimetry

    NASA Astrophysics Data System (ADS)

    Vigo, I.; Sanchez-Reales, J. M.; Belda, S.

    2012-12-01

    About twenty years of multi-satellite radar altimeter data are analyzed to investigate the sea-level variation (SLV) of the North Atlantic Ocean. In particular seasonal variations and inter-seasonal trends are studied. Sea surface temperature and ice mass lost variations at Greenland are investigated as potential contributors of SLV in the case. It was found a quadratic acceleration term to be significant at some areas mainly located at the sub-polar gyre region. Results are consistent with changes in temperature data.

  4. Glacial surface temperatures of the southeast Atlantic Ocean.

    PubMed

    Sachs, J P; Anderson, R F; Lehman, S J

    2001-09-14

    A detailed record of sea surface temperature from sediments of the Cape Basin in the subtropical South Atlantic indicates a previously undocumented progression of marine climate change between 41 and 18 thousand years before the present (ky B.P.), during the last glacial period. Whereas marine records typically indicate a long-term cooling into the Last Glacial Maximum (around 21 ky B.P.) consistent with gradually increasing global ice volume, the Cape Basin record documents an interval of substantial temperate ocean warming from 41 to 25 ky B.P. The pattern is similar to that expected in response to changes in insolation owing to variations in Earth's tilt.

  5. Aerosol isotopic ammonium signatures over the remote Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Lin, C. T.; Jickells, T. D.; Baker, A. R.; Marca, A.; Johnson, M. T.

    2016-05-01

    We report aerosol ammonium 15N signatures for samples collected from research cruises on the South Atlantic and Caribbean using a new high sensitivity method. We confirm a pattern of isotopic signals from generally light (δ15N -5 to -10‰), for aerosols with very low (<2 nmol m-3) ammonium concentrations from the remote high latitude ocean, to generally heavier values (δ15N +5 to +10‰), for aerosols collected in temperate and tropical latitudes and with higher ammonium concentrations (>2 nmol m-3). We discuss whether this reflects a mixing of aerosols from two end-members (polluted continental and remote marine emissions), or isotopic fractionation during aerosol transport.

  6. Atlantic Ocean forcing of North American and European summer climate.

    PubMed

    Sutton, Rowan T; Hodson, Daniel L R

    2005-07-01

    Recent extreme events such as the devastating 2003 European summer heat wave raise important questions about the possible causes of any underlying trends, or low-frequency variations, in regional climates. Here, we present new evidence that basin-scale changes in the Atlantic Ocean, probably related to the thermohaline circulation, have been an important driver of multidecadal variations in the summertime climate of both North America and western Europe. Our findings advance understanding of past climate changes and also have implications for decadal climate predictions.

  7. Atmospheric deposition of methanol over the Atlantic Ocean.

    PubMed

    Yang, Mingxi; Nightingale, Philip D; Beale, Rachael; Liss, Peter S; Blomquist, Byron; Fairall, Christopher

    2013-12-10

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air-sea methanol transfer along a ∼10,000-km north-south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air-sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface-an important term for improving air-sea gas exchange models.

  8. 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.

  9. Atmospheric deposition of methanol over the Atlantic Ocean

    PubMed Central

    Yang, Mingxi; Nightingale, Philip D.; Beale, Rachael; Liss, Peter S.; Blomquist, Byron; Fairall, Christopher

    2013-01-01

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air–sea methanol transfer along a ∼10,000-km north–south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air–sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface—an important term for improving air–sea gas exchange models. PMID:24277830

  10. Atlantic Ocean Circulation at the Last Glacial Maximum: Inferences from Data and Models

    DTIC Science & Technology

    2012-09-01

    development of estimates of ocean state that are (1) within error bounds of a given dataset, (2) consistent with known oceanic dynamics, and (3...United States Government. This thesis should be cited as: Holly Janine Dail, 2012. Atlantic Ocean Circulation at the Last Glacial Maximum: Inferences...this thesis a novel approach to dynamical reconstruction is applied to make estimates of LGM Atlantic Ocean state that are consistent with these proxy

  11. Oceanic Situational Awareness Over the Western Atlantic Track Routing System

    NASA Technical Reports Server (NTRS)

    Welch, Bryan; Greenfeld, Israel

    2005-01-01

    Air traffic control (ATC) mandated, aircraft separations over the oceans impose a limitation on traffic capacity for a given corridor, given the projected traffic growth over the Western Atlantic Track Routing System (WATRS). The separations result from a lack of acceptable situational awareness over oceans where radar position updates are not available. This study considers the use of Automatic Dependent Surveillance (ADS) data transmitted over a commercial satellite communications system as an approach to provide ATC with the needed situational awareness and thusly allow for reduced aircraft separations. This study uses Federal Aviation Administration data from a single day for the WATRS corridor to analyze traffic loading to be used as a benchmark against which to compare several approaches for coordinating data transmissions from the aircraft to the satellites.

  12. Pathways of Atlantic Waters into the Arctic Ocean: Eddy-permitting ocean and sea ice simulations

    NASA Astrophysics Data System (ADS)

    Wekerle, Claudia; von Appen, Wilken-Jon; Danilov, Sergey; Jung, Thomas; Kanzow, Torsten; Schauer, Ursula; Timmermann, Ralph; Wang, Qiang

    2015-04-01

    Fram Strait is the only deep gateway connecting the central Arctic with the North Atlantic. Boundary currents on each side are responsible for the exchange of water masses between the Arctic and North Atlantic. The East Greenland Current (EGC) carries fresh and cold Arctic waters and sea ice southward, whereas the West Spitsbergen Current (WSC) carries warm Atlantic Waters (AW) into the Arctic Ocean. The complex topography in Fram Strait leads to a branching of the northward flowing WSC, with one branch recirculating between 78°N and 81°N which then joins the EGC. To date, the dynamics as well as the precise location of this recirculation are unclear. The goal of this research project is to quantify the amount and variability of AW which recirculates immediately in Fram Strait, and to investigate the role of atmospheric forcing and oceanic meso-scale eddies for the recirculation. We use simulations carried out with a global configuration of the Finite Element Sea ice-Ocean Model (FESOM) at eddy-permitting scales. The advantage of this model is the finite element discretization of the governing equations, which allows us to locally refine the mesh in areas of interest and keep it coarse in other parts of the global oceans without the need for traditional nesting. Here we will show the first results of the model validation. The model has ~9 km resolution in the Nordic Seas and Fram Strait and 1 deg south of 50°N. We assess the model capabilities in simulating the ocean circulation in the Nordic Seas and Fram Strait by comparing with the available observational data, e.g. with data from the Fram Strait oceanographic mooring array. The ocean volume and heat transport from the Atlantic Ocean into the Nordic Seas and at the Fram Strait are analyzed. Our results show that the model can capture some of the observed key ocean properties in our region of interest, while some tuning is required to further improve the model. In the next phase of this project we will focus

  13. Eddy length scales in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Eden, Carsten

    2007-06-01

    Eddy length scales are calculated from satellite altimeter products and in an eddy-resolving model of the North Atlantic Ocean. Four different measures for eddy length scales are derived from kinetic energy densities in wave number space and spatial decorrelation scales. Observational estimates and model simulation agree well in all these measures near the surface. As found in previous studies, all length scales are, in general, decreasing with latitude. They are isotropic and proportional to the local first baroclinic Rossby radius (Lr) north of about 30°N, while south of 30°N (or for Lr > 30 km), zonal length scales tend to be larger than meridional ones, and (scalar) length scales show no clear relation to Lr anymore. Instead, they appear to be related to the local Rhines scale. In agreement with a recent theoretical prediction by Theiss [2004], the observed and simulated pattern of eddy length scales appears to be indicative of two different dynamical regimes in the North Atlantic: anisotropic turbulence in the subtropics and isotropic turbulence in the subpolar North Atlantic. Both regions can be roughly characterized by the ration between Lr and the Rhines scales (LR), with LR > Lr in the isotropic region and LR < Lr in the anisotropic region. The critical latitude that separates both regions, i.e., where LR = Lr, is about 30°N.

  14. 77 FR 63722 - Special Local Regulations; Palm Beach World Championship, Atlantic Ocean; Jupiter, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-17

    ..., Atlantic Ocean; Jupiter, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast... Indiantown Road and Donald Ross Road, just offshore of Jupiter, Florida during the Palm Beach World... will be held on the waters of the Atlantic Ocean, just offshore of Jupiter, Florida. The high speed...

  15. 77 FR 50019 - Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa... establishing a temporary safety zone on the waters of the Atlantic Ocean located east of Cocoa Beach, Florida during the Cocoa Beach Air Show. The Cocoa Beach Air Show will include aircraft engaging in aerobatic...

  16. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic Ocean...

  17. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic Ocean...

  18. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area is...

  19. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The area...

  20. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section...

  1. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section...

  2. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic Ocean...

  3. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area is...

  4. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The area...

  5. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic Ocean...

  6. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic Ocean...

  7. 33 CFR 165.T01-0542 - Safety Zones: Neptune Deepwater Port, Atlantic Ocean, Boston, MA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zones: Neptune Deepwater Port, Atlantic Ocean, Boston, MA. 165.T01-0542 Section 165.T01-0542 Navigation and Navigable Waters... Guard District § 165.T01-0542 Safety Zones: Neptune Deepwater Port, Atlantic Ocean, Boston, MA. (a...

  8. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic Ocean...

  9. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The area...

  10. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area is...

  11. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section...

  12. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section...

  13. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic Ocean...

  14. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic Ocean...

  15. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters CORPS... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The...

  16. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area is...

  17. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The area...

  18. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic Ocean...

  19. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters CORPS... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The...

  20. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The area...

  1. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters CORPS... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The...

  2. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters CORPS... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The...

  3. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters CORPS... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The...

  4. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic Ocean...

  5. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section...

  6. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area is...

  7. 78 FR 56151 - Safety Zone, North Atlantic Ocean; Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, North Atlantic Ocean; Virginia Beach, VA... zone on the navigable waters of the North Atlantic Ocean in Virginia Beach, VA to support the Virginia... Delegation No. 0170.1. ] On September 12, 2013 the City of Virginia Beach will host a fireworks display...

  8. 78 FR 35596 - Special Local Regulation; Long Beach Regatta, Powerboat Race, Atlantic Ocean, Long Beach, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-13

    ... Race, Atlantic Ocean, Long Beach, NY AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed Rulemaking... Atlantic Ocean off Long Beach, NY during the Long Beach Regatta Powerboat Race scheduled for August 24-25, 2013. This action is necessary to provide for the safety of life of participants and spectators...

  9. 78 FR 41844 - Safety Zone; Fairfield Estates Fireworks Display, Atlantic Ocean, Sagaponack, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ..., Atlantic Ocean, Sagaponack, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the navigable waters of the Atlantic Ocean, in... safety of life on navigable waters during the event. Entering into, transiting through,...

  10. 76 FR 68314 - Special Local Regulations; Key West World Championship, Atlantic Ocean; Key West, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-04

    ..., Atlantic Ocean; Key West, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing special local regulations on the waters of the Atlantic Ocean located southwest of..., November 13, 2011. These special local regulations are necessary to provide for the safety of life...

  11. 78 FR 70901 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key... proposes to establish a temporary safety zone on the waters of the Atlantic Ocean in Key West, Florida... for the safety of life on navigable waters during the event. Persons and vessels are prohibited...

  12. 77 FR 75853 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key... establishing a temporary safety zone on the waters of the Atlantic Ocean in Key West, Florida, during the Bone... life on navigable waters during the event. Persons and vessels are prohibited from entering,...

  13. The Indian Ocean Dipole's influence on Atlantic tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Marinaro, Alan Joseph

    Improving early tropical cyclone forecasts would assist reinsurance decision makers as they seek information that can minimize risks. Early lead forecasts are based on model variables before December 1 (Year 0) that predict Atlantic tropical cyclone activity (Year +1). The autumn Indian Ocean Dipole (IOD) has an 8 to 14 month antecedent correlation with the El Nino - Southern Oscillation (ENSO). ENSO is traditionally the best non-lead and overall predictor of Atlantic tropical cyclone activity. Analyses were performed over a 30-year period from 1984/85-2013/14, with some time variation depending on the test. Correlation, spatial, and wavelet analyses were utilized to find associations between the IOD, west and east components of the IOD, and four other variables related to the following season's ENSO state and tropical cyclone activity. The prior western pole of the October IOD (WIOD) was demonstrated to have statistically significant r-squared values (i.e. 99% confidence interval) to upcoming tropical storm activity (i.e. explained 25% of the variance), named storm counts (28%), and ENSO (21%). The WIOD has no connection with U.S. hurricane landfalls. Wavelet analysis between October IOD variables and following August-October ENSO data was observed to have the best time-frequency relationship. Dynamic reasoning for these relationships reside within the idealized biennial IOD-ENSO cycle, Walker circulation process, and the impact of ENSO on the state of the Atlantic Basin. The WIOD's integration into early-lead forecast models could be an advantage for those in the reinsurance industry and other decision makers impacted by Atlantic tropical cyclonesn.

  14. Factors influencing particulate lipid production in the East Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gašparović, B.; Frka, S.; Koch, B. P.; Zhu, Z. Y.; Bracher, A.; Lechtenfeld, O. J.; Neogi, S. B.; Lara, R. J.; Kattner, G.

    2014-07-01

    Extensive analyses of particulate lipids and lipid classes were conducted to gain insight into lipid production and related factors along the biogeochemical provinces of the Eastern Atlantic Ocean. Data are supported by particulate organic carbon (POC), chlorophyll a (Chl a), phaeopigments, Chl a concentrations and carbon content of eukaryotic micro-, nano- and picophytoplankton, including cell abundances for the latter two and for cyanobacteria and prokaryotic heterotrophs. We focused on the productive ocean surface (2 m depth and deep Chl a maximum (DCM). Samples from the deep ocean provided information about the relative reactivity and preservation potential of particular lipid classes. Surface and DCM particulate lipid concentrations (3.5-29.4 μg L-1) were higher than in samples from deep waters (3.2-9.3 μg L-1) where an increased contribution to the POC pool was observed. The highest lipid concentrations were measured in high latitude temperate waters and in the North Atlantic Tropical Gyral Province (13-25°N). Factors responsible for the enhanced lipid synthesis in the eastern Atlantic appeared to be phytoplankton size (micro, nano, pico) and the low nutrient status with microphytoplankton having the most expressed influence in the surface and eukaryotic nano- and picophytoplankton in the DCM layer. Higher lipid to Chl a ratios suggest enhanced lipid biosynthesis in the nutrient poorer regions. The various lipid classes pointed to possible mechanisms of phytoplankton adaptation to the nutritional conditions. Thus, it is likely that adaptation comprises the replacement of membrane phospholipids by non-phosphorus containing glycolipids under low phosphorus conditions. The qualitative and quantitative lipid compositions revealed that phospholipids were the most degradable lipids, and their occurrence decreased with increasing depth. In contrast, wax esters, possibly originating from zooplankton, survived downward transport probably due to the fast sinking

  15. Are Global In-Situ Ocean Observations Fit-for-purpose? Applying the Framework for Ocean Observing in the Atlantic.

    NASA Astrophysics Data System (ADS)

    Visbeck, M.; Fischer, A. S.; Le Traon, P. Y.; Mowlem, M. C.; Speich, S.; Larkin, K.

    2015-12-01

    There are an increasing number of global, regional and local processes that are in need of integrated ocean information. In the sciences ocean information is needed to support physical ocean and climate studies for example within the World Climate Research Programme and its CLIVAR project, biogeochemical issues as articulated by the GCP, IMBER and SOLAS projects of ICSU-SCOR and Future Earth. This knowledge gets assessed in the area of climate by the IPCC and biodiversity by the IPBES processes. The recently released first World Ocean Assessment focuses more on ecosystem services and there is an expectation that the Sustainable Development Goals and in particular Goal 14 on the Ocean and Seas will generate new demands for integrated ocean observing from Climate to Fish and from Ocean Resources to Safe Navigation and on a healthy, productive and enjoyable ocean in more general terms. In recognition of those increasing needs for integrated ocean information we have recently launched the Horizon 2020 AtlantOS project to promote the transition from a loosely-coordinated set of existing ocean observing activities to a more integrated, more efficient, more sustainable and fit-for-purpose Atlantic Ocean Observing System. AtlantOS takes advantage of the Framework for Ocean observing that provided strategic guidance for the design of the project and its outcome. AtlantOS will advance the requirements and systems design, improving the readiness of observing networks and data systems, and engaging stakeholders around the Atlantic. AtlantOS will bring Atlantic nations together to strengthen their complementary contributions to and benefits from the internationally coordinated Global Ocean Observing System (GOOS) and the Blue Planet Initiative of the Global Earth Observation System of Systems (GEOSS). AtlantOS will fill gaps of the in-situ observing system networks and will ensure that their data are readily accessible and useable. AtlantOS will demonstrate the utility of

  16. 77 FR 15006 - Special Local Regulations; Third Annual Space Coast Super Boat Grand Prix, Atlantic Ocean, Cocoa...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-14

    ... Super Boat Grand Prix, Atlantic Ocean, Cocoa Beach, FL AGENCY: Coast Guard, DHS. ACTION: Notice of... of the Atlantic Ocean east of Cocoa Beach, Florida during the Third Annual Space Coast Super Boat...-speed boat races. The event will be held on the waters of the Atlantic Ocean east of Cocoa Beach...

  17. 33 CFR 334.590 - Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Cape Canaveral... RESTRICTED AREA REGULATIONS § 334.590 Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base, Fla. (a) The danger zone. An area in the Atlantic Ocean immediately offshore from...

  18. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  19. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  20. 33 CFR 334.590 - Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Cape Canaveral... RESTRICTED AREA REGULATIONS § 334.590 Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base, Fla. (a) The danger zone. An area in the Atlantic Ocean immediately offshore from...

  1. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  2. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  3. 33 CFR 334.590 - Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Cape Canaveral... RESTRICTED AREA REGULATIONS § 334.590 Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base, Fla. (a) The danger zone. An area in the Atlantic Ocean immediately offshore from...

  4. 33 CFR 334.590 - Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Cape Canaveral... RESTRICTED AREA REGULATIONS § 334.590 Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base, Fla. (a) The danger zone. An area in the Atlantic Ocean immediately offshore from...

  5. 33 CFR 334.590 - Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off Cape Canaveral... RESTRICTED AREA REGULATIONS § 334.590 Atlantic Ocean off Cape Canaveral, Fla.; Air Force missile testing area, Patrick Air Force Base, Fla. (a) The danger zone. An area in the Atlantic Ocean immediately offshore from...

  6. 33 CFR 334.500 - St. Johns River, Atlantic Ocean, Sherman Creek; restricted areas and danger zone, Naval Station...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false St. Johns River, Atlantic Ocean... AND RESTRICTED AREA REGULATIONS § 334.500 St. Johns River, Atlantic Ocean, Sherman Creek; restricted... area and the Atlantic Ocean restricted area described in paragraphs (a)(2) and (a)(3) of this section...

  7. 33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary to..., which are tributary to or connected by other waterways with the Atlantic Ocean south of Chesapeake...

  8. Mass, nutrient and oxygen budgets for the northeastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Maze, G.; Mercier, H.; Thierry, V.; Memery, L.; Morin, P.; Perez, F. F.

    2012-10-01

    The northeast Atlantic is a key horizontal and vertical crossroads region for the meridional overturning circulation, but basic nutrient and oxygen fluxes are still poorly constrained by observations in the region. A surface to bottom northeast Atlantic Ocean budget for mass, nutrients (nitrate and phosphate) and oxygen is determined using an optimization method based on three surveys of the OVIDE transect (from Greenland to Portugal) completed with the World Ocean Atlas 2009. Budgets are derived for two communicating boxes representing the northeastern European basin (NEEB) and the Irminger Sea. For the NEEB (Irminger) box, it is found that 30% of the mass import (export) across the OVIDE section reach (originate from) the Nordic Seas, while 70% are redistributed between both boxes through the Reykjanes Ridge (9.3 ± 0.7 × 109 kg s-1). Net biological source/sink terms of nitrate point to both the Irminger and NEEB boxes as net organic matter production sites (consuming nitrate at a rate of -7.8 ± 6.5 kmol s-1 and -8.4 ± 6.6 kmol s-1, respectively). Using a standard Redfield ratio of C : N = 106 : 16, nitrate consumption rates indicate that about 40 TgC yr-1 of carbon is fixed by organic matter production between the OVIDE transect and the Greenland-Scotland Ridge. Nutrient fluxes also induce a net biological production of oxygen of 73 ± 60 kmol s-1 and 79 ± 62 kmol s-1 in the Irminger and NEEB boxes, which points to the region as being autotrophic. The abiotic air-sea oxygen flux leads to an oceanic oxygen uptake in the two regions (264 ± 66 kmol s-1 in the north and 443 ± 70 kmol s-1 in the south). The abiotic flux is partitioned into a mixing and a thermal component. It is found that the Irminger Sea oceanic oxygen uptake is driven by an air-sea heat flux cooling increasing the ocean surface oxygen solubility. Over the northeastern European basin the mixing component is about half the thermal flux, presumably because of the oxygen minimum in the

  9. Ocean-Atmosphere coupling and CO2 exchanges in the Southwestern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Souza, R.; Pezzi, L. P.; Carmargo, R.; Acevedo, O. C.

    2013-05-01

    The establishment of the INTERCONF Program (Air-Sea Interactions at the Brazil-Malvinas Confluence Zone) in 2004 and subsequent developing of projects such as the SIMTECO (Integrated System for Monitoring the Weather, the Climate and the Ocean in the South of Brazil) and ACEx (Atlantic Ocean Carbon Experiment) from 2010 in Brazil brought to light the importance of understanding the impact of the Southwestern Atlantic Ocean's mesoscale variability on the modulation of the atmospheric boundary layer (ABL) at the synoptic scale. Recent results of all these projects showed that the ABL modulation, as well as the ocean-atmosphere turbulent (heat, momentum and CO2) fluxes are dependent on the behavior of the ocean's surface thermal gradients, especially those found in the Brazil-Malvinas Confluence Zone and at the southern coast off Brazil during the winter. As expected, when atmospheric large scale systems are not present over the study area, stronger heat fluxes are found over regions of higher sea surface temperature (SST) including over warm core eddies shed towards the subantarctic (cold) environment. In the coastal region off southern Brazil, the wintertime propagation of the Brazilian Costal Current (La Plata Plume) acts rising the chlorophyll concentration over the continental shelf as well as diminishing considerably the SST - hence producing prominent across-shore SST gradients towards the offshore region dominated by the Brazil Current waters. Owing to that, heat fluxes are directed towards the ocean in coastal waters that are also responsible for the carbon sinking off Brazil in wintertime. All this description is dependent on the synoptic atmospheric cycle and strongly perturbed when transient systems (cold fronts, subtropical cyclones) are present in the area. However, remote sensing data used here suggest that the average condition of the atmosphere directly responding to the ocean's mesoscale variability appears to imprint a signal that extends from the

  10. The Transient Tracers in the Ocean (TTO) program: The North Atlantic Study, 1981; The Tropical Atlantic Study, 1983

    NASA Astrophysics Data System (ADS)

    Brewer, Peter G.; Sarmiento, Jorge L.; Smethie, William M.

    1985-01-01

    The scientific papers here collected result from the Transient Tracers in the Ocean (TTO) program. The two parts of this major geochemical and physical oceanographie expedition took place in the North Atlantic Ocean in 1981 and in the Tropical Atlantic in 1983 on the research vessel Knorr of the Woods Hole Oceanographie Institution. The expeditions, sponsored by the National Science Foundation and the U.S. Department of Energy (North Atlantic only), were designed to observe the passage of man-made geochemical tracers into the interior of the ocean. The foundations for such an experiment were laid in the 1972-1978 GEOSECS program. Here, for the first time, a systematic survey revealed the penetration into the thermocline and deep ocean of the products of man's military/industrial activities, principally tritium and carbon-14 resulting from atmospheric testing of nuclear weapons, which terminated with the nuclear test ban treaty in 1962.

  11. Sea surface salinity fronts in the Tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Ruiz-Etcheverry, L.; Maximenko, N. A.; Melnichenko, O.

    2016-12-01

    Marine fronts are narrow boundaries that separate water masses of different properties. These fronts are caused by various forcing and believed to be an important component of the coupled ocean-atmosphere system, particularly in the tropical oceans. In this study, we use sea surface salinity (SSS) observations from Aquarius satellite to investigate the spatial structure and temporal variability of SSS fronts in the tropical Atlantic. A number of frontal features have been identified. The mean magnitude of the SSS gradient is maximum near the mouth of the Congo River (0.3-0.4 psu/100km). Relative maxima are also observed in the Inter Tropical Convergence Zone (ITCZ), the Gulf of Guinea, and the mouth of the Amazon River. The pattern of the magnitude of the SSS anomaly gradient revealed that the interaction between river plumes and saltier interior water is complex and highly variable during the three-year observation period. The variability of the magnitude of the density anomaly gradient computed from Aquarius SSS and Reynolds SST is also discussed. Images of the ocean color are utilized to trace the movement of the Congo and Amazon River plumes and compare them with the magnitude of the SSS gradient. Additionally, we analyze de circulation associated with the Amazon plume with altimetry data, and the vertical structure and its changes in time through Argo profiles.

  12. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A close-up of the recently recovered Liberty Bell 7 Project Mercury capsule from the ocean floor shows the lettering 'United States' still clearly visible on its side. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14-year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  13. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Retrieved from the ocean floor three miles deep, the Liberty Bell 7 Project Mercury capsule is revealed to photographers and the media in Port Canaveral, Fla. The capsule was found and raised by Curt Newport (left), leading an expedition sponsored by the Discovery Channel. After its successful 16-minute suborbital flight on July 21, 1961, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  14. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A close-up of the recently recovered Liberty Bell 7 Project Mercury capsule from the ocean floor shows the lettering 'United States' still clearly visible on its side. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14-year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  15. Late Quaternary carbonate accumulation along eastern South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Crabill, K.; Slowey, N. C.; Foreman, A. D.; Charles, C.

    2016-12-01

    Water masses originating from both the North Atlantic Ocean and the Southern Ocean intersect the Walvis Ridge and Namibian margin of southwest Africa. Changes in the distribution and properties of these water masses through time are reflected by variations in the nature of the sediments accumulating along this margin. A suite of piston and gravity cores that possess sediment records corresponding to the most recent glacial-interglacial cycles were collected from the water depth range of 550 to 3700 meters. Sediment dry bulk density, XRF analyses and the concentration of CaCO3 were precisely determined at regular depth intervals in these cores. Foraminiferal δ18O along with XRF Fe/Ca data provide an age-depth model for key cores. The age-depth model and dry bulk density will be used with the calcium carbonate contents to calculate the accumulation rates of CaCO3 during each MIS 1-5e. The spatial and temporal variability in both the CaCO3 content and the CaCO3 mass accumulation rates along the Namibian continental slope will be described. Based on comparisons of these two parameters, inferences will be made about how variations of CaCO3 production, dilution of by non-CaCO3 sediment components, and dissolution of CaCO3 due to changes in ocean circulation/climate have occurred during intervals of the last glacial-interglacial cycle.

  16. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Retrieved from the ocean floor three miles deep, the Liberty Bell 7 Project Mercury capsule is revealed to photographers and the media in Port Canaveral, Fla. The capsule was found and raised by Curt Newport (left), leading an expedition sponsored by the Discovery Channel. After its successful 16-minute suborbital flight on July 21, 1961, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  17. South Georgia Island in the South Atlantic Ocean

    NASA Image and Video Library

    1974-02-28

    SL4-142-4577 (28 Jan. 1974) --- Two large ice islands in the vicinity of South Georgia Island in the South Atlantic Ocean, as photographed from the Skylab space station in Earth orbit by one of the Skylab 4 crewmen. The camera used was a hand-held 70mm Hasselblad, with SO-368 medium-speed Ektachrome. One of the ice islands is partially obscured by clouds. Ice islands were observed as large as 45 by 60 kilometers (27 x 37 miles) and as far north as 45 degrees south latitude. The size and distribution of the "small" icebergs (to a ship they would look very large) can be used to study the local winds and currents. Recent research has suggested the possibility of towing such Antarctic icebergs to selected areas and using them as water supplies. One such iceberg would contain many times the water as in Lake Powell. Photo credit: NASA

  18. Sulfide in surface waters of the western Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cutter, Gregory A.; Krahforst, Christian F.

    1988-11-01

    Using newly developed techniques, some preliminary data on hydrogen sulfide in surface waters of the western Atlantic have been obtained. Concentrations of total sulfide range from <0.1 to 1.1 nmol/L, and vary on a diel basis. At these concentrations, sulfide may affect the cycling of several trace metals via the formation of stable complexes. Production of sulfide in oxygenated seawater may occur through the hydrolysis of carbonyl sulfide or by sulfate reduction within macroscopic particles in the water column. Removal mechanisms can include oxidation, complexation with particulate trace metals, and metal sulfide precipitation. However, the temporal and spatial distributions suggest a complex set of processes governing the behavior of sulfide in the surface ocean.

  19. Brazil, Atlantic Ocean, Africa & Antarctica seen from Apollo 4

    NASA Image and Video Library

    1967-11-09

    AS04-01-580 (9 Nov. 1967) --- Earth as viewed from 10,000 miles. In 1969, the Apollo 4 (Spacecraft 017/Saturn 501) unmanned test flight made a great ellipse around Earth as a test of the translunar motors and of the high speed entry required of a manned flight returning from the moon. A 70mm camera was programmed to look out a window toward Earth, and take a series of photographs from "high apogee". Coastal Brazil, Atlantic Ocean, West Africa, Antarctica, looking west. This photograph was made when the Apollo 4 spacecraft, still attached to the S-IVB (third) stage, was orbiting Earth at an altitude of 9,544 miles.

  20. GLOBEC (Global Ocean Ecosystems Dynamics: Northwest Atlantic program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The specific objective of the meeting was to plan an experiment in the Northwestern Atlantic to study the marine ecosystem and its role, together with that of climate and physical dynamics, in determining fisheries recruitment. The underlying focus of the GLOBEC initiative is to understand the marine ecosystem as it related to marine living resources and to understand how fluctuation in these resources are driven by climate change and exploitation. In this sense the goal is a solid scientific program to provide basic information concerning major fisheries stocks and the environment that sustains them. The plan is to attempt to reach this understanding through a multidisciplinary program that brings to bear new techniques as disparate as numerical fluid dynamic models of ocean circulation, molecular biology and modern acoustic imaging. The effort will also make use of the massive historical data sets on fisheries and the state of the climate in a coordinated manner.

  1. Macroecological patterns of archaeal ammonia oxidizers in the Atlantic Ocean.

    PubMed

    Sintes, Eva; De Corte, Daniele; Ouillon, Natascha; Herndl, Gerhard J

    2015-10-01

    Macroecological patterns are found in animals and plants, but also in micro-organisms. Macroecological and biogeographic distribution patterns in marine Archaea, however, have not been studied yet. Ammonia-oxidizing Archaea (AOA) show a bipolar distribution (i.e. similar communities in the northernmost and the southernmost locations, separated by distinct communities in the tropical and gyral regions) throughout the Atlantic, detectable from epipelagic to upper bathypelagic layers (<2000 m depth). This tentatively suggests an influence of the epipelagic conditions of organic matter production on bathypelagic AOA communities. The AOA communities below 2000 m depth showed a less pronounced biogeographic distribution pattern than the upper 2000 m water column. Overall, AOA in the surface and deep Atlantic waters exhibit distance-decay relationships and follow the Rapoport rule in a similar way as bacterial communities and macroorganisms. This indicates a major role of environmental conditions in shaping the community composition and assembly (species sorting) and no, or only weak limits for dispersal in the oceanic thaumarchaeal communities. However, there is indication of a different strength of these relationships between AOA and Bacteria, linked to the intrinsic differences between these two domains. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  2. Anthropogenic CO2 changes in the Equatorial Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Fajar, N. M.; Guallart, E. F.; Steinfeldt, R.; Ríos, A. F.; Pelegrí, J. L.; Pelejero, C.; Calvo, E.; Pérez, F. F.

    2015-05-01

    Methods based on CO2 and chlorofluorocarbon (CFC) data are used to describe and evaluate the anthropogenic CO2 (Cant) concentrations, Cant specific inventories, and Cant storage rates in the Equatorial Atlantic Ocean. The Cant variability in the water masses is evaluated from the comparison of two hydrographic sections along 7.5°N carried out in 1993 and 2010. During both cruises, high Cant concentrations are detected in the upper layers, with values decreasing progressively towards the deep layers. Overall, the Cant concentrations increase from 1993 to 2010, with a large increment in the upper North Atlantic Deep Water layer of about 0.18 ± 0.03 μmol kg-1 y-1. In 2010, the Cant inventory along the whole section amounts to 58.9 ± 2.2 and 45.1 ± 2.0 mol m-2 using CO2 and CFC based methods, respectively, with most Cant accumulating in the western basin. Considering the time elapsed between the two cruises, Cant storage rates of 1.01 ± 0.18 and 0.75 ± 0.17 mol m-2 y-1 (CO2 and CFC based methods, respectively) are obtained. Below ∼1000 m, these rates follow the pace expected from a progressive increase of Cant at steady state; above ∼1000 m, Cant increases faster, mainly due to the retreat of the Antarctic Intermediate Waters.

  3. Melt anomalies of the northern Atlantic Ocean basin

    NASA Astrophysics Data System (ADS)

    Wang, T.; Lin, J.; Tucholke, B. E.

    2009-12-01

    We investigated the melt anomalies and lithosphere dynamics of the northern Atlantic Ocean between 76°N and 8°S through combined analysis of seafloor bathymetry, shipboard and satellite-derived gravity, and sediment thickness. Residual mantle Bouguer anomaly (RMBA) was calculated by removing from free-air gravity anomaly the predicted attractions of water-sediment, sediment-crust, and crust-mantle interfaces as well as the effect of lithospheric plate cooling. Residual bathymetry anomaly (RBA) was obtained by subtracting from observed seafloor topography the predicted effects of plate cooling and the observed sediment load. Our analysis indicates that more than 50% of the seafloor has been affected by melt anomalies. The most prominent features that we observe include: (1) A pronounced negative RMBA associated with the Iceland hotspot, the Reykjanes Ridge, and the Mid-Atlantic Ridge (MAR) north of Iceland. The region of enhanced magma supply extends southward to the Charlie Gibbs F.Z., northward to the Jan Mayen F.Z., and to both the eastern and western basin margins. The strong negative RMBA associated with the submarine part of the Iceland hotspot reaches -450 mGal, corresponding to modeled crustal thickness of more than 22 km. (2) A widespread effect of the Azores hotspot on crustal accretion at the MAR since 40-50 Ma, as reflected in negative RMBA and positive RBA that extend southward to at least 26.5°N and northward to 44°N. The strongest RMBA anomaly associated with the Azores melt anomaly reaches about -230 mGal, corresponding to crustal thickening about half of that in Iceland. (3) A ~ 500 km wide corridor of negative RMBA is found along the west African margin between 40°N and 6°S, indicating that this region was influenced extensively by melt anomalies associated with the Horseshoe Seamounts, Madeira Islands, Canary Islands, and Cape Verde Islands. Negative RMBA of -100 to -180 mGal is also associated with the Bermuda Rise in the western Atlantic

  4. Variations in freshwater pathways from the Arctic Ocean into the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Wang, Zeliang; Hamilton, James; Su, Jie

    2017-06-01

    Understanding the mechanisms that drive exchanges between the Arctic Ocean and adjacent oceans is critical to building our knowledge of how the Arctic is reacting to a warming climate, and how potential changes in Arctic Ocean freshwater export may impact the AMOC (Atlantic Meridional Overturning Circulation). Here, freshwater pathways from the Arctic Ocean to the North Atlantic are investigated using a 1 degree global model. An EOF analysis of modeled sea surface height (SSH) demonstrates that while the second mode accounts for only 15% of the variability, the associated geostrophic currents are strongly correlated with freshwater exports through CAA (Canadian Arctic Archipelago; r = 0.75), Nares Strait (r = 0.77) and Fram Strait (r = -0.60). Separation of sea level into contributing parts allows us to show that the EOF1 is primarily a barotropic mode reflecting variability in bottom pressure equivalent sea level, while the EOF2 mode reflects changes in steric height in the Arctic Basin. This second mode is linked to momentum wind driven surface current, and dominates the Arctic Ocean freshwater exports. Both the Arctic Oscillation and Arctic Dipole atmospheric indices are shown to be linked to Arctic Ocean freshwater exports, with the forcing associated with the Arctic Dipole reflecting the out-of-phase relationship between transports through the CAA and those through Fram Strait. Finally, observed freshwater transport variation through the CAA is found to be strongly correlated with tide gauge data from the Beaufort Sea coast (r = 0.81), and with the EOF2 mode of GRACE bottom pressure data (r = 0.85) on inter-annual timescales.

  5. Abundant proteorhodopsin genes in the North Atlantic Ocean.

    PubMed

    Campbell, Barbara J; Waidner, Lisa A; Cottrell, Matthew T; Kirchman, David L

    2008-01-01

    Proteorhodopsin (PR) is a light-driven proton pump that has been found in a variety of marine bacteria, including Pelagibacter ubique, a member of the ubiquitous SAR11 clade. The goals of this study were to explore the diversity of PR genes and to estimate their abundance in the North Atlantic Ocean using quantitative polymerase chain reaction (QPCR). We found that PR genes in the western portion of the Sargasso Sea could be grouped into 27 clusters, but five clades had the most sequences. Sets of specific QPCR primers were designed to examine the abundance of PR genes in the following four of the five clades: SAR11 (P. ubique and other SAR11 Alphaproteobacteria), BACRED17H8 (Alphaproteobacteria), HOT2C01 (Alphaproteobacteria) and an uncultured subgroup of the Flavobacteria. Two groups (SAR11 and HOT2C01) dominated PR gene abundance in oligotrophic waters, but were significantly less abundant in nutrient- and chlorophyll-rich waters. The other two groups (BACRED17H8 and Flavobacteria subgroup NASB) were less abundant in all waters. Together, these four PR gene types were found in 50% of all bacteria in the Sargasso Sea. We found a significant negative correlation between total PR gene abundance and nutrients and chlorophyll but no significant correlation with light intensity for three of the four PR types in the depth profiles north of the Sargasso Sea. Our data suggest that PR is common in the North Atlantic Ocean, especially in SAR11 bacteria and another marine alphaproteobacterial group (HOT2C01), and that these PR-bearing bacteria are most abundant in oligotrophic waters.

  6. Chondrichthyan egg cases from the south-west Atlantic Ocean.

    PubMed

    Mabragaña, E; Figueroa, D E; Scenna, L B; Díaz de Astarloa, J M; Colonello, J H; Delpiani, G

    2011-11-01

    Egg cases of 21 oviparous chondrichthyan species from the south-west Atlantic Ocean are described and compared. The catshark Schroederichthys bivius has a cigar-shaped egg case with curled tendrils only at the posterior end. Egg cases of the elephant fish Callorhinchus callorynchus are spindle-shaped with anterior and posterior tubular extensions and lateral flanges. The skate Amblyraja doellojuradoi presents medium-sized egg cases (71 mm in length) with a lateral keel extending to the first portion of the horns. The endemic skate species of the genus Atlantoraja have medium to large egg cases (69-104 mm in length) and present relatively large posterior horns. Egg cases of the genus Bathyraja have a medium size, 75-98 mm in length, and are characterized by a very similar morphology, a relatively smooth to rough surface case and posterior horns strongly curved inwards. Egg cases of the genera Dipturus and Zearaja are very large, 115-230 mm in length, and have a well-developed posterior apron. Despite the problematical identification of skates at species level, the egg capsules of the endemic genus Psammobatis are easily diagnosed; the capsules are small (25-53 mm in length), those of Psammobatis rutrum being the smallest known to date in the world. Egg cases of Rioraja agassizi have a medium size, 61-68 mm in length, relatively straight sides, a smooth surface and silky attachment fibres placed in the lateral keel next to each horn. Those of the genus Sympterygia are small to medium sized, 51-86 mm in length, and display the thickest lateral keel and the longest posterior horns among the skates of the world. Egg cases can be a useful tool for identifying species and egg-laying areas; therefore, a provisional key for the south-west Atlantic Ocean chondrichthyan capsules is presented.

  7. Comparison of Deep-Water Viromes from the Atlantic Ocean and the Mediterranean Sea

    PubMed Central

    Winter, Christian; Garcia, Juan A. L.; Weinbauer, Markus G.; DuBow, Michael S.; Herndl, Gerhard J.

    2014-01-01

    The aim of this study was to compare the composition of two deep-sea viral communities obtained from the Romanche Fracture Zone in the Atlantic Ocean (collected at 5200 m depth) and the southwest Mediterranean Sea (from 2400 m depth) using a pyro-sequencing approach. The results are based on 18.7% and 6.9% of the sequences obtained from the Atlantic Ocean and the Mediterranean Sea, respectively, with hits to genomes in the non-redundant viral RefSeq database. The identifiable richness and relative abundance in both viromes were dominated by archaeal and bacterial viruses accounting for 92.3% of the relative abundance in the Atlantic Ocean and for 83.6% in the Mediterranean Sea. Despite characteristic differences in hydrographic features between the sampling sites in the Atlantic Ocean and the Mediterranean Sea, 440 virus genomes were found in both viromes. An additional 431 virus genomes were identified in the Atlantic Ocean and 75 virus genomes were only found in the Mediterranean Sea. The results indicate that the rather contrasting deep-sea environments of the Atlantic Ocean and the Mediterranean Sea share a common core set of virus types constituting the majority of both virus communities in terms of relative abundance (Atlantic Ocean: 81.4%; Mediterranean Sea: 88.7%). PMID:24959907

  8. Comparison of deep-water viromes from the atlantic ocean and the mediterranean sea.

    PubMed

    Winter, Christian; Garcia, Juan A L; Weinbauer, Markus G; DuBow, Michael S; Herndl, Gerhard J

    2014-01-01

    The aim of this study was to compare the composition of two deep-sea viral communities obtained from the Romanche Fracture Zone in the Atlantic Ocean (collected at 5200 m depth) and the southwest Mediterranean Sea (from 2400 m depth) using a pyro-sequencing approach. The results are based on 18.7% and 6.9% of the sequences obtained from the Atlantic Ocean and the Mediterranean Sea, respectively, with hits to genomes in the non-redundant viral RefSeq database. The identifiable richness and relative abundance in both viromes were dominated by archaeal and bacterial viruses accounting for 92.3% of the relative abundance in the Atlantic Ocean and for 83.6% in the Mediterranean Sea. Despite characteristic differences in hydrographic features between the sampling sites in the Atlantic Ocean and the Mediterranean Sea, 440 virus genomes were found in both viromes. An additional 431 virus genomes were identified in the Atlantic Ocean and 75 virus genomes were only found in the Mediterranean Sea. The results indicate that the rather contrasting deep-sea environments of the Atlantic Ocean and the Mediterranean Sea share a common core set of virus types constituting the majority of both virus communities in terms of relative abundance (Atlantic Ocean: 81.4%; Mediterranean Sea: 88.7%).

  9. Tracing the Sinking of Dense Ocean Waters in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Brueggemann, N.; Katsman, C. A.; Dijkstra, H.

    2016-02-01

    In this study, we investigate the sinking of dense water masses in the North Atlantic. Therefore, we use data from an eddy permitting (0.1o) ocean model of the Parallel Ocean Program (POP). Velocity fields of the model are used to advect Lagrangian floats with the Connectivity Modelling System (CMS). Model and float data are used to identify regions where water masses sink into the deep ocean. Theoretical considerations predict that water masses can only sink if the geostrophic balance is broken. We identify mechanisms that are responsible for the ageostrophic dynamics and compare our findings with frequently discussed theories. Since eddies seem to play a dominant role for the deep water sinking, it is questionable to which extent coarser resolved ocean models that do not resolve the eddies are able to capture the deep water sinking. Especially, we aim to clarify if the sinking in a coarser resolved counterpart of the POP ocean model (1o) is due to different mechanisms compared to its eddy permitting (0.1o) counterpart. By this, we aim at understanding how the deep sinking of water masses as one part of the Meridional Overturning Circulation is represented in typically coarser resolved climate models and how realistic these processes are represented in comparison to higher resolved ocean models.

  10. Temporal and spatial variability of cobalt in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Saito, Mak A.; Moffett, James W.

    2002-06-01

    The spatial and temporal variability of cobalt in the Atlantic Ocean was investigated by means of adsorptive cathodic stripping voltammetry. A vertical profile of total dissolved cobalt at the Bermuda Atlantic Time Series station ranged from 17 to 73 pM and displayed surface depletion indicative of biological utilization. This profile when compared with a cobalt profile from the northeast Pacific shows no increase in deep-water concentrations with thermohaline circulation through the deep ocean basins. Moreover, the middepth maximum observed in northeast Pacific profiles is not present in the Sargasso Sea, perhaps because of the lack of cobalt scavenging by particulate manganese oxides in surface waters and to the absence of a suboxic oxygen minimum zone, which, if present, could dissolve the manganese oxides. Total dissolved cobalt measurements were also made on a surface transect from the Sargasso Sea to coastal Massachusetts, USA, and on time-series samples from the Moored In Situ Trace Element Serial Sampler. Dissolved cobalt on this transect correlated strongly with salinity (r2 = 0.93) and ranged from 19 to 133 pM, indicating mixing of cobalt from shelf waters into the Sargasso Sea. Time-series samples near Bermuda did not show an obvious response to the summer maximum in aeolian dust deposition, with an annual average of 20 ± 10 pM at 40- to 47-m depths. By use of this annual value and particulate cobalt data from the literature, 100-m surface-water residence times were calculated to be as low as 0.32 yr for cobalt. Several sharp decreases in cobalt were observed in the time series that occurred simultaneously with a shallowing of the thermocline depth. These decreases could be caused by nutrient drawdown associated with higher productivity mesoscale eddy events. A west-east surface transect across the South Atlantic showed high cobalt concentrations at the boundaries of the transect and low concentrations in the center despite the high precipitation rates

  11. Antimony and arsenic biogeochemistry in the western Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cutter, Gregory A.; Cutter, Lynda S.; Featherstone, Alison M.; Lohrenz, Steven E.

    The subtropical to equatorial Atlantic Ocean provides a unique regime in which one can examine the biogeochemical cycles of antimony and arsenic. In particular, this region is strongly affected by inputs from the Amazon River and dust from North Africa at the surface, and horizontal transport at depth from high-latitude northern (e.g., North Atlantic Deep Water) and southern waters (e.g., Antarctic Bottom and Intermediate Waters). As a part of the 1996 Intergovernmental Oceanographic Commission's Contaminant Baseline Survey, data for dissolved As(III+V), As(III), mono- and dimethyl arsenic, Sb(III+V), Sb(III), and monomethyl antimony were obtained at six vertical profile stations and 44 sites along the 11,000 km transect from Montevideo, Uruguay, to Bridgetown, Barbados. The arsenic results were similar to those in other oceans, with moderate surface depletion, deep-water enrichment, a predominance of arsenate (>85% As(V)), and methylated arsenic species and As(III) in surface waters that are likely a result of phytoplankton conversions to mitigate arsenate "stress" (toxicity). Perhaps the most significant discovery in the arsenic results was the extremely low concentrations in the Amazon Plume (as low as 9.8 nmol/l) that appear to extend for considerable distances offshore in the equatorial region. The very low concentration of inorganic arsenic in the Amazon River (2.8 nmol/l; about half those in most rivers) is probably the result of intense iron oxyhydroxide scavenging. Dissolved antimony was also primarily in the pentavalent state (>95% antimonate), but Sb(III) and monomethyl antimony were only detected in surface waters and displayed no correlations with biotic tracers such as nutrients and chlorophyll a. Unlike As(III+V)'s nutrient-type vertical profiles, Sb(III+V) displayed surface maxima and decreased into the deep waters, exhibiting the behavior of a scavenged element with a strong atmospheric input. While surface water Sb had a slight correlation with

  12. 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

  13. Tropical climate variability: interactions across the Pacific, Indian, and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Kajtar, Jules B.; Santoso, Agus; England, Matthew H.; Cai, Wenju

    2016-06-01

    Complex interactions manifest between modes of tropical climate variability across the Pacific, Indian, and Atlantic Oceans. For example, the El Niño-Southern Oscillation (ENSO) extends its influence on modes of variability in the tropical Indian and Atlantic Oceans, which in turn feed back onto ENSO. Interactions between pairs of modes can alter their strength, periodicity, seasonality, and ultimately their predictability, yet little is known about the role that a third mode plays. Here we examine the interactions and relative influences between pairs of climate modes using ensembles of 100-year partially coupled experiments in an otherwise fully coupled general circulation model. In these experiments, the air-sea interaction over each tropical ocean basin, as well as pairs of ocean basins, is suppressed in turn. We find that Indian Ocean variability has a net damping effect on ENSO and Atlantic Ocean variability, and conversely they each promote Indian Ocean variability. The connection between the Pacific and the Atlantic is most clearly revealed in the absence of Indian Ocean variability. Our model runs suggest a weak damping influence by Atlantic variability on ENSO, and an enhancing influence by ENSO on Atlantic variability.

  14. Tropical climate variability: interactions across the Pacific, Indian, and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Kajtar, Jules B.; Santoso, Agus; England, Matthew H.; Cai, Wenju

    2017-04-01

    Complex interactions manifest between modes of tropical climate variability across the Pacific, Indian, and Atlantic Oceans. For example, the El Niño-Southern Oscillation (ENSO) extends its influence on modes of variability in the tropical Indian and Atlantic Oceans, which in turn feed back onto ENSO. Interactions between pairs of modes can alter their strength, periodicity, seasonality, and ultimately their predictability, yet little is known about the role that a third mode plays. Here we examine the interactions and relative influences between pairs of climate modes using ensembles of 100-year partially coupled experiments in an otherwise fully coupled general circulation model. In these experiments, the air-sea interaction over each tropical ocean basin, as well as pairs of ocean basins, is suppressed in turn. We find that Indian Ocean variability has a net damping effect on ENSO and Atlantic Ocean variability, and conversely they each promote Indian Ocean variability. The connection between the Pacific and the Atlantic is most clearly revealed in the absence of Indian Ocean variability. Our model runs suggest a weak damping influence by Atlantic variability on ENSO, and an enhancing influence by ENSO on Atlantic variability.

  15. An intimate coupling of ocean-atmospheric interaction over the extratropical North Atlantic and Pacific

    NASA Astrophysics Data System (ADS)

    Li, Chun; Wu, Lixin; Wang, Qi; Qu, Liwei; Zhang, Liping

    2009-05-01

    The inter-basin teleconnection between the North Atlantic and the North Pacific ocean-atmosphere interaction is studied using a coupled ocean-atmosphere general circulation model. In the model, an idealized oceanic temperature anomaly is initiated over the Kuroshio and the Gulf Stream extension region to track the coupled evolution of ocean and atmosphere interaction, respectively. The experiments explicitly demonstrate that both the North Pacific and the North Atlantic ocean-atmosphere interactions are intimately coupled through an inter-basin atmospheric teleconnection. This fast inter-basin communication can transmit oceanic variability between the North Atlantic and the North Pacific through local ocean-to-atmosphere feedbacks. The leading mode of the extratropical atmospheric internal variability plays a dominant role in shaping the hemispheric-scale response forced by oceanic variability over the North Atlantic and Pacific. Modeling results also suggest that a century (two centuries) long observations are necessary for the detection of Pacific response to Atlantic forcings (Atlantic response to Pacific forcing).

  16. Comment on "The Atlantic Multidecadal Oscillation without a role for ocean circulation".

    PubMed

    Zhang, Rong; Sutton, Rowan; Danabasoglu, Gokhan; Delworth, Thomas L; Kim, Who M; Robson, Jon; Yeager, Stephen G

    2016-06-24

    Clement et al (Reports, 16 October 2015, p. 320) claim that the Atlantic Multidecadal Oscillation (AMO) is a thermodynamic response of the ocean mixed layer to stochastic atmospheric forcing and that ocean circulation changes have no role in causing the AMO. These claims are not justified. We show that ocean dynamics play a central role in the AMO.

  17. Comment on “The Atlantic Multidecadal Oscillation without a role for ocean circulation”

    NASA Astrophysics Data System (ADS)

    Zhang, Rong; Sutton, Rowan; Danabasoglu, Gokhan; Delworth, Thomas L.; Kim, Who M.; Robson, Jon; Yeager, Stephen G.

    2016-06-01

    Clement et al. (Reports, 16 October 2015, p. 320) claim that the Atlantic Multidecadal Oscillation (AMO) is a thermodynamic response of the ocean mixed layer to stochastic atmospheric forcing and that ocean circulation changes have no role in causing the AMO. These claims are not justified. We show that ocean dynamics play a central role in the AMO.

  18. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Gunther Wendt takes a turn at the podium after viewing the recovered Liberty Bell 7 Project Mercury capsule, seen in the background. At right is Curt Newport who led the expedition to find and retrieve the capsule. The expedition was sponsored by the Discovery Channel. Wendt worked on the Liberty Bell 7 before its launch July 21, 1961. After its successful 16-minute suborbital flight, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  19. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This photograph shows two mercury dimes that were found inside the recently recovered Liberty Bell 7 Project Mercury capsule. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14- year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The dimes had apparently been placed in the capsule before its launch July 21, 1961. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  20. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Gunther Wendt takes a turn at the podium after viewing the recovered Liberty Bell 7 Project Mercury capsule, seen in the background. At right is Curt Newport who led the expedition to find and retrieve the capsule. The expedition was sponsored by the Discovery Channel. Wendt worked on the Liberty Bell 7 before its launch July 21, 1961. After its successful 16-minute suborbital flight, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  1. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This photograph shows two mercury dimes that were found inside the recently recovered Liberty Bell 7 Project Mercury capsule. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14- year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The dimes had apparently been placed in the capsule before its launch July 21, 1961. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  2. Acoustic habitat of an oceanic archipelago in the Southwestern Atlantic

    NASA Astrophysics Data System (ADS)

    Bittencourt, Lis; Barbosa, Mariana; Secchi, Eduardo; Lailson-Brito, José; Azevedo, Alexandre

    2016-09-01

    Underwater soundscapes can be highly variable, and in natural conditions are often dominated by biological signals and physical features of the environment. Few studies, however, focused on oceanic islands soundscapes. Islands in the middle of ocean basins can provide a good example of how untouched marine soundscapes are. Autonomous acoustic recordings were carried out in two different seasons in Trindade-Martin Vaz Archipelago, Southwestern Atlantic, providing nearly continuous data for both periods. Sound levels varied daily and between seasons. During summer, higher frequencies were noisier than lower frequencies, with snapping shrimp being the dominating sound source. During winter, lower frequencies were noisier than higher frequencies due to humpback whale constant singing. Biological signal detection had a marked temporal pattern, playing an important role in the soundscape. Over 1000 humpback whale sounds were detected hourly during winter. Fish vocalizations were detected mostly during night time during both summer and winter. The results show an acoustic habitat dominated by biological sound sources and highlight the importance of the island to humpback whales in winter.

  3. Changes in ocean circulation in the South-east Atlantic Ocean during the Pliocene

    NASA Astrophysics Data System (ADS)

    Petrick, B. F.; McClymont, E.; Felder, S.; Leng, M. J.

    2013-12-01

    The Southeast Atlantic Ocean is an important ocean gateway because major oceanic systems interact with each other in a relatively small geographic area. These include the Benguela Current, Antarctic Circumpolar Current, and the input of warm and saline waters from the Indian Ocean via the Agulhas leakage. However, there remain questions about circulation change in this region during the Pliocene, including whether there was more or less Agulhas Leakage, which may have implications for the strength of the global thermohaline circulation. ODP Site 1087 (31°28'S, 15°19'E, 1374m water depth) is located outside the Benguela upwelling region and is affected by Agulhas leakage in the modern ocean. Sea-surface temperatures (SSTs) are thus sensitive to the influence of Agulhas Leakage at this site. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the Pliocene history of ODP 1087, including the UK37' index (SSTs), pigments (primary productivity) and planktonic foraminifera (water mass changes). SSTs during the Pliocene range from 17 to 22.5 °C (mean SSTs at 21 °C), and show variability on orbital and suborbital time scales. Our results indicate that the Benguela upwelling system had intensified and/or shifted south during the Pliocene. We find no evidence of Agulhas leakage, meaning that either Agulhas Leakage was severely reduced or displaced during the mid-Pliocene. Potential causes of the observed signals include changes to the local wind field and/or changes in the temperature of intermediate waters which upwell in the Benguela system. Pronounced cooling is observed during cold stages in the Pliocene, aligned with the M2 and KM2 events. These results may indicate that changes to the extent of the Antarctic ice sheet had impact on circulation in the south east Atlantic during the Pliocene via displacement of the Antarctic Circumpolar Currents.

  4. Molecular biogeochemical provinces in the Atlantic Surface Ocean

    NASA Astrophysics Data System (ADS)

    Koch, B. P.; Flerus, R.; Schmitt-Kopplin, P.; Lechtenfeld, O. J.; Bracher, A.; Cooper, W.; Frka, S.; Gašparović, B.; Gonsior, M.; Hertkorn, N.; Jaffe, R.; Jenkins, A.; Kuss, J.; Lara, R. J.; Lucio, M.; McCallister, S. L.; Neogi, S. B.; Pohl, C.; Roettgers, R.; Rohardt, G.; Schmitt, B. B.; Stuart, A.; Theis, A.; Ying, W.; Witt, M.; Xie, Z.; Yamashita, Y.; Zhang, L.; Zhu, Z. Y.; Kattner, G.

    2010-12-01

    One of the most important aspects to understand marine organic carbon fluxes is to resolve the molecular mechanisms which convert fresh, labile biomolecules into semi-labile and refractory dissolved and particulate organic compounds in the ocean. In this interdisciplinary project, which was performed on a cruise with RV Polarstern, we carried out a detailed molecular characterisation of dissolved organic matter (DOM) on a North-South transect in the Atlantic surface ocean in order to relate the data to different biological, climatic, oceanographic, and meteorological regimes as well as to terrestrial input from riverine and atmospheric sources. Our goal was to achieve a high resolution data set for the biogeochemical characterisation of the sources and reactivity of DOM. We applied ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS), nutrient, trace element, amino acid, and lipid analyses and other biogeochemical measurements for 220 samples from the upper water column (0-200m) and eight deep profiles. Various spectroscopic techniques were applied continuously in a constant sample water flow supplied by a fish system and the moon pool. Radiocarbon dating enabled assessing DOC residence time. Bacterial abundance and production provided a metabolic context for the DOM characterization work and pCO2 concentrations. Combining molecular organic techniques and inductively coupled plasma mass spectrometry (ICP-MS) established an important link between organic and inorganic biogeochemical studies. Multivariate statistics, primarily based on FT-ICR-MS data for 220 samples, allowed identifying geographical clusters which matched ecological provinces proposed previously by Longhurst (2007). Our study demonstrated that marine DOM carries molecular information reflecting the “history” of ocean water masses. This information can be used to define molecular biogeochemical provinces and to improve our understanding of element fluxes in

  5. North Atlantic Ocean control on surface heat flux on multidecadal timescales.

    PubMed

    Gulev, Sergey K; Latif, Mojib; Keenlyside, Noel; Park, Wonsun; Koltermann, Klaus Peter

    2013-07-25

    Nearly 50 years ago Bjerknes suggested that the character of large-scale air-sea interaction over the mid-latitude North Atlantic Ocean differs with timescales: the atmosphere was thought to drive directly most short-term--interannual--sea surface temperature (SST) variability, and the ocean to contribute significantly to long-term--multidecadal--SST and potentially atmospheric variability. Although the conjecture for short timescales is well accepted, understanding Atlantic multidecadal variability (AMV) of SST remains a challenge as a result of limited ocean observations. AMV is nonetheless of major socio-economic importance because it is linked to important climate phenomena such as Atlantic hurricane activity and Sahel rainfall, and it hinders the detection of anthropogenic signals in the North Atlantic sector. Direct evidence of the oceanic influence of AMV can only be provided by surface heat fluxes, the language of ocean-atmosphere communication. Here we provide observational evidence that in the mid-latitude North Atlantic and on timescales longer than 10 years, surface turbulent heat fluxes are indeed driven by the ocean and may force the atmosphere, whereas on shorter timescales the converse is true, thereby confirming the Bjerknes conjecture. This result, although strongest in boreal winter, is found in all seasons. Our findings suggest that the predictability of mid-latitude North Atlantic air-sea interaction could extend beyond the ocean to the climate of surrounding continents.

  6. Knowledge of marine fish trematodes of Atlantic and Eastern Pacific Oceans.

    PubMed

    Bray, Rodney A; Diaz, Pablo E; Cribb, Thomas H

    2016-03-01

    A brief summary of the early history of the study of Atlantic Ocean marine fish digeneans is followed by a discussion of the occurrence and distribution of these worms in the Atlantic Ocean and adjacent Eastern Pacific Ocean, using the Provinces of the 'Marine Ecoregions' delimited by Spalding et al. (Bioscience 57:573-583, 2007). The discussion is based on a database of 9,880 records of 1,274 species in 430 genera and 45 families. 8,633 of these records are from the Atlantic Ocean, including 1,125 species in 384 genera and 45 families. About 1,000 species are endemic to the Atlantic Ocean Basin. The most species-rich families in the Atlantic Ocean are the Opecoelidae Ozaki, 1925, Hemiuridae Looss, 1899 and Bucephalidae Poche, 1907, and the most wide-spread the Opecoelidae, Hemiuridae, Acanthocolpidae Lühe, 1906, Lepocreadiidae Odhner, 1905 and Lecithasteridae Odhner, 1905. A total of 109 species are shared by the Atlantic Ocean and the Eastern Pacific, made up of cosmopolitan, circum-boreal, trans-Panama Isthmus and Magellanic species. The lack of genetic evaluation of identifications is emphasised and the scope for much more work is stressed.

  7. Atlantic Ocean Carbon Experiment (acex): Implementation of Eddy Covariance Implementation of Eddy Covariance CO2 Flux Measurements on the SW Atlantic Ocean and Results from the Second Cruise

    NASA Astrophysics Data System (ADS)

    Schultz, C.; Pezzi, L. P.; Miller, S. D.; Martins, L. G.; Araujo, R. G.; Acevedo, O. C.; Moller, O.; Souza, R.; Tavano, V. M.; Farias, P.; Casagrande, F.

    2013-05-01

    The project observational and numerical study of heat, momentum and CO2 fluxes at the ocean-atmosphere interface in the South Atlantic Ocean - Atlantic Ocean Carbon Experiment (ACEx) combines observational and modeling approaches to characterize heat, momentum and CO2 fluxes at the ocean-atmosphere interface in the South Atlantic Ocean. This project is part of an innovative initiative aimed at providing a better understanding of the chemical, physical and dynamic processes of ocean-atmosphere interaction in micro and meso-scales at the South Atlantic Ocean, as well as fluxes across this interface. The ACEx project has performed three cruises so far, collecting measurements with CTDs and XBTs, launching radiosondes, and deploying a micro-meteorological tower to make in situ measurements of heat, momentum and CO2 fluxes. Our successful deployment of this tower represents the first use of a CO2 flux measurement system using eddy covariance technique in the Southwestern Atlantic Ocean. In this work, we present results from the second ACEx cruise, in which the crew onboard the Hydro-oceanographic Vessel Cruzeiro do Sul took measurements at 31 stations between Paranaguá (PR) and Chuí (RS). In addition to physical data, this cruise collected phytoplankton and nutrient data, allowing carbonic gas fluxes to be analyzed and compared with both physical and biological forcings. The highest chlorophyll concentrations were found in water derived from the La Plata River, which showed low salinity waters close to the surface. The influence of these waters was observed mainly at the southernmost stations of the cruise, coincident with increases on the CO2 fluxes that had remained slightly negative until then. This suggests that the biological forcings might have a significant impact on the gas fluxes in this area, through both respiration and the consumption of organic matter. We are currently working to apply circulation and biogeochemical models to evaluate the importance of

  8. Recent Changes in Arctic Ocean Sea Ice Motion Associated with the North Atlantic Oscillation

    NASA Technical Reports Server (NTRS)

    Kwok, R.

    1999-01-01

    Examination of a new ice motion dataset of the Arctic Ocean over a recent eighteen year period (1978-1996) reveals patterns of variability that can be linked directly to the North Atlantic Oscillation.

  9. Early opening of initially closed Gulf of Mexico and central North Atlantic ocean

    SciTech Connect

    Van Siclen, D.C.

    1984-09-01

    This paper presents ideas on the early opening and evolution of the Gulf of Mexico and the central North Atlantic ocean. It discusses rifting activity, plate tectonics, magnetic anomalies, and the geologic time elements involved.

  10. 78 FR 31840 - Safety Zone; USO Patriotic Festival Air Show, Atlantic Ocean; Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-28

    ... Patriotic Festival Air Show. This action is intended to restrict vessel traffic movement in the restricted... navigable waters of the Atlantic Ocean in Virginia Beach, VA in order to restrict vessel traffic movement to...

  11. 77 FR 50062 - Safety Zone; Embry-Riddle Wings and Waves, Atlantic Ocean; Daytona Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Embry-Riddle Wings and Waves, Atlantic... Daytona Beach, Florida during the Embry-Riddle Wings and Waves air show. The event is scheduled to take...: Sec. 165.T07-0653 Safety Zone; Embry Riddle Wings and Waves, Atlantic Ocean, Daytona Beach, FL....

  12. Depth Profiles of Persistent Organic Pollutants in the North and Tropical Atlantic Ocean.

    PubMed

    Sun, Caoxin; Soltwedel, Thomas; Bauerfeind, Eduard; Adelman, Dave A; Lohmann, Rainer

    2016-06-21

    Little is known of the distribution of persistent organic pollutants (POPs) in the deep ocean. Polyethylene passive samplers were used to detect the vertical distribution of truly dissolved POPs at two sites in the Atlantic Ocean. Samplers were deployed at five depths covering 26-2535 m in the northern Atlantic and Tropical Atlantic, in approximately one year deployments. Samplers of different thickness were used to determine the state of equilibrium POPs reached in the passive samplers. Concentrations of POPs detected in the North Atlantic near the surface (e.g., sum of 14 polychlorinated biphenyls, PCBs: 0.84 pg L(-1)) were similar to previous measurements. At both sites, PCB concentrations showed subsurface maxima (tropical Atlantic Ocean -800 m, North Atlantic -500 m). Currents seemed more important in moving POPs to deeper water masses than the biological pump. The ratio of PCB concentrations in near surface waters (excluding PCB-28) between the two sites was inversely correlated with congeners' subcooled liquid vapor pressure, in support of the latitudinal fractionation. The results presented here implied a significant amount of HCB is stored in the Atlantic Ocean (4.8-26% of the global HCB environmental burdens), contrasting traditional beliefs that POPs do not reach the deep ocean.

  13. Southern Ocean origin for the resumption of Atlantic thermohaline circulation during deglaciation.

    PubMed

    Knorr, Gregor; Lohmann, Gerrit

    2003-07-31

    During the two most recent deglaciations, the Southern Hemisphere warmed before Greenland. At the same time, the northern Atlantic Ocean was exposed to meltwater discharge, which is generally assumed to reduce the formation of North Atlantic Deep Water. Yet during deglaciation, the Atlantic thermohaline circulation became more vigorous, in the transition from a weak glacial to a strong interglacial mode. Here we use a three-dimensional ocean circulation model to investigate the impact of Southern Ocean warming and the associated sea-ice retreat on the Atlantic thermohaline circulation. We find that a gradual warming in the Southern Ocean during deglaciation induces an abrupt resumption of the interglacial mode of the thermohaline circulation, triggered by increased mass transport into the Atlantic Ocean via the warm (Indian Ocean) and cold (Pacific Ocean) water route. This effect prevails over the influence of meltwater discharge, which would oppose a strengthening of the thermohaline circulation. A Southern Ocean trigger for the transition into an interglacial mode of circulation provides a consistent picture of Southern and Northern hemispheric climate change at times of deglaciation, in agreement with the available proxy records.

  14. Persistent organic pollutants in the Atlantic and southern oceans and oceanic atmosphere.

    PubMed

    Luek, Jenna L; Dickhut, Rebecca M; Cochran, Michele A; Falconer, Renee L; Kylin, Henrik

    2017-04-01

    Persistent organic pollutants (POPs) continue to cycle through the atmosphere and hydrosphere despite banned or severely restricted usages. Global scale analyses of POPs are challenging, but knowledge of the current distribution of these compounds is needed to understand the movement and long-term consequences of their global use. In the current study, air and seawater samples were collected Oct. 2007-Jan. 2008 aboard the Icebreaker Oden en route from Göteborg, Sweden to McMurdo Station, Antarctica. Both air and surface seawater samples consistently contained α-hexachlorocyclohexane (α-HCH), γ-HCH, hexachlorobenzene (HCB), α-Endosulfan, and polychlorinated biphenyls (PCBs). Sample concentrations for most POPs in air were higher in the northern hemisphere with the exception of HCB, which had high gas phase concentrations in the northern and southern latitudes and low concentrations near the equator. South Atlantic and Southern Ocean seawater had a high ratio of α-HCH to γ-HCH, indicating persisting levels from technical grade sources. The Atlantic and Southern Ocean continue to be net sinks for atmospheric α-, γ-HCH, and Endosulfan despite declining usage. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Seismic Imaging of Thermohaline Circulation in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Falder, M.; White, N. J.; Sheen, K. L.; Caulfield, C. P.

    2012-12-01

    We present seismic reflection images of the full water column acquired during a 2010 cruise in the North Atlantic Ocean on the RSS James Cook. A total of 2600 km of seismic data with a horizontal resolution of ~10 m were acquired, including two long transects > 1000 km long. These transects extend from Hatton Bank to the Greenland shelf and cross smooth, intermediate and rough bathymetry. Coeval, expendable conductivity-temperature-depth probes and ADCP measurements permit hydrographic calibration of the seismic images. Seismic processing included dense (~ 1.5 km) velocity picking and iterative pre-stack depth migration, which optimised the acoustic velocity model and increased our confidence in the depth conversion. On both transects, we observe thermohaline structures, such as eddies, fronts and internal waves, together with lateral changes in geometry and reflective character. In places, the amplitude and character of the internal waves may be affected by interaction with rough bathymetry. The largest mesoscale eddy is 60 km in diameter, occurring between 300 and 1100 m depth. Asymmetric reflections wrap around this feature. ADCP data demonstrate that this eddy rotates clockwise at 0.4 m/s in agreement with previous studies. Spectral analysis of internal waves show the classic transition from a Garrett-Munk to a Kolmogorov/Bachelor slope, allowing diapycnal diffusivity estimates to be made. In this way, we hope to test the paradigm that enhanced mixing rates occur over rougher bathymetry in oceanic basins. These long transects are rich in detail and we hope that a quantitative analysis will yield useful physical oceanographic insights.

  16. Smoke from Canadian fires over the Atlantic Ocean

    NASA Image and Video Library

    2017-09-27

    Generally the old saying “where there is smoke, there is fire” rings true, but when thick, hot smoke rises high aloft into the atmosphere it may travel hundreds, sometimes thousands of kilometers away from the source. This was the case on July 6, 2013 when the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument flying on NASA’s Terra satellite captured this true-color image of a thick river of smoke curling across the Atlantic Ocean. In the west of the image, the green land of Canada can be seen, most of which is covered by a thin gray haze. A thick veil of smoke obscures much of southern Canada, and this tan-gray veil blows to the east, then to the northeast. The color of the smoke appears both tan and gray, and is stretched into brush-stroke like curves across the ocean, which disappears from view under the smoke. The smoke filled plume is so high that it even hides the bright white clouds from view as it travels over them. Fires have been burning across Canada since early June, especially in Manitoba and Quebec. Rain in Quebec on July 5 helped diminish the fires in that location, although a severe fire was ignited when a freight train carrying oil derailed in the small, picturesque town of Lac-Megantic. This accident, which occurred on July 6, the same day this image was captured, killed at least 35 people and poured thick smoke into the skies. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  17. Carbon disulfide measurements in the atmosphere of the western North Atlantic and the northwestern South Atlantic Oceans

    NASA Technical Reports Server (NTRS)

    Bandy, Alan R.; Thornton, Donald C.; Johnson, James E.

    1993-01-01

    Carbon disulfide (CS2) measurements were made over the western and equatorial North Atlantic Ocean and the northwestern and equatorial South Atlantic Ocean. Carbon disulfide was in the range 0.4-50 pptrv in the atmosphere of the western North Atlantic Ocean. Emissions from anthropogenic sources and wet lands were found to be important although anthropogenic sources were 4-6 times larger than biogenic sources. The flux of CS2 from eastern North America between 30 and 39 deg latitude was estimated to be 2 x 10(exp 8)g/yr or sulfur. The anthropogenic contribution was 1.8 x 10(exp 8)g/yr of sulfur whereas the contribution of marshes was 0.2 x 10(exp 8)g/yr of sulfur. Sources of CS2 at high latitudes in the northern hemisphere were comparatively weak. Carbon disulfide levels in the western South Atlantic Ocean between -5 and 1 deg latitude were in the range 0.2-6 pptrv. Most of the CS2 appeared to come from biomass burning in Africa. Carbon disulfide was much higher close to shore suggesting that the South American continent was a significant source although too few data were available to quantify it. On ferry lights from Wallops, Virginia to Natal, Brazil, CS2 levels at the ferry altitude of about 6 km averaged 1.2 pptrv. This background CS2 was adequate to account for all the carbonyl sulfide (OCS) in the atmosphere.

  18. Microbial growth and macromolecular synthesis in the northwestern Atlantic Ocean

    SciTech Connect

    Cuhel, R.L.; Jannasch, H.W.; Taylor, C.D.

    1983-01-01

    Simultaneous time-course measurements of /sup 35/SO/sub 4//sup 2 -/, /sup 32/PO/sup 43 -/, /sup 15/NH/sub 4//sup +/, and (/sup 14/C)acetate, glucose, and glutamate uptake were made at three stations in the northwestern Atlantic Ocean, using water samples taken from well below the euphotic zone. Marked deviations from linearity were observed in 14 of the 15 cases. At the two most inshore stations uptake of /sup 15/NH/sub 4//sup +/ or incorporation of /sup 35/SO/sub 4//sup 2 -/ into protein was undetectable for 16-30 h, followed by very rapid increases in the rates of activity. The sudden burst of SO/sub 4//sup 2 -/and NH/sub 4//sup +/ uptake was accompanied by a major increase in the incorporation of /sup 32/P into RNA and lipid fractions of the microbial population at a continental slope station. At a station in Sargasso Sea, all substrates were taken up without lag. Extended incubations led to a growth plateau which may be a measure of the total biologically labile organic nutrient supply. In all cases tested, chloramphenicol severely restricted uptake. One of the inshore stations was revisited a year later with similar results. The combined data demonstrate the utility of using inorganic nutrient uptake and subcellular incorporation patterns to measure microbial growth and metabolism and stress the necessity of time-course rather than end-point incubations.

  19. Iberian Atlantic Margins Group investigates deep structure of ocean margins

    NASA Astrophysics Data System (ADS)

    The Iberian Atlantic Margins Group; Banda, Enric; Torne, Montserrat

    With recent seismic reflection data in hand, investigators for the Iberian Atlantic Margins project are preparing images of the deep continental and oceanic margins of Iberia. In 1993, the IAM group collected near vertical incidence seismic reflection data over a total distance of 3500 km along the North and Western Iberian Margins, Gorringe Bank Region and Gulf of Cadiz (Figure 1). When combined with data on the conjugate margin off Canada, details of the Iberian margin's deep structure should aid in distinguishing rift models and improve understanding of the processes governing the formation of margins.The North Iberian passive continental margin was formed during a Permian to Triassic phase of extension and matured during the early Cretaceous by rotation of the Iberian Peninsula with respect to Eurasia. From the late Cretaceous to the early Oligocene period, Iberia rotated in a counterclockwise direction around an axis located west of Lisbon. The plate boundary between Iberia and Eurasia, which lies along the Pyrenees, follows the north Spanish marginal trough, trends obliquely in the direction of the fossil Bay of Biscay triple junction, and continues along the Azores-Biscay Rise [Sibuet et al., 1994]. Following the NE-SW convergence of Iberia and Eurasia, the reactivation of the North Iberian continental margin resulted in the formation of a marginal trough and accretionary prism [Boillot et al., 1971].

  20. Multiphase halogen chemistry in the tropical Atlantic Ocean.

    PubMed

    Sommariva, Roberto; von Glasow, Roland

    2012-10-02

    We used a one-dimensional model to simulate the chemical evolution of air masses in the tropical Atlantic Ocean, with a focus on halogen chemistry. The model results were compared to the observations of inorganic halogen species made in this region. The model could largely reproduce the measurements of most chlorine species, especially under unpolluted conditions, but overestimated sea salt chloride, BrCl, and bromine species. Agreement with the measurements could be improved by taking into account the reactivity with aldehydes and the effects of dimethyl sulfide (DMS) and Saharan dust on aerosol pH; a hypothetical HOX → X(-) aqueous-phase reaction could also improve the agreement with measured Cl(2) and HOCl, especially under semipolluted conditions. The results also showed that halogens speciation and concentrations are very sensitive to cloud processing. The model was used to calculate the impact of the observed levels of halogens: Cl atoms accounted for 5.4-11.6% of total methane sinks and halogens (mostly bromine and iodine) accounted for 35-40% of total ozone destruction.

  1. Ocean color variability in the southern Atlantic and southeastern Pacific

    NASA Astrophysics Data System (ADS)

    Rudorff, Natalia M.; Frouin, Robert J.; Kampel, Milton

    2012-10-01

    The chlorophyll-a concentration (Chla) of surface waters is commonly retrieved from space using an empirical polynomial function of the maximum band ratio (MBR), i.e., the maximum ratio of remote sensing reflectance in selected spectral bands in the visible. Recent studies have revealed significant deviations in the relation between MBR and Chla across the oceans. The present work aims at accessing the main sources of MBR variability across the Southern Atlantic and South-east Pacific, using in situ data. The data was collected at 19 bio-optical CTD stations and 40 flowthrough stations during a cruise onboard the R/V Melville, from South Africa to Chile (February-March, 2011). The MBR was derived from modeled remote sensing reflectance using absorption and backscattering measurements. The second order MBR variations (MBR*) were obtained after subtraction of a global polynomial fit for CChla and Chla biases. Multivariate analyses were used to explain the variations with bio-optical properties and phytoplankton pigments. Chla overestimations were associated to high specific phytoplankton absorption (0.73), specific particle backscattering coefficient (0.42) and colored dissolved and particle organic matter (CDM) absorption normalized by non-water absorption (0.38), and vice-versa. The overestimations occurred at stations with dominance of small picoplankton, high concentration of bacteria, and high CDM, while underestimations were in microplankton dominated waters and low CDM. The results reveal important relations of the MBR* with the specific coefficient and associated phytoplankton community structure.

  2. Multi-phase halogen chemistry in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Sommariva, R.; von Glasow, R.

    2012-04-01

    We used a one-dimensional model to simulate the chemical evolution of air masses in the eastern tropical Atlantic Ocean (Cape Verde region), with a focus on halogen chemistry. The model results were compared to the observations of inorganic halogen (particularly chlorine and bromine) species made in this region. The model could reproduce the measurements of chlorine species, especially under unpolluted conditions, but it overestimated sea-salt chloride and bromine species. Agrement with the measurements could be improved by taking into account the reactivity with aldehydes and the effects of DMS and Saharan dust on aerosol pH; an hypothetical HOX -> X- aqueous-phase reaction could also improve the agreement with measured Cl2 and HOCl, particularly under semi-polluted conditions. The results showed that halogen levels and speciation are very sensitive to cloud processing, although the model could not reproduce the observations under cloudy conditions. The model results were used to calculate the impact of the observed levels of halogens: Cl accounted for 5.4 - 11.6% of total methane sinks and halogens (mostly bromine and iodine) accounted for 35 - 40% of total ozone destruction.

  3. Ocean impact on decadal Atlantic climate variability revealed by sea-level observations.

    PubMed

    McCarthy, Gerard D; Haigh, Ivan D; Hirschi, Joël J-M; Grist, Jeremy P; Smeed, David A

    2015-05-28

    Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres--the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States.

  4. Ocean impact on decadal Atlantic climate variability revealed by sea-level observations

    NASA Astrophysics Data System (ADS)

    McCarthy, Gerard D.; Haigh, Ivan D.; Hirschi, Joël J.-M.; Grist, Jeremy P.; Smeed, David A.

    2015-05-01

    Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres--the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States.

  5. Distribution of tropospheric ozone over the Tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Oyola, M. I.; Joseph, E.; Nalli, N. R.; Morris, V. R.; Stearns, C. A.; Barnet, C.; Wolfe, D. E.

    2013-12-01

    troposphere. We present a comprehensive study of tropospheric ozone based upon an unprecedented dataset of electrochemical cell (ECC) ozone soundings over the tropical Atlantic Ocean acquired from intensive observation periods (IOP) conducted during seven separate NOAA Aerosols and Ocean Science Expedition (AEROSE) campaigns (2006-2011, 2013) and the 1999 AEROSOL99 campaign. A composite of well-resolved and accurate (5%) tropospheric profiles retrieved from daily ozonesondes, launched along latitudes between 33N to 34 S, are used to describe the Atlantic Ocean ozone geographical and vertical distribution during boreal Winter, Spring and Summer months. Laminae obtained applying the Pierce-Teitelbaum (PT) method are coupled to GW and RW, exploiting their relationship with vertical displacement and quasi-horizontal transport respectively. We apply optical depth measurements, ship-borne tracers, Lagrangian backtrajectory modeling and reanalysis data to characterize the different atmospheric conditions and processes that are believed to ignite the formation of these layers. Furthermore, we present an initial attempt to quantify the contribution of each to the total ozone tropospheric budget due to stratospheric-tropospheric interactions, boundary layer processes, advection of pollutants and regional convection and lightning.

  6. The dominant mechanisms of variability in Atlantic Ocean Heat Transport in a Coupled Ocean-Atmosphere GCM

    NASA Astrophysics Data System (ADS)

    Dong, B.-W.; Sutton, R. T.

    The variability of the Atlantic meridional ocean heat transport (OHT) has been diagnosed from a simulation of a coupled ocean-atmosphere general circulation model (GCM), and the mechanisms responsible for this variability have been elucidated. Interannual variability is dominated by windstress-driven Ekman fluctuations, which account for 50.3% of the OHT variance. By contrast, decadal and multidecadal variability in Atlantic OHT is dominated by a mixed thermohaline/gyre mode driven by variations in buoyancy fluxes and windstress curl. It accounts for 55.6% of low pass filtered OHT variance. The North Atlantic Oscillation (NAO) has a significant role in both the interannual mode and the low frequency mode, but it is not the only important driver. A notable feature of both modes is significant changes in the tropical atmosphere and ocean. We highlight a number of potential mechanisms involved in the tropical-extratropical teleconnections.

  7. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic Ocean...

  8. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic Ocean...

  9. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic Ocean...

  10. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic Ocean...

  11. New data on Lepidion schmidti (Gadiformes: Moridae) from the north-east Atlantic Ocean.

    PubMed

    Arronte, J C; Bañón, R; Quigley, D T G; Pis-Millán, J A; Heredia, J

    2011-12-01

    A new record of Lepidion schmidti (Gadiformes: Moridae) is reported from the Bay of Biscay (north-east Atlantic Ocean). Lepidion schmidti is a rare and poorly known species, scarcely described in the ichthyological literature. Morphometric and meristic characteristics of the specimen are given. A compilation of the specimens caught in the north-east Atlantic Ocean was carried out and the current status of the species in Atlantic waters is discussed. Lepidion schmidti is characterized mainly by the presence of an inverted V-shaped patch of vomerine teeth and a V-shaped crest on the dorsal surface of the head with the apex anterior. The presence of supernumerary anal fin rays in this species is described for the first time. The results obtained confirm the presence of L. schmidti from the north-east Atlantic Ocean.

  12. Study of mass and heat transport of the tropical Atlantic Ocean using models and altimeter data

    NASA Technical Reports Server (NTRS)

    Merle, Jacques; Arnault, S.; Morliere, A.; Verstraete, J. M.; Menard, Yves; Gourdeau, L.

    1991-01-01

    The specific objectives of this proposal are: (1) to assess the quality of the TOPEX/POSEIDON surface altimeter data in regard to its use for a large, low-frequency monitoring of the surface topography of the tropical Atlantic Ocean; (2) to develop a method, on a demonstration basis, to derive from the tropical Atlantic the depth of the thermocline and the heat content changes from the surface altimeter data field; (3) to develop a method of assimilation of altimeter data into Oceanic General Circulation Models (OGCM's) for the purpose of preparing an operational, permanent, three-dimensional now casting of the tropical Atlantic Ocean (a TOGA objective); and (4) to derive from these models global circulation fields and a time series of mass and meridional heat transports across the tropical Atlantic region (a WOCE objective).

  13. Stable isotopes in surface waters of the Atlantic Ocean: Indicators of ocean-atmosphere water fluxes and oceanic mixing processes

    NASA Astrophysics Data System (ADS)

    Benetti, M.; Reverdin, G.; Aloisi, G.; Sveinbjörnsdóttir, Á.

    2017-06-01

    The surface ocean hydrological cycle is explored based on ˜300 new δ18O and δD measurements from surface waters of the Atlantic Ocean and the Mediterranean Sea over the period 2010-2016. Our approach combines these surface observations with salinity (S) and stable isotope measurements of atmospheric water vapor. The distinct regional S-δ distributions are used to identify different surface water masses and their horizontal advection. Moreover, based on assumptions on the δ-S characteristics of seawater sources and the isotope composition of the evaporative (δe) and meteoric water (δMW) fluxes, the δ-S distribution is used to indicate the relative importance of evaporation (E) and meteoric water inputs (MW). Here δe is estimated from the Craig and Gordon's equation using 120 days of measurements of the ambient air above the Atlantic Ocean collected during three cruises. To provide quantitative estimates of the E:MW ratio, we use the box model from Craig and Gordon (1965). This identifies the subtropical gyre as a region where E:MW ˜2 and the tropical ocean as a region were MW:E ˜2. Finally, we show that the δ18O-δD distribution is better represented by a linear fit than the δ-S relationship, even in basins governed by different hydrological processes. We interpret the δ18O-δD distribution considering the kinetic fractionation processes associated with evaporation. In the tropical region where MW exceeds E, the δ18O-δD distribution identifies the MW inputs from their kinetic signature, whereas in regions where E exceeds MW, the δ18O-δD distribution traces the humidity at the sea surface.

  14. 75 FR 4348 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... National Oceanic and Atmospheric Administration RIN 0648-XU05 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of public hearings. SUMMARY: The Mid-Atlantic Fishery Management... Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP). See SUPPLEMENTARY INFORMATION...

  15. Heat content variability in the North Atlantic Ocean in ocean reanalyses

    PubMed Central

    Häkkinen, Sirpa; Rhines, Peter B; Worthen, Denise L

    2015-01-01

    Warming of the North Atlantic Ocean from the 1950s to 2012 is analyzed on neutral density surfaces and vertical levels in the upper 2000 m. Three reanalyses and two observational data sets are compared. The net gain of 5 × 1022 J in the upper 2000 m is roughly 30% of the global ocean warming over this period. Upper ocean heat content (OHC) is dominated in most regions by heat transport convergence without widespread changes in the potential temperature/salinity relation. The heat convergence is associated with sinking of midthermocline isopycnals, with maximum sinking occurring at potential densities σ0 = 26.4−27.3, which contain subtropical mode waters. Water masses lighter than σ0 = 27.3 accumulate heat by increasing their volume, while heavier waters lose heat by decreasing their volume. Spatially, the OHC trend is nonuniform: the low latitudes, 0–30°N are warming steadily while large multidecadal variability occurs at latitudes 30–65°N. Key Points Heat content change dominated by heat transport convergence Due to widespread sinking trend of midthermocline isopycnals over 50+ years PMID:26709321

  16. Heat content variability in the North Atlantic Ocean in ocean reanalyses.

    PubMed

    Häkkinen, Sirpa; Rhines, Peter B; Worthen, Denise L

    2015-04-28

    Warming of the North Atlantic Ocean from the 1950s to 2012 is analyzed on neutral density surfaces and vertical levels in the upper 2000 m. Three reanalyses and two observational data sets are compared. The net gain of 5 × 10(22) J in the upper 2000 m is roughly 30% of the global ocean warming over this period. Upper ocean heat content (OHC) is dominated in most regions by heat transport convergence without widespread changes in the potential temperature/salinity relation. The heat convergence is associated with sinking of midthermocline isopycnals, with maximum sinking occurring at potential densities σ0 = 26.4-27.3, which contain subtropical mode waters. Water masses lighter than σ0 = 27.3 accumulate heat by increasing their volume, while heavier waters lose heat by decreasing their volume. Spatially, the OHC trend is nonuniform: the low latitudes, 0-30°N are warming steadily while large multidecadal variability occurs at latitudes 30-65°N.

  17. An Analysis of the ENSO Signal in the Tropical Atlantic and Western Indian Oceans

    NASA Astrophysics Data System (ADS)

    Nicholson, Sharon E.

    1997-03-01

    This article examines the time-space evolution of the El Niño-Southern Oscillation (ENSO) signal in the tropical Atlantic and western Indian Oceans, using harmonic analysis. Composites of sea-surface temperatures (SSTs) and other variables are examined for a 24-month period beginning 6 months prior to the year of maximum warming in the Pacific (termed year 0). An ENSO signal is apparent in the Atlantic in six out of eight Pacific episodes and in the Indian Ocean in all eight episodes. Warming begins along the south-eastern Atlantic coast early in year 0, some months later elsewhere in the Atlantic and in the Indian Ocean. Maximum warming occurs in the Atlantic in October-December of year 0, but in the following January-March in the Indian Ocean.In these oceans a cold phase occurs synchronously with the first half of the Pacific episode (July of year -1 to June of year 0, in the Rasmusson-Carpenter terminology), a warm phase with the second half. Maximum cooling is 1 year prior to maximum warming in both oceans. In the Atlantic the cold phase occurs most consistently; in the Indian Ocean the warm phase occurs most consistently. There is a season-by-season reversal of SST anomalies and, to a lesser extent, pressure anomalies between the cold and warm phases. This is the basis for the biennial component of the ENSO signal.Our results indicate that the ENSO signal in African rainfall variability is a manifestation of ENSO's influence on SSTs in the Atlantic and Indian Oceans and, in turn, their influence on rainfall. The cold and warm phases correspond roughly to enhanced and reduced rainfall over the African continent, respectively. A similar reversal of rainfall anomalies is apparent season-by-season during these phases. The timing of the warming and cooling is relatively constant in the Indian Ocean. However, the onset of the warming and cooling in the south and equatorial Atlantic occurs progressively later from south to north, thus the signal propagates northward

  18. Enhanced Weathering Strategies for Stabilizing Climate and Averting Ocean Acidification - Supplementary Information

    NASA Technical Reports Server (NTRS)

    Taylor, Lyla L.; Quirk, Joe; Thorley, Rachel M. S.; Kharecha, Pushker A.; Hansen, James; Ridgwell, Andy; Lomas, Mark R.; Banwart, Steve A.; Beerling, David J.

    2015-01-01

    Chemical breakdown of rocks, weathering, is an important but very slow part of the carbon cycle that ultimately leads to CO2 being locked up in carbonates on the ocean floor. Artificial acceleration of this carbon sink via distribution of pulverized silicate rocks across terrestrial landscapes may help offset anthropogenic CO2 emissions. We show that idealized enhanced weathering scenarios over less than a third of tropical land could cause significant drawdown of atmospheric CO2 and ameliorate ocean acidification by 2100. Global carbon cycle modelling driven by ensemble Representative Concentration Pathway (RCP) projections of twenty-first-century climate change (RCP8.5, business-as-usual; RCP4.5, medium-level mitigation) indicates that enhanced weathering could lower atmospheric CO2 by 30-300 ppm by 2100, depending mainly on silicate rock application rate (1 kg or 5 kg m(exp. -2) yr (exp -1)) and composition. At the higher application rate, end-of-century ocean acidification is reversed under RCP4.5 and reduced by about two-thirds under RCP8.5. Additionally, surface ocean aragonite saturation state, a key control on coral calcification rates, is maintained above 3.5 throughout the low latitudes, thereby helping maintain the viability of tropical coral reef ecosystems. However, we highlight major issues of cost, social acceptability, and potential unanticipated consequences that will limit utilization and emphasize the need for urgent efforts to phase down fossil fuel emissions.

  19. Enhanced Weathering Strategies for Stabilizing Climate and Averting Ocean Acidification - Supplementary Information

    NASA Technical Reports Server (NTRS)

    Taylor, Lyla L.; Quirk, Joe; Thorley, Rachel M. S.; Kharecha, Pushker A.; Hansen, James; Ridgwell, Andy; Lomas, Mark R.; Banwart, Steve A.; Beerling, David J.

    2015-01-01

    Chemical breakdown of rocks, weathering, is an important but very slow part of the carbon cycle that ultimately leads to CO2 being locked up in carbonates on the ocean floor. Artificial acceleration of this carbon sink via distribution of pulverized silicate rocks across terrestrial landscapes may help offset anthropogenic CO2 emissions. We show that idealized enhanced weathering scenarios over less than a third of tropical land could cause significant drawdown of atmospheric CO2 and ameliorate ocean acidification by 2100. Global carbon cycle modelling driven by ensemble Representative Concentration Pathway (RCP) projections of twenty-first-century climate change (RCP8.5, business-as-usual; RCP4.5, medium-level mitigation) indicates that enhanced weathering could lower atmospheric CO2 by 30-300 ppm by 2100, depending mainly on silicate rock application rate (1 kg or 5 kg m(exp. -2) yr (exp -1)) and composition. At the higher application rate, end-of-century ocean acidification is reversed under RCP4.5 and reduced by about two-thirds under RCP8.5. Additionally, surface ocean aragonite saturation state, a key control on coral calcification rates, is maintained above 3.5 throughout the low latitudes, thereby helping maintain the viability of tropical coral reef ecosystems. However, we highlight major issues of cost, social acceptability, and potential unanticipated consequences that will limit utilization and emphasize the need for urgent efforts to phase down fossil fuel emissions.

  20. Cold Air Outbreaks Over the Gulf Stream and Implications for the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Strey, Sara T.

    During Cold Air Outbreak (CAO) events over North America during winter, cold dry air is often advected over the ocean offshore of the East Coast. A motivating hypothesis of this study is that the air-sea fluxes associated with CAO events will be manifested in offshore ocean variations that will be advected poleward by the Gulf Stream, possibly impacting the subpolar regions where oceanic deep convection drives the thermohaline circulation. This study uses an observational data analysis and model experiments with CESM's Parallel Ocean Processor to examine CAO intensive winters alongside contrasting years of winter warm events to quantify impacts on the North Atlantic Ocean, including the subpolar seas. The main findings of this study do not confirm the original hypotheses about downstream (subpolar) oceanic impacts of cold air outbreaks. They do, however, provide information relevant to the variability of the subpolar North Atlantic. In particular, the observational analysis shows that CAOs over the Gulf Stream produce large upward sensible and latent heat fluxes from the ocean to the atmosphere. These fluxes remove heat from the ocean's mixed layer, altering temperatures in the upper ocean. The model experiments show similar results off of the East Coast of the US, with colder, denser waters over the Gulf Stream in CAO years and associated variations of density patterns in the subpolar North Atlantic. Wind forcing from regions of warm air advection further north dominates downstream impacts of CAOs over the Gulf Stream, as the model experiments show regions of warmer, less dense water in the geographic region of North Atlantic Deep Water formation. This bipolarity of the wind forcing and its oceanic impacts are manifestations of the North Atlantic Oscillation. The results indicate that the NAO may well be the key to ocean variations that drive the global thermohaline circulation.

  1. 78 FR 25008 - Safety Zone; Fairfield Estates Fireworks Display, Atlantic Ocean, Sagaponack, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ..., Atlantic Ocean, Sagaponack, NY AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed Rulemaking. SUMMARY... Ocean, in Sagaponack, NY for the Fairfield Estates fireworks display. This action is necessary to provide for the safety of life on navigable waters during the event. Entering into, transiting...

  2. Did the North Atlantic Ocean sequester more CO2 during the last glacial?

    NASA Astrophysics Data System (ADS)

    Yu, J.; Thornalley, D. J.; Jin, Z.; Rohling, E. J.; Menviel, L.; McCave, I. N. N.

    2015-12-01

    To explain the ~90 ppm lower atmospheric CO2 content during the Last Glacial Maximum, much effort has been focused on the mechanisms that helped to limit the outgassing of CO2 from the deep ocean to the atmosphere via the Southern Ocean. Field measurements and modeling studies suggest that the North Atlantic Ocean has been an important sink of CO2 during preindustrial and modern times. However, the role of the North Atlantic in sequestering atmospheric CO2 in the past largely remains unconstrained. Here, we use a suite of geochemical proxies to reconstruct nutrient and carbonate ion concentrations of both surface and deep waters in the North Atlantic during the last ~25 kyr. When normalized to the same nutrient levels, we find that the gradient in carbonate ion content between surface and mid-depth waters increased during the last glacial. Although a combination of factors including changes in Redfield ratio and rain ratio and increased CO2 absorption at the air-sea boundary might have caused the observed change, the greater gradient most likely suggests an enhanced sequestration of CO2 in the North Atlantic Ocean during the Last Glacial Maximum. Therefore, we infer that, in addition to changes in the Southern Ocean, processes in the North Atlantic Ocean enhanced the uptake of CO2 and synergistically contributed to the low atmospheric CO2 during ice ages.

  3. Multi-decadal uptake of carbon dioxide into subtropical mode water of the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Bates, N. R.

    2012-07-01

    Natural climate variability impacts the multi-decadal uptake of anthropogenic carbon dioxide (Cant) into the North Atlantic Ocean subpolar and subtropical gyres. Previous studies have shown that there is significant uptake of CO2 into subtropical mode water (STMW) of the North Atlantic. STMW forms south of the Gulf Stream in winter and constitutes the dominant upper-ocean water mass in the subtropical gyre of the North Atlantic Ocean. Observations at the Bermuda Atlantic Time-series Study (BATS) site near Bermuda show an increase in dissolved inorganic carbon (DIC) of +1.51 ± 0.08 μmol kg-1 yr-1 between 1988 and 2011, but also an increase in ocean acidification indicators such as pH at rates (-0.0022 ± 0.0002 yr-1) higher than the surface ocean (Bates et al., 2012). It is estimated that the sink of CO2 into STMW was 0.985 ± 0.018 Pg C (Pg = 1015 g C) between 1988 and 2011 (70 ± 1.8% of which is due to uptake of Cant). The sink of CO2 into the STMW is 20% of the CO2 uptake in the North Atlantic Ocean between 14°-50° N (Takahashi et al., 2009). However, the STMW sink of CO2 was strongly coupled to the North Atlantic Oscillation (NAO), with large uptake of CO2 into STMW during the 1990s during a predominantly NAO positive phase. In contrast, uptake of CO2 into STMW was much reduced in the 2000s during the NAO neutral/negative phase. Thus, NAO induced variability of the STMW CO2 sink is important when evaluating multi-decadal changes in North Atlantic Ocean CO2 sinks.

  4. The Condor seamount at Mid-Atlantic Ridge as a supplementary source of trace and rare earth elements to the sediments

    NASA Astrophysics Data System (ADS)

    Caetano, Miguel; Vale, Carlos; Anes, Bárbara; Raimundo, Joana; Drago, Teresa; Schimdt, Sabine; Nogueira, Marta; Oliveira, Anabela; Prego, Ricardo

    2013-12-01

    The Condor Seamount rises from seabed to 180m water depth, being located 10 nautical miles southwest of the island of Faial, Azores Archipelago at the Mid-Atlantic Ridge (MAR). The vertical distribution of major, minor, trace and rare earth elements (REE) and Pb isotopes was studied in four sediment cores: one from the top of the Condor Seamount (200m, MC9), two from the seamount base (1400m, MC2 and MC4), and one from a deep area (1900m, MC8). Sediments from the top of the Condor were composed by coarser particles being the fine fraction lower than 1%. Conversely the other sediments were constituted by 51-92% of fine particles (<63μm). Individual fragments of volcanic material (>2mm) were found at several depths of the cores sampled at the base of the seamount. The core collected in the top of the Condor showed higher carbonate content (76-86%) compared with the other cores (41-64%). The chemical compositions of MC2 and MC4 point to an enhancement of V, Cr, Co, Ni and Fe concentrations. Lower concentrations in MC8 hypothesis that Condor seamount constitutes a supplementary source of trace elements. The most plausible explanation for the enhancement found in sediments of the seamount base is the weathering of slopes with volcanic activities, which supply particles with higher element concentrations than pelagic sediments. This hypothesis is corroborated by REE data, showing increased chondrite normalized ratios in MC2 and MC4. Moreover, the REE pattern found in those cores was comparable to that existing in volcanic material with Light REE enrichment in comparison to Heavy REE. These results indicate a substantial contribution of particles derived from volcanic activities to sediments settled in the vicinity of the Condor Seamount. It is argued the potential use of REE in sediments from this region as tracers of volcanic activities. Depth profiles of 206Pb/207Pb and 206Pb/208Pb showed lower ratios in the first 8cm sediment layers, reflecting atmospheric input of

  5. Abrupt climate fluctuations in the tropics: the influence of Atlantic Ocean circulation

    NASA Astrophysics Data System (ADS)

    Street-Perrott, F. Alayne; Perrott, R. Alan

    1990-02-01

    Several prolonged droughts in the Sahel and tropical Mexico during the past 14,000 years were coincident with large injections of fresh water into the northern North Atlantic Ocean. The link between these phenomena lies in the thermohaline circulation of the oceans: input of fresh water decreases salinity leading to reduced North Atlantic Deep Water formation and anomalies of sea surface temperature of the kind associated with decreased rainfall in the northern tropics. Ice-sheet disintegration, the most important source of fresh-water input to the oceans, should therefore be considered explicitly in models of past and future climate.

  6. Interannual variability of temperature at a depth of 125 meters in the North Atlantic Ocean

    SciTech Connect

    Levitus, S.; Boyer, T.P.; Antonov, J.I.

    1994-10-07

    Analyses of historical ocean temperature data at a depth of 125 meters in the North Atlantic Ocean indicate that from 1950-1990 the subtropical and subartic gyres exhibited linear trends that were opposite in phase. In addition, multivariate analyses of yearly mean temperature anomaly fields between 20{degrees}N and 70{degrees}N in the North Atlantic show a characteristic space-time temperature oscillation from 1947 to 1990. A quasidecadal oscillation, first-identified at Ocean Weather Station C, is part of a basin-wide feature. Gyre and basin-scale variations such as these provide the observational basis for climate diagnostic and modeling studies.

  7. Interannual variability of temperature at a depth of 125 meters in the north atlantic ocean.

    PubMed

    Levitus, S; Antonov, J I; Boyer, T P

    1994-10-07

    Analyses of historical ocean temperature data at a depth of 125 meters in the North Atlantic Ocean indicate that from 1950 to 1990 the subtropical and subarctic gyres exhibited linear trends that were opposite in phase. In addition, multivariate analyses of yearly mean temperature anomaly fields between 20 degrees N and 70 degrees N in the North Atlantic show a characteristic space-time temperature oscillation from 1947 to 1990. A quasidecadal oscillation, first identified at Ocean Weather Station C, is part of a basin-wide feature. Gyre and basin-scale variations such as these provide the observational basis for climate diagnostic and modeling studies.

  8. 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.

  9. Using Particle Size Distribution and Habitat Models to Predict Phytoplankton Functional Types in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Brown, C.; Moore, T.

    2016-02-01

    Phytoplankton community composition in the oceans is a critical determinant to both marine ecosystem structure and biogeochemical processes. A model was constructed to predict the dominant of five phytoplankton functional types (PFT) in the surface layer of the Atlantic Ocean as a fraction of biomass using a combination of particle size distribution (PSD) retrieved from satellite ocean color radiometric measurements and empirical niche models developed for each PFT. Presence of dominant PFTs were developed from a pigment data set from the Atlantic Ocean and co-located with gridded satellite, modeled and climatological data. The PFT model employs PSD, sea-surface temperature, photosynthetically available radiation, mixed-layer depth, wind and nutrients as inputs, and successfully classified the dominant groups 85% using data from the training set and 70% using an independent data set. The predicted monthly distribution patterns of the dominant PFT in the Atlantic during the SeaWiFS era appear reasonable yet require additional validation.

  10. The signature of low-frequency oceanic forcing in the Atlantic Multidecadal Oscillation

    NASA Astrophysics Data System (ADS)

    O'Reilly, Christopher H.; Huber, Markus; Woollings, Tim; Zanna, Laure

    2016-03-01

    The Atlantic Multidecadal Oscillation (AMO) significantly influences the climate of the surrounding continents and has previously been attributed to variations in the Atlantic Meridional Overturning Circulation. Recently, however, similar multidecadal variability was reported in climate models without ocean circulation variability. We analyze the relationship between turbulent heat fluxes and sea surface temperatures (SSTs) over the midlatitude North Atlantic in observations and coupled climate model simulations, both with and without ocean circulation variability. SST anomalies associated with the AMO are positively correlated with heat fluxes on decadal time scales in both observations and models with varying ocean circulation, whereas in models without ocean circulation variability the anomalies are negatively correlated when heat flux anomalies lead. These relationships are captured in a simple stochastic model and rely crucially on low-frequency forcing of SST. The fully coupled models that better capture this signature more effectively reproduce the observed impact of the AMO on European summertime temperatures.

  11. Aerosol iron solubility: Observations from the Atlantic and Pacific oceans

    NASA Astrophysics Data System (ADS)

    Buck, Clifton Stryker

    Large portions of the world ocean are less productive than they should be based on their nutrient concentrations. Dubbed high-nutrient low-chlorophyll (HNLC) regions, primary productivity in these areas may be limited by any number of factors including high zooplankton grazing rates as well as light and silicon limitation but, in general, iron (Fe) appears to most often be the factor limiting production. With approximately 30% of the world ocean comprised of Fe-limited HNLC waters, it is clear that the input of Fe to these waters, and its subsequent bioavailability, has an important role in stimulating primary productivity and lowering pCO2 possibly moderating the rise of atmospheric CO2 concentrations and therefore could influence the planet's climate. The work described in this dissertation represents an effort to characterize the elemental solubility, including Fe, of marine aerosols. The research was conducted on four oceanographic research cruises in the North Atlantic and Pacific Oceans. In total, over 170 aerosol samples were collected in both total and size-fractionated samples. Precipitation events were sampled when possible to characterize the wet deposition of marine aerosols. The data will constrain estimates of aerosol Fe deposition to HNLC regions and improve models of the global carbon cycle. Elemental solubilities were measured using both seawater and ultrapure deionized water leaching methods under trace metal clean conditions. Leaching of the aerosol samples was conducted using a rapid exposure, small volume technique. Ultrapure deionized water leaches were analyzed directly by high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS), a relatively simple analysis technique. Soluble Fe in seawater leaches was analyzed by HR-ICP-MS following column extraction. Additionally, soluble aerosol Fe(II) was measured on four of the cruises. The sampling and analytical methods will be discussed in this dissertation and the results compared

  12. SPURS: Salinity Processes in the Upper-Ocean Regional Study: THE NORTH ATLANTIC EXPERIMENT

    NASA Technical Reports Server (NTRS)

    Lindstrom, Eric; Bryan, Frank; Schmitt, Ray

    2015-01-01

    In this special issue of Oceanography, we explore the results of SPURS-1, the first part of the ocean process study Salinity Processes in the Upper-ocean Regional Study (SPURS). The experiment was conducted between August 2012 and October 2013 in the subtropical North Atlantic and was the first of two experiments (SPURS come in pairs!). SPURS-2 is planned for 20162017 in the tropical eastern Pacific Ocean.

  13. The Atlantic Coast of Maryland, Sediment Budget Update: Tier 2, Assateague Island and Ocean City Inlet

    DTIC Science & Technology

    2016-06-01

    Tier 2, Assateague Island and Ocean City Inlet by Ernest R. Smith, Joseph C. Reed, and Ian L. Delwiche PURPOSE: This Coastal and Hydraulics...of the Atlantic Ocean shoreline within the U.S. Army Corps of Engineers (USACE) Baltimore District’s Area of Responsibility, which for coastal...111 – Rivers and Harbors Act), the navigational structures at the Ocean City Inlet, and a number of Federally authorized channels (Figure 1). Reed

  14. Response to Comment on "The Atlantic Multidecadal Oscillation without a role for ocean circulation".

    PubMed

    Clement, Amy; Cane, Mark A; Murphy, Lisa N; Bellomo, Katinka; Mauritsen, Thorsten; Stevens, Bjorn

    2016-06-24

    Zhang et al interpret the mixed-layer energy budget in models as showing that "ocean dynamics play a central role in the AMO." Here, we show that their diagnostics cannot reveal the causes of the Atlantic Multidecadal Oscillation (AMO) and that their results can be explained with minimal ocean influence. Hence, we reaffirm our findings that the AMO in models can be understood primarily as the upper-ocean thermal response to stochastic atmospheric forcing.

  15. Year Five of Southeast Atlantic Coastal Ocean Observing System (SEACOOS) Implementation

    DTIC Science & Technology

    2008-09-30

    Luettich and H. E. Seim, 2005. Measurements of Reynolds stress in a wind driven lagoonal estuary, Ocean Dynamics ., doi:10.1007/s10236-005-0038-x...1 Year Five of Southeast Atlantic Coastal Ocean Observing System (SEACOOS) Implementation Harvey E. Seim Dept. of Marine Sciences, University...GOALS To significantly increase the quantity and quality of environmental information from the coastal ocean of the SE U.S. and make this readily

  16. Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

    PubMed Central

    Rosenbaum, Howard C.; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S.; Best, Peter B.; Findlay, Ken P.; Minton, Gianna; Ersts, Peter J.; Collins, Timothy; Engel, Marcia H.; Bonatto, Sandro L.; Kotze, Deon P. G. H.; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-01-01

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region. PMID:19812698

  17. Population structure of humpback whales from their breeding grounds in the South Atlantic and Indian Oceans.

    PubMed

    Rosenbaum, Howard C; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S; Best, Peter B; Findlay, Ken P; Minton, Gianna; Ersts, Peter J; Collins, Timothy; Engel, Marcia H; Bonatto, Sandro L; Kotze, Deon P G H; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-10-08

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region.

  18. It is the time for oceanic seabirds: Tracking year-round distribution of gadfly petrels across the Atlantic Ocean

    USGS Publications Warehouse

    Ramos, Raul; Carlile, Nicholas; Madeiros, Jeremy; Ramirez, Ivan; Paiva, Vitor H.; Dinis, Herculano A.; Zino, Francis; Biscoito, Manuel; Leal, Gustavo R.; Bugoni, Leandro; Jodice, Patrick G.; Ryan, Peter G.; Gonzalez-Solis, Jacob

    2017-01-01

    AimAnthropogenic activities alter and constrain the structure of marine ecosystems with implications for wide-ranging marine vertebrates. In spite of the environmental importance of vast oceanic ecosystems, most conservation efforts mainly focus on neritic areas. To identify relevant oceanic areas for conservation, we assessed the year-round spatial distribution and spatio-temporal overlap of eight truly oceanic seabird species of gadfly petrels (Pterodroma spp.) inhabiting the Atlantic Ocean.LocationAtlantic Ocean.MethodsUsing tracking data (mostly from geolocators), we examined year-round distributions, the timing of life-cycle events, and marine habitat overlap of eight gadfly petrel species that breed in the Atlantic Ocean.ResultsWe compiled 125 year-round tracks. Movement strategies ranged from non-migratory to long-distance migrant species and from species sharing a common non-breeding area to species dispersing among multiple non-breeding sites. Gadfly petrels occurred throughout the Atlantic Ocean but tended to concentrate in subtropical regions. During the boreal summer, up to three species overlapped spatio-temporally over a large area around the Azores archipelago. During the austral summer, up to four species coincided in a core area in subtropical waters around Cape Verde, and three species shared habitat over two distinct areas off Brazil. The petrels used many national Exclusive Economic Zones, although they also exploited offshore international waters.Main conclusionsTracking movements of highly mobile vertebrates such as gadfly petrels can provide a powerful tool to evaluate and assess the potential need for and location of protected oceanic areas. As more multispecies, year-round data sets are collected from wide-ranging vertebrates, researchers and managers will have greater insight into the location of biodiversity hotspots. These can subsequently inform and guide marine spatial planning efforts that account for both conservation and

  19. The North Atlantic Oscillation: A dominant factor in variations of oceanic circulation systems of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Dvoryaninov, G. S.; Kubryakov, A. A.; Sizov, A. A.; Stanichny, S. V.; Shapiro, N. B.

    2016-01-01

    On the basis of altimetry data, the dynamics of the interaction between the subtropical anticyclonic (SA) and subpolar cyclonic (SC) gyres of the North Atlantic is considered. It is shown that the westerlies in the lower troposphere represented by the North Atlantic Oscillation (NAO) index are the main factor responsible for the dynamics of the gyres, which controls the inflow of warm Atlantic water into the Polar basin.

  20. The influence of Southern Ocean winds on the North Atlantic carbon sink

    NASA Astrophysics Data System (ADS)

    Bronselaer, Ben; Zanna, Laure; Munday, David R.; Lowe, Jason

    2016-06-01

    Observed and predicted increases in Southern Ocean winds are thought to upwell deep ocean carbon and increase atmospheric CO2. However, Southern Ocean dynamics affect biogeochemistry and circulation pathways on a global scale. Using idealized Massachusetts Institute of Technology General Circulation Model (MITgcm) simulations, we demonstrate that an increase in Southern Ocean winds reduces the carbon sink in the North Atlantic subpolar gyre. The increase in atmospheric CO2 due to the reduction of the North Atlantic carbon sink is shown to be of the same magnitude as the increase in atmospheric CO2 due to Southern Ocean outgassing. The mechanism can be described as follows: The increase in Southern Ocean winds leads to an increase in upper ocean northward nutrient transport. Biological productivity is therefore enhanced in the tropics, which alters the chemistry of the subthermocline waters that are ultimately upwelled in the subpolar gyre. The results demonstrate the influence of Southern Ocean winds on the North Atlantic carbon sink and show that the effect of Southern Ocean winds on atmospheric CO2 is likely twice as large as previously thought in past, present, and future climates.

  1. Global linkages originating from decadal oceanic variability in the subpolar North Atlantic

    NASA Astrophysics Data System (ADS)

    Chafik, L.; Häkkinen, S.; England, M. H.; Carton, J. A.; Nigam, S.; Ruiz-Barradas, A.; Hannachi, A.; Miller, L.

    2016-10-01

    The anomalous decadal warming of the subpolar North Atlantic Ocean (SPNA), and the northward spreading of this warm water, has been linked to rapid Arctic sea ice loss and more frequent cold European winters. Recently, variations in this heat transport have also been reported to covary with global warming slowdown/acceleration periods via a Pacific climate response. We here examine the role of SPNA temperature variability in this Atlantic-Pacific climate connectivity. We find that the evolution of ocean heat content anomalies from the subtropics to the subpolar region, likely due to ocean circulation changes, coincides with a basin-wide Atlantic warming/cooling. This induces an Atlantic-Pacific sea surface temperature seesaw, which in turn, strengthens/weakens the Walker circulation and amplifies the Pacific decadal variability that triggers pronounced global-scale atmospheric circulation anomalies. We conclude that the decadal oceanic variability in the SPNA is an essential component of the tropical interactions between the Atlantic and Pacific Oceans.

  2. Longitudinal and latitudinal distribution of perfluoroalkyl compounds in the surface water of the Atlantic Ocean.

    PubMed

    Ahrens, Lutz; Barber, Jonathan L; Xie, Zhiyong; Ebinghaus, Ralf

    2009-05-01

    Perfluoroalkyl compounds (PFCs) were determined in 2 L surface water samples collected in the Atlantic Ocean onboard the research vessels Maria S. Merian along the longitudinal gradient from Las Palmas (Spain) to St. Johns (Canada) (15 degrees W to 52 degrees W) and Polarstern along the latitudinal gradient from the Bay of Biscay to the South Atlantic Ocean (46 degrees N to 26 degrees S) in spring and fall 2007, respectively. After filtration the dissolved and particulate phases were extracted separately, and PFC concentrationswere determined using high-performance liquid chromatography interfaced to tandem mass spectrometry. No PFCs were detected in the particulate phase. This study provides the first concentration data of perfluorooctanesulfonamide (FOSA), perfluorohexanoic acid, and perfluoroheptanoic acid from the Atlantic Ocean. Results indicate that trans-Atlantic Ocean currents caused the decreasing concentration gradient from the Bay of Biscay to the South Atlantic Ocean and the concentration drop-off close to the Labrador Sea. Maximum concentrations were found for FOSA, perfluorooctanesulfonate, and perfluorooctanoic acid at 302, 291, and 229 pg L(-1), respectively. However, the concentration of each single compound was usually in the tens of picograms per liter range. South of the equator only FOSA and below 4 degrees S no PFCs could be detected.

  3. Atlantic Water variability in the 20th century Arctic Ocean from observations, climatology and a global ocean model.

    NASA Astrophysics Data System (ADS)

    Muilwijk, Morven; Ilicak, Mehmet; Smedsrud, Lars Henrik; Drange, Helge

    2017-04-01

    Warm and salty Atlantic Water enters the Arctic Ocean through the Fram Strait and the Western Barents Sea. The Atlantic Water has a direct impact on the sea ice cover in regions north of Svalbard. Both historical observations and outcome from a fully coupled earth system model show a warming trend in core temperature of this Atlantic Water inflow over the last few decades (1977-2015). For example, the upper 50-200m of the West Spitsbergen Current shows an observed overall warming of 1.1 ͦC since 1977. A portion of this recent large warming has been attributed to current global warming and possibly anthropogenic activity. However, low frequency oscillations (50-80 year time-scale) in Atlantic Water temperature have been documented. Over the twentieth century, the Atlantic Water temperature records from observations show two warm periods, in the 1930s-40s and in recent decades, and two colder periods, early in the 1900s and in the 1960s-70s. For example, north of Svalbard the Atlantic Water was as warm as in 2015, during the Nautilus expedition in 1931. We believe that the Atlantic Water warming trend in the Arctic Ocean may be part of long-term multidecadal variability, which is influenced and reinforced by strong anthropogenic forcing. In this work we investigate this long term variability and discuss its relative contribution to the recent warming trend by using a global ocean model. Simulations for the period 1871-2009 with the ocean-sea ice component of the Norwegian Earth System Model (NorESM-O) were forced by a Twentieth Century Reanalysis data set. Atlantic Water characteristics in these simulations are compared to available observations in a region north of Svalbard. Amongst these observations are hydrography measurements obtained during the Norwegian Young Sea Ice Cruise (N-ICE2015). Atlantic Water pathways in the Arctic Ocean for the period from 1871 to 2009 will also be presented as part of this study.

  4. Ocean stratification versus vertical mixing in the north Atlantic Ocean during the last glacial

    NASA Astrophysics Data System (ADS)

    Feldmeijer, Wouter; Ganssen, Gerald; Prins, Maarten

    2013-04-01

    The fluctuating cover of sea ice and melting glaciers in the North Atlantic region during the most recent three Marine Isotopic Stages (MIS) has been well documented. The consequences of this, either seasonal or perennial ice cover, on oceanographic conditions (i.e. mixing or stratification) has yet to be fully unravelled. Within the scope of the Darwin Center project Sensing Seasonality we shed light on the effects of melting sea-ice versus land-ice on the ocean conditions during short term (i.e. Heinrich Events) and long term (LGM) cold events. Core T88-3P is strategically located just north of the IRD belt (56°43.8N; 27°79.7W; 2819m water depth). The stable isotope data of different species of planktonic and benthic foraminifera reflect the degree of water mass stratification. As we apply single specimen foraminiferal isotope analysis we are able to extract the full seasonal range (i.e. annual mean, minima and maxima) of sea surface temperatures. Combining stable isotopes with faunal abundance, IRD provenance and other geochemical proxies (e.g. XRF data) the state of the sub-surface ocean system during Heinrich and Dansgaard/Oeschger Events within the last glacial can be reconstructed.

  5. Emission Corridors Preserving the Atlantic Ocean Thermohaline Circulation

    NASA Astrophysics Data System (ADS)

    Zickfeld, K.; Bruckner, T.

    2001-12-01

    The Atlantic thermohaline circulation (THC) transports large amounts of heat northward, acting as a heating system for the northern North Atlantic and north-western Europe. A large number of model simulations have shown the THC to be self-sustaining within certain limits, with well-defined thresholds where the circulation shuts down. Manabe and Stouffer (1993), for example, have simulated a complete shutdown of the THC for a quadrupling of atmospheric CO2. Because of the possibly severe consequences that a collapse of the THC would have upon the North Atlantic and north-western Europe, such an event may be considered as "dangerous anthropogenic interference with the climate system" that Article 2 of the UN Framework Convention on Climate Change (UNFCCC) calls to avoid. Here we present bundles of emission paths (the so called "emission corridors") that preserve the Atlantic thermohaline circulation. These corridors are calculated on the methodological and conceptual basis of the Tolerable Windows Approach. For this purpose a multi-gas reduced-form climate model has been supplemented by a dynamic Stommel-type boxmodel of the Atlantic thermohaline circulation. Both models allow for the relevant uncertainties (i.e., emissions of non-CO2 greenhouse gases, climate sensitivity, Atlantic hydrological sensitivity) to be taken into account. The sensitivity of emissions corridors with respect to the uncertain parameters is explored and the implications for a climate policy committed to the preservation of the Atlantic thermohaline circulation in the sense of Article 2 are discussed.

  6. Simulated spatiotemporal response of ocean heat transport to freshwater enhancement in North Atlantic and associated mechanisms

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Gao, Yongqi

    2011-06-01

    The Atlantic Meridional Overturning Circulation (AMOC) transports a large amount of heat to northern high latitudes, playing an important role in the global climate change. Investigation of the freshwater perturbation in North Atlantic (NA) has become one of the hot topics in the recent years. In this study, the mechanism and pathway of meridional ocean heat transport (OHT) under the enhanced freshwater input to the northern high latitudes in the Atlantic are investigated by an ocean-sea ice-atmosphere coupled model. The results show that the anomalous OHT in the freshwater experiment (FW) is dominated by the meridional circulation kinetic and ocean thermal processes. In the FW, OHT drops down during the period of weakened AMOC while the upper tropical ocean turns warmer due to the retained NA warm currents. Conversely, OHT recovers as the AMOC recovers, and the mechanism can be generalized as: 1) increased ocean heat content in the tropical Southern Ocean during the early integration provides the thermal condition for the recovery of OHT in NA; 2) the OHT from the Southern Ocean enters the NA through the equator along the deep Ekman layer; 3) in NA, the recovery of OHT appears mainly along the isopycnic layers of 24.70-25.77 below the mixing layer. It is then transported into the mixing layer from the "outcropping points" in northern high latitudes, and finally released to the atmosphere by the ocean-atmosphere heat exchange.

  7. Otolith chemistry discriminates natal signatures of yellowfin tuna (Thunnus albacares) in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kitchens, L. L.; Rooker, J. R.

    2016-02-01

    In this study, the otolith chemistry of young-of-the-year (YOY) yellowfin tuna (Thunnus albacares) was examined to determine whether chemical signatures are distinct across different putative spawning areas in the Atlantic Ocean. Yellowfin tuna is a highly migratory species that is currently managed as a single panmictic stock in the Atlantic Ocean; however, uncertainty remains regarding the population structure of yellowfin in this region, particularly concerning the degree of mixing between spawning populations. Analysis of naturally occurring chemical tracers in otoliths provides a valuable means to reconstruct a fish's environmental history and is thus a promising approach for delineating stock structure of Atlantic yellowfin tuna. YOY yellowfin tuna otoliths were collected from 5 locations in the Atlantic Ocean (Gulf of Mexico, SE Caribbean, Brazil, Cape Verde, and Gulf of Guinea) from 2013-2015 and trace element (Li, Mg, Mn, Co, Cu, Sr, Zn, and Ba) and stable isotope (δ13C and δ18O) analyses were conducted to investigate regional variation in otolith chemical composition. Results show significant differences among nursery areas in both trace element (MANOVA, p<0.001) and δ13C and δ18O signatures (ANOVA, p=0.017 and p=0.001, respectively). Particularly high spatial separation was observed based on eastern Atlantic (Gulf of Guinea + Cape Verde) and western Atlantic (Gulf of Mexico + Brazil + Martinique) nursery areas, indicating the approach has promise for distinguishing migrants displaying trans-ocean movement. These chemical signatures will be used to assign adult yellowfin tuna to their nursery of origin, ultimately providing an improved understanding of the stock structure and movement of yellowfin tuna in the Atlantic Ocean.

  8. Sea-level fluctuations show Ocean Circulation controls Atlantic Multidecadal Variability

    NASA Astrophysics Data System (ADS)

    McCarthy, Gerard; Haigh, Ivan; Hirschi, Joel; Grist, Jeremy; Smeed, David

    2015-04-01

    We present observational evidence that ocean circulation controls the decadal evolution of heat content and consequently sea-surface temperatures (SST) in the North Atlantic. One of the most prominent modes of Atlantic variability is the Atlantic multidecadal oscillation (AMO) observed in SSTs. Positive (negative) phases of the AMO are associated with warmer (cooler) SSTs. Positive phases of the AMO have been linked with decadal climate fluctuations including increased summer precipitation in Europe; increased northern hemisphere land temperatures, fewer droughts in the Sahel region of Africa and increased Atlantic hurricane activity. It is widely believed that the Atlantic circulation controls the phases of the AMO by controlling the decadal changes in heat content in the North Atlantic. However, due to the lack of ocean circulation observations, this link has not been previously proven. We present a new interpretation of the sea-level gradient along to the east coast of the United States to derive a measure of ocean circulation spanning decadal timescales. We use this to estimate heat content changes that we validate against direct estimates of heat content. We use the longevity of the tide gauge record to show that circulation, as interpreted in sea-level gradient changes, drives the major transitions in the AMO since the 1920's. We show that the North Atlantic Oscillation is highly correlated with this sea-level gradient, indicating that the atmosphere drives the circulation changes. The circulation changes are essentially integrated by the ocean in the form of ocean heat content and returned to the atmosphere as the AMO. An additional consequence of our interpretation is that recently reported accelerations in sea-level rise along the US east coast are consistent with a declining AMO that has been predicted by a number of authors.

  9. Negative ocean--atmosphere feedback in the South Atlantic Convergence Zone

    NASA Astrophysics Data System (ADS)

    de Almeida, R. F.; Nobre, P.; Haarsma, R. J.; Campos, E. J.

    2007-05-01

    The temporal evolution of the coupled variability between the South Atlantic Convergence Zone (SACZ) and the underlying sea surface temperature (SST) during austral summer is investigated using monthly data from the NCEP/NCAR reanalysis. A maximum covariance analysis shows that the SACZ is intensified [weakened] by warm [cold] SST anomalies in the beginning of summer, drifting northward. This migration is accompanied by the cooling [warming] of the underlying oceanic anomalies. The results confirm earlier analyses using numerical models, and suggest the existence of a negative feedback between the SACZ and the underlying South Atlantic SST field. A linear regression of daily anomalies of SST and omega at 500 hPa to the equations of a stochastic oscillator reveals a negative ocean--atmosphere feedback in the western South Atlantic, stronger during January and February and directly underneath the oceanic band of the SACZ.

  10. Negative ocean-atmosphere feedback in the South Atlantic Convergence Zone

    NASA Astrophysics Data System (ADS)

    De Almeida, R. A. F.; Nobre, P.; Haarsma, R. J.; Campos, E. J. D.

    2007-09-01

    The temporal evolution of the coupled variability between the South Atlantic Convergence Zone (SACZ) and the underlying sea surface temperature (SST) during austral summer is investigated using monthly data from the NCEP/NCAR reanalysis. A maximum covariance analysis shows that the SACZ is intensified [weakened] by warm [cold] SST anomalies in the beginning of summer, drifting northward. This migration is accompanied by the cooling [warming] of the original oceanic anomalies. The results confirm earlier analyses using numerical models that suggest the existence of a negative feedback between the SACZ and the underlying South Atlantic SST field. A linear regression of daily anomalies of SST and omega at 500 hPa to the equations of a stochastic oscillator reveals a negative ocean-atmosphere feedback in the western South Atlantic, stronger during January and February directly underneath the oceanic band of the SACZ.

  11. Atmospheric transport of pollutants from North America to the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Harriss, R. C.; Browell, E. V.; Sebacher, D. I.; Gregory, G. L.; Hinton, R. R.; Beck, S. M.; Mcdougal, D. S.; Shipley, S. T.

    1984-01-01

    Ground-based measurements strongly support the hypothesis that pollutant materials of anthropogenic origin are being transported over long distances in the midtroposphere and are a significant source of acid rain, acid snow, trace metal deposition, ozone and visibility-reducing aerosols in remote oceanic and polar regions of the Norhern Hemisphere. Atmospheric sulphur budget calculations and studies of acid rain on Bermuda indicate that a large fraction of pollutant materials emitted into the atmosphere in eastern North America are advected eastwards over the North Atlantic Ocean. The first direct airborne measurements of the vertical distribution of tropospheric aerosols over the western North Atlantic is reported here. A newly developed airborne differential adsorption lidar system was used to obtain continuous, remotely sensed aerosol distributions along its flight path. The data document two episodes of long-distance transport of pollutant materials from North America over the North Atlantic Ocean.

  12. Atmospheric transport of pollutants from North America to the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Harriss, R. C.; Browell, E. V.; Sebacher, D. I.; Gregory, G. L.; Hinton, R. R.; Beck, S. M.; Mcdougal, D. S.; Shipley, S. T.

    1984-01-01

    Ground-based measurements strongly support the hypothesis that pollutant materials of anthropogenic origin are being transported over long distances in the midtroposphere and are a significant source of acid rain, acid snow, trace metal deposition, ozone and visibility-reducing aerosols in remote oceanic and polar regions of the Norhern Hemisphere. Atmospheric sulphur budget calculations and studies of acid rain on Bermuda indicate that a large fraction of pollutant materials emitted into the atmosphere in eastern North America are advected eastwards over the North Atlantic Ocean. The first direct airborne measurements of the vertical distribution of tropospheric aerosols over the western North Atlantic is reported here. A newly developed airborne differential adsorption lidar system was used to obtain continuous, remotely sensed aerosol distributions along its flight path. The data document two episodes of long-distance transport of pollutant materials from North America over the North Atlantic Ocean.

  13. Microplastic pollution in the Northeast Atlantic Ocean: validated and opportunistic sampling.

    PubMed

    Lusher, Amy L; Burke, Ann; O'Connor, Ian; Officer, Rick

    2014-11-15

    Levels of marine debris, including microplastics, are largely un-documented in the Northeast Atlantic Ocean. Broad scale monitoring efforts are required to understand the distribution, abundance and ecological implications of microplastic pollution. A method of continuous sampling was developed to be conducted in conjunction with a wide range of vessel operations to maximise vessel time. Transects covering a total of 12,700 km were sampled through continuous monitoring of open ocean sub-surface water resulting in 470 samples. Items classified as potential plastics were identified in 94% of samples. A total of 2315 particles were identified, 89% were less than 5mm in length classifying them as microplastics. Average plastic abundance in the Northeast Atlantic was calculated as 2.46 particles m(-3). This is the first report to demonstrate the ubiquitous nature of microplastic pollution in the Northeast Atlantic Ocean and to present a potential method for standardised monitoring of microplastic pollution.

  14. Arctic contribution to upper-ocean variability in the North Atlantic

    NASA Technical Reports Server (NTRS)

    Walsh, John E.; Chapman, William L.

    1990-01-01

    The potential climatic leverage of salinity and temperature anomalies in the high-latitude North Atlantic is large. Substantial variations of sea ice have accompanied North Atlantic salinity and temperature anomalies. Atmospheric pressure data are used here to show that the local forcing of high-latitude North Atlantic Ocean fluctuations is augmented by antecedent atmospheric circulation anomalies over the central Arctic. These circulation anomalies are consistent with enhanced wind-forcing of thicker older ice into the Transpolar Drift Stream and an enhanced export of sea ice (fresh water) from the Arctic into the Greenland Sea prior to major episodes of ice severity in the Greenland and Iceland seas.

  15. Meridional Distribution of Aerosol Optical Thickness over the Tropical Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Kishcha, P.; Silva, Arlindo M.; Starobinets, B.; Long, C. N.; Kalashnikova, O.; Alpert, P.

    2015-01-01

    Previous studies showed that, over the global ocean, there is hemispheric asymmetry in aerosols and no noticeable asymmetry in cloud fraction (CF). In the current study, we focus on the tropical Atlantic (30 Deg N 30 Deg S) which is characterized by significant amounts of Saharan dust dominating other aerosol species over the North Atlantic. We found that, by contrast to the global ocean, over a limited area such as the tropical Atlantic, strong meridional asymmetry in dust aerosols was accompanied by meridional CF asymmetry. During the 10-year study period (July 2002 June 2012), NASA Aerosol Reanalysis (aka MERRAero) showed that, when the meridional asymmetry in dust aerosol optical thickness (AOT) was the most pronounced (particularly in July), dust AOT averaged separately over the tropical North Atlantic was one order of magnitude higher than dust AOT averaged over the tropical South Atlantic. In the presence of such strong meridional asymmetry in dust AOT in July, CF averaged separately over the tropical North Atlantic exceeded CF averaged over the tropical South Atlantic by 20%. Our study showed significant cloud cover, up to 0.8 - 0.9, in July along the Saharan Air Layer which contributed to above-mentioned meridional CF asymmetry. Both Multi-Angle Imaging SpectroRadiometer (MISR) measurements and MERRAero data were in agreement on seasonal variations in meridional aerosol asymmetry. Meridional asymmetry in total AOT over the Atlantic was the most pronounced between March and July, when dust presence over the North Atlantic was maximal. In September and October, there was no noticeable meridional asymmetry in total AOT and meridional CF distribution over the tropical Atlantic was almost symmetrical.

  16. Oceanic forcing of the wintertime North Atlantic Oscillation and European climate

    NASA Astrophysics Data System (ADS)

    Rodwell, M. J.; Rowell, D. P.; Folland, C. K.

    1999-03-01

    The weather over the North Atlantic Ocean, particularly in winter, is often characterized by strong eastward air-flow between the `Icelandic low' and the `Azores high', and by a `stormtrack' of weather systems which move towards western Europe. The North Atlantic Oscillation - an index of which can be defined as the difference in atmospheric pressure at sea level between the Azores and Iceland - is an important mode of variability in the global atmosphere, and is intimately related to the position and strength of the North Atlantic stormtrack owing to dynamic processes internal to the atmosphere,. Here we use a general circulation model of the atmosphere to investigate the ocean's role in forcing North Atlantic and European climate. Our simulations indicate that much of the multiannual to multidecadal variability of the winter North Atlantic Oscillation over the past half century may be reconstructed from a knowledge of North Atlantic sea surface temperature. We argue that sea surface temperature characteristics are `communicated' to the atmosphere through evaporation, precipitation and atmospheric-heating processes, leading to changes in temperature, precipitation and storminess over Europe. As it has recently been proposed that there may be significant multiannual predictability of North Atlantic sea surface temperature patterns, our results are encouraging for the prediction of European winter climate up to several years in advance.

  17. Advection of sulfur dioxide over the western Atlantic Ocean during CITE 3

    NASA Technical Reports Server (NTRS)

    Thornton, D. C.; Bandy, A. R.; Beltz, N.; Driedger, A. R., III; Ferek, R.

    1993-01-01

    During the NASA Chemical Instrumentation Test and Evaluation 3 sulfur intercomparison over the western Atlantic Ocean, five techniques for the determination of sulfur dioxide were evaluated. The response times of the techniques varied from 3 to 30 min. Based on the ensemble of measurements reported, it was clear that advection of SO2 from the North American continent occurred in the boundary layer (altitude less than 1 km) with only one exception. The vertical distribution of SO2 above the boundary layer for the northern and southern Atlantic Ocean was remarkably similar duing this experiment.

  18. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island...

  19. 76 FR 26931 - Safety Zone; Second Annual Space Coast Super Boat Grand Prix, Atlantic Ocean, Cocoa Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... Prix, Atlantic Ocean, Cocoa Beach, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY... Cocoa Beach, Florida during the Second Annual Space Coast Super Boat Grand Prix. The Second Annual Space... will be held on the waters of the Atlantic Ocean east of Cocoa Beach, Florida. Approximately 30 high...

  20. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic...

  1. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  2. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL; restricted area. 334.595 Section 334.595... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape...

  3. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its tributaries. 165.511 Section 165.511... Limited Access Areas Fifth Coast Guard District § 165.511 Security Zone; Atlantic Ocean, Chesapeake...

  4. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles of...

  5. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles of...

  6. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL; restricted area. 334.595 Section 334.595... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape...

  7. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  8. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its tributaries. 165.511 Section 165.511... Limited Access Areas Fifth Coast Guard District § 165.511 Security Zone; Atlantic Ocean, Chesapeake...

  9. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles of...

  10. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  11. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL; restricted area. 334.595 Section 334.595... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape...

  12. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its tributaries. 165.511 Section 165.511... Limited Access Areas Fifth Coast Guard District § 165.511 Security Zone; Atlantic Ocean, Chesapeake...

  13. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its tributaries. 165.511 Section 165.511... Limited Access Areas Fifth Coast Guard District § 165.511 Security Zone; Atlantic Ocean, Chesapeake...

  14. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island...

  15. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  16. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  17. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  18. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL; restricted area. 334.595 Section 334.595... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape...

  19. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  20. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island...

  1. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  2. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles of...

  3. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL; restricted area. 334.595 Section 334.595... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape...

  4. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  5. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island...

  6. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  7. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its tributaries. 165.511 Section 165.511... Limited Access Areas Fifth Coast Guard District § 165.511 Security Zone; Atlantic Ocean, Chesapeake...

  8. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles of...

  9. 77 FR 43158 - Special Local Regulation; Battle on the Bay Powerboat Race Atlantic Ocean, Fire Island, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-24

    ... Race Atlantic Ocean, Fire Island, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY... Atlantic Ocean off Smith Point Park, Fire Island, NY during the Battle on the Bay Powerboat Race. This action is necessary to provide for the safety of life of participants and spectators during this...

  10. Increasing anti-Aβ-induced neurotoxicity ability of Antrodia camphorata-fermented product with deep ocean water supplementary.

    PubMed

    Shi, Yeuching; Yang, Shuyuan; Lee, David Yuewei; Lee, Chunlin

    2016-11-01

    Antrodia camphorata is proven to probably inhibit the neurotoxicity of amyloid β-peptide (Aβ), known as a risk factor toward the development of Alzheimer's disease. Deep ocean water (DOW), drawn from an ocean depth of more than 200 m, has proven to stimulate the growth and metabolite biosynthesis of fungi owing to its rich minerals and trace elements. Based on these advantages of DOW, this study used statistical response surface methodology (RSM) to investigate the effects of DOW on the growth and anti-Aβ-induced neurocytotoxicity ability of A. camphorata. The results showed that DOW was useful for increasing the biomass of A. camphorata and enhancing its neuroprotective capability. The anti-Aβ40-induced neurocytotoxicity ability of filtrate was increased via raising the mycelium-secreted components. Furthermore, the anti-Aβ40-induced neurocytotoxicity ability of mycelium was also increased by the DOW-stimulated intracellular antioxidants. Using 80% DOW concentration, initial pH 3.3 and 20% inoculum size as the optimal culture conditions of A. camphorata significantly stimulated the biomass and mycelium-mediated Aβ40-induced cell viability from 302 ± 14 mg per 100 mL and 49.2 ± 2.2% to 452 ± 33 mg per 100 mL and 65.0 ± 7.4% respectively. This study indicated that DOW could be used as a promising supplementary for the production of A. camphorata secondary metabolites with strong antioxidant activity to protect neuron cells from damage based on Aβ stimulation cytotoxicity. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  11. Bipolar Atlantic deepwater circulation in the middle-late Eocene: Effects of Southern Ocean gateway openings

    NASA Astrophysics Data System (ADS)

    Borrelli, Chiara; Cramer, Benjamin S.; Katz, Miriam E.

    2014-04-01

    We present evidence for Antarctic Circumpolar Current (ACC)-like effects on Atlantic deepwater circulation beginning in the late-middle Eocene. Modern ocean circulation is characterized by a thermal differentiation between Southern Ocean and North Atlantic deepwater formation regions. In order to better constrain the timing and nature of the initial thermal differentiation between Northern Component Water (NCW) and Southern Component Water (SCW), we analyze benthic foraminiferal stable isotope (δ18Obf and δ13Cbf) records from Ocean Drilling Program Site 1053 (upper deep water, western North Atlantic). Our data, compared with published records and interpreted in the context of ocean circulation models, indicate that progressive opening of Southern Ocean gateways and initiation of a circum-Antarctic current caused a transition to a modern-like deep ocean circulation characterized by thermal differentiation between SCW and NCW beginning ~38.5 Ma, in the initial stages of Drake Passage opening. In addition, the relatively low δ18Obf values recorded at Site 1053 show that the cooling trend of the middle-late Eocene was not global, because it was not recorded in the North Atlantic. The timing of thermal differentiation shows that NCW contributed to ocean circulation by the late-middle Eocene, ~1-4 Myr earlier than previously thought. We propose that early NCW originated in the Labrador Sea, based on tectonic reconstructions and changes in foraminiferal assemblages in this basin. Finally, we link further development of meridional isotopic gradients in the Atlantic and Pacific in the late Eocene with the Tasman Gateway deepening (~34 Ma) and the consequent development of a circumpolar proto-ACC.

  12. Variability in North Atlantic heat content and heat transport in a coupled ocean-atmosphere GCM

    NASA Astrophysics Data System (ADS)

    Dong, B.; Sutton, R. T.

    2002-06-01

    A coupled ocean-atmosphere general circulation model has been used to study the variations of North Atlantic upper ocean heat content (OHC), sea surface temperature (SST) and ocean heat transport (OHT), and the relationships between these three quantities. We find that OHC anomalies, and salinity anomalies, propagate anti-cyclonically around the North Atlantic subtropical gyre. They propagate eastward in midlatitudes and westward in low latitudes. Both the advection of mean temperature by anomalous currents and the advection of temperature anomalies by mean currents are responsible for these zonal propagations. In addition to zonal propagations, upper ocean temperature anomalies propagate southward in the eastern North Atlantic, where subduction plays a dominant role. Variability in the northward OHT in the Atlantic is primarily governed by variability in the ocean circulation rather than variability in temperatures. Fluctuations in OHT are the major cause of anomalies in OHC and SST in the Gulf Stream extension region. This is true both for interannual variability and for decadal variability. On interannual time scales, however, surface fluxes also make a significant contribution. Analysis of the relationships of OHT with OHC and SST suggests that a knowledge of OHT fluctuations could be used to predict variations in OHC, and therefore sea surface temperatures, several years in advance.

  13. Invariable biomass-specific primary production of taxonomically discrete picoeukaryote groups across the Atlantic Ocean.

    PubMed

    Grob, Carolina; Hartmann, Manuela; Zubkov, Mikhail V; Scanlan, Dave J

    2011-12-01

    Oceanic photosynthetic picoeukaryotes (< 3 µm) are responsible for > 40% of total primary production at low latitudes such as the North-Eastern tropical Atlantic. In the world ocean, warmed by climate changes, the expected gradual shift towards smaller primary producers could render the role of photosynthetic picoeukaryotes even more important than they are today. Little is still known, however, about how the taxonomic composition of this highly diverse group affects primary production at the basin scale. Here, we combined flow cytometric cell sorting, NaH¹⁴CO₃ radiotracer incubations and class-specific fluorescence in situ hybridization (FISH) probes to determine cell- and biomass-specific inorganic carbon fixation rates and taxonomic composition of two major photosynthetic picoeukaryote groups on a ∼7500-km-long latitudinal transect across the Atlantic Ocean (Atlantic Meridional Transect, AMT19). We show that even though larger cells have, on average, cell-specific CO₂ uptake rates ∼5 times higher than the smaller ones, the average biomass-specific uptake is statistically similar for both groups. On the other hand, even at a high taxonomic level, i.e. class, the contributions to both groups by Prymnesiophyceae, Chrysophyceae and Pelagophyceae are significantly different (P < 0.001 in all cases). We therefore conclude that these group's carbon fixation rates are independent of the taxonomic composition of photosynthetic picoeukaryotes across the Atlantic Ocean. Because the above applies across different oceanic regions the diversity changes seem to be a secondary factor determining primary production.

  14. A New Starting point for the History of South and Equatorial Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Moulin, M.; Aslanian, D.; Olivet, J.; Labails, C.; Rabineau, M.

    2005-05-01

    The nature and genesis of the large, thinned transitional zone of the continental passive margins is still a matter of debate. Any further progress in that subject must imply an intregrated structural study of homologous margins, replaced in a very precise pre-opening kinematic reconstruction to constraint horizontal movements. In South and Equatorial Atlantic oceans, the pre-opening misfits problem has been already addressed by several authors and requires an assessment of rigidity of african and/or south american continental plates which border those oceans. Nevertheless the lack of magnetic anomalies, the pre-opening fit of the Equatorial Atlantic ocean is well constrained due to the presence of well-defined oceanic fracture zones, homologous Demerara and Guinea Plateaus, paralellism of the coasts and Kandi and Sobral continental lineations. This contraint compels us to resort to intraplate deformation to close the South Atlantic Ocean. Intregrating all continental deformations of both plates described in the litterature, we propose here the closest pre-opening fit for the Central part of the South Atlantic. This pre-opening fit leaves a large pre-drift thinned basin of several hundred kilometers which cannot be explained by any process which implies more horizontal movement (stretching, simple shear.). South of the Walvis-Rio Grande ridges, the pre-opening fit implies intraplate deformation in Paraña, Solado and Colorado basins (South America) as already suggested by Unternehr et al (1988) and Nürnberg & Müller (1991).

  15. No Evidence for Ocean Circulation Driving the Atlantic Multi-Decadal Oscillation

    NASA Astrophysics Data System (ADS)

    Cane, M. A.

    2016-02-01

    The Atlantic Multi-decadal Oscillation (AMO), a basin-wide sea surface temperature (SST) change in the North Atlantic, is a major mode of climate variability. Its many important societal impacts include Atlantic hurricane frequency and droughts in North America and North Africa. While there is no consensus on the causes of the AMO, most previous explanations identify the driver as the ocean circulation, specifically changes in the Atlantic Meridional Overturning Circulation (AMOC). Here we show that main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot drive variability in the atmosphere or SST. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the spatial and temporal characteristics of the AMO in current-generation climate models. We conclude that the simplest explanation for the AMO is that it is the low frequency response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling between the atmosphere and the upper ocean allowing the AMO signal to extend into the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response, not a cause.

  16. Genetic discontinuity among regional populations of Lophelia pertusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, C.L.; Ross, Steve W.; Nizinski, M.S.; Brooke, S.; Jarnegren, J.; Waller, R.G.; Johnson, R.L.; King, T.L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U. S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U. S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks. ?? 2011 US Government.

  17. Genetic discontinuity among regional populations of Lophelia perfusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, Cheryl L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U.S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U.S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks

  18. Troposphere-stratosphere response to large-scale North Atlantic Ocean variability in an atmosphere/ocean coupled model

    NASA Astrophysics Data System (ADS)

    Omrani, N.-E.; Bader, Jürgen; Keenlyside, N. S.; Manzini, Elisa

    2016-03-01

    The instrumental records indicate that the basin-wide wintertime North Atlantic warm conditions are accompanied by a pattern resembling negative North Atlantic oscillation (NAO), and cold conditions with pattern resembling the positive NAO. This relation is well reproduced in a control simulation by the stratosphere resolving atmosphere-ocean coupled Max-Planck-Institute Earth System Model (MPI-ESM). Further analyses of the MPI-ESM model simulation shows that the large-scale warm North Atlantic conditions are associated with a stratospheric precursory signal that propagates down into the troposphere, preceding the wintertime negative NAO. Additional experiments using only the atmospheric component of MPI-ESM (ECHAM6) indicate that these stratospheric and tropospheric changes are forced by the warm North Atlantic conditions. The basin-wide warming excites a wave-induced stratospheric vortex weakening, stratosphere/troposphere coupling and a high-latitude tropospheric warming. The induced high-latitude tropospheric warming is associated with reduction of the growth rate of low-level baroclinic waves over the North Atlantic region, contributing to the negative NAO pattern. For the cold North Atlantic conditions, the strengthening of the westerlies in the coupled model is confined to the troposphere and lower stratosphere. Comparing the coupled and uncoupled model shows that in the cold phase the tropospheric changes seen in the coupled model are not well reproduced by the standalone atmospheric configuration. Our experiments provide further evidence that North Atlantic Ocean variability (NAV) impacts the coupled stratosphere/troposphere system. As NAV has been shown to be predictable on seasonal-to-decadal timescales, these results have important implications for the predictability of the extra-tropical atmospheric circulation on these time-scales.

  19. Atlantic Induced Pan-tropical Climate Variability in the Upper-ocean and Atmosphere

    NASA Astrophysics Data System (ADS)

    Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.

    2016-02-01

    During the last three decades, tropical sea surface temperature (SST) exhibited dipole-like trends, with warming over the tropical Atlantic and Indo-Western Pacific but cooling over the Eastern Pacific. The Eastern Pacific cooling has recently been identified as a driver of the global warming hiatus. Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian Ocean, which could potentially contribute to this zonally asymmetric SST pattern. However, the mechanisms and the interactions between these teleconnections remain unclear. To investigate these questions, we performed a `pacemaker' simulation by restoring the tropical Atlantic SST changes in a state-of-the-art climate model - the CESM1. Results show that the Atlantic plays a key role in initiating the tropical-wide teleconnections, and the Atlantic-induced anomalies contribute 55%-75% of the total tropical SST and circulation changes during the satellite era. A hierarchy of oceanic and atmospheric models are then used to investigate the physical mechanisms of these teleconnections: the Atlantic warming enhances atmospheric deep convection, drives easterly wind anomalies over the Indo-Western Pacific through the Kelvin wave, and westerly anomalies over the eastern Pacific as Rossby waves, in line with Gill's solution (Fig1a). These wind changes induce an Indo-Western Pacific warming via the wind-evaporation-SST effect, and this warming intensifies the La Niña-type response in the upper Pacific Ocean by enhancing the easterly trade winds and through the Bjerknes ocean-dynamical processes (Fig1b). The teleconnection finally develops into a tropical-wide SST dipole pattern with an enhanced trade wind and Walker circulation, similar as the observed changes during the satellite era. This mechanism reveals that the tropical ocean basins are more tightly connected than previously thought, and the Atlantic plays a key role in the tropical climate pattern formation and further the

  20. Drivers of surface ocean mercury concentrations and air-sea exchange in the West Atlantic Ocean.

    PubMed

    Soerensen, Anne L; Mason, Robert P; Balcom, Prentiss H; Sunderland, Elsie M

    2013-07-16

    Accurately characterizing net evasion of elemental mercury (Hg(0)) from marine systems is essential for understanding the global biogeochemical mercury (Hg) cycle and the pool of divalent Hg (Hg(II)) available for methylation. Few high resolution measurements of Hg(0) are presently available for constraining global and regional flux estimates and for understanding drivers of spatial and temporal variability in evasion. We simultaneously measured high-resolution atmospheric and surface seawater Hg(0) concentrations as well as the total Hg distribution during six cruises in the West Atlantic Ocean between 2008 and 2010 and examined environmental factors affecting net Hg(0) formation and evasion. We observed the lowest fraction of Hg as Hg(0) (7.8 ± 2.4%) in the near-coastal and shelf areas that are influenced by riverine inputs. Significantly higher %Hg(0) observed in open ocean areas (15.8 ± 3.9%) may reflect lower dissolved organic carbon (DOC) in offshore environments, which is known to affect both the reducible Hg(II) pool and redox kinetics. Calculated Hg(0) evasion changed by more than a factor of 3 between cruises (range: 2.1 ± 0.7 to 6.8 ± 5.1 ng m(-2) h(-1)), driven mainly by variability in Hg(0) and wind speed. Our results suggest that further mechanistic understanding of the role of DOC on Hg redox kinetics in different types of marine environments is needed to explain variability in Hg(0) concentrations and improve global estimates of air-sea exchange.

  1. Upper Ocean Circulation in the Glacial Northeast Atlantic during Heinrich Stadials Ice-Sheet Retreat

    NASA Astrophysics Data System (ADS)

    Toucanne, S.; Soulet, G.; Bosq, M.; Marjolaine, S.; Zaragosi, S.; Bourillet, J. F.; Bayon, G.

    2016-12-01

    Intermediate ocean water variability is involved in climate changes over geological timescales. As a prominent example, changes in North Atlantic subsurface water properties (including warming) during Heinrich Stadials may have triggered the so-called Heinrich events through ice-shelf loss and attendant ice-stream acceleration. While the origin of Heinrich Stadials and subsequent iceberg calving remains controversial, paleoceanographic research efforts mainly focus on the deep Atlantic overturning, leaving the upper ocean largely unexplored. To further evaluate variability in upper ocean circulation and its possible relationship with ice-sheet instabilities, a depth-transect of eight cores (BOBGEO and GITAN-TANDEM cruises) from the Northeast Atlantic (down to 2 km water depth) have been used to investigate kinematic and chemical changes in the upper ocean during the last glacial period. Our results reveal that near-bottom flow speeds (reconstructed by using sortable silt mean grain-size and X-ray fluorescence core-scanner Zr/Rb ratio) and water-masses chemistry (carbon and neodymium isotopes performed on foraminifera) substantially changed in phase with the millennial-scale climate changes recognized in the ice-core records. Our results are compared with paleoceanographic reconstructions of the 'Western Boundary Undercurrent' in order to discuss regional hydrographic differences at both sides of the North Atlantic, as well as with the fluctuations of both the marine- (through ice-rafted debris) and terrestrial-terminating ice-streams (through meltwater discharges) of the circum-Atlantic ice-sheets. Particular attention will be given to the Heinrich Stadials and concomitant Channel River meltwater discharges into the Northeast Atlantic in response to the melting of the European Ice-Sheet. This comparison helps to disentangle the cryosphere-ocean interactions throughout the last ice age, and the sequence of events occurring in the course of the Heinrich Stadials.

  2. On Pleistocene Surface Temperatures of the North Atlantic and Arctic Oceans.

    PubMed

    Ewing, M; Donn, W L

    1960-01-08

    Two additional interpretations are given for the important data of D. B. Ericson on the correlation of coiling directions of Globigerina pachyderma in late Pleistocene North Atlantic sediments with ocean surface temperatures. One interpretation relates the distribution of this species to the distribution and circulation of ocean water masses. On the basis of our ice-age theory, our second interpretation uses the data and correlations of Ericson to establish temperature limits of a thermal node, a line on which glacial and interglacial temperatures were equal, for the North Atlantic Ocean. This line crosses the strait between Greenland and Scandinavia. Further, Ericson's interpretation of the 7.2 degrees C isotherm implies that the glacial-stage surface waters of the Arctic Ocean were between 0 degrees and 3.5 degrees C.

  3. The roles of surface heat flux and ocean heat transport convergence in determining Atlantic Ocean temperature variability

    NASA Astrophysics Data System (ADS)

    Grist, Jeremy P.; Josey, Simon A.; Marsh, Robert; Good, Simon A.; Coward, Andrew. C.; de Cuevas, Beverly A.; Alderson, Steven G.; New, Adrian L.; Madec, Gurvan

    2010-08-01

    The temperature variability of the Atlantic Ocean is investigated using an eddy-permitting (1/4°) global ocean model (ORCA-025) forced with historical surface meteorological fields from 1958 to 2001. The simulation of volume-averaged temperature and the vertical structure of the zonally averaged temperature trends are compared with those from observations. In regions with a high number of observations, in particular above a depth of 500 m and between 22° N and 65° N, the model simulation and the dataset are in good agreement. The relative contribution of variability in ocean heat transport (OHT) convergence and net surface heat flux to changes in ocean heat content is investigated with a focus on three regions: the subpolar and subtropical gyres and the tropics. The surface heat flux plays a relatively minor role in year-to-year changes in the subpolar and subtropical regions, but in the tropical North Atlantic, its role is of similar significance to the ocean heat transport convergence. The strongest signal during the study period is a cooling of the subpolar gyre between 1970 and 1990, which subsequently reversed as the mid-latitude OHT convergence transitioned from an anomalously weak to an anomalously strong state. We also explore whether model OHT anomalies can be linked to surface flux anomalies through a Hovmöller analysis of the Atlantic sector. At low latitudes, increased ocean heat gain coincides with anomalously strong northward transport, whereas at mid-high latitudes, reduced ocean heat loss is associated with anomalously weak heat transport.

  4. Hurricane Havens Handbook for the North Atlantic Ocean. Change 1.

    DTIC Science & Technology

    1983-06-01

    WASHINGT.ON DC 20505 SILVER SPRING, MO 20910 uSAFETAC/Ty, DIRECTOR CIVIL ENGINEERING LAOMNCEC SCOTT AF , L 622 8 TECHNICAL INFORMATION ENERGI PROGRAM OFFICE...different frmee Report) I. SUPPLEMENTARY NOTES (1) Qualified requestors may obtain additional copies from the Defense Technical Information Center (DTIC...all others should apply to the National Technical Information Service (NTIS). (2) Printing history of this publication given on reverse. 19. KEY WORDS

  5. North Atlantic meridional overturning circulation variations from GRACE ocean bottom pressure anomalie

    NASA Astrophysics Data System (ADS)

    Landerer, F. W.; Wiese, D. N.; Bentel, K.; Boening, C.; Watkins, M. M.

    2015-12-01

    The important role of the North-Atlantic Meridonal Overturning Circulation (AMOC) for regional as well as global climate is well recognized. Concerns about potential future AMOC changes imply the need for a continuous, large-scale observation capability to detect any such changes on interannual to decadal time scales. Here, we present the first measurements of lower North-Atlantic-Deep-Water (LNADW) monthly transport changes using only space-based time-variable gravity observations from Gravity Recovery and Climate Experiment (GRACE) satellites, continuously covering the time period from 2003 until now. Improved monthly gravity field retrievals allow the detection of North Atlantic interannual bottom pressure anomalies and yield LNADW transport estimates that are in good agreement with those from the ocean in-situ RAPID-MOCA array at 26.5N. Concurrent with the observed AMOC transport anomalies from late-2009 through early-2010, GRACE measured ocean bottom pressures changes in the 3000-5000 m deep western North Atlantic of -20 mm-H2O, implying a southward volume transport anomaly in that layer of approximately -5.5 Sv. Our results highlight the efficacy of space-gravimetry to observe and detect meridional ocean transport variations that can potentially be retrieved over all latitude ranges in the Atlantic.

  6. Detection of Natural Oil Seeps in the Atlantic Ocean Using MODIS

    NASA Technical Reports Server (NTRS)

    Reahard, Ross; Jones, Jason B.; Mitchell, Mark

    2010-01-01

    Natural oil seepage is the release of crude oil into the ocean from fissures in the seabed. Oil seepage is a major contributor to the total amount of oil entering the world s oceans. According to a 2003 study by the National Academy of Sciences (NAS), 47 percent of oil entering the world s oceans is from natural seeps, and 53 percent is from human sources (extraction, transportation, and consumption). Oil seeps cause smooth oil slicks to form on the water s surface. Oil seeps can indicate the location of stores of fossil fuel beneath the ocean floor. Knowledge of the effect of oil seepage on marine life and marine ecosystems remains limited. In the past, remote sensing has been used to detect oil seeps in the Gulf of Mexico and off of the coast of southern California. This project utilized sun glint MODIS imagery to locate oil slicks off of the Atlantic coast, an area that had not previously been surveyed for natural oil seeps using remote sensing. Since 1982, the Atlantic Ocean has been closed to any oil and gas drilling. Recently, however, the U.S. Minerals Management Services (MMS) has proposed a lease for oil and gas drilling off the coasts of Virginia and North Carolina. Determining the location of seepage sites in the Atlantic Ocean will help MMS locate potential deposits of oil and natural gas, thereby reducing the risk of leasing areas for petroleum extraction that do not contain these natural resources.

  7. Rapid freshening of the deep North Atlantic Ocean over the past four decades.

    PubMed

    Dickson, Bob; Yashayaev, Igor; Meincke, Jens; Turrell, Bill; Dye, Stephen; Holfort, Juergen

    2002-04-25

    The overflow and descent of cold, dense water from the sills of the Denmark Strait and the Faroe Shetland channel into the North Atlantic Ocean is the principal means of ventilating the deep oceans, and is therefore a key element of the global thermohaline circulation. Most computer simulations of the ocean system in a climate with increasing atmospheric greenhouse-gas concentrations predict a weakening thermohaline circulation in the North Atlantic as the subpolar seas become fresher and warmer, and it is assumed that this signal will be transferred to the deep ocean by the two overflows. From observations it has not been possible to detect whether the ocean's overturning circulation is changing, but recent evidence suggests that the transport over the sills may be slackening. Here we show, through the analysis of long hydrographic records, that the system of overflow and entrainment that ventilates the deep Atlantic has steadily changed over the past four decades. We find that these changes have already led to sustained and widespread freshening of the deep ocean.

  8. Strong-mixing induced deep ocean heat uptake events in the North Atlantic.

    NASA Astrophysics Data System (ADS)

    Somavilla Cabrillo, Raquel; Gonzalez-Pola, Cesar; Schauer, Ursula; Budeus, Gedeon

    2015-04-01

    The deceleration of the upper ocean heat storage during the last decade has resulted in an active search for the 'missing heat' in the deep ocean. Modeling work has provided new insights into the role of the central Pacific Ocean on the present hiatus in global warming and the efficient transfer of heat to the deep ocean, but recent studies have highlighted also the large contribution of the North Atlantic basin to these processes, mainly based on ocean observations. The deep ocean heat uptake (below 300 m) in the North Atlantic is not confined to the subpolar gyre region but extends to mid-latitudes of the Eastern North Atlantic (ENA), requiring an additional process for its explanation other than deep convection considered until now. Here, using oceanographic in-situ data, we describe a mechanism of heat and salt injection to the deep ocean after years of warming and saltening at the surface occurred both in regions of mode (43°-48°N) and deep water (74°-76°N) formation in the ENA. The mechanism, although punctual meditated by strong winter mixing events, is between 2 and 6 times higher than the 2000-2010 ocean heat uptake at depths of mode (300-700m) and deep water (>2000m) formation, contributing significantly to the observed deep ocean heat uptake in the North Atlantic. Nutrient, hydrographic and reanalysis data indicate that the strong mixing-induced deep ocean heat uptake events at areas of mode and deep water formation in the North Atlantic are connected through the northward propagation of salty ENA mode waters triggered by the contraction of the subpolar gyre reinforced by the occurrences of blocking anomalies in the ENA. Such connection is not unique of the last decade but observed also during the 1960s. Natural climate variability seems the ultimate driver of the strong mixing-induced deep ocean heat uptake events, although the anthropogenic global warming and its forcing on the Arctic sea-ice retreat and frequency of extreme weather events could

  9. Streamflow from the United States into the Atlantic Ocean during 1931-1960

    USGS Publications Warehouse

    Bue, Conrad D.

    1970-01-01

    Streamflow from the United States into the Atlantic Ocean, between the international stream St. Croix River, inclusive, and Cape Sable, Fla., averaged about 355,000 cfs (cubic feet per second) during the 30-year period 1931-60, or roughly 20 percent of the water that, on the average flows out of the conterminous United States. The area drained by streams flowing into the Atlantic Ocean is about 288,000 square miles, including the Canadian part of the St. Croix and Connecticut River basins, or a little less than 10 percent of the area of the conterminous United States. Hence, the average streamflow into the Atlantic Ocean, in terms of cubic feet per second per square mile, is about twice the national average of the flow that leaves the conterminous United States. Flow from about three-fourths of the area draining into the Atlantic Ocean is gaged at streamflow measuring stations of the U.S. Geological Survey. The remaining one-fourth of the drainage area consists mostly of low-lying coastal areas from which the flow was estimated, largely on the basis of nearby gaging stations. Streamflow, in terms of cubic feet per second per square mile, decreases rather progressively from north to south. It averages nearly 2 cfs along the Maine coast, about 1 cfs along the North Carolina coast, and about 0.9 cfs along the Florida coast.

  10. Cumulus cloud formation over West Atlantic Ocean north of South America

    NASA Image and Video Library

    1962-10-03

    S62-06613 (3 Oct. 1962) --- Cumulus cloud formation over West Atlantic Ocean north of South American during the fourth orbit pass of the Mercury-Atlas 8 (MA-8) mission by astronaut Walter M. Schirra Jr. with a hand-held camera. Photo credit: NASA

  11. Mercury-Atlas 6 spacecraft retrieved from Atlantic Ocean following mission

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The Mercury-Atlas 6 'Friendship 7' spacecraft is retrieved from the Atlantic Ocean following Astronaut John H. Glenn Jr.'s three-orbit space mission. In this view, the capsule is still in the water, with retrieval cable connected to it.

  12. The diversity of cyanomyovirus populations along a North-South Atlantic Ocean transect.

    PubMed

    Jameson, Eleanor; Mann, Nicholas H; Joint, Ian; Sambles, Christine; Mühling, Martin

    2011-11-01

    Viruses that infect the marine cyanobacterium Prochlorococcus have the potential to impact the growth, productivity, diversity and abundance of their hosts. In this study, changes in the microdiversity of cyanomyoviruses were investigated in 10 environmental samples taken along a North-South Atlantic Ocean transect using a myoviral-specific PCR-sequencing approach. Phylogenetic analyses of 630 viral g20 clones from this study, with 786 published g20 sequences, revealed that myoviral populations in the Atlantic Ocean had higher diversity than previously reported, with several novel putative g20 clades. Some of these clades were detected throughout the Atlantic Ocean. Multivariate statistical analyses did not reveal any significant correlations between myoviral diversity and environmental parameters, although myoviral diversity appeared to be lowest in samples collected from the north and south of the transect where Prochlorococcus diversity was also lowest. The results were correlated to the abundance and diversity of the co-occurring Prochlorococcus and Synechococcus populations, but revealed no significant correlations to either of the two potential host genera. This study provides evidence that cyanophages have extremely high and variable diversity and are distributed over large areas of the Atlantic Ocean.

  13. 77 FR 42651 - Disestablishment of Restricted Area, Rhode Island Sound, Atlantic Ocean, Approximately 4 Nautical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Army, Corps of Engineers 33 CFR Part 334 Disestablishment of Restricted Area, Rhode Island Sound, Atlantic Ocean, Approximately 4 Nautical Miles Due South of Lands End in Newport, RI AGENCY: U.S...

  14. Artificial Radionuclides (236U and 129I) in the Arctic and North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Casacuberta, N.; Christl, M.; Henderson, G. M.; Rutgers van der Loeff, M.; Masque, P.; Vockenhuber, C.; Bauch, D.; Walther, C.

    2016-02-01

    Global fallout and continuous liquid releases by the two European Nuclear Reprocessing Plants of Sellafield (Great Britain) and La Hague (France) are the major contributors of artificial radionuclides to the Arctic and North Atlantic Oceans. Anthropogenic 236U and the 236U/238U ratio are becoming a new transient tracer in oceanography, which combined to 129I (129I/236U ratio) can be used as a novel oceanographic tool in the Arctic and North Atlantic Oceans. Main strengths of using 129I/236U and 236U/238U atomic ratios are: i) identify sources of artificial radionuclides in water masses (global fallout, reprocessing plants and/or rivers); and ii) evaluating water mass ages. Here we will present results from different GEOTRACES expeditions in the Arctic and North Atlantic Oceans during the years 2011 - 2015, including the two pan-arctic expeditions onboard German RV Polarstern and US RV Healy. Seawater samples and ice cores are analyzed for 129I and 236U, contributing to a better understanding of the general Arctic water circulation and their further transport to the North Atlantic Ocean.

  15. Ecological Condition of Coastal Ocean Waters Along the U.S. Mid-Atlantic Bight: 2006

    EPA Science Inventory

    This report presents the results of an assessment of ecological condition in coastal-ocean waters of the U.S. mid-Atlantic Bight (MAB), along the U.S. continental shelf from Cape Cod, MA and Nantucket Shoals to the northeast to Cape Hatteras to the south, based on sampling conduc...

  16. Atlantic Ocean, Antarctica as seen from the Apollo 4 unmanned spacecraft

    NASA Image and Video Library

    1967-11-09

    AS04-01-750 (9 Nov. 1967) --- Atlantic Ocean, Antarctica, looking west, as photographed from the Earth-orbital Apollo 4 (Spacecraft 017/Saturn 501) unmanned space mission. This picture was taken when the Spacecraft 017 and the Saturn S-IVB (third) stage was orbiting Earth at an altitude of 8,628 nautical miles.

  17. 78 FR 22814 - Special Local Regulations; Miami Super Boat Grand Prix, Atlantic Ocean; Miami Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-17

    ..., Atlantic Ocean; Miami Beach, FL AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY... Miami Beach, Florida during the Miami Super Boat Grand Prix. The Miami Super Boat Grand Prix will... Beach, Florida. Approximately 25 high- speed power boats will be participating in the races, and it is...

  18. 77 FR 13519 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY... Virginia Beach, VA. This action is necessary to provide for the safety of life on navigable waters during...

  19. 77 FR 27120 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-09

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The... Beach, VA to support the Virginia Beach Oceanfront Air Show. This action is necessary to provide for the...

  20. Satellite-derived coastal ocean and estuarine salinity in the Mid-Atlantic

    NASA Astrophysics Data System (ADS)

    Geiger, Erick F.; Grossi, Matthew D.; Trembanis, Arthur C.; Kohut, Josh T.; Oliver, Matthew J.

    2013-07-01

    Coastal salinity is a basic oceanographic property that is not routinely estimated by satellites. Efforts to measure ocean salinity from space are designed for large scale open ocean environments, not coastal regions. In the Mid-Atlantic coastal ocean, salinity is critical for understanding circulation patterns, river plumes, and transport, which in turn impact the status of the ecosystem. However, the spatial and temporal coverage of in situ salinity measurements in this region are sparse and do not synoptically capture salinity in the coastal ocean. We compiled ˜2 million salinity records from four regional research vessels between the years 2003-2008 and found ˜9 thousand salinity records that could be adequately matched to MODIS-Aqua data. We show that the spectral shape of water-leaving radiance and sea surface temperature are most correlated with in situ salinity. Four neural network models designed to predict salinity were developed for the Mid-Atlantic coastal region and three of its major estuaries (Hudson, Delaware, and Chesapeake). Our models predict salinity with RMS errors between 1.40psu and 2.29psu, which are much less than the null model ranges (4.87-10.08psu) and the natural range of the system (0-32psu). Seasonal climatologies for the Chesapeake, Delaware, and Mid-Atlantic regions based on these models are fresher than the existing NODC climatologies. We also found significant freshening trends in the Mid-Atlantic over a 6 year period.

  1. Atlantic-Arctic exchange in a series of ocean model simulations (CORE-II)

    NASA Astrophysics Data System (ADS)

    Roth, Christina; Behrens, Erik; Biastoch, Arne

    2014-05-01

    In this study we aim to improve the understanding of exchange processes between the North Atlantic and the Arctic Ocean. The Nordic Sea builds an important connector between these regions, by receiving and modifying warm and saline Atlantic waters, and by providing dense overflow as a backbone of the Atlantic Meridional Overturning Circulation (AMOC). Using a hierarchy of global ocean/sea-ice models, the specific role of the Nordic Seas, both providing a feedback with the AMOC, but also as a modulator of the Atlantic water flowing into the Arctic Ocean, is examined. The models have been performed under the CORE-II protocol, in which atmospheric forcing of the past 60 years was applied in a subsequent series of 5 iterations. During the course of this 300-year long integration, the AMOC shows substantial changes, which are correlated with water mass characteristics in the Denmark Strait overflow characteristics. Quantitative analyses using Lagrangian trajectories explore the impact of these trends on the Arctic Ocean through the Barents Sea and the Fram Strait.

  2. Methanol, acetaldehyde, and acetone in the surface waters of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Beale, Rachael; Dixon, Joanna L.; Arnold, Steve R.; Liss, Peter S.; Nightingale, Philip D.

    2013-10-01

    Oceanic methanol, acetaldehyde, and acetone concentrations were measured during an Atlantic Meridional Transect (AMT) cruise from the UK to Chile (49°N to 39°S) in 2009. Methanol (48-361 nM) and acetone (2-24 nM) varied over the track with enrichment in the oligotrophic Northern Atlantic Gyre. Acetaldehyde showed less variability (3-9 nM) over the full extent of the transect. These oxygenated volatile organic compounds (OVOCs) were also measured subsurface, with methanol and acetaldehyde mostly showing homogeneity throughout the water column. Acetone displayed a reduction below the mixed layer. OVOC concentrations did not consistently correlate with primary production or chlorophyll-a levels in the surface Atlantic Ocean. However, we did find a novel and significant negative relationship between acetone concentration and bacterial leucine incorporation, suggesting that acetone might be removed by marine bacteria as a source of carbon. Microbial turnover of both acetone and acetaldehyde was confirmed. Modeled atmospheric data are used to estimate the likely air-side OVOC concentrations. The direction and magnitude of air-sea fluxes vary for all three OVOCs depending on location. We present evidence that the ocean may exhibit regions of acetaldehyde under-saturation. Extrapolation suggests that the Atlantic Ocean represents an overall source of these OVOCs to the atmosphere at 3, 3, and 1 Tg yr-1 for methanol, acetaldehyde, and acetone, respectively.

  3. Heat and Freshwater Convergence Anomalies in the Atlantic Ocean Inferred from Observations

    NASA Astrophysics Data System (ADS)

    Kelly, K. A.; Drushka, K.; Thompson, L.

    2015-12-01

    Observations of thermosteric and halosteric sea level from hydrographic data, ocean mass from GRACE and altimetric sea surface height are used to infer meridional heat transport (MHT) and freshwater convergence (FWC) anomalies for the Atlantic Ocean. An "unknown control" version of a Kalman filter in each of eight regions extracts smooth estimates of heat transport convergence (HTC) and FWC from discrepancies between the sea level response to monthly surface heat and freshwater fluxes and observed heat and freshwater content. The model is run for 1993-2014. Estimates of MHT anomalies are derived by summing the HTC from north to south and adding a spatially uniform, time-varying MHT derived from updated MHT estimates at 41N (Willis 2010). Estimated anomalies in MHT are comparable to those recently observed at the RAPID/MOCHA line at 26.5N. MHT estimates are relatively insensitive to the choice of heat flux products and are highly coherent spatially. MHT anomalies at 35S resemble estimates of Agulhas Leakage derived from altimeter (LeBars et al 2014) suggesting that the Indian Ocean is the source of the anomalous heat inflow. FWC estimates in the Atlantic Ocean (67N to 35S) resemble estimates of Atlantic river inflow (de Couet and Maurer, GRDC 2009). Increasing values of FWC after 2002 at a time when MHT was decreasing may indicate a feedback between the Atlantic Meridional Overturning Circulation and FWC that would accelerate the AMOC slowdown.

  4. 78 FR 60255 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    ... Company. The intent of this notice is to comply with regulations for the Atlantic surfclam and ocean quahog fisheries and to promote efficient distribution of cage tags. ADDRESSES: Written inquiries may be... given that National Band and Tag Company of Newport, Kentucky, is the authorized vendor of cage...

  5. Mercury-Atlas 6 "Friendship 7" spacecraft is retrieved from the Atlantic Ocean

    NASA Image and Video Library

    1962-03-16

    S62-00941 (20 Feb. 1962) --- The Mercury-Atlas 6 (MA-6) "Friendship 7" spacecraft is retrieved from the Atlantic Ocean following astronaut John H. Glenn Jr.'s three-orbit space mission. In this view, the capsule is still in the water, with retrieval cable connected to it. Photo credit: NASA

  6. Apollo 4 Mission - Atlantic Ocean,coastal Brazil and West Africa

    NASA Image and Video Library

    1967-11-09

    AS04-01-200 (9 Nov. 1967) --- Coastal Brazil, Atlantic Ocean, West Africa, Sahara, looking northwest, as photographed from the unmanned Apollo 4 (Spacecraft 017/Saturn 501) earth-orbital space mission. This picture was taken when the Spacecraft 017 and the Saturn IVB stage were orbiting Earth at an altitude of 9,060 nautical miles.

  7. First occurrence of the lined seahorse Hippocampus erectus in the eastern Atlantic Ocean.

    PubMed

    Woodall, L C; Koldewey, H J; Santos, S V; Shaw, P W

    2009-10-01

    A seahorse specimen from Banco Açores (Azores Archipelago) was identified using morphological and molecular genetic data as Hippocampus erectus. This specimen represents the first record of H. erectus in the eastern Atlantic Ocean, well outside its reported range, and may provide evidence of long-distance translocation in what are assumed to be relatively sedentary fish.

  8. Micropaleontological evidence for increased meridional heat transport in the North Atlantic Ocean during the pliocene

    USGS Publications Warehouse

    Dowsett, H.J.; Cronin, T. M.; Poore, R.Z.; Thompson, R.S.; Whatley, R.C.; Wood, A.M.

    1992-01-01

    The Middle Pliocene (???3 million years ago) has been identified as the last time the Earth was significantly warmer than it was during the Last Interglacial and Holocene. A quantitative micropaleontological paleotemperature transect from equator to high latitudes in the North Atlantic indicates that Middle Pliocene warmth involved increased meridional oceanic heat transport.

  9. Definition, properties, and Atlantic Ocean distribution of the new tracer TrOCA

    NASA Astrophysics Data System (ADS)

    Touratier, Franck; Goyet, Catherine

    2004-05-01

    Natural and anthropogenic tracers in the ocean are widely used not only to better understand water masses circulation and mixing but also to understand and quantify the ocean uptake and storage capacity of greenhouse gases. However, since each tracer is different, it is best to use the complementarity of several tracers to unequivocally identify the various water masses. Here we illustrate the conservative properties and the spatial distribution of the new composite tracer TrOCA ( Tracer combining Oxygen, inorganic Carbon, and total Alkalinity) using oxygen (O 2), dissolved inorganic carbon (TCO 2), and total alkalinity (TA), from the Atlantic Ocean. The significant accuracy improvement of TCO 2 and TA measurements since the 1970s, combined to a large effort in measuring these parameters during large scale cruises throughout the Atlantic Ocean, makes this tracer TrOCA an additional tool in analyzing water mass distribution. This tracer is shown to be conservative in intermediate, deep, and bottom waters. For instance, we show that the independence of TrOCA from other tracers provides further information on the origin and mixing of the main Atlantic water masses. Furthermore, TrOCA combined with the composite tracer NO, in particular the ratio TrOCA/NO, can be used to unequivocally identify and separate the Antarctic Intermediate Water, the Antarctic Bottom Water, and the North Atlantic Deep Water.

  10. Ecological Condition of Coastal Ocean Waters Along the U.S. Mid-Atlantic Bight: 2006

    EPA Science Inventory

    This report presents the results of an assessment of ecological condition in coastal-ocean waters of the U.S. mid-Atlantic Bight (MAB), along the U.S. continental shelf from Cape Cod, MA and Nantucket Shoals to the northeast to Cape Hatteras to the south, based on sampling conduc...

  11. Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States

    PubMed Central

    McCabe, Gregory J.; Palecki, Michael A.; Betancourt, Julio L.

    2004-01-01

    More than half (52%) of the spatial and temporal variance in multidecadal drought frequency over the conterminous United States is attributable to the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). An additional 22% of the variance in drought frequency is related to a complex spatial pattern of positive and negative trends in drought occurrence possibly related to increasing Northern Hemisphere temperatures or some other unidirectional climate trend. Recent droughts with broad impacts over the conterminous U.S. (1996, 1999–2002) were associated with North Atlantic warming (positive AMO) and northeastern and tropical Pacific cooling (negative PDO). Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought. PMID:15016919

  12. Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States

    USGS Publications Warehouse

    McCabe, G.J.; Palecki, M.A.; Betancourt, J.L.

    2004-01-01

    More than half (52%) of the spatial and temporal variance in multidecadal drought frequency over the conterminous United States is attributable to the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). An additional 22% of the variance in drought frequency is related to a complex spatial pattern of positive and negative trends in drought occurrence possibly related to increasing Northern Hemisphere temperatures or some other unidirectional climate trend. Recent droughts with broad impacts over the conterminous U.S. (1996, 1999-2002) were associated with North Atlantic warming (positive AMO) and north-eastern and tropical Pacific cooling (negative PDO). Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought.

  13. Arctic and N Atlantic Crustal Thickness and Oceanic Lithosphere Distribution from Gravity Inversion

    NASA Astrophysics Data System (ADS)

    Kusznir, Nick; Alvey, Andy

    2014-05-01

    The ocean basins of the Arctic and N. Atlantic formed during the Mesozoic and Cenozoic as a series of distinct ocean basins, both small and large, leading to a complex distribution of oceanic crust, thinned continental crust and rifted continental margins. The plate tectonic framework of this region was demonstrated by the pioneering work of Peter Ziegler in AAPG Memoir 43 " Evolution of the Arctic-North Atlantic and the Western Tethys" published in 1988. The spatial evolution of Arctic Ocean and N Atlantic ocean basin geometry and bathymetry are critical not only for hydrocarbon exploration but also for understanding regional palaeo-oceanography and ocean gateway connectivity, and its influence on global climate. Mapping crustal thickness and oceanic lithosphere distribution represents a substantial challenge for the Polar Regions. Using gravity anomaly inversion we have produced comprehensive maps of crustal thickness and oceanic lithosphere distribution for the Arctic and N Atlantic region, We determine Moho depth, crustal basement thickness, continental lithosphere thinning and ocean-continent transition location using a 3D spectral domain gravity inversion method, which incorporates a lithosphere thermal gravity anomaly correction (Chappell & Kusznir 2008). Gravity anomaly and bathymetry data used in the gravity inversion are from the NGA (U) Arctic Gravity Project and IBCAO respectively; sediment thickness is from a new regional compilation. The resulting maps of crustal thickness and continental lithosphere thinning factor are used to determine continent-ocean boundary location and the distribution of oceanic lithosphere. Crustal cross-sections using Moho depth from the gravity inversion allow continent-ocean transition structure to be determined and magmatic type (magma poor, "normal" or magma rich). Our gravity inversion predicts thin crust and high continental lithosphere thinning factors in the Eurasia, Canada, Makarov, Podvodnikov and Baffin Basins

  14. Late quaternary paleoceanography of the Atlantic Ocean: foraminiferal faunal and stable-isotopic evidence

    SciTech Connect

    Mix, A.C.

    1986-01-01

    The timing, frequencies, and rates of change of tropical Atlantic climates are studied on a glacial/interglacial scale, using foraminferal faunal abundance and stable isotopic data to estimate temperatures, ice volumes, and water mass properties of the surface and deep ocean. Oxygen-isotope and radiocarbon data constrain the timing of the last deglacial transition (Termination 1) to between 14,000 and 6000 yr BP. Deglaciation was not a continuous process, but may have occurred in steps from 14,000 to 12,000 yr BP, 10,000 to 8000 yr BP, and 7000 to 6000 yr BP. Changes in the ..delta../sup 18/O of glacier ice may induce a lag of the marine ..delta../sup 18/O record behind ice volume of 1000 to 3000 years. Temperature changes estimated by foraminferal transfer functions were not detected in down-core planktonic foraminferal ..delta../sup 18/O data. Hemispheric symmetry of glacial cooling may reflect linkage to high latitude climate changes via trade wind intensities and/or directions. During deglaciation, the North Atlantic was relatively cold, the South Atlantic was relatively warm, and equatorial seasonal contrast was low. This may reflect reduction of northward cross-equatorial heat transport in the ocean, and possible monsoonal effects. Climate changes also extend to the deep ocean. At mid-depths of the tropical Atlantic, minimum Atlantic-Pacific ..delta../sup 13/C difference occurring on average during deglaciation (with a strong 23,000-yr precession cycle) suggests reduced formation of a warm component of NADW during deglaciation. A deeper sites in the North Atlantic, reduced ventilation of deep basins during glacial maxima is linked to surface-water variability of the subpolar North Atlantic.

  15. Future change in ocean productivity: Is the Arctic the new Atlantic?

    NASA Astrophysics Data System (ADS)

    Yool, A.; Popova, E. E.; Coward, A. C.

    2015-12-01

    One of the most characteristic features in ocean productivity is the North Atlantic spring bloom. Responding to seasonal increases in irradiance and stratification, surface phytopopulations rise significantly, a pattern that visibly tracks poleward into summer. While blooms also occur in the Arctic Ocean, they are constrained by the sea-ice and strong vertical stratification that characterize this region. However, Arctic sea-ice is currently declining, and forecasts suggest this may lead to completely ice-free summers by the mid-21st century. Such change may open the Arctic up to Atlantic-style spring blooms, and do so at the same time as Atlantic productivity is threatened by climate change-driven ocean stratification. Here we use low and high-resolution instances of a coupled ocean-biogeochemistry model, NEMO-MEDUSA, to investigate productivity. Drivers of present-day patterns are identified, and changes in these across a climate change scenario (IPCC RCP 8.5) are analyzed. We find a globally significant decline in North Atlantic productivity (> -20%) by 2100, and a correspondingly significant rise in the Arctic (> +50%). However, rather than the future Arctic coming to resemble the current Atlantic, both regions are instead transitioning to a common, low nutrient regime. The North Pacific provides a counterexample where nutrients remain high and productivity increases with elevated temperature. These responses to climate change in the Atlantic and Arctic are common between model resolutions, suggesting an independence from resolution for key impacts. However, some responses, such as those in the North Pacific, differ between the simulations, suggesting the reverse and supporting the drive to more fine-scale resolutions. This article was corrected on 5 JAN 2016. See the end of the full text for details.

  16. Parallel adaptive evolution of geographically distant herring populations on both sides of the North Atlantic Ocean

    PubMed Central

    Lamichhaney, Sangeet; Fuentes-Pardo, Angela P.; Rafati, Nima; Ryman, Nils; McCracken, Gregory R.; Bourne, Christina; Singh, Rabindra; Ruzzante, Daniel E.; Andersson, Leif

    2017-01-01

    Atlantic herring is an excellent species for studying the genetic basis of adaptation in geographically distant populations because of its characteristically large population sizes and low genetic drift. In this study we compared whole-genome resequencing data of Atlantic herring populations from both sides of the Atlantic Ocean. An important finding was the very low degree of genetic differentiation among geographically distant populations (fixation index = 0.026), suggesting lack of reproductive isolation across the ocean. This feature of the Atlantic herring facilitates the detection of genetic factors affecting adaptation because of the sharp contrast between loci showing genetic differentiation resulting from natural selection and the low background noise resulting from genetic drift. We show that genetic factors associated with timing of reproduction are shared between genetically distinct and geographically distant populations. The genes for thyroid-stimulating hormone receptor (TSHR), the SOX11 transcription factor (SOX11), calmodulin (CALM), and estrogen receptor 2 (ESR2A), all with a significant role in reproductive biology, were among the loci that showed the most consistent association with spawning time throughout the species range. In fact, the same two SNPs located at the 5′ end of TSHR showed the most significant association with spawning time in both the east and west Atlantic. We also identified unexpected haplotype sharing between spring-spawning oceanic herring and autumn-spawning populations across the Atlantic Ocean and the Baltic Sea. The genomic regions showing this pattern are unlikely to control spawning time but may be involved in adaptation to ecological factor(s) shared among these populations. PMID:28389569

  17. Parallel adaptive evolution of geographically distant herring populations on both sides of the North Atlantic Ocean.

    PubMed

    Lamichhaney, Sangeet; Fuentes-Pardo, Angela P; Rafati, Nima; Ryman, Nils; McCracken, Gregory R; Bourne, Christina; Singh, Rabindra; Ruzzante, Daniel E; Andersson, Leif

    2017-04-25

    Atlantic herring is an excellent species for studying the genetic basis of adaptation in geographically distant populations because of its characteristically large population sizes and low genetic drift. In this study we compared whole-genome resequencing data of Atlantic herring populations from both sides of the Atlantic Ocean. An important finding was the very low degree of genetic differentiation among geographically distant populations (fixation index = 0.026), suggesting lack of reproductive isolation across the ocean. This feature of the Atlantic herring facilitates the detection of genetic factors affecting adaptation because of the sharp contrast between loci showing genetic differentiation resulting from natural selection and the low background noise resulting from genetic drift. We show that genetic factors associated with timing of reproduction are shared between genetically distinct and geographically distant populations. The genes for thyroid-stimulating hormone receptor (TSHR), the SOX11 transcription factor (SOX11), calmodulin (CALM), and estrogen receptor 2 (ESR2A), all with a significant role in reproductive biology, were among the loci that showed the most consistent association with spawning time throughout the species range. In fact, the same two SNPs located at the 5' end of TSHR showed the most significant association with spawning time in both the east and west Atlantic. We also identified unexpected haplotype sharing between spring-spawning oceanic herring and autumn-spawning populations across the Atlantic Ocean and the Baltic Sea. The genomic regions showing this pattern are unlikely to control spawning time but may be involved in adaptation to ecological factor(s) shared among these populations.

  18. Anomalies in the western boundary system of the tropical Atlantic ocean associated with the inter-ocean exchanges variability

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Campos, E. J.; Piera, J.

    2016-02-01

    Outputs of a numerical assimilation with the Hybrid Coordinate Ocean Model (1/12 degree resolution) in the South Atlantic from 1970-2010, forced my monthly NCEP wind data are assessed and used to study the variations of the Agulhas System and their impact into the tropical Atlantic ocean, focusing in the western boundary system. The assimilation represents well the large scale circulation in the South and tropical Atlantic. The 1/12 degree model resolves the mesoscale processes, with the South Atlantic having two important regions of high energy, the Brazil/Malvinas Confluence and the Agulhas Retroflection. Principally, the Agulhas system plays an important role in global climate, by its contribution to the "warm water route" of the thermohaline circulation. Results show an increase in the North Brazil Current (NBC) and decrease of the Brazil Current since the last decade (1990-2010), while that the transport of the Agulhas leakage increased. This study also reveals that the increase in the volumen transport of the NBC impact the latent heat flux and the precipitation in the Brazilian coast.

  19. Observations of Upper-Ocean Thermal Structure in the Tropical Atlantic Ocean during Hurricane Danny and Tropical Storm Erika (2015)

    NASA Astrophysics Data System (ADS)

    Ridinger, S.; Jesse, J. A.; Sanabia, E.; Jayne, S. R.; Swick, W. A.

    2016-02-01

    In August 2015, Hurricane Danny and Tropical Storm Erika formed in close proximity within the Main Development Region over the tropical Atlantic Ocean. The westward tropical cyclone tracks remained within 1.5° latitude for more than 1500 km before reaching the Lesser Antilles. The upper-ocean thermal structure beneath these two tropical systems is investigated using AXBT, ALAMO, and Argo float observations, and changes over time are analyzed. The 59 AXBT and 12 ALAMO floats deployed from USAFR WC-130J aircraft as part of the USNA TROPIC program and AXBT Demonstration Project, along with the Argo floats, provide insight into temporal and spatial scales of the impact of wind-stress on the upper ocean. Several observations are highlighted and observed changes in the mixed layer are compared to theoretical results obtained using the Price-Weller-Pinkel ocean mixed layer model.

  20. The nonlinear North Atlantic-Arctic ocean response to CO2 forcing

    NASA Astrophysics Data System (ADS)

    van der Linden, Eveline C.; Bintanja, Richard; Hazeleger, Wilco

    2017-04-01

    Most climate models project an increase in oceanic energy transport towards high northern latitudes in future climate projections, but the physical mechanisms are not yet fully understood. To obtain a more fundamental understanding of the processes that cause the ocean heat transport to increase, we carried out a set of sensitivity experiments using a coupled atmosphere-ocean general circulation model. Within these experiments, atmospheric CO2 levels are instantaneously set to one-fourth to four times current values. These model integrations, each with a length of 550 years, result in five considerably different quasi-equilibrium climate states. Our simulations show that poleward ocean heat transport in the Atlantic sector of the Arctic at 70°N increases from 0.03 PW in the coldest climate state to 0.2 PW in the warmest climate state. This increase is caused primarily by changes in sea ice cover, in horizontal ocean currents owing to anomalous winds in response to sea ice changes, and in ocean advection of thermal anomalies. Surprisingly, at subpolar latitudes, the subpolar gyre is found to weaken toward both the warmer and colder climates, relative to the current climate. This nonlinear response is caused by a complex interplay between seasonal sea ice melt, the near-surface wind response to sea ice changes, and changes in the density-driven circulation. The Atlantic Meridional Overturning Circulation (AMOC) and its associated heat transport even oppose the total ocean heat transport towards the Arctic in the warmest climate. Going from warm to cold climates, or from high to low CO2 concentrations, the strength of the AMOC initially increases, but then declines towards the coldest climate, implying a nonlinear AMOC-response to CO2-induced climate change. Evidently, the North Atlantic-Arctic ocean heat transport depends on an interplay between various (remote) coupled ocean-atmosphere-sea ice mechanisms that respond in a nonlinear way to climate change.

  1. Mechanisms of Internally Generated Multidecadal Variability of SST in the Atlantic Ocean in a Coupled GCM

    NASA Astrophysics Data System (ADS)

    Chen, Hua; Schneider, Edwin; Wu, Zhiwei

    2015-04-01

    Mechanisms of the internally generated multidecadal variability of SST in the Atlantic Ocean are investigated in a long control simulation of the Community Climate System Model version 3 with constant external forcing. The interactive ensemble (IE) coupling strategy, with an ensemble of atmospheric GCMs (AGCM) coupled to an ocean model, a sea-ice model and a land model, is used to diagnose the roles of various processes in the coupled GCM (CGCM). The noise components of heat flux, wind stress and fresh water flux of the control simulation, determined from the CGCM surface fluxes by subtracting the SST-forced surface fluxes, estimated as the ensemble mean of AGCM simulations, are applied at the ocean surface of the IE in different regions and in different combinations. The IE simulations demonstrate that the climate variability in the control simulation is predominantly forced by noise. The local noise forcing is found to be responsible for the SST variability in the Atlantic Ocean, with noise heat flux and noise wind stress playing a critical role. The control run Atlantic multidecadal variability (AMV) index is decomposed into interannual, decadal, multidecadal and centennial modes based on the ensemble empirical mode decomposition, and the multidecadal mode of 50-year period is examined in detail. The North Atlantic Oscillation (NAO) pattern in the atmosphere, dominated by the noise component, forces the AMV 50-year mode through noise heat flux and noise wind stress. The noise wind stress forcing on AMV is associated with ocean dynamics, including gyre adjustment and the Atlantic Meridional Overturning Circulation. The atmospheric response to SST, including the SST-forced heat flux and SST-forced wind stress, acts as a damping on AMV.

  2. Evolutionary Diversification of Banded Tube-Dwelling Anemones (Cnidaria; Ceriantharia; Isarachnanthus) in the Atlantic Ocean

    PubMed Central

    Stampar, Sergio N.; Maronna, Maximiliano M.; Vermeij, Mark J. A.; Silveira, Fabio L. d.; Morandini, André C.

    2012-01-01

    The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed. PMID:22815928

  3. Evolutionary diversification of banded tube-dwelling anemones (Cnidaria; Ceriantharia; Isarachnanthus) in the Atlantic Ocean.

    PubMed

    Stampar, Sergio N; Maronna, Maximiliano M; Vermeij, Mark J A; Silveira, Fabio L d; Morandini, André C

    2012-01-01

    The use of molecular data for species delimitation in Anthozoa is still a very delicate issue. This is probably due to the low genetic variation found among the molecular markers (primarily mitochondrial) commonly used for Anthozoa. Ceriantharia is an anthozoan group that has not been tested for genetic divergence at the species level. Recently, all three Atlantic species described for the genus Isarachnanthus of Atlantic Ocean, were deemed synonyms based on morphological simmilarities of only one species: Isarachnanthus maderensis. Here, we aimed to verify whether genetic relationships (using COI, 16S, ITS1 and ITS2 molecular markers) confirmed morphological affinities among members of Isarachnanthus from different regions across the Atlantic Ocean. Results from four DNA markers were completely congruent and revealed that two different species exist in the Atlantic Ocean. The low identification success and substantial overlap between intra and interspecific COI distances render the Anthozoa unsuitable for DNA barcoding, which is not true for Ceriantharia. In addition, genetic divergence within and between Ceriantharia species is more similar to that found in Medusozoa (Hydrozoa and Scyphozoa) than Anthozoa and Porifera that have divergence rates similar to typical metazoans. The two genetic species could also be separated based on micromorphological characteristics of their cnidomes. Using a specimen of Isarachnanthus bandanensis from Pacific Ocean as an outgroup, it was possible to estimate the minimum date of divergence between the clades. The cladogenesis event that formed the species of the Atlantic Ocean is estimated to have occured around 8.5 million years ago (Miocene) and several possible speciation scenarios are discussed.

  4. Water-mass transformation in the Atlantic Ocean in a Lagrangian frame work

    NASA Astrophysics Data System (ADS)

    Berglund, Sara; Döös, Kristofer; Nycander, Jonas

    2017-04-01

    The world ocean is constantly moving, mostly due to density differences and atmospheric winds. This circulation is commonly refereed to as the Conveyor Belt circulation. In the Southern parts of the Atlantic, around the tip of South Africa, warm and saline water is entering. The water travels northward towards the equator where it increases in salinity. After passing the equator and reaching the North Atlantic, the water becomes cold and fresh, due to heat release to the atmosphere. Previous studies has introduced and computed the thermohaline stream function to connect water-mass transformations to the Conveyor Belt circulation in a temperature and salinity space. It has been suggested that the northward flowing water mass in the Atlantic Ocean can be shown in the stream function as water that converts from warm and saline to cold and fresh, and that the conversion is due to air-sea interactions. In the present study, Lagrangian trajectories are used to quantify the northward flowing water masses in the Atlantic Oceans contribution to the Conveyor Belt circulation in TS-space by introducing the Lagrangian thermohaline stream function. The stream function shows the Atlantic water-mass transformation, where warm and saline water is converted to cold and fresh, as the water flows from 17°S to 58°N. This conversion is found to be both isopycnal and diapycnal. To connect the water-mass transformation to a geographical position in the Atlantic Ocean, the Lagrangian divergence of heat and salt flux is introduced. Conversions of temperature and salinity shown by the Lagrangian thermohaline stream function are found to occur in the same region of the domain, however, with a different spread. The conversion of temperature is found to take place in the Gulf Stream, the upper flank of the North Atlantic subtropical gyre, and in the North Atlantic Drift, whereas the conversion of salinity occurs over a narrower band in the same regions. To be able to study the processes

  5. The increasing control of the Atlantic Ocean on ENSO after the early 1990s

    NASA Astrophysics Data System (ADS)

    Yu, J. Y.; Paek, H.; Wang, L.; Lyu, K.

    2016-12-01

    The El Niño-Southern Oscillation (ENSO) is the most powerful interannual variability in Earth's climate system. Previous studies have emphasized processes within the tropical Pacific or Indian Oceans for the generation of ENSO. Recent studies have increasingly suggested that the Atlantic Ocean may play an active role in forcing ENSO variability. In this talk, we will present evidence from observational analyses and modeling experiments to show that the Atlantic Ocean became more capable of influencing ENSO properties after the Atlantic Multidecadal Oscillation (AMO) changed to its positive phase in the early-1990s. A wave source mechanism is proposed to explain how the positive phase of the AMO can intensify the North Pacific Subtropical High (NPSH) to change the ENSO from the Eastern Pacific (EP) type to the Central Pacific (CP) type. A sequence of processes are identified to suggest that the AMO can displace the Pacific Walker circulation, induce a wave source in the tropical central Pacific, and excite a barotropic wave train toward higher-latitudes to enhance the NPSH, which then triggers subtropical Pacific atmospheric forcing and atmosphere-ocean coupling to increase the occurrence of the CP ENSO. An Atlantic capacitor mechanism is also proposed to explain how the positive phase of the AMO can intensify the quasi-biennial (QB) component of ENSO resulting in a more frequent occurrence of ENSO events. We will show that the capacitor mechanism works only after the AMO warmed up the Atlantic sea surface temperatures after the early-1990s. The increased feedback from the Atlantic to the Pacific has enabled the Atlantic capacitor mechanism to intensify the biennial variability in the Pacific during the past two decades. Our suggestion is very different from the previous prevailing views that have emphasized the Indo-Pacific Oceans as the pacemaker for the biennial variability in ENSO. The increasing control of the Atlantic has enabled the CP ENSO dynamics to

  6. Geographical distribution of pelagic decapod shrimp in the Atlantic Ocean.

    PubMed

    Judkins, David C

    2014-12-16

    Ninety-one species of pelagic decapod shrimp were identified in 938 midwater-trawl collections taken between 1963 and 1974 from the North and South Atlantic. Distributional maps are provided for the most frequently occurring species. Nighttime abundance of most species was greatest within the upper 200 m. Degree of geographical overlap was estimated using the geometric mean of the proportion of joint occurrences with a value ≥ 0.5 deemed significant. Geographical distributions tended to be unique, and only 31 species had values ≥ 0.5 with one or more other species. Species within genera and within phylogenetic subgroups of Sergia were generally parapatric or partially overlapping in distribution. Five geographical groupings of co-occurring species across genera were identified: Subpolar-Temperate, Southern Hemisphere, Central, Tropical, Eastern Tropical and Western Tropical. The two species of the Southern Hemisphere group are circumpolar at temperate latitudes. The 12 species of the Central group occurred throughout the subtropical and tropical North and South Atlantic. The eight species of the Tropical group occurred broadly across the equatorial Atlantic and Caribbean with ranges usually extending into the Gulf of Mexico and northward in the Gulf Stream. The two species of the Western Tropical group occurred most often in the western tropics, but there were scattered occurrences at subtropical latitudes. The four species of the Eastern Tropical group were endemic to the Mauritanian Upwelling and the Angola-Benguela Frontal zones off western Africa. Two of the three species in the Subpolar-Temperate group had bipolar distributions, and all three occurred in the Mediterranean and in the Mauritanian Upwelling zone. Most Central, Tropical and Western Tropical species were present in the in the Gulf of Mexico. The 10 species from the Mediterranean were a mixture of Subpolar-Temperate, Central and benthopelagic species. Patterns of distribution in Atlantic pelagic

  7. Tropical Atlantic climate response to different freshwater input in high latitudes with an ocean-only general circulation model

    NASA Astrophysics Data System (ADS)

    Men, Guang; Wan, Xiuquan; Liu, Zedong

    2016-10-01

    Tropical Atlantic climate change is relevant to the variation of Atlantic meridional overturning circulation (AMOC) through different physical processes. Previous coupled climate model simulation suggested a dipole-like SST structure cooling over the North Atlantic and warming over the South Tropical Atlantic in response to the slowdown of the AMOC. Using an ocean-only global ocean model here, an attempt was made to separate the total influence of various AMOC change scenarios into an oceanic-induced component and an atmospheric-induced component. In contrast with previous freshwater-hosing experiments with coupled climate models, the ocean-only modeling presented here shows a surface warming in the whole tropical Atlantic region and the oceanic-induced processes may play an important role in the SST change in the equatorial south Atlantic. Our result shows that the warming is partly governed by oceanic process through the mechanism of oceanic gateway change, which operates in the regime where freshwater forcing is strong, exceeding 0.3 Sv. Strong AMOC change is required for the gateway mechanism to work in our model because only when the AMOC is sufficiently weak, the North Brazil Undercurrent can flow equatorward, carrying warm and salty north Atlantic subtropical gyre water into the equatorial zone. This threshold is likely to be model-dependent. An improved understanding of these issues may have help with abrupt climate change prediction later.

  8. Basin-scale observations of isoprene and monoterpenes in the Arctic and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Carpenter, L.; Hackenberg, S.; Andrews, S.; Minaeian, J.; Chance, R.; Arnold, S.; Spracklen, D. V.; Walker, H.; Brewin, R. J.; Tarran, G.; Tilstone, G.; Small, A.; Bouman, H. A.

    2016-12-01

    We report surface ocean concentrations, atmospheric mixing ratios and calculated sea-to-air fluxes of isoprene and six monoterpenes (α- and β-pinene, myrcene, Δ 3-carene, ocimene, and limonene) spanning approximately 130 degrees of latitude (80 °N- 50 °S) in the Arctic and Atlantic Oceans. Oceanic isoprene concentrations showed covariance with a number of concurrently monitored biological parameters, and these relationships were dependent on sea surface temperatures. Parameterisations of isoprene seawater concentrations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data. Levels of all monoterpenes were generally low, with oceanic concentrations ranging from below the detection limit of <1 pmol L-1 to 5 pmol L-1 . In air, monoterpene mixing ratios varied from below the detection limit ( 1 pptv) to 5 pptv, after careful filtering for ship-related contamination. Unlike in previous studies, no clear trends or relationships of the monoterpenes with biological data were found. Limonene showed generally the highest levels in water (up to 84 pmol L-1 in the Atlantic Ocean) and air; however this was attributed mostly to shipborne contamination. We calculate global sea-air fluxes of isoprene and monoterpenes based on this data and compare to previous estimates.

  9. The impact of polar mesoscale storms on northeast Atlantic Ocean circulation

    NASA Astrophysics Data System (ADS)

    Condron, Alan; Renfrew, Ian A.

    2013-01-01

    Atmospheric processes regulate the formation of deep water in the subpolar North Atlantic Ocean and hence influence the large-scale ocean circulation. Every year thousands of mesoscale storms, termed polar lows, cross this climatically sensitive region of the ocean. These storms are often either too small or too short-lived to be captured in meteorological reanalyses or numerical models. Here we present simulations with a global, eddy-permitting ocean/sea-ice circulation model, run with and without a parameterization of polar lows. The parameterization reproduces the high wind speeds and heat fluxes observed in polar lows as well as their integrated effects, and leads to increases in the simulated depth, frequency and area of deep convection in the Nordic seas, which in turn leads to a larger northward transport of heat into the region, and southward transport of deep water through Denmark Strait. We conclude that polar lows are important for the large-scale ocean circulation and should be accounted for in short-term climate predictions. Recent studies predict a decrease in the number of polar lows over the northeast Atlantic in the twenty-first century that would imply a reduction in deep convection and a potential weakening of the Atlantic meridional overturning circulation.

  10. Variability of The Southwest Indian and Atlantic Oceans and Connexions To Atmospheric Anomalies

    NASA Astrophysics Data System (ADS)

    Fauchereau, N.; Trzaska, S.; Richard, Y.; Roucou, P.

    Sea-Surface-Temperature variability in the Southern Indian and Atlantic Oceans is in- vestigated using Empirical Orthogonal Functions analysis over the 1950-1999 period. It reveals a significant pattern of co-variability between the SouthWest Indian and SouthWest Atlantic Oceans (roughly located in the Southwestern branches of the sub- tropical gyres and their retroflection regions). The robustness of this mode is assessed through correlation between box-averaged indices and composite analysis. This mode is phase-locked on the Austral Summer (november to january) and is associated with significant anomalies in the SLP field. A discussion on the potential mechanisms in- volved in such Ocean Atmosphere anomalies is given and attention is devoted to their impact on the precipitation anomalies over Southern America and mainly Southern Africa. Relations to the SST - atmosphere patterns of variability recently described by Behera et Yamagata (2001. Geophysical Research Letters, 28, 2, 327-330) for the Indian Ocean and Venegas et al (1997. Journal of Climate, 19, 2904-2920) for the Atlantic Ocean is also discussed.

  11. Polyhalogenated Very Short Live Substances in the Atlantic Ocean, and their Linkages with Ocean Primary Production

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yvon-Lewis, S. A.; Hu, L.; Bianchi, T. S.; Campbell, L.; Smith, R. W.

    2011-12-01

    The Halocarbon Air-Sea Transect - Atlantic (HalocAST-A) cruise was conducted aboard FS Polarstern during the ANT-XXVII/1 expedition. The ship departed from Bremerhaven, Germany on October 25th and arrived in Cape Town, South Africa on November 24th in 2010. The HalocAST-A cruise was devoted to studying air-sea fluxes of a suite of halocarbon compounds. Atmospheric mixing ratios and seawater concentrations of the halocarbons were continuously measured with the gas chromatograph - mass spectrometer (GC-MS). This study focuses on the polyhalogenated very short lived substances (VSLSs) such as bromoform (CHBr3), dibromomethane (CH2Br2), chlorodibromomethane (CHClBr2), and bromodichloromethane (CHBrCl2). The goal of this study is to examine the distributions of these compounds and possible relationship between their emissions and oceanic primary production. Therefore, along with the halocarbon concentrations, parameters like dissolved organic carbon concentrations, nutrient concentrations, pigment concentrations, and picoplankton and heterotrophic bacteria counts were also determined. The observed saturation anomalies indicated these VSLSs were supersaturated for almost the entire duration of the cruise. The highest seawater concentrations for these compounds were observed near the Canary Islands. Air mixing ratios were also elevated in this region. The net fluxes for CHBr3, CH2Br2, CHClBr2, and CHBrCl2 were 13.8 nmol m-2 d-1, 4.5 nmol m-2 d-1, 4.5 nmol m-2 d-1 and 1.2 nmol m-2 d-1, respectively. During the HalocAST-A cruise, these compounds exhibit similar trends with total chlorophyll a. Contributions from selected phytoplankton group will be further assessed through the use of individual pigment biomarkers.

  12. North Atlantic ocean circulation and abrupt climate change during the last glaciation.

    PubMed

    Henry, L G; McManus, J F; Curry, W B; Roberts, N L; Piotrowski, A M; Keigwin, L D

    2016-07-29

    The most recent ice age was characterized by rapid and hemispherically asynchronous climate oscillations, whose origin remains unresolved. Variations in oceanic meridional heat transport may contribute to these repeated climate changes, which were most pronounced during marine isotope stage 3, the glacial interval 25 thousand to 60 thousand years ago. We examined climate and ocean circulation proxies throughout this interval at high resolution in a deep North Atlantic sediment core, combining the kinematic tracer protactinium/thorium (Pa/Th) with the deep water-mass tracer, epibenthic δ(13)C. These indicators suggest reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning. These results provide direct evidence for the ocean's persistent, central role in abrupt glacial climate change.

  13. Spinner dolphin whistle in the Southwest Atlantic Ocean: Is there a geographic variation?

    PubMed

    Moron, Juliana Rodrigues; Amorim, Thiago Orion Simões; Sucunza, Federico; de Castro, Franciele Rezende; Rossi-Santos, Marcos; Andriolo, Artur

    2015-10-01

    Acoustic parameters for the spinner dolphins' bioacoustic sounds have previously been described. However, the dolphins in the Southwest Atlantic Ocean were only recently studied near the Fernando de Noronha Archipelago. Therefore, to contribute to additional knowledge of this cosmopolitan species, this study compares previous results with a Brazilian recording. Despite statistically significant differences, the mean value comparison indicated that Hawaiian and Southwest Atlantic Ocean spinners emit similar whistles. The fact that geographical isolation does not lead the dissemblance nor the similarity of the acoustic variations in this species raises the possibility of other factors influencing those emissions. Here those differences and similarities are discussed, thereby contributing to an understanding of how distinct populations and/or species communicate through different ocean basins.

  14. Microplastic abundance, distribution and composition along a latitudinal gradient in the Atlantic Ocean.

    PubMed

    Kanhai, La Daana K; Officer, Rick; Lyashevska, Olga; Thompson, Richard C; O'Connor, Ian

    2017-02-15

    Microplastics in the world's oceans are a global concern due to the potential threat they pose to marine organisms. This study investigated microplastic abundance, distribution and composition in the Atlantic Ocean on a transect from the Bay of Biscay to Cape Town, South Africa. Microplastics were sampled from sub-surface waters using the underway system of the RV Polarstern. Potential microplastics were isolated from samples and FT-IR spectroscopy was used to identify polymer types. Of the particles analysed, 63% were rayon and 37% were synthetic polymers. The majority of microplastics were identified as polyesters (49%) and blends of polyamide or acrylic/polyester (43%). Overall, fibres (94%) were predominant. Average microplastic abundance in the Atlantic Ocean was 1.15±1.45particlesm(-3). Of the 76 samples, 14 were from the Benguela upwelling and there was no statistically significant difference in microplastic abundance between upwelled and non-upwelled sites.

  15. Metabolism of Centropages species in the Mediterranean Sea and the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gaudy, Raymond; Thibault-Botha, Delphine

    2007-02-01

    Information on the metabolism rates of Centropages typicus and congeneric species ( C. hamatus, C. furcatus, C. brachiatus and C. abdominalis) in neritic areas of the Mediterranean Sea, the North Atlantic Ocean and the Pacific Ocean are reported here. Respiration rates and excretion rates are strongly influenced by abiotic (i.e. temperature, salinity) and biotic factors (i.e. food availability and composition). Differences in the response of respiratory rates to temperature of acclimated, acclimatized and adapted individuals are clearly observed among regions of the Mediterranean Sea and the West and East shores of the Atlantic Ocean. Food supply also strongly affects respiration and excretion rates, as well as the size, sex and stage development of the individuals. The co-measurement of these two rates allows confirmation of the omnivory or carnivory oriented feeding habits of these species. The role of this neritic genus in coastal environment is also discussed.

  16. RESEARCH NOTE: On the roughness of Mesozoic oceanic crust in the western North Atlantic

    NASA Astrophysics Data System (ADS)

    Minshull, T. A.

    1999-01-01

    Seismic reflection profiles from Mesozoic oceanic crust around the Blake Spur Fracture Zone (BSFZ) in the western North Atlantic have been widely used in constraining tectonic models of slow-spreading mid-ocean ridges. These profiles have anomalously low basement relief compared to crust formed more recently at the Mid-Atlantic Ridge at the same spreading rate. Profiles from other regions of Mesozoic oceanic crust also have greater relief. The anomalous basement relief and slightly increased crustal thickness in the BSFZ survey area may be due to the presence of a mantle thermal anomaly close to the ridge axis at the time of crustal formation. If so, the intracrustal structures observed may be representative of an atypical tectonic regime.

  17. Influence of the reduction of the incoming raditaion over the Atlantic Southern Ocean on the simulation of the tropical Atlantic variability and its impacts on the equatorial Pacific.

    NASA Astrophysics Data System (ADS)

    Losada, Teresa; Rodríguez-Fonseca, Belén; Castaño-Tierno, Antonio; Mohino, Elsa; Mechoso, C. Roberto

    2017-04-01

    Coupled global climate models (CGCMs) show important biases in the simulation of SST, not only in the tropics, but also over the Southern Ocean. A recent work has shown that improving the errors in the Southern Ocean SST can result in a improvement of the tropical biases in the UCLA CGCM. In this work, we analyse how this model simulates the tropical Atlantic Niño mode in a control run and we compare the results with the variability of a second simulation in which we apply an idealized reduction of the incoming shortwave radiation over the Atlantic sector of the Southern Ocean. Our results show an improvement of the simulation of the tropical Atlantic variability at interannual timescales in the idealized simulation. The representation of the interbasin tropical teleconnection between Atlantic and Pacific Niños is also improved, with a realistic representation of its multidecadal variability.

  18. Nature Run for the North Atlantic Ocean Hurricane Region: System Evaluation and Regional Applications

    NASA Astrophysics Data System (ADS)

    Kourafalou, V.; Androulidakis, I.; Halliwell, G. R., Jr.; Kang, H.; Mehari, M. F.; Atlas, R. M.

    2016-02-01

    A prototype ocean Observing System Simulation Experiments (OSSE) system, first developed and data validated in the Gulf of Mexico, has been applied on the extended North Atlantic Ocean hurricane region. The main objectives of this study are: a) to contribute toward a fully relocatable ocean OSSE system by expanding the Gulf of Mexico OSSE to the North Atlantic Ocean; b) demonstrate and quantify improvements in hurricane forecasting when the ocean component of coupled hurricane models is advanced through targeted observations and assimilation. The system is based on the Hybrid Coordinate Ocean Model (HYCOM) and has been applied on a 1/250 Mercator mesh for the free-running Nature Run (NR) and on a 1/120 Mercator mesh for the data assimilative forecast model (FM). A "fraternal twin" system is employed, using two different realizations for NR and FM, each configured to produce substantially different physics and truncation errors. The NR has been evaluated using a variety of available observations, such as from AVISO, GDEM climatology and GHRSST observations, plus specific regional products (upper ocean profiles from air-borne instruments, surface velocity maps derived from the historical drifter data set and tropical cyclone heat potential maps derived from altimetry observations). The utility of the OSSE system to advance the knowledge of regional air-sea interaction processes related to hurricane activity is demonstrated in the Amazon region (salinity induced surface barrier layer) and the Gulf Stream region (hurricane impact on the Gulf Stream extension).

  19. Latitudinal variation in virus-induced mortality of phytoplankton across the North Atlantic Ocean.

    PubMed

    Mojica, Kristina D A; Huisman, Jef; Wilhelm, Steven W; Brussaard, Corina P D

    2016-02-01

    Viral lysis of phytoplankton constrains marine primary production, food web dynamics and biogeochemical cycles in the ocean. Yet, little is known about the biogeographical distribution of viral lysis rates across the global ocean. To address this, we investigated phytoplankton group-specific viral lysis rates along a latitudinal gradient within the North Atlantic Ocean. The data show large-scale distribution patterns of different virus groups across the North Atlantic that are associated with the biogeographical distributions of their potential microbial hosts. Average virus-mediated lysis rates of the picocyanobacteria Prochlorococcus and Synechococcus were lower than those of the picoeukaryotic and nanoeukaryotic phytoplankton (that is, 0.14 per day compared with 0.19 and 0.23 per day, respectively). Total phytoplankton mortality (virus plus grazer-mediated) was comparable to the gross growth rate, demonstrating high turnover rates of phytoplankton populations. Virus-induced mortality was an important loss process at low and mid latitudes, whereas phytoplankton mortality was dominated by microzooplankton grazing at higher latitudes (>56°N). This shift from a viral-lysis-dominated to a grazing-dominated phytoplankton community was associated with a decrease in temperature and salinity, and the decrease in viral lysis rates was also associated with increased vertical mixing at higher latitudes. Ocean-climate models predict that surface warming will lead to an expansion of the stratified and oligotrophic regions of the world's oceans. Our findings suggest that these future shifts in the regional climate of the ocean surface layer are likely to increase the contribution of viral lysis to phytoplankton mortality in the higher-latitude waters of the North Atlantic, which may potentially reduce transfer of matter and energy up the food chain and thus affect the capacity of the northern North Atlantic to act as a long-term sink for CO2.

  20. Latitudinal variation in virus-induced mortality of phytoplankton across the North Atlantic Ocean

    PubMed Central

    Mojica, Kristina D A; Huisman, Jef; Wilhelm, Steven W; Brussaard, Corina P D

    2016-01-01

    Viral lysis of phytoplankton constrains marine primary production, food web dynamics and biogeochemical cycles in the ocean. Yet, little is known about the biogeographical distribution of viral lysis rates across the global ocean. To address this, we investigated phytoplankton group-specific viral lysis rates along a latitudinal gradient within the North Atlantic Ocean. The data show large-scale distribution patterns of different virus groups across the North Atlantic that are associated with the biogeographical distributions of their potential microbial hosts. Average virus-mediated lysis rates of the picocyanobacteria Prochlorococcus and Synechococcus were lower than those of the picoeukaryotic and nanoeukaryotic phytoplankton (that is, 0.14 per day compared with 0.19 and 0.23 per day, respectively). Total phytoplankton mortality (virus plus grazer-mediated) was comparable to the gross growth rate, demonstrating high turnover rates of phytoplankton populations. Virus-induced mortality was an important loss process at low and mid latitudes, whereas phytoplankton mortality was dominated by microzooplankton grazing at higher latitudes (>56°N). This shift from a viral-lysis-dominated to a grazing-dominated phytoplankton community was associated with a decrease in temperature and salinity, and the decrease in viral lysis rates was also associated with increased vertical mixing at higher latitudes. Ocean-climate models predict that surface warming will lead to an expansion of the stratified and oligotrophic regions of the world's oceans. Our findings suggest that these future shifts in the regional climate of the ocean surface layer are likely to increase the contribution of viral lysis to phytoplankton mortality in the higher-latitude waters of the North Atlantic, which may potentially reduce transfer of matter and energy up the food chain and thus affect the capacity of the northern North Atlantic to act as a long-term sink for CO2. PMID:26262815

  1. Arctic climate sensitivity to changes in North Pacific and North Atlantic ocean heat flux

    NASA Astrophysics Data System (ADS)

    Praetorius, S. K.; Rugenstein, M.; Caldeira, K.

    2016-12-01

    Paleoclimate records indicate abrupt swings in Arctic temperature that were coeval with abrupt changes in sea surface temperature (SST) in both the North Pacific and North Atlantic oceans throughout the late Pleistocene, suggesting a strong coupling between extratropical ocean heat flux and Arctic climate. While the processes that contribute to Arctic amplification, including surface-albedo, cloud, and temperature feedbacks, are generally well-established, the relative impacts of changes in ocean heat flux sourced from different ocean basins on poleward heat transfer and Arctic climate feedbacks are not well understood. We employ simulations with the Community Earth System Model version 1.0.4 using a slab ocean configuration with modified ocean-to-atmosphere heat fluxes sourced from the North Pacific and North Atlantic (30-60°N) to determine the sensitivity of Arctic amplification processes to zonal heterogeneities in northern hemisphere SST patterns. We find that a local heat flux magnitude equivalent to a globally averaged +1 W/m2 sourced from the North Pacific results in greater Arctic surface warming/cooling and sea ice decline/advance than the equivalent heat flux perturbation originating from the North Atlantic. We attribute this response primarily to greater net moisture transfer between the North Pacific and Arctic (relative to the North Atlantic simulations) in response to changes in surface ocean heat flux, with accompanying impacts on cloud, sea ice, and temperature feedbacks that amplify the Arctic surface temperature response. In the case of a positive ocean-to-atmosphere heat flux anomaly from the North Pacific, greater moisture transport into the Arctic results in: 1) enhanced sensible and latent heat transfer to the Arctic 2) enhanced low cloud formation and attendant surface infrared radiation in the Arctic, and 3) enhanced area of sea ice decline, which is promoted by the first two processes and further amplifies surface warming through the ice

  2. Reevaluation of plate motion models based on hotspot tracks in the Atlantic and Indian Oceans

    SciTech Connect

    Baksi, A.K.

    1999-01-01

    Plate motion models based on hotspot tracks in the Atlantic and Indian Oceans predict minimal movement (less than a few millimeters per year) between these hotspots and their counterparts in the Pacific Ocean for the past {approximately}100 m.yr., whereas plate circuit exercises indicate relative motions of {approximately}20 mm/yr. Hotspot-based models also suggest that the Rajmahal Traps, India, were located {approximately}1,000 km away from the Kerguelen hotspot at {approximately}115 Ma, and the Deccan Traps, India, were located a similar distance from the Reunion hotspot at {approximately}65 Ma; this is at odds with conclusions derived from paleomagnetism, plate circuits, and geochemical parameters that suggest a genetic link between flood basalt provinces in India and hotspots in the Indian Ocean. These divergent views may be explained by plume action {approximately}1,000 km from its center or errors in the hotspot motion models. The latter hypothesis is scrutinized in this article by examination of the radiometric ages for hotspot tracks in the Atlantic and Indian Oceans. The {sup 40}/{sup 39}Ar step-heating data for rocks defining the tracks of the Reunion and Kerguelen hotspots in the Indian Ocean and the Great Metero and Tristan da Cunha hotspots in the Atlantic Ocean are critically reexamined. Of {approximately}35 such ages utilized for deriving plate motion models for the past 130 m.yr., at best, only three ({approximately}32, {approximately}50, and {approximately}52 Ma) in the Indian Ocean and one ({approximately}65 Ma) for the Atlantic Ocean may be treated as crystallization ages. Conclusions based on hotspot track modeling for Late Cretaceous to Eocene time are suspect, and those for the Early to Late Cretaceous period are untenable. In the absence of precise age data for the tracks of hotspots in the Atlantic and Indian Oceans, and inconsistent age progressions noted within a single volcanic chain, plate circuit models serve as the superior technique

  3. Contrasting ocean changes between the subpolar and polar North Atlantic during the past 135 ka

    NASA Astrophysics Data System (ADS)

    Bauch, Henning A.; Kandiano, Evguenia S.; Helmke, Jan P.

    2012-06-01

    Variations in the poleward-directed Atlantic heat transfer was investigated over the past 135 ka with special emphasis on the last and present interglacial climate development (Eemian and Holocene). Both interglacials exhibited very similar climatic oscillations during each preceding glacial terminations (deglacial TI and TII). Like TI, also TII has pronounced cold-warm-cold changes akin to events such as H1, Bølling/Allerød, and the Younger Dryas. But unlike TI, the cold events in TII were associated with intermittent southerly invasions of an Atlantic faunal component which underscores quite a different water mass evolution in the Nordic Seas. Within the Eemian interglaciation proper, peak warming intervals were antiphased between the Nordic Seas and North Atlantic. Moreover, inferred temperatures for the Nordic Seas were generally colder in the Eemian than in the Holocene, and vice versa for the North Atlantic. A reduced intensity of Atlantic Ocean heat transfer to the Arctic therefore characterized the Eemian, requiring a reassessment of the actual role of the ocean-atmosphere system behind interglacial, but also, glacial climate changes.

  4. Higher Laurentide and Greenland ice sheets strengthen the North Atlantic ocean circulation

    NASA Astrophysics Data System (ADS)

    Gong, Xun; Zhang, Xiangdong; Lohmann, Gerrit; Wei, Wei; Zhang, Xu; Pfeiffer, Madlene

    2015-07-01

    During the last glacial-interglacial cycle, changes in the large-scale North Atlantic ocean circulation occurred, and at the same time topography of the Laurentide and Greenland ice sheets also varied. In this study, we focus on detecting the changes of the North Atlantic gyres, western boundary current, and the Atlantic meridional overturning circulation (AMOC) corresponding to different Laurentide and Greenland ice sheet topographies. Using an Earth System Model, we conducted simulations for five climate states with different ice sheet topographies: Pre-industrial, Mid Holocene, Last Glacial Maximum, 32 kilo years before present and Eemian interglacial. Our simulation results indicate that higher topographies of the Laurentide and Greenland ice sheets strengthen surface wind stress curl over the North Atlantic ocean, intensifying the subtropical and subpolar gyres and the western boundary currents. The corresponding decrease in sea surface height from subtropical to subpolar favors a stronger AMOC. An offshore shift of the Gulf Stream is also identified during the glacial periods relative to that during the Pre-industrial due to lower sea levels, explaining a weaker glacial Gulf Stream detected in proxy data. Meanwhile, the North Atlantic gyres and AMOC demonstrate a positively correlated relation under each of the climate conditions with higher ice sheets.

  5. Oxygen minimum zones in the eastern tropical Atlantic and Pacific oceans

    NASA Astrophysics Data System (ADS)

    Karstensen, Johannes; Stramma, Lothar; Visbeck, Martin

    2008-06-01

    Within the eastern tropical oceans of the Atlantic and Pacific basin vast oxygen minimum zones (OMZ) exist in the depth range between 100 and 900 m. Minimum oxygen values are reached at 300-500 m depth which in the eastern Pacific become suboxic (dissolved oxygen content <4.5 μmol kg -1) with dissolved oxygen concentration of less than 1 μmol kg -1. The OMZ of the eastern Atlantic is not suboxic and has relatively high oxygen minimum values of about 17 μmol kg -1 in the South Atlantic and more than 40 μmol kg -1 in the North Atlantic. About 20 (40%) of the North Pacific volume is occupied by an OMZ when using 45 μmol kg -1 (or 90 μmol kg -1, respectively) as an upper bound for OMZ oxygen concentration for ocean densities lighter than σθ < 27.2 kg m -3. The relative volumes reduce to less than half for the South Pacific (7% and 13%, respectively). The abundance of OMZs are considerably smaller (1% and 7%) for the South Atlantic and only ∼0% and 5% for the North Atlantic. Thermal domes characterized by upward displacements of isotherms located in the northeastern Pacific and Atlantic and in the southeastern Atlantic are co-located with the centres of the OMZs. They seem not to be directly involved in the generation of the OMZs. OMZs are a consequence of a combination of weak ocean ventilation, which supplies oxygen, and respiration, which consumes oxygen. Oxygen consumption can be approximated by the apparent oxygen utilization (AOU). However, AOU scaled with an appropriate consumption rate (aOUR) gives a time, the oxygen age. Here we derive oxygen ages using climatological AOU data and an empirical estimate of aOUR. Averaging oxygen ages for main thermocline isopycnals of the Atlantic and Pacific Ocean exhibit an exponential increase with density without an obvious signature of the OMZs. Oxygen supply originates from a surface outcrop area and can also be approximated by the turn-over time, the ratio of ocean volume to ventilating flux. The turn-over time

  6. Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese

    NASA Astrophysics Data System (ADS)

    van Hulten, Marco; Middag, Rob; Dutay, Jean-Claude; de Baar, Hein; Roy-Barman, Matthieu; Gehlen, Marion; Tagliabue, Alessandro; Sterl, Andreas

    2017-03-01

    Dissolved manganese (Mn) is a biologically essential element. Moreover, its oxidised form is involved in removing itself and several other trace elements from ocean waters. Here we report the longest thus far (17 500 km length) full-depth ocean section of dissolved Mn in the west Atlantic Ocean, comprising 1320 data values of high accuracy. This is the GA02 transect that is part of the GEOTRACES programme, which aims to understand trace element distributions. The goal of this study is to combine these new observations with new, state-of-the-art, modelling to give a first assessment of the main sources and redistribution of Mn throughout the ocean. To this end, we simulate the distribution of dissolved Mn using a global-scale circulation model. This first model includes simple parameterisations to account for the sources, processes and sinks of Mn in the ocean. Oxidation and (photo)reduction, aggregation and settling, as well as biological uptake and remineralisation by plankton are included in the model. Our model provides, together with the observations, the following insights: - The high surface concentrations of manganese are caused by the combination of photoreduction and sources contributing to the upper ocean. The most important sources are sediments, dust, and, more locally, rivers. - Observations and model simulations suggest that surface Mn in the Atlantic Ocean moves downwards into the southward-flowing North Atlantic Deep Water (NADW), but because of strong removal rates there is no elevated concentration of Mn visible any more in the NADW south of 40° N. - The model predicts lower dissolved Mn in surface waters of the Pacific Ocean than the observed concentrations. The intense oxygen minimum zone (OMZ) in subsurface waters is deemed to be a major source of dissolved Mn also mixing upwards into surface waters, but the OMZ is not well represented by the model. Improved high-resolution simulation of the OMZ may solve this problem. - There is a mainly

  7. Environmental controls on the biogeography of diazotrophy and Trichodesmium in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Snow, J. T.; Schlosser, C.; Woodward, E. M. S.; Mills, M. M.; Achterberg, E. P.; Mahaffey, C.; Bibby, T. S.; Moore, C. M.

    2015-06-01

    The cyanobacterium Trichodesmium is responsible for a significant proportion of the annual "new" nitrogen introduced into the global ocean. Despite being arguably the best studied marine diazotroph, the factors controlling the distribution and growth of Trichodesmium remain a subject of debate, with sea surface temperature, the partial pressure of CO2, and nutrients including iron (Fe) and phosphorus (P), all suggested to be important. Synthesizing data from seven cruises collectively spanning large temporal and spatial scales across the Atlantic Ocean, including two previously unreported studies crossing the largely undersampled South Atlantic gyre, we assessed the relationship between proposed environmental drivers and both community N2 fixation rates and the distribution of Trichodesmium. Simple linear regression analysis would suggest no relationship between any of the sampled environmental variables and N2 fixation rates. However, considering the concentrations of iron and phosphorus together within a simplified resource-ratio framework, illustrated using an idealized numerical model, indicates the combined effects these nutrients have on Trichodesmium and broader diazotroph biogeography, alongside the reciprocal maintenance of different biogeographic provinces of the (sub)tropical Atlantic in states of Fe or P oligotrophy by diazotrophy. The qualitative principles of the resource-ratio framework are argued to be consistent with both the previously described North-South Atlantic contrast in Trichodesmium abundance and the presence and consequence of a substantial non-Trichodesmium diazotrophic community in the western South Atlantic subtropical gyre. A comprehensive, observation-based explanation of the interactions between Trichodesmium and the wider diazotrophic community with iron and phosphorus in the Atlantic Ocean is thus revealed.

  8. Barium isotopes reveal role of ocean circulation on barium cycling in the Atlantic

    NASA Astrophysics Data System (ADS)

    Bates, Stephanie L.; Hendry, Katharine R.; Pryer, Helena V.; Kinsley, Christopher W.; Pyle, Kimberley M.; Woodward, E. Malcolm S.; Horner, Tristan J.

    2017-05-01

    We diagnose the relative influences of local-scale biogeochemical cycling and regional-scale ocean circulation on Atlantic barium cycling by analysing four new depth profiles of dissolved Ba concentrations and isotope compositions from the South and tropical North Atlantic. These new profiles exhibit systematic vertical, zonal and meridional variations that reflect the influence of both local-scale barite cycling and large-scale ocean circulation. Epipelagic decoupling of dissolved Ba and Si reported previously in the tropics is also found to be associated with significant Ba isotope heterogeneity. As such, we contend that this decoupling originates from the depth segregation of opal and barite formation but is exacerbated by weak vertical mixing. Zonal influence from isotopically-'heavy' water masses in the western North Atlantic evidence the advective inflow of Ba-depleted Upper Labrador Sea Water, which is not seen in the eastern basin or the South Atlantic. Meridional variations in Atlantic Ba isotope systematics below 2000 m appear entirely controlled by conservative mixing. Using an inverse isotopic mixing model, we calculate the Ba isotope composition of the Ba-poor northern end-member as +0.45 ‰ and the Ba-rich southern end-member +0.26 ‰, relative to NIST SRM 3104a. The near-conservative behaviour of Ba below 2000 m indicates that Ba isotopes can serve as an independent tracer of the provenance of northern- versus southern-sourced water masses in the deep Atlantic Ocean. This finding may prove useful in palaeoceanographic studies, should appropriate sedimentary archives be identified, and offers new insights into the processes that cycle Ba in seawater.

  9. 78 FR 25574 - Special Local Regulations; Third Annual Space Coast Super Boat Grand Prix, Atlantic Ocean; Cocoa...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-02

    ... Super Boat Grand Prix, Atlantic Ocean; Cocoa Beach, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final... Ocean east of Cocoa Beach, Florida during the Space Coast Super Boat Grand Prix, a series of high-speed... Ocean east of Cocoa Beach, Florida. Approximately 30 high-speed power boats are anticipated to...

  10. Interhemispheric Changes in Atlantic Ocean Heat Content and Their Link to Global Monsoons

    NASA Astrophysics Data System (ADS)

    Lopez, H.; Lee, S. K.; Dong, S.; Goni, G. J.

    2015-12-01

    This study tested the hypothesis whether low frequency decadal variability of the South Atlantic meridional heat transport (SAMHT) influences decadal variability of the global monsoons. A multi-century run from a state-of-the-art coupled general circulation model is used as basis for the analysis. Our findings indicate that multi-decadal variability of the South Atlantic Ocean plays a key role in modulating atmospheric circulation via interhemispheric changes in Atlantic Ocean heat content. Weaker SAMHT produces anomalous ocean heat divergence over the South Atlantic resulting in negative ocean heat content anomaly about 15 years later. This, in turn, forces a thermally direct anomalous interhemispheric Hadley circulation in the atmosphere, transporting heat from the northern hemisphere (NH) to the southern hemisphere (SH) and moisture from the SH to the NH, thereby intensify (weaken) summer (winter) monsoon in the NH and winter (summer) monsoon in the SH. Results also show that anomalous atmospheric eddies, both transient and stationary, transport heat northward in both hemispheres producing eddy heat flux convergence (divergence) in the NH (SH) around 15-30°, reinforcing the anomalous Hadley circulation. The effect of eddies on the NH (SH) poleward of 30° is opposite with heat flux divergence (convergence), which must be balanced by sinking (rising) motion, consistent with a poleward (equatorward) displacement of the jet stream and mean storm track. The mechanism described here could easily be interpreted for the case of strong SAMHT, with the reverse influence on the interhemispheric atmospheric circulation and monsoons. Overall, SAMHT decadal variability leads its atmospheric response by about 15 years, suggesting that the South Atlantic is a potential predictor of global climate variability.

  11. Development of passive volcanic margins of the Central Atlantic and initial opening of ocean

    NASA Astrophysics Data System (ADS)

    Melankholina, E. N.; Sushchevskaya, N. M.

    2015-01-01

    Geological and geophysical data on the Central Atlantic are discussed in order to elucidate the tectonic setting of the initial magmatic activity, rifting, and breakup resulting in the origination of Mesozoic ocean. The structural, magmatic, and historical aspects of the problem are considered. It has been established that the initial dispersed rifting and low-capacity magmatism at proximal margins was followed by the migration of the process toward the central part of region with the formation of distal zones and the development of vigorous magmmatism, further breakup of the lithosphere and ocean opening. Magmatism, its sources, and the features of newly formed magmatic crust at both the rifting and breakup stages of margin development are discussed and compared with subsequent spreading magmatism. Sr, Nd, and Pb isotopic compositions show that the magmatic evolution of the Central Atlantic proximal margins bears the features of two enriched components, one of which is related to the EM-1 source, developing only at the North American margin. Another enriched component typical of the province as a whole is related to the EM-2 source. To a lesser extent, this component is expressed in igneous rocks of Guyana, which also bear the signature of the MORB-type depleted source typical of spreading tholeiites in the Atlantic Ocean. Similar conditions are assumed for subsequent magmatism at the distal margins and for the early spreading basalts in the adjacent Atlantic belt, which also contain a small admixture of enriched material. A comparison of the magmatism at the margins of Central and North Atlantic reveals their specificity distinctly expressed in isotopic compositions of igneous rocks. In contrast to the typical region of the North Atlantic, the immediate melting of the enriched lithospheric source without the participation of plume-related melts is reconstructed for the proximal margins of the Central Atlantic. At the same time, decompression and melting in the

  12. Periodic variations of precipitation in the tropical Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Rao, M. S. V.; Theon, J. S.

    1979-01-01

    Statistical analysis of the satellite-borne Electrically Scanning Microwave Radiometer data in the tropical Atlantic region reveals that the rainfall near local noon is higher both in frequency of occurrence and intensity than the rainfall in the same area near local midnight. Another striking feature that stands out from the analysis is an oscillation with a period of 3.3. days in rainfall occurrence and intensity. This periodicty is consistent with easterly waves traveling from the African continent to the region under study.

  13. Tropical Atlantic Impacts on the Decadal Climate Variability of the Tropical Ocean and Atmosphere.

    NASA Astrophysics Data System (ADS)

    Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.

    2015-12-01

    Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian Ocean. In particular, several recent works indicate that the Atlantic sea surface temperature (SST) may contribute to the climate variability over the equatorial Pacific. Inspired by these studies, our work aims at investigating the impact of the tropical Atlantic on the entire tropical climate system, and uncovering the physical dynamics under these tropical teleconnections. We first performed a 'pacemaker' simulation by restoring the satellite era tropical Atlantic SST changes in a fully coupled model - the CESM1. Results reveal that the Atlantic warming heats the Indo-Western Pacific and cools the Eastern Pacific, enhances the Walker circulation and drives the subsurface Pacific to a La Niña mode, contributing to 60-70% of the above tropical changes in the past 30 years. The same pan-tropical teleconnections have been validated by the statistics of observations and 106 CMIP5 control simulations. We then used a hierarchy of atmospheric and oceanic models with different complexities, to single out the roles of atmospheric dynamics, atmosphere-ocean fluxes, and oceanic dynamics in these teleconnections. With these simulations we established a two-step mechanism as shown in the schematic figure: 1) Atlantic warming generates an atmospheric deep convection and induces easterly wind anomalies over the Indo-Western Pacific in the form of Kelvin waves, and westerly wind anomalies over the eastern equatorial Pacific as Rossby waves, in line with Gill's solution. This circulation changes warms the Indo-Western Pacific and cools the Eastern Pacific with the wind-evaporation-SST effect, forming a temperature gradient over the Indo-Pacific basins. 2) The temperature gradient further generates a secondary atmospheric deep convection, which reinforces the easterly wind anomalies over the equatorial Pacific and enhances the Walker circulation, triggering the Pacific to a La Ni

  14. Nitrous oxide in the tropical Atlantic Ocean: first results from the german SOLAS cruise M55

    NASA Astrophysics Data System (ADS)

    Walter, S.; Bange, H.; Wallace, D.

    2003-04-01

    NITROUS OXIDE IN THE TROPICAL ATLANTIC: FIRST RESULTS FROM THE GERMAN SOLAS CRUISE M55 S. Walter, H.W. Bange, D.W.R. Wallace Marine Biogeochemistry Division, Institute for Marine Research, Düsternbrooker Weg 20, 24105 Kiel, Germany swalter@ifm.uni-kiel.de Nitrous oxide (N2O) is an atmospheric trace gas which received increased attention in recent years because of its relevance for the Earth's climate and stratospheric chemistry. N2O is formed during microbial processes such as nitrification and denitrification in considerable amounts in the subsurface layer of the ocean. Thus, oceanic emissions of N2O play a major role for its atmospheric budget. However, measurements of N2O in the tropical Atlantic are sparse. The spatial distribution of N2O in the tropical Atlantic Ocean was determined during the first German SOLAS (Surface Ocean - Lower Atmosphere Study) cruise Meteor 55 from Willemstad (Curacao, Netherlands Antilles) to Douala (Cameroon) from 12 October to 17 November 2002. At 21 selected stations about 1200 N2O concentrations measurements were performed with a GC/ECD headspace technique. The mean relative error of the measurements was about 2%. Four general features are visible from the N2O depth profiles: (i) N2O is supersaturated throughout the water column. (ii) There is a considerable accumulation of N2O below the euphotic zone with maximum values at 250-400m water depth associated with lower oxygen concentrations. (iii) An increasing trend in the maximum N2O concentrations from the western to the eastern Atlantic which is inversely correlated with dissolved oxygen values in the oxygen minimum zone. (iv) An increasing trend in the N2O concentrations from the western to the eastern Atlantic basin in depths below 2000m which seems to be correlated with the age of the water masses. The inverse correlation with oxygen suggests that N2O in the tropical Atlantic is formed mainly by nitrification. Our results will be discussed in view of global-change induced

  15. Biogeochemical cycling of cadmium isotopes along a high-resolution section through the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Conway, Tim M.; John, Seth G.

    2015-01-01

    Cadmium (Cd) is a bioactive trace element in the oceans, with a nutrient-like distribution that closely matches dissolved phosphate. Seawater-dissolved stable Cd isotope ratios (δ114Cd) are a relatively new parameter, which show much promise for furthering our understanding of the biogeochemical cycling of Cd in the oceans. Here we present a high-resolution paired section of dissolved Cd concentrations and dissolved δ114Cd from 21 open-ocean stations along the US GEOTRACES GA03 transect through the North Atlantic Ocean. Dissolved Cd concentrations along the section are strongly influenced by water-mass distribution and the cycling of Cd. The highest dissolved Cd concentrations (400-540 pmol kg-1) are associated with Antarctic-sourced water masses, whilst biological uptake in the surface ocean results in a strong vertical gradient in dissolved Cd towards the surface, reaching as low as 0.03 pmol kg-1 in western surface waters. Dissolved δ114Cd is also characterized by a vertical gradient from ∼+0.2‰ in the deep ocean to +2‰ to +5‰ in the Cd-depleted surface ocean (relative to NIST SRM 3108). This variability in δ114Cd can be ascribed to mixing of Antarctic and North Atlantic water masses, together with fractionation due to in situ biological uptake of light Cd in the very surface ocean. Subtle deviations from this overall pattern of dissolved Cd concentration and dissolved δ114Cd are observed within low-oxygen waters off North Africa, where a dissolved Cd deficit relative to phosphate is associated with higher dissolved δ114Cd values. Together with elevated particulate Cd and Ba, this suggests that Cd sulfide precipitation is occurring within the water column of the North Atlantic, constituting a potentially important sink for isotopically light Cd. Additionally, the first measurements of dissolved δ114Cd within a hydrothermal plume at the Mid-Atlantic Ridge show that Cd is scavenged from the dissolved phase, leaving the remnant dissolved Cd

  16. Enhanced Oceanic Situational Awareness for the North Atlantic Corridor

    NASA Technical Reports Server (NTRS)

    Welch, Bryan; Greenfield, Israel

    2004-01-01

    Air traffic control (ATC) mandated, aircraft separations over the oceans, impose a limitation of traffic capacity for a given corridor. The separations result from a lack of acceptable situational awareness over oceans where radar position updates are not available. This study considers the use of Automatic Dependent Surveillance (ADS) data transmitted over a commercial satellite communications system as an approach to provide ATC with the needed situational awareness and thusly allow for reduced aircraft separations. Traffic loading from a specific day are used as a benchmark against which to compare several approaches for coordinating data transmissions from aircraft to the satellites.

  17. High connectivity of the crocodile shark between the Atlantic and Southwest Indian Oceans: highlights for conservation.

    PubMed

    da Silva Ferrette, Bruno Lopes; Mendonça, Fernando Fernandes; Coelho, Rui; de Oliveira, Paulo Guilherme Vasconcelos; Hazin, Fábio Hissa Vieira; Romanov, Evgeny V; Oliveira, Claudio; Santos, Miguel Neves; Foresti, Fausto

    2015-01-01

    Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity π = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index ΦST = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.

  18. High Connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: Highlights for Conservation

    PubMed Central

    da Silva Ferrette, Bruno Lopes; Mendonça, Fernando Fernandes; Coelho, Rui; de Oliveira, Paulo Guilherme Vasconcelos; Hazin, Fábio Hissa Vieira; Romanov, Evgeny V.; Oliveira, Claudio; Santos, Miguel Neves; Foresti, Fausto

    2015-01-01

    Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity π = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index ΦST = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai. PMID:25689742

  19. Directly measured mid-depth circulation in the northeastern North Atlantic Ocean.

    PubMed

    Bower, A S; Le Cann, B; Rossby, T; Zenk, W; Gould, J; Speer, K; Richardson, P L; Prater, M D; Zhang, H-M

    2002-10-10

    The circulation of water masses in the northeastern North Atlantic Ocean has a strong influence on global climate owing to the northward transport of warm subtropical water to high latitudes. But the ocean circulation at depths below the reach of satellite observations is difficult to measure, and only recently have comprehensive, direct observations of whole ocean basins been possible. Here we present quantitative maps of the absolute velocities at two levels in the northeastern North Atlantic as obtained from acoustically tracked floats. We find that most of the mean flow transported northward by the Gulf Stream system at the thermocline level (about 600 m depth) remains within the subpolar region, and only relatively little enters the Rockall trough or the Nordic seas. Contrary to previous work, our data indicate that warm, saline water from the Mediterranean Sea reaches the high latitudes through a combination of narrow slope currents and mixing processes. At both depths under investigation, currents cross the Mid-Atlantic Ridge preferentially over deep gaps in the ridge, demonstrating that sea-floor topography can constrain even upper-ocean circulation patterns.

  20. The impact of salinity perturbations on the future uptake of heat by the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Smith, Robin S.; Sutton, Rowan; Gregory, Jonathan M.

    2014-12-01

    Anthropogenic ocean heat uptake is a key factor in determining climate change and sea level rise. There is considerable uncertainty in projections of freshwater forcing of the ocean, with the potential to influence ocean heat uptake. We investigate this by adding either -0.1 Sv (sverdrup (106 m3/s)) or +0.1 Sv freshwater to the Atlantic in global climate model simulations, simultaneously imposing an atmospheric CO2 increase. The resulting changes in the Atlantic meridional overturning circulation are roughly equal and opposite (±2 Sv). The impact of the perturbation on ocean heat content is more complex, although it is relatively small (˜5%) compared to the total anthropogenic heat uptake. Several competing processes either accelerate or retard warming at different depths. While positive freshwater perturbations cause an overall heating of the Atlantic, negative perturbations produce insignificant net changes in heat content. The processes active in our model appear robust, although their net result is likely model dependent and experiment dependent.

  1. Socially segregated, sympatric sperm whale clans in the Atlantic Ocean

    PubMed Central

    Bøttcher, Anne; Whitehead, Hal

    2016-01-01

    Sperm whales (Physeter macrocephalus) are unusual in that there is good evidence for sympatric populations with distinct culturally determined behaviour, including potential acoustic markers of the population division. In the Pacific, socially segregated, vocal clans with distinct dialects coexist; by contrast, geographical variation in vocal repertoire in the Atlantic has been attributed to drift. We examine networks of acoustic repertoire similarity and social interactions for 11 social units in the Eastern Caribbean. We find the presence of two socially segregated, sympatric vocal clans whose dialects differ significantly both in terms of categorical coda types produced by each clan (Mantel test between clans: matrix correlation = 0.256; p ≤ 0.001) and when using classification-free similarity which ignores defined types (Mantel test between clans: matrix correlation = 0.180; p ≤ 0.001). The more common of the two clans makes a characteristic 1 + 1 + 3 coda, while the other less often sighted clan makes predominantly regular codas. Units were only observed associating with other units within their vocal clan. This study demonstrates that sympatric vocal clans do exist in the Atlantic, that they define a higher order level of social organization as they do in the Pacific, and suggests that cultural identity at the clan level is probably important in this species worldwide. PMID:27429766

  2. Wintertime atmospheric response to Atlantic multidecadal variability: effect of stratospheric representation and ocean-atmosphere coupling

    NASA Astrophysics Data System (ADS)

    Peings, Yannick; Magnusdottir, Gudrun

    2016-08-01

    The impact of the Atlantic multidecadal variability (AMV) on the wintertime atmosphere circulation is investigated using three different configurations of the Community Atmospheric Model version 5 (CAM5). Realistic SST and sea ice anomalies associated with the AMV in observations are prescribed in CAM5 (low-top model) and WACCM5 (high-top model) to assess the dependence of the results on the representation of the stratosphere. In a third experiment, the role of ocean-atmosphere feedback is investigated by coupling CAM5 to a slab-ocean model in which the AMV forcing is prescribed through oceanic heat flux anomalies. The three experiments give consistent results concerning the response of the NAO in winter, with a negative NAO signal in response to a warming of the North Atlantic ocean. This response is found in early winter when the high-top model is used, and in late winter with the low-top model. With the slab-ocean, the negative NAO response is more persistent in winter and shifted eastward over the continent due to the damping of the atmospheric response over the North Atlantic ocean. Additional experiments suggest that both tropical and extratropical SST anomalies are needed to obtain a significant modulation of the NAO, with small influence of sea ice anomalies. Warm tropical SST anomalies induce a northward shift of the ITCZ and a Rossby-wave response that is reinforced in the mid-latitudes by the extratropical SST anomalies through eddy-mean flow interactions. This modeling study supports that the positive phase of the AMV promotes the negative NAO in winter, while illustrating the impacts of the stratosphere and of the ocean-atmosphere feedbacks in the spatial pattern and timing of this response.

  3. Present-day transatlantic Saharan dust deposition across the equatorial North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Korte, Laura; Brummer, Geert-Jan; van der Does, Michelle; Guerreiro, Catarina; Hennekam, Rick; van Hateren, Johannes; Jong, Dirk; Munday, Chris; Schouten, Stefan; Jan-Berend, Stuut

    2017-04-01

    Massive amounts of Saharan dust are blown from the African coast across the Atlantic Ocean towards the Americas each year. This dust has direct and indirect effects on global climate including reflection and absorption of solar radiation as well as transport and deposition of nutrients and metals fertilizing both ocean and land. To determine the temporal and spatial variability of Saharan dust transport and deposition and their marine environmental effects across the equatorial North Atlantic Ocean, we have set up a monitoring experiment using deep-ocean sediment traps as well as on land-based dust collectors. The sediment traps were deployed at five sampling sites on a transect between northwest Africa and the Caribbean along 12⁰ N, in a down-wind extension of the land-based dust collectors placed at 19⁰ N on the Mauritanian coast in Iwik. We establish the temporal distribution of the particle fluxes deposited in the Atlantic and compare chemical compositions with the land-based dust collectors propagating to the down-wind sediment trap sites. First-year results show that the total mass fluxes in the ocean are highest at the sampling sites in the East and West, closest to the African continent and the Caribbean, respectively. Element ratios reveal that the lithogenic particles deposited nearest to Africa are most similar in composition to the Saharan dust collected in Iwik. Down-wind Al and Fe contents suggest a downwind change in the mineralogical composition of Saharan dust and indicate an increasing contribution of clay minerals towards the west. In the westernmost Atlantic, gradients suggest admixture of re-suspended clay-sized sediment advected towards the deep sediment trap. Seasonality is most prominent near both continents but generally weak, with mass fluxes dominated by calcium carbonate and clear seasonal maxima of biogenic silica towards the west. See also: www.nioz.nl/dust

  4. Helminth parasites of the oceanic horse mackerel Trachurus picturatus Bowdich 1825 (Pisces: Carangidae) from Madeira Island, Atlantic Ocean, Portugal.

    PubMed

    Costa, G; Melo-Moreira, E; Pinheiro de Carvalho, M A A

    2012-09-01

    The helminth parasite fauna of the oceanic horse mackerel Trachurus picturatus Bowdich 1825, caught off the Madeira Islands was composed of six different taxa. Prevalence and abundance of larval Anisakis sp. (Nematoda: Anisakidae) and Nybelinia lingualis (Trypanorhyncha: Tentaculariidae), the most common parasite taxa, were 24.3%, 0.9 and 37.9%, 0.7, respectively. Bolbosoma vasculosum (Acanthocephala: Polymorphidae) and the monogeneans Heteraxinoides atlanticus (Monogenea: Heteraxinidae) and Pseudaxine trachuri (Monogenea: Gastrocotylidae) were comparatively rare. The depauperate helminth fauna of the oceanic horse mackerel at Madeira compared to other geographical regions of the north-eastern Atlantic, namely the Azores banks and the West African coast, may be attributed to the paucity of nutrients off oceanic islands and to a low density of the fish population.

  5. Resolving the abundance and air-sea fluxes of airborne microorganisms in the North Atlantic Ocean.

    PubMed

    Mayol, Eva; Jiménez, María A; Herndl, Gerhard J; Duarte, Carlos M; Arrieta, Jesús M

    2014-01-01

    Airborne transport of microbes may play a central role in microbial dispersal, the maintenance of diversity in aquatic systems and in meteorological processes such as cloud formation. Yet, there is almost no information about the abundance and fate of microbes over the oceans, which cover >70% of the Earth's surface and are the likely source and final destination of a large fraction of airborne microbes. We measured the abundance of microbes in the lower atmosphere over a transect covering 17° of latitude in the North Atlantic Ocean and derived estimates of air-sea exchange of microorganisms from meteorological data. The estimated load of microorganisms in the atmospheric boundary layer ranged between 6 × 10(4) and 1.6 × 10(7) microbes per m(2) of ocean, indicating a very dynamic air-sea exchange with millions of microbes leaving and entering the ocean per m(2) every day. Our results show that about 10% of the microbes detected in the boundary layer were still airborne 4 days later and that they could travel up to 11,000 km before they entered the ocean again. The size of the microbial pool hovering over the North Atlantic indicates that it could play a central role in the maintenance of microbial diversity in the surface ocean and contribute significantly to atmospheric processes.

  6. Resolving the abundance and air-sea fluxes of airborne microorganisms in the North Atlantic Ocean

    PubMed Central

    Mayol, Eva; Jiménez, María A.; Herndl, Gerhard J.; Duarte, Carlos M.; Arrieta, Jesús M.

    2014-01-01

    Airborne transport of microbes may play a central role in microbial dispersal, the maintenance of diversity in aquatic systems and in meteorological processes such as cloud formation. Yet, there is almost no information about the abundance and fate of microbes over the oceans, which cover >70% of the Earth's surface and are the likely source and final destination of a large fraction of airborne microbes. We measured the abundance of microbes in the lower atmosphere over a transect covering 17° of latitude in the North Atlantic Ocean and derived estimates of air-sea exchange of microorganisms from meteorological data. The estimated load of microorganisms in the atmospheric boundary layer ranged between 6 × 104 and 1.6 × 107 microbes per m2 of ocean, indicating a very dynamic air-sea exchange with millions of microbes leaving and entering the ocean per m2 every day. Our results show that about 10% of the microbes detected in the boundary layer were still airborne 4 days later and that they could travel up to 11,000 km before they entered the ocean again. The size of the microbial pool hovering over the North Atlantic indicates that it could play a central role in the maintenance of microbial diversity in the surface ocean and contribute significantly to atmospheric processes. PMID:25400625

  7. The North Atlantic inflow to the Arctic Ocean: High-resolution model study

    NASA Astrophysics Data System (ADS)

    Aksenov, Yevgeny; Bacon, Sheldon; Coward, Andrew C.; Nurser, A. J. George

    2010-01-01

    North Atlantic Water (NAW) plays a central role in the ocean climate of the Nordic Seas and Arctic Ocean. Whereas the pathways of the NAW in the Nordic Seas are mostly known, those into the Arctic Ocean are yet to be fully understood. To elucidate these routes the results of a high-resolution global coupled ice-ocean model are used. We demonstrate that in 1989-2004 the NAW inflow was equally divided between the Fram Strait and Barents Sea. We find that salt influx within the branches is comparable but that most of the heat entered the Arctic Ocean through Fram Strait. The model shows complex NAW circulation patterns in the Barents Sea. Two mode waters in the Barents Sea branch are identified: a halocline water produced by surface cooling at shallow convective sites in the northern Barents Sea, and bottom water formed from NAW in the southeastern Barents Sea via full-depth convection and mixing. These two modes continue into the Nansen Basin along two separate routes: one through the northern Barents Sea shelf, and the other through the southeastern Barents Sea with halocline mode water dominating the outflow. Overall, less than half of the NAW coming into the Nordic Seas reaches the Arctic Ocean relatively unmodified, and the rest of it will have been modified in the Barents and Kara Seas with a large fraction re-circulating into the North Atlantic.

  8. Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source

    NASA Astrophysics Data System (ADS)

    Saito, Mak A.; Noble, Abigail E.; Tagliabue, Alessandro; Goepfert, Tyler J.; Lamborg, Carl H.; Jenkins, William J.

    2013-09-01

    Low levels of the micronutrient iron limit primary production and nitrogen fixation in large areas of the global ocean. The location and magnitude of oceanic iron sources remain uncertain, however, owing to a scarcity of data, particularly in the deep ocean. Although deep-sea hydrothermal vents along fast-spreading ridges have been identified as important contributors to the oceanic iron inventory, slow-spreading ridges, which contribute more than half of the submarine ridge-crest environment, are assumed to be less significant and remain relatively unexplored. Here, we present measurements of dissolved iron and manganese concentrations along a full-depth section in the South Atlantic Ocean, running from offshore of Brazil to Namibia. We detect a large dissolved iron- and manganese-rich plume over the slow-spreading southern Mid-Atlantic Ridge. Using previously collected measurements of helium-3 concentrations--a tracer of hydrothermal activity--we calculate the ratio of dissolved iron to hydrothermal helium in the plume waters and find that it is 80-fold higher than that reported for plume waters emanating from faster-spreading ridges in the southeastern Pacific. Only the application of a higher ratio in global ocean model simulations yields iron fluxes from these slow-spreading submarine ridges that are in line with our observations. We suggest that global iron contributions from hydrothermal vents are significantly higher than previously thought, owing to a greater contribution from slow-spreading regions.

  9. High bacterivory by the smallest phytoplankton in the North Atlantic Ocean.

    PubMed

    Zubkov, Mikhail V; Tarran, Glen A

    2008-09-11

    Planktonic algae <5 m in size are major fixers of inorganic carbon in the ocean. They dominate phytoplankton biomass in post-bloom, stratified oceanic temperate waters. Traditionally, large and small algae are viewed as having a critical growth dependence on inorganic nutrients, which the latter can better acquire at lower ambient concentrations owing to their higher surface area to volume ratios. Nonetheless, recent phosphate tracer experiments in the oligotrophic ocean have suggested that small algae obtain inorganic phosphate indirectly, possibly through feeding on bacterioplankton. There have been numerous microscopy-based studies of algae feeding mixotrophically in the laboratory and field as well as mathematical modelling of the ecological importance of mixotrophy. However, because of methodological limitations there has not been a direct comparison of obligate heterotrophic and mixotrophic bacterivory. Here we present direct evidence that small algae carry out 40-95% of the bacterivory in the euphotic layer of the temperate North Atlantic Ocean in summer. A similar range of 37-70% was determined in the surface waters of the tropical North-East Atlantic Ocean, suggesting the global significance of mixotrophy. This finding reveals that even the smallest algae have less dependence on dissolved inorganic nutrients than previously thought, obtaining a quarter of their biomass from bacterivory. This has important implications for how we perceive nutrient acquisition and limitation of carbon-fixing protists as well as control of bacterioplankton in the ocean.

  10. Modelling the Oceanic Nd Isotopic Composition With a North Atlantic Eddy Permitting Model

    NASA Astrophysics Data System (ADS)

    Peronne, S.; Treguier, A.; Arsouze, T.; Dutay, J.; Lacan, F.; Jeandel, C.

    2006-12-01

    The oceanic water masses differ by their temperatures, salinity, but also a number of geochemical tracers characterized by their weak concentrations and their ability to quantify oceanic processes (mixing, scavenging rates etc). Among these tracers, the Nd isotopic composition (hereafter epsilon-Nd) is a (quasi) conservative tracer of water mass mixing in the ocean interior, far from any lithogenic inputs. It has been recently established that exchange of Nd at the oceanic margins could be the dominant process controlling both its concentration and isotopic composition distribution in the ocean. This was demonstrated using in situ measurements and budget calculations and has recently been confirmed by a low resolution (2°) modeling approach (Arsouze et al., 2006). However, the currents flowing on the ocean margins are not correctly represented in coarse ocean models. It is the case in the North Atlantic ocean, which is of particular interest since i) it is the area of deep water formation and ii) these deep waters are characterized by the most negative epsilon-Nd values of the world ocean, which are used as "imprint" of the present and past thermohaline circulation. It is therefore essential to understand how these water masses acquire their epsilon-Nd signature. We propose here the first results of the modeling of oceanic Nd isotopic composition at eddy-permitting resolution, with the North Atlantic 0.25° version of the NEMO model used for the DRAKKAR European project. A 150 years off-line experiment and a shorter on-line experiment are performed. Simulated Nd distributions are compared to the present-day data base, vertical profiles, and the results of the low resolution model (in the North Atlantic). The eddy permitting model generally provides improved results, provided a high enough exchange rate is imposed in the deep ocean. Deficiencies of the simulated distribution in the Nordic Seas and the subpolar gyre are explained by errors in the input function on

  11. Decadal variability of the Tropical Atlantic Ocean Surface Temperature in shipboard measurements and in a Global Ocean-Atmosphere model

    NASA Technical Reports Server (NTRS)

    Mehta, Vikram M.; Delworth, Thomas

    1995-01-01

    Sea surface temperature (SST) variability was investigated in a 200-yr integration of a global model of the coupled oceanic and atmospheric general circulations developed at the Geophysical Fluid Dynamics Laboratory (GFDL). The second 100 yr of SST in the coupled model's tropical Atlantic region were analyzed with a variety of techniques. Analyses of SST time series, averaged over approximately the same subregions as the Global Ocean Surface Temperature Atlas (GOSTA) time series, showed that the GFDL SST anomalies also undergo pronounced quasi-oscillatory decadal and multidecadal variability but at somewhat shorter timescales than the GOSTA SST anomalies. Further analyses of the horizontal structures of the decadal timescale variability in the GFDL coupled model showed the existence of two types of variability in general agreement with results of the GOSTA SST time series analyses. One type, characterized by timescales between 8 and 11 yr, has high spatial coherence within each hemisphere but not between the two hemispheres of the tropical Atlantic. A second type, characterized by timescales between 12 and 20 yr, has high spatial coherence between the two hemispheres. The second type of variability is considerably weaker than the first. As in the GOSTA time series, the multidecadal variability in the GFDL SST time series has approximately opposite phases between the tropical North and South Atlantic Oceans. Empirical orthogonal function analyses of the tropical Atlantic SST anomalies revealed a north-south bipolar pattern as the dominant pattern of decadal variability. It is suggested that the bipolar pattern can be interpreted as decadal variability of the interhemispheric gradient of SST anomalies. The decadal and multidecadal timescale variability of the tropical Atlantic SST, both in the actual and in the GFDL model, stands out significantly above the background 'red noise' and is coherent within each of the time series, suggesting that specific sets of

  12. Decadal variability of the Tropical Atlantic Ocean Surface Temperature in shipboard measurements and in a Global Ocean-Atmosphere model

    NASA Technical Reports Server (NTRS)

    Mehta, Vikram M.; Delworth, Thomas

    1995-01-01

    Sea surface temperature (SST) variability was investigated in a 200-yr integration of a global model of the coupled oceanic and atmospheric general circulations developed at the Geophysical Fluid Dynamics Laboratory (GFDL). The second 100 yr of SST in the coupled model's tropical Atlantic region were analyzed with a variety of techniques. Analyses of SST time series, averaged over approximately the same subregions as the Global Ocean Surface Temperature Atlas (GOSTA) time series, showed that the GFDL SST anomalies also undergo pronounced quasi-oscillatory decadal and multidecadal variability but at somewhat shorter timescales than the GOSTA SST anomalies. Further analyses of the horizontal structures of the decadal timescale variability in the GFDL coupled model showed the existence of two types of variability in general agreement with results of the GOSTA SST time series analyses. One type, characterized by timescales between 8 and 11 yr, has high spatial coherence within each hemisphere but not between the two hemispheres of the tropical Atlantic. A second type, characterized by timescales between 12 and 20 yr, has high spatial coherence between the two hemispheres. The second type of variability is considerably weaker than the first. As in the GOSTA time series, the multidecadal variability in the GFDL SST time series has approximately opposite phases between the tropical North and South Atlantic Oceans. Empirical orthogonal function analyses of the tropical Atlantic SST anomalies revealed a north-south bipolar pattern as the dominant pattern of decadal variability. It is suggested that the bipolar pattern can be interpreted as decadal variability of the interhemispheric gradient of SST anomalies. The decadal and multidecadal timescale variability of the tropical Atlantic SST, both in the actual and in the GFDL model, stands out significantly above the background 'red noise' and is coherent within each of the time series, suggesting that specific sets of

  13. Does Saharan dust deposition influence the export of particle fluxes in the tropical North Atlantic Ocean?

    NASA Astrophysics Data System (ADS)

    Korte, Laura; van der Does, Michèlle; Munday, Chris; Brummer, Geert-Jan; Stuut, Jan-Berend

    2015-04-01

    Every year over 200 million tons of Saharan dust are blown over the Atlantic Ocean towards the Caribbean. On its journey most of the dust is removed from the atmosphere by either dry or wet deposition and is ending up in the ocean. Its input potentially stimulates phytoplankton growth and possibly also drags down organic matter through the water column to the sea floor. The role of dust as a means to export organic carbon from the surface ocean to the deep is still controversially discussed. However, aggregation plays a critical role in carbon export since sinking velocities depend amongst others on particle constituents, size and shape, porosity and way of formation. Higher sinking velocities lead to less degradation and remineralization, or, in other words: fresher material. Here we present particle fluxes from one year (October 2012 until November 2013) collected by three sediment traps at 1200 m depth along a profile across the tropical North Atlantic Ocean. Average total mass fluxes vary between 40 and 111 mg/m2/d depending on the location in the ocean. Peak fluxes of 230 and 270 mg/m2/d in the second half of April and by the end of October/start of November 2013 in the western tropical ocean are worth mentioning since they differ in nature; carbonaceous material dominate fluxes in spring and biogenic opal in autumn. The calculated rest fractions, which we interpret as wind-blown dust, vary between 41 mg/m2/d closest to the African coast, and 10 to 18 mg/m2/d to the western open ocean. Total organic carbon (TOC) and biogenic opal are related to the rest fraction for two traps; this relation improves with distance to the source. Unexpectedly, the rest fraction of the sediment trap closest to the African coast, do neither show a relation to organic matter nor to biogenic opal. Same findings hold true for the 15Ntot values of the material: they correlate negatively with the rest fraction, indicating fresher material. These correlations become stronger to the

  14. Convective Lofting Links Indian Ocean Air Pollution to Paradoxical South Atlantic Ozone Maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert B.; Guan, Hong; Thompson, Anne M.; Witte, Jacquelyn C.

    2003-01-01

    We describe a broad resolution of the "Atlantic Paradox" concerning the seasonal and geographic distribution of tropical tropospheric ozone. We describe periods of significant maximum tropospheric O3 for Jan.-April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO)O3 maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.- March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 30 or 60 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  15. Convective lofting links Indian Ocean air pollution to paradoxical South Atlantic ozone maxima

    NASA Technical Reports Server (NTRS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J. C.

    2005-01-01

    We describe a broad resolution of the Atlantic Parado concerning the seasonal and geographic distribution, of tropical tropospheric ozone. We highlight periods of significant maximum tropospheric O3 for Jan.- April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO) maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, possible stratospheric input, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.-March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 20-50 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  16. Mid-Pliocene planktic foraminifer assemblage of the North Atlantic Ocean

    USGS Publications Warehouse

    Dowsett, H.J.; Robinson, M.M.

    2007-01-01

    The US Geological Survey Pliocene Research, Interpretation and Synoptic Mapping (PRISM) North Atlantic faunal data set provides a unique, temporally constrained perspective to document and evaluate the quantitative geographic distribution of key mid-Pliocene taxa. Planktic foraminifer census data from within the PRISM time slab (3.29 to 2.97 Ma) at thirteen sites in the North Atlantic Ocean have been analyzed. We have compiled Scanning Electron Micrographs for an atlas of mid-Pliocene assemblages from the North Atlantic with descriptions of each taxon to document the taxonomic concepts that accompany the PRISM data. In mid-Pliocene assemblages, the geographic distributions of extant taxa are similar to their present day distributions, although some are extended to the north. We use the distribution of extinct taxa to assess previous assumptions regarding environmental preferences.

  17. Convective lofting links Indian Ocean air pollution to paradoxical South Atlantic ozone maxima

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J. C.

    2004-03-01

    We describe a broad resolution of the ``Atlantic Parado'' concerning the seasonal and geographic distribution of tropical tropospheric ozone. We highlight periods of significant maximum tropospheric O3 for Jan.-April, 1999, exploiting satellite estimates and SHADOZ (Southern Hemisphere Additional Ozonesondes). Trajectory analyses connecting sondes and Total Tropospheric Ozone (TTO) maps suggest a complex influence from the Indian Ocean: beginning with mixed combustion sources, then low level transport, cumulonimbus venting, possible stratospheric input, and finally high-level transport to the west, with possible mixing over Africa. For the Jan.-March highest column-O3 periods in the Atlantic, distinct sounding peaks trace to specific NO sources, especially lightning, while in the same episodes, recurring every 20-50 days, more diffuse buildups of Indian-to-Atlantic pollution make important contributions.

  18. Meridional fluxes of dissolved organic matter in the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Walsh, John J.; Carder, Kendall L.; Mueller-Karger, Frank E.

    1992-01-01

    Biooptical estimates of gelbstoff and a few platinum measurements of dissolved organic carbon (DOCpt) are used to construct a budget of the meridional flux of DOC and dissolved organic nitrogen (DON) across 36 deg 25 min N in the North Atlantic from previous inverse models of water and element transport. Distinct southward subsurface fluxes of dissolved organic matter within subducted shelf water, cabelled slope water, and overturned basin water are inferred. Within two cases of a positive gradient of DOCpt between terrestrial/shelf and offshore stocks, the net equatorward exports of O2 and DOCpt from the northern North Atlantic yield molar ratios of 2.1 to 9.1, compared to the expected Redfield O2/C ratio of 1.3. It is concluded that some shelf export of DOC, with a positive gradient between coastal and oceanic stocks, as well as falling particles, are required to balance carbon, nitrogen, and oxygen budgets of the North Atlantic.

  19. Meridional fluxes of dissolved organic matter in the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Walsh, John J.; Carder, Kendall L.; Mueller-Karger, Frank E.

    1992-01-01

    Biooptical estimates of gelbstoff and a few platinum measurements of dissolved organic carbon (DOCpt) are used to construct a budget of the meridional flux of DOC and dissolved organic nitrogen (DON) across 36 deg 25 min N in the North Atlantic from previous inverse models of water and element transport. Distinct southward subsurface fluxes of dissolved organic matter within subducted shelf water, cabelled slope water, and overturned basin water are inferred. Within two cases of a positive gradient of DOCpt between terrestrial/shelf and offshore stocks, the net equatorward exports of O2 and DOCpt from the northern North Atlantic yield molar ratios of 2.1 to 9.1, compared to the expected Redfield O2/C ratio of 1.3. It is concluded that some shelf export of DOC, with a positive gradient between coastal and oceanic stocks, as well as falling particles, are required to balance carbon, nitrogen, and oxygen budgets of the North Atlantic.

  20. THE ECOLOGICAL CONDITION OF ESTUARIES: A FOCUS ON THE ATLANTIC OCEAN AND GULF OF MEXICO COASTS OF THE UNITED STATES

    EPA Science Inventory

    Monitoring the estuaries of the Atlantic Ocean and Gulf of Mexico coastlines was performed annually from 1990 to 1997 to assess ecological conditions on a regional basis for four biogeographic provinces. These province estimates - Virginian, Carolinian, West Indian, and Louisiani...

  1. THE ECOLOGICAL CONDITION OF ESTUARIES: A FOCUS ON THE ATLANTIC OCEAN AND GULF OF MEXICO COASTS OF THE UNITED STATES

    EPA Science Inventory

    Monitoring the estuaries of the Atlantic Ocean and Gulf of Mexico coastlines was performed annually from 1990 to 1997 to assess ecological conditions on a regional basis for four biogeographic provinces. These province estimates - Virginian, Carolinian, West Indian, and Louisiani...

  2. Geomagnetic observations on tristan da cunha, south atlantic ocean

    USGS Publications Warehouse

    Matzka, J.; Olsen, N.; Maule, C.F.; Pedersen, L.W.; Berarducci, A.M.; Macmillan, S.

    2009-01-01

    Few geomagnetic ground observations exist of the Earth's strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37?? 05' S, 12?? 18' W, is therefore of crucial importance. We have conducted several sets of repeat station measurements during magnetically quiet conditions (Kp 2o or less) in 2004. The procedures are described and the results are compared to those from earlier campaigns and to the predictions of various global field models. Features of the local crustal bias field and the solar quiet daily variation are discussed. We also evaluate the benefit of continuous magnetic field recordings from Tristan da Cunha, and argue that such a data set is a very valuable addition to geomagnetic satellite data. Recently, funds were set up to establish and operate a magnetometer station on Tristan da Cunha during the Swarm magnetic satellite mission (2011-2014).

  3. The rotations opening the Central and Northern Atlantic Ocean: compilation, drift lines, and flow lines

    NASA Astrophysics Data System (ADS)

    Greiner, Bernd; Neugebauer, Joachim

    2013-07-01

    We provide an up-to-date compilation of Euler rotations that model the evolution of the Central and Northern Atlantic Ocean (Table 1). The data basis forms seafloor spreading magnetic anomalies of the Atlantic. We checked the published rotations and selected those that form a consistent model. The increments of the Euler rotations going back in time from magnetic anomaly to magnetic anomaly can be illustrated by chains of points on "drift lines" that are paths of motions from continent to continent. Along these paths, the continents bordering the Atlantic Ocean can be moved back to their Mesozoic position within Pangea. Other figures exhibit the early rifting of the North Atlantic, the drift of Iberia, and the evolution of the Greenland-Ellesmere region. The points on the drift lines do not correspond directly to the lines of magnetic anomalies or their "picks" displayed today symmetrically in the Atlantic Ocean. To acquire correspondence, symmetric "flow lines" are constructed analogous to the spreading procedure. But points on the flow lines constructed by half of the increments partially also deviate from the expected symmetric position and in this way quantify displacements or jumps of the axis of rifting or spreading. Most of the selected rotations are from the excellent analyses of previous work. Essential deviations from published rotations are the M 0 rotations of Eurasia and of the Porcupine unit with respect to North America (EUR-NAM and POR-NAM). They lead to a better coincidence between the back-rotated M 0 magnetic anomalies in the Bay of Biscay on the one side and a change of the first transform motions between Greenland and Svalbard on the other side. Through this explanation, an overlap in Pangea SW of Svalbard is avoided and transform motions instead of strong extension are predicted. Some additional data are needed to complete the model: the earliest part of the path of Iberia to North America (IBA-NAM) up to M 4 is calculated assuming that Iberia

  4. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    EPA Science Inventory

    Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emis...

  5. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    EPA Science Inventory

    Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emis...

  6. 75 FR 59226 - Fisheries of the South Atlantic, Gulf of Mexico, and Caribbean; Southeastern Data, Assessment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-27

    ... the Gulf States Marine Fisheries Commission; implemented the Southeast Data, Assessment and Review... National Oceanic and Atmospheric Administration RIN 0648-XZ25 Fisheries of the South Atlantic, Gulf of...) 769-4520. SUPPLEMENTARY INFORMATION: The South Atlantic, Gulf of Mexico, and Caribbean...

  7. 76 FR 50719 - Fisheries of the South Atlantic, Gulf of Mexico, and Caribbean; Southeastern Data, Assessment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... Fisheries Commission, and the Gulf States Marine Fisheries Commission; implemented the Southeast Data... National Oceanic and Atmospheric Administration RIN 0648-XA639 Fisheries of the South Atlantic, Gulf of... (866) SAFMC-10; fax: (843) 769-4520. SUPPLEMENTARY INFORMATION: The South Atlantic, Gulf of Mexico,...

  8. Oceanic heat, carbon uptake and enhanced Atlantic sea level rise under high carbon emission rates

    NASA Astrophysics Data System (ADS)

    Krasting, J. P.; Dunne, J. P.; Hallberg, R.; Stouffer, R. J.

    2016-12-01

    Thermal expansion of the ocean in response to anthropogenic climate warming is an important component of historical sea-level rise. Unlike global surface air temperature and other closely related climate variables that are nearly proportional to cumulative carbon emissions, the relationship between global sea level rise and cumulative emissions is less certain. The magnitude of sea level rise resulting from past carbon emissions depends on the integrated amount of warming and the time scales on which that warming occurs. Here, we present results from the GFDL-ESM2G model forced with range of idealized carbon emission rates - ranging from 2 to 25 Gt C yr-1 - that highlight the relationships between cumulative carbon emissions and heat and carbon uptake. Here we show that the Atlantic basin average sea level rise is larger than the Pacific on centennial time scales under present-day rates of carbon emissions and higher. This asymmetry relates to the shorter flushing time scales of the Atlantic and weakening of the Atlantic Meridional Overturning Circulation (AMOC). For a given level of cumulative emissions, we also find that sea-level rise is largest at low emission rates and is related to the long time scales of climate response associated with lower emission rates. While sea level rise is not proportional to cumulative emissions, our results do show, however, that there is a robust relationship between cumulative emissions and upper ocean (0-700m) Atlantic-minus-Pacific temperature differences across the range of emission rates tested with the model. In addition to local subsidence, changes in offshore winds, and ocean dynamical changes, we conclude that present-day high greenhouse gas emission rates make Atlantic coastal areas more vulnerable to sea-level rise over the coming decades. These results give further evidence that single global average measures become less representative of regional scale changes in sea level rise.

  9. Sound Speed Structure of the Western South Atlantic Ocean.

    DTIC Science & Technology

    1982-07-01

    through and in the environs of the Vema Channel is discussed in detail by Johnson, McDowell, Sullivan, and Biscayne (1976). The presence of AABW would also...71), August, 185 p. Johnson, D. A., S. E, McDowell, L. G. Sullivan, and P. E. Biscayne (1976). Abyssal Hydrography, Nephelometry, Currents, and Benthic...TAEAS) (1) 540 Ocean Measurements (1) 550 Mapping, Charting & Geodesy Program (1) ONRDET Director, ONR Science & Technology Detachment, Bay St. Louis

  10. Sinking of North Atlantic waters in a global ocean model: location and controlling factors

    NASA Astrophysics Data System (ADS)

    Katsman, Caroline; Drijfhout, Sybren; Dijkstra, Henk; Spall, Michael

    2017-04-01

    The Atlantic Meridional Overturning Circulation (AMOC) plays an important role in climate. The classical view of an ocean conveyor belt with northward surface currents and southward return currents transporting convectively-formed waters from the subpolar North Atlantic Ocean to other ocean basins suggests a tight relation between convection and sinking. However, convection regions feature very little vertical mass transport. Instead, it has been argued that the sinking of waters must take place near boundaries where ageostrophic processes affect the flow. So far, this has been confirmed in highly idealized regional model studies and in laboratory experiments. It is, however, unclear how well the sinking of dense waters is represented in the current generation of global ocean models and climate models, and whether the factors driving and controlling the sinking in these models are in accordance with the developed theory. This is of crucial importance for our confidence in projections of the future behavior of the AMOC, which are based on this type of model. In this study, we analyze the characteristics of the vertical transport in two global ocean models: an eddy-permitting model at 0.25 degree resolution and its coarser 1.0 degree resolution counterpart. We show that the sinking indeed predominantly occurs in a narrow region close to the boundary in both model simulations, and not in deep convection regions. Notably, the amount of vertical transport that is found along the edges of the North Atlantic Ocean is highly variable in space, and large differences exist between the two model versions. In the eddy-permitting model, the magnitude of the local sinking appears to be governed by alongshore variations in density near the boundary, in line with theory.

  11. North Atlantic ocean circulation and abrupt climate change during the last glaciation

    NASA Astrophysics Data System (ADS)

    Henry, L. G.; McManus, J. F.; Curry, W. B.; Roberts, N. L.; Piotrowski, A. M.; Keigwin, L. D.

    2016-07-01

    The most recent ice age was characterized by rapid and hemispherically asynchronous climate oscillations, whose origin remains unresolved. Variations in oceanic meridional heat transport may contribute to these repeated climate changes, which were most pronounced during marine isotope stage 3, the glacial interval 25 thousand to 60 thousand years ago. We examined climate and ocean circulation proxies throughout this interval at high resolution in a deep North Atlantic sediment core, combining the kinematic tracer protactinium/thorium (Pa/Th) with the deep water-mass tracer, epibenthic δ13C. These indicators suggest reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning. These results provide direct evidence for the ocean’s persistent, central role in abrupt glacial climate change.

  12. Diversity of culturable bacteria in deep-sea water from the South Atlantic Ocean.

    PubMed

    Kai, Wang; Peisheng, Yan; Rui, Ma; Wenwen, Jia; Zongze, Shao

    2017-01-31

    The variability of culturable bacterial diversity and distribution was studied by phylogenetic analysis of 16S rRNA sequences. Seventeen water samples were examined and were collected, from different depths in the range of 5 m to 2700 m at 3 sampling sites (CTD06, CTD10 and CTD11) in the South Atlantic Ocean. Phylogenetic analysis of 16S rRNA gene sequences revealed a significant diversity of culturable bacteria. A total of 247 strains clustered into 8 classes: γ-Proteobacteria, α-Proteobacteria, Actinobacteria, Actinomycetales, Bacilli, Flavobacteria, Opitutae and Sphingobacteria. The 17 water samples were dominated by populations of strains belonging to the genus Erythrobacter (16.60%). Of the 247 strains, 10 were potential new species and might form a minor population in the deep sea. To our knowledge, this is the first report to analyze the diversity of culturable bacteria in the South Atlantic Ocean from different depths across the water column.

  13. Synoptic situation in the Atlantic Ocean region during ANT V/5

    SciTech Connect

    Behr, H.D. ); Gravenhorst, G. )

    1990-11-20

    During a 4-week Atlantic Ocean cruise from March 21 to April 15, 1987, along 30{degree}W between 40{degree}S and 40{degree}N, several investigations on trace substances in the air and in the sea were made on board the German R/V Polarstern (ANT V/5). Some of them are discussed in this issue. To better understand these results and to put them into a framework of the general atmospheric situation, daily and long-term mean meteorological data were combined to characterize the atmospheric conditions during this cruise. First, continuous record of surface and rawinsonde data (sea and air temperature, humidity, wind direction and speed, and pressure) was evaluated. Then, as the cruise traversed several climatological zones of the Atlantic Ocean, meridional distributions of surface and upper air data could be worked out; they do not differ significantly from long-term means of this area.

  14. Growth and mortality rates of bigeye tuna Thunnus obesus (Perciformes: Scombridae) in the central Atlantic Ocean.

    PubMed

    Zhu, Guoping; Xu, Liuxiong; Zhou, Yingqi; Chen, Xinjun

    2009-01-01

    Age and growth parameters were estimated for bigeye tuna Thunnus obesus Lowe, 1839 sampled from China longline fisheries in the central Atlantic Ocean from October 2002 to July 2003 and from August 2004 to March 2005. The von Bertalanffy growth parameters were estimated at L(infinity)=217.9 cm fork length, k=0.23 year(-1), and t(0)=-0.44 year. The total mortality rate (Z) was estimated to be from 0.82 to 1.02, the fishing mortality (F) and the natural mortality were 0.54 year(-1) and 0.39 year(-1), respectively. The exploitation ratio (E) was 0.35. This study provides the detailed estimates of growth and mortality rate for bigeye tuna in the central Atlantic Ocean, which can be used as biological input parameters in further stock evaluations in this region. However, age analysis, additional validation of the size composition and stock structure are needed for future studies.

  15. Pathways of Atlantic Waters in the Nordic seas: locally eddy-permitting ocean simulation in a global setup

    NASA Astrophysics Data System (ADS)

    Wekerle, C.; Wang, Q.; Danilov, S.; Jung, T.; Schourup-Kristensen, V.

    2016-02-01

    Atlantic Water (AW) passes through the Nordic Seas and enters the Arctic Ocean through the shallow Barents Sea and the deep Fram Strait. Since the 1990's, observations indicate a series of anomalously warm pulses of Atlantic Water that entered the Arctic Ocean. In fact, poleward oceanic heat transport may even increase in the future, which might have implications for the heat uptake in the Arctic Ocean as well as for the sea ice cover. The ability of models to faithfully simulate the pathway of the AW and accompanying dynamics is thus of high climate relevance. In this study, we explore the potential of a global multi-resolution sea ice-ocean model with a locally eddy-permitting resolution (around 4.5 km) in the Nordic seas region and Arctic Ocean in improving the representation of Atlantic Water inflow, and more broadly, the dynamics of the circulation in the Northern North Atlantic and Arctic. The simulation covers the time period 1969-2009. We find that locally increased resolution improves the localization and thickness of the Atlantic Water layer in the Nordic seas, compared with a 20 km resolution reference simulation. In particular, the inflow of Atlantic Waters through the Greenland Scotland Ridge and the narrow branches of the Norwegian Atlantic Current can be realistically represented. Lateral spreading due to simulated eddies essentially reduces the bias in the surface temperature. In addition, a qualitatively good agreement of the simulated eddy kinetic energy field with observations can be achieved. This study indicates that a substantial improvement in representing local ocean dynamics can be reached through the local refinement, which requires a rather moderate computational effort. The successful model assessment allows us to further investigate the variability and mechanisms behind Atlantic Water transport into the Arctic Ocean.

  16. Convective Lofting Links Indian Ocean Air Pollution to Recurrent South Atlantic Ozone Maxima

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Guan, H.; Thompson, A. M.; Witte, J.

    2003-12-01

    We extend on our analysis of equatorial tropospheric ozone to illustrate the contributions of South Asian pollution export in forming episodes of high O3 over the Atlantic Ocean. We amplify on an earlier description of a broad resolution of the "Atlantic Paradox," for the Jan-Feb-March period, which included initial indications of a very long-distance contribution from South Asia. The approach has been to describe typical periods of significant maximum and minimum tropospheric ozone for early 1999, exploiting TOMS tropospheric ozone estimates jointly with characteristic features of the SHADOZ (Southern Hemisphere Additional Ozonesondes) ozone soundings. Further investigation of the Total Tropospheric Ozone (TTO) record for all of 1999 suggests that there are repeated periods of very long-distance Asian influence crossing Africa, with an apparent effect on those portions of the Atlantic Equatorial troposphere which are downwind. Trajectory analyses suggest that the pattern over the Indian Ocean is complex: a sequence invoving multiple or mixed combustion sources, low level transport, cumulonimbus venting, and high-level transport to the west seem to be indicated by the TTO record. Biomass burning, fossil and biofuel combustion, and lighting seem to all contribute. For the Atlantic, burning and lighting on adjacent continents as well as episodes of this cross-Africa long-distance transport are all linked in a coordinated seasonal march: all are related by movement of the sun. However, interseasonal tropical variability related to the Madden-Julian oscillation allows intermittent ozone buildups that depart from the seasonal norm.

  17. Oceanic and Atmospheric Patterns Associated with Hurricanes Making Gulf of Mexico vs. Atlantic Coast Landfalls

    NASA Astrophysics Data System (ADS)

    Paxton, C. H.; Collins, J. M.

    2011-12-01

    A multi-year clustering is apparent in the location of landfalling hurricanes of Category 2 or greater striking the U.S. Differences in the evolution of hurricane seasons in which landfalls were distinctly on the Gulf of Mexico vs. the Atlantic coast will be presented. Eight seasons with Gulf of Mexico coast landfalls and eight seasons with Atlantic coast landfalls were chosen to illustrate the atmospheric and ocean differences between the two landfall regimes. Monthly averages from December prior to the hurricane season through October were produced to show the evolution of the patterns. For example, La Niña onset was more likely to occur prior to the hurricane season in years with Atlantic coast landfalls, but the onset was later for Gulf of Mexico coast landfall years. More persistent westerly flow in February to May was common for the Gulf of Mexico landfalls, as were negative sea level pressure anomalies over the southern Pacific Ocean. Positive precipitable water anomalies over the main development region were significant and increased from February to September during Gulf of Mexico coast landfall years. Persistent sea level pressure anomalies were present over North Africa in the Atlantic landfalling years but not in the Gulf coast years. The results of this research can be used as guidance to indicate potential landfall locations of strong tropical cyclones during the coming hurricane season.

  18. Emerging impact of Greenland meltwater on deepwater formation in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Böning, Claus W.; Behrens, Erik; Biastoch, Arne; Getzlaff, Klaus; Bamber, Jonathan L.

    2016-07-01

    The Greenland ice sheet has experienced increasing mass loss since the 1990s. The enhanced freshwater flux due to both surface melt and outlet glacier discharge is assuming an increasingly important role in the changing freshwater budget of the subarctic Atlantic. The sustained and increasing freshwater fluxes from Greenland to the surface ocean could lead to a suppression of deep winter convection in the Labrador Sea, with potential ramifications for the strength of the Atlantic meridional overturning circulation. Here we assess the impact of the increases in the freshwater fluxes, reconstructed with full spatial resolution, using a global ocean circulation model with a grid spacing fine enough to capture the small-scale, eddying transport processes in the subpolar North Atlantic. Our simulations suggest that the invasion of meltwater from the West Greenland shelf has initiated a gradual freshening trend at the surface of the Labrador Sea. Although the freshening is still smaller than the variability associated with the episodic `great salinity anomalies', the accumulation of meltwater may become large enough to progressively dampen the deep winter convection in the coming years. We conclude that the freshwater anomaly has not yet had a significant impact on the Atlantic meridional overturning circulation.

  19. Foraminiferal isotope evidence of reduced nitrogen fixation in the ice age Atlantic Ocean.

    PubMed

    Ren, H; Sigman, D M; Meckler, A N; Plessen, B; Robinson, R S; Rosenthal, Y; Haug, G H

    2009-01-09

    Fixed nitrogen (N) is a limiting nutrient for algae in the low-latitude ocean, and its oceanic inventory may have been higher during ice ages, thus helping to lower atmospheric CO2 during those intervals. In organic matter within planktonic foraminifera shells in Caribbean Sea sediments, we found that the 15N/14N ratio from the last ice age is higher than that from the current interglacial, indicating a higher nitrate 15N/14N ratio in the Caribbean thermocline. This change and other species-specific differences are best explained by less N fixation in the Atlantic during the last ice age. The fixation decrease was most likely a response to a known ice age reduction in ocean N loss, and it would have worked to balance the ocean N budget and to curb ice age-interglacial change in the N inventory.

  20. Non-Rayleigh control of upper-ocean Cd isotope fractionation in the western South Atlantic

    NASA Astrophysics Data System (ADS)

    Xie, Ruifang C.; Galer, Stephen J. G.; Abouchami, Wafa; Rijkenberg, Micha J. A.; de Baar, Hein J. W.; De Jong, Jeroen; Andreae, Meinrat O.

    2017-08-01

    We present seawater Cd isotopic compositions in five depth profiles and a continuous surface water transect, from 50°S to the Equator, in the western South Atlantic, sampled during GEOTRACES cruise 74JC057 (GA02 section, Leg 3), and investigate the mechanisms governing Cd isotope cycling in the upper and deep ocean. The depth profiles generally display high ε 112 / 110Cd at the surface and decrease with increasing depth toward values typical of Antarctic Bottom Water (AABW). However, at stations north of the Subantarctic Front, the decrease in ε 112 / 110Cd is interrupted by a shift to values intermediate between those of surface and bottom waters, which occurs at depths occupied by North Atlantic Deep Water (NADW). This pattern is associated with variations in Cd concentration from low surface values to a maximum at mid-depths and is attributed to preferential utilization of light Cd by phytoplankton in the surface ocean. Our new results show that in this region Cd-deficient waters do not display the extreme, highly fractionated ε 112 / 110Cd reported in some earlier studies from other oceanic regions. Instead, in the surface and subsurface southwest (SW) Atlantic, when [Cd] drops below 0.1 nmol kg-1, ε 112 / 110Cd are relatively homogeneous and cluster around a value of +3.7, in agreement with the mean value of 3.8 ± 3.3 (2SD, n = 164) obtained from a statistical evaluation of the global ocean Cd isotope dataset. We suggest that Cd-deficient surface waters may acquire their Cd isotope signature via sorption of Cd onto organic ligands, colloids or bacterial/picoplankton extracellular functional groups. Alternatively, we show that an open system, steady-state model is in good accord with the observed Cd isotope systematics in the upper ocean north of the Southern Ocean. The distribution of ε 112 / 110Cd in intermediate and deep waters is consistent with the water mass distribution, with the north-south variations reflecting changes in the mixing proportion

  1. Ocean science: Radiocarbon variability in the western North Atlantic during the last deglaciation

    USGS Publications Warehouse

    Robinson, L.F.; Adkins, J.F.; Keigwin, L.D.; Southon, J.; Fernandez, D.P.; Wang, S.-L.; Scheirer, D.S.

    2005-01-01

    We present a detailed history of glacial to Holocene radiocarbon in the deep western North Atlantic from deep-sea corals and paired benthic-planktonic foraminifera. The deglaciation is marked by switches between radiocarbon-enriched and -depleted waters, leading to large radiocarbon gradients in the water column. These changes played an important role in modulating atmospheric radiocarbon. The deep-ocean record supports the notion of a bipolar seesaw with increased Northern-source deep-water formation linked to Northern Hemisphere warming and the reverse. In contrast, the more frequent radiocarbon variations in the intermediate/deep ocean are associated with roughly synchronous changes at the poles.

  2. 78 FR 57796 - Safety Zone; Pro Hydro-X Tour, Atlantic Ocean, Islamorada, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Pro Hydro-X Tour, Atlantic Ocean... Hydro- X Tour. The Pro Hydro-X Tour is a series of Jet Ski races. The race course is in an oval configuration. There will be 7 Jet Skis on the course for each race. The Pro Hydro-X Tour is scheduled to take...

  3. Hogfish Lachnolaimus maximus (Labridae) confirmed in the south-western Atlantic Ocean.

    PubMed

    Sampaio, C L S; Santander-Neto, J; Costa, T L A

    2016-09-01

    Based on material deposited in collections, photographic records and other reports from fishermen and divers, the occurrence of the hogfish Lachnolaimus maximus (Labridae) is confirmed in the south-western Atlantic Ocean, near the Brazilian coast as far south as southern Brazil. The recognized range of this species should therefore be extended c. 3000 km further south. © 2016 The Fisheries Society of the British Isles.

  4. Cheirimedon foscae sp. nov. (Amphipoda: Lysianassidae: Tryphosinae) from the deep sea Campos Basin, Southwestern Atlantic Ocean.

    PubMed

    Siqueira, Silvana Gomes L; Serejo, Cristiana S

    2014-10-15

    A new species of lysianassid amphipod belonging to the genus Cheirimedon was collected on the continental slope of the Campos Basin, the largest oil reserve in Brazilian waters. This is the first record of the genus Cheirimedon from the Atlantic Ocean, which was previously restricted to the Antarctic and Tasmanian sea. The new species is fully illustrated and compared with related species. Additionally, a world key to the Cheirimedon species is provided. 

  5. Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean

    PubMed Central

    He, Peng; Hou, Xiaolin; Aldahan, Ala; Possnert, Göran; Yi, Peng

    2013-01-01

    Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters for both 127I and 129I. Despite the rather constant ratios of 127I−/127IO3−, the 129I−/129IO3− values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic 129I in ocean environments and impact on climate at the ocean boundary layer. PMID:24284916

  6. The Lone Ranger Mission: Understanding Synthetic Polymer Microbe Interactions In the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Mielke, R.; Neal, A.; Stam, C. N.; Ferry, J. G.; Schlegel, R.; Tsapin, A. I.; Park, S.; Bhartia, R.; Salas, E.; Hug, W.; Behar, A. E.; Nadeau, J.

    2011-12-01

    Pollution is one of the most ubiquitous and insidious problems currently facing the oceans. As synthetic polymer debris degrades, it becomes increasingly accessible to organisms that forage or absorb food particles. However, research on this significant environmental pollution problem has not been able to keep up with the scope of the issue, since some of the first studies published in 1972 by Edward Carpenter. In January 2011, The Lone Ranger Atlantic Expedition, a collaboration between Blue Ocean Sciences (BOS) and the Schmidt Ocean Institute (SOI) transected the Atlantic Ocean covering 3,100 nautical miles sampling the first 15cm of the water column to investigate microbial interactions with synthetic polymer marine debris. Using established and novel techniques of Fourier transform infrared spectroscopy (FT-IR), scanning transmission electron microscopy (STEM), environmental scanning electron microscopy (ESEM), and gas chromatography-mass spectrometry (GC-MS), we were able to image and locate material degradation of pre-production, association of microbial biofilms, and accumulation of persistent organic pollutants (POP's) on environmental microplastics. We then used Spectroscopic Organic Analysis and ArcGIS mapping systems to observe the material degradation and the associated biofilm lattice on the environmental microplastics. This data sheds light on possible mechanisms of material weathering of synthetic polymers in deep ocean environments and new methods for identifying POP's association with them. These new techniques are highly transferable to many studies on material biofilm interactions in the environment.

  7. Does the mid-Atlantic United States sea level acceleration hot spot reflect ocean dynamic variability?

    NASA Astrophysics Data System (ADS)

    Kopp, Robert E.

    2013-08-01

    To test a hypothesized faster-than-global sea level acceleration along the mid-Atlantic United States, I construct a Gaussian process model that decomposes tide gauge data into short-term variability and longer-term trends, and into globally coherent, regionally coherent, and local components. While tide gauge records indicate a faster-than-global increase in the rate of mid-Atlantic U.S. sea level rise beginning ˜1975, this acceleration could reflect either the start of a long-term trend or ocean dynamic variability. The acceleration will need to continue for ˜2 decades before the rate of increase of the sea level difference between the mid-Atlantic and southeastern U.S. can be judged as very likely unprecedented by 20th century standards. However, the difference is correlated with the Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and Gulf Stream North Wall indices, all of which are currently within the range of past variability.

  8. Intestinal helminth fauna of the shortfin mako Isurus oxyrinchus (Elasmobranchii: Lamnidae) in the northeast Atlantic Ocean.

    PubMed

    Penadés-Suay, Jaime; Tomás, Jesús; Merchán, Manuel; Aznar, Francisco Javier

    2017-02-08

    Large oceanic sharks represent a suitable model to investigate the influence of a host's oceanic conditions on the structure of its helminth communities. In this study, we describe the intestinal helminth fauna, and investigate determinants of infracommunity structure, in 39 specimens of shortfin mako Isurus oxyrinchus collected in the NE Atlantic. Six cestode species were found in the spiral valve of makos: 3 are typical from lamnid sharks, namely, gravid specimens of Clistobothrium montaukensis, Gymnorhynchus isuri and Ceratobothrium xanthocephalum, and 3 are immature specimens of cestode species common to several elasmobranchs, namely, Dinobothrium septaria, Nybelinia lingualis, and Phyllobothrium cf. lactuca. In addition, L3 larvae of Anisakis sp. type I were detected. Infracommunities were species poor and had low total helminth abundance. The result of Schluter's variance ratio test was compatible with the hypothesis of independent colonization of helminth taxa. These results conform to previous studies on oceanic predators that have hypothesized that these hosts should have depauperate and unpredictable helminth infracommunities because oceanic conditions hamper parasite transmission. However, mean species richness and mean total abundance of cestodes of shortfin mako and other oceanic sharks did not significantly differ from those of elasmobranchs from other habitats. This suggests that the large body size and prey consumption rates of oceanic sharks offset the negative 'dilution' effect of oceanic habitat on transmission rates. Additionally, or alternatively, parasites of oceanic sharks may have expanded the use of intermediate hosts through the trophic web to spread out the risk of failure to complete their life cycles.

  9. The biogeochemical cycling of zinc and zinc isotopes in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Conway, Tim M.; John, Seth G.

    2014-10-01

    Zinc (Zn) is a marine micronutrient, with an overall oceanic distribution mirroring the major macronutrients, especially silicate. Seawater Zn isotope ratios (δ66Zn) are a relatively new oceanographic parameter which may offer insights into the biogeochemical cycling of Zn. To date, the handful of published studies of seawater δ66Zn show the global deep ocean to be both remarkably homogeneous (approximately +0.5‰) and isotopically heavier than the marine sources of Zn (+0.1 to +0.3‰). Here we present the first high-resolution oceanic section of δ66Zn, from the U.S. GEOTRACES GA03 North Atlantic Transect, from Lisbon to Woods Hole. Throughout the surface ocean, biological uptake and release of isotopically light Zn, together with scavenging of heavier Zn, leads to large variability in δ66Zn. In the ocean below 1000 m, δ66Zn is generally homogeneous (+0.50 ± 0.14‰; 2 SD), though deviations from +0.5‰ allow us to identify specific sources of Zn. The Mediterranean Outflow is characterized by δ66Zn of +0.1 to +0.3‰, while margin sediments are a source of isotopically light Zn (-0.5 to -0.8‰), which we attribute to release of nonregenerated biogenic Zn. Mid-Atlantic Ridge hydrothermal vents are also a source of light Zn (close to -0.5‰), though Zn is not transported far from the vents. Understanding the biogeochemical cycling of Zn in the modern ocean begins to address the imbalance between the light δ66Zn signature of marine sources and the globally homogeneous deep oceans (δ66Zn of +0.5‰) on long timescales, with overall patterns pointing to sediments as an important sink for isotopically light Zn throughout the oceans.

  10. 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

  11. PAHs on a west-to-east transect across the tropical Atlantic Ocean.

    PubMed

    Lohmann, Rainer; Klanova, Jana; Pribylova, Petra; Liskova, Hana; Yonis, Shifra; Bollinger, Kevyn

    2013-03-19

    Surface water and atmospheric samples were collected across the tropical Atlantic Ocean on a transect of the R/V Endeavor in summer 2009 and analyzed for polycyclic aromatic hydrocarbons (PAHs). Across the entire tropical Atlantic Ocean, phenanthrene displayed on average highest dissolved concentrations (170 pg L(-1)), followed by pyrene (70 pg L(-1)) and fluoranthene (30 pg L(-1)). The Amazon plume was characterized by elevated dissolved concentrations of phenanthrene and benzo(g,h,i)fluoranthene. The warm eddy that we accidentally sampled at 66° W displayed highest concentrations of PAHs across the entire cruise, with phenanthrene, pyrene, and fluoranthrene all >1 ng L(-1). After having crossed the warm core, concentrations decreased back to previous levels. Samples taken in the Gulf Stream were below detection limit for all parent PAHs, implying very efficient removal processes. Dissolved dimethylphenanthrenes were frequently detected in the samples from the southern hemisphere, the Amazon plume, and in samples characteristic of the Gulf Stream and the U.S. East Coast. Atmospheric concentrations were dominated by gas-phase fluoranthene, pyrene, phenanthrene, and retene. Air-water gradients indicated that PAHs are mostly undergoing net deposition across the tropical Atlantic Ocean, with conditions closer to equilibrium off the U.S. East Coast and in Rhode Island Sound.

  12. Mercury fluxes between an impacted coastal lagoon and the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Pato, P.; Lopes, C.; Válega, M.; Lillebø, A. I.; Dias, J. M.; Pereira, E.; Duarte, A. C.

    2008-03-01

    The objective was to estimate the seasonal and inter-tidal variability of dissolved and particulate mercury fluxes between the Ria de Aveiro (Portugal) and the Atlantic Ocean. The mercury fluxes were estimated by means of a two-dimensional vertically integrated hydrodynamic model. Results showed that the particulate fraction plays an important role in the transport of mercury while the contribution of the seston fraction to the transport of mercury was always <0.5%. During spring tides, in summer, about 2% of mercury transported in seston was present in an organic form. The mass balance for the mercury fractions revealed that the mercury export to the Atlantic Ocean varied with season and tidal regime, mainly in terms of the relative importance of the dissolved and particulate fractions. An approximate range of values for the annual mass balance between 42 and 77 kg shows that the export of dissolved and particulate mercury makes little impact on the near shore region of the Atlantic Ocean and that the recovery of the lagoon from mercury contamination is likely to remain a long-term issue.

  13. Atlantic and Pacific Ocean synergistic forcing of the Mesomerican monsoon over the last two millennia

    NASA Astrophysics Data System (ADS)

    Lachniet, M. S.; Asmerom, Y.; Polyak, V. J.; Bernal, J. P.

    2015-12-01

    We present a new replicated, high resolution (~2 yrs) and precisely-dated (± 4 yr) wet season hydroclimate reconstruction for the Mesoamerican sector of the North American Monsoon over the past 2250 years. Our new reconstruction is based on two aragonite stalagmites from southwestern Mexico which replicate oxygen isotope variations over the 950-1950 CE interval, and are calibrated to instrumental rainfall variations in the Basin of Mexico. Such data complement existing dendroclimatic reconstructions of early wet season and winter drought severity. Comparisons to indices of ocean-atmosphere circulation show a combined forcing by the North Atlantic Oscillation and the El Niño/Southern Oscillation. Monsoon strengthening coincided with synergistic forcing of a La Niña-like mode and a negative North Atlantic Oscillation, and vice versa for droughts. Although drought is commonly invoked as an stressor leading to societal change, the role of intensified monsoon onto cultural development is rarely explored. We observe that prominent transitions from drought to pluvial conditions are associated with population increases in three of the major highland Mexico civilizations of Teotihuacan, Tula Grande, and the Aztecs. These data suggest a role for ocean-atmosphere dynamics arising from the Atlantic and Pacific Oceans on Mesoamerican monsoon strength.

  14. Population structure of Squatina guggenheim (Squatiniformes, Squatinidae) from the south-western Atlantic Ocean.

    PubMed

    Garcia, G; Pereyra, S; Gutierrez, V; Oviedo, S; Miller, P; Domingo, A

    2015-01-01

    Population genetic analyses based on both mitochondrial cytochrome b and the internal transcribed spacer 2 of recombinant (r)DNA genes were implemented to examine hypotheses of population differentiation in the angular angel shark Squatina guggenheim, one of the four most-widespread endemic species inhabiting coastal ecosystems in the south-western Atlantic Ocean. A total of 82 individuals of S. guggenheim from 10 sampling sites throughout the Río de la Plata mouth, its maritime front, the outer shelf at the subtropical confluence and the coastal areas of the south-west Atlantic Ocean, were included. The analysis of molecular variance (AMOVA) based on the second internal transcribed spacer (its-2) region supports that the samples from the outer shelf represent an isolated group from other sites. Historical gene flow in a coalescent-based approach revealed significant immigration and emigration asymmetry between sampling sites. Based on the low level of genetic diversity, the existence of a long-term population decline or a past recent population expansion following a population bottleneck could be proposed in S. guggenheim. This demographic differentiation suggests a degree of vulnerability to overexploitation in this endemic and endangered south-west Atlantic Ocean shark, given its longevity and low reproductive potential.

  15. Development of continental margins of the Atlantic Ocean and successive breakup of the Pangaea-3 supercontinent

    NASA Astrophysics Data System (ADS)

    Melankholina, E. N.; Sushchevskaya, N. M.

    2017-01-01

    Comparative tectonic analysis of passive margins of the Atlantic Ocean has been performed. Tectonotypes of both volcanic and nonvolcanic margins are described, and their comparison with other passive Atlantic margins is given. The structural features of margins, peculiarities of magmatism, its sources and reasons for geochemical enrichment of melts are discussed. The important role of melting of the continental lithosphere in the development of magmatism is demonstrated. Enriched EM I and EM II sources are determined for the lower parts of the volcanic section, and a depleted or poorly enriched source is determined for the upper parts of the volcanic section based on isotope data. The conclusions of the paper relate to tectonic settings of the initial occurrence of magmatism and rifting and breakup during the period of opening of the Mesozoic Ocean. It was found out that breakup and magmatism at proximal margins led only to insignificant structural transformations and reduction of the thickness of the ancient continental crust, while very important magmatic events happened later in the distal zone. New growth of magmatic crust at the stage of continental breakup is determined as a typical feature of distal zones of the margins under study. The relationship of development of margins with the impact of deep plumes as the source of magmatic material or a heat source only is discussed. Progradation of the zone of extension and breakup into the areas of cold lithosphere of the Atlantic and the formation of a single tectonomagmatic system of the ocean are under consideration.

  16. Role of oceanic circulation on contaminant lead distribution in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Alleman, L. Y.; Church, T. M.; Ganguli, P.; Véron, A. J.; Hamelin, B.; Flegal, A. R.

    Both the relatively high lead concentrations and their characteristic anthropogenic isotopic compositions attest to the widespread contamination of industrial lead in the western Equatorial and South Atlantic Ocean. Spatial gradients in those isotopic signatures evidence the conservative lateral transport of lead in oceanic water masses, while the discrete isotopic signatures in deep oceanic waters substantiate the complementary hypothesis that the release of lead from settling particles is relatively small on a decadal time-scale. Specifically, the relatively low radiogenic lead (e.g., 206Pb/ 207Pb=1.148±0.009) in the Lower-North Atlantic Deep Water (l-NADW) south of 10° North is primarily attributed to US industrial lead emitted in the Northern Hemisphere prior to 1965, and the more radiogenic lead (e.g., 206Pb/ 207Pb=1.180±0.006) in the Upper-North Atlantic Deep Water (u-NADW) is primarily attributed to subsequent industrial lead emissions in that hemisphere. In contrast, the relatively radiogenic lead (e.g., 206Pb/ 207Pb=1.186±0.007) in the Antarctic Bottom Water (AABW) seemingly reflects a mixture of natural and anthropogenic lead sources within the Southern Hemisphere; and its isotopic dissimilarity with that (e.g., 206Pb/ 207Pb=1.159±0.002) of Antarctic Intermediate Water (AAIW) and the AABW may be due to differences in either their aeolian or water-mass inputs.

  17. Optimizing and Enhancing the Integrated Atlantic Ocean Observing System to enhance the societal, scientific and economic benefit

    NASA Astrophysics Data System (ADS)

    Reitz, Anja; Karstensen, Johannes; Visbeck, Martin; AtlantOS Consortium, the

    2017-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements of heterogeneous international, national and regional design to support science and a wide range of information products. Thus there is tremendous opportunity to develop the systems towards a fully integrated Atlantic Ocean Observing System consistent with the recently developed 'Framework of Ocean Observing'. The vision of AtlantOS is to improve and innovate Atlantic Ocean observing by establishing an international, more sustainable, more efficient, more integrated, and fit-for-purpose system. Hence, the EU Horizon 2020 project AtlantOS with its 62 partners from 18 countries (European and international) and several members will have a long-lasting and sustainable contribution to the societal, economic and scientific benefit by supporting the full cycle of the integrated ocean observation value chain from requirements via data gathering and observation, product generation, information, prediction, dissemination and stakeholder dialogue towards information and product provision. The benefits will be delivered by improving the value for money, extent, completeness, quality and ease of access to Atlantic Ocean data required by industries, product supplying agencies, scientist and citizens. The overarching target of the AtlantOS initiative is to deliver an advanced framework for the development of an integrated Atlantic Ocean Observing System that goes beyond the state-of -the-art, and leaves a legacy of sustainability after the life of the project. The legacy will derive from the following aims: i) to improve international collaboration in the design, implementation and benefit sharing of ocean observing, ii) to promote engagement and innovation in all aspects of ocean observing, iii) to facilitate free and open access to ocean data and information, iv) to enable and disseminate methods of achieving quality

  18. Metamorphism in oceanic layer 3, Gorringe Bank, eastern Atlantic

    NASA Astrophysics Data System (ADS)

    Mevel, Catherine

    1988-12-01

    Gorringe Bank is an anomalously high structure of the eastern part of the north Atlantic, which was known to be composed of mantle-derived peridotites (layer 4) and gabbros (layer 3). During the submersible cruise CYAGOR II in 1981, the contact between layer 4 and layer 3 was observed on Mount Gettysburg and interpreted as tectonic. The overlying series of gabbro was extensively sampled on both mounts composing the bank, Gettysburg and Ormonde. Coarse-grained to pegmatoid clinopyroxene gabbros predominate and are associated with differentiated rocks (ferrogabbros and diorites). Cumulate gabbros are missing. The gabbroic section sampled is therefore interpreted as the upper part of the plutonic section. Most samples were strongly recrystallized during two distinct events. Metamorphism occurred close to the ridge axis, from interaction of a seawater-derived fluid with still hot gabbros. High temperature shear zones favoured fluid circulation, but the water/rock ratio — estimated from the sodium input — was very small in undeformed rocks (<1). The low W/R ratio explains the strong evolution of the fluid phase and therefore some particular compositions of secondary minerals. Low temperature alteration occurred when the gabbros were tectonically emplaced close to the sea bottom.

  19. Stacked jets in the deep equatorial Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Eden, Carsten; Dengler, Marcus

    2008-04-01

    Middepth current measurements in the equatorial Atlantic are characterized by elevated levels of energy contained in zonal flows of high baroclinic mode number. These alternating zonal flows, often called equatorial stacked jets, have amplitudes up to 20 cm s-1 and vertical wavelengths of 600 m. The jets are most pronounced in the depth range between 500 and 2500 m. Repeated direct velocity observations at 35°W indicate that the jets are coherent within ±1° of the equator. Individual jets can persist for 1-2 years, but they appear and decay rather irregularly. The equatorial stacked jets are also found in realistic general circulation model simulations. The features grow in amplitude with increasing horizontal and vertical model resolution. However, even at very high model resolutions, their amplitudes are still underestimated. In all model simulations, high levels of energy related to the stacked jets are found in the vicinity of the western boundary currents (WBCs). Depth range and strength of the WBCs in different experiments are related to depth range and strength of the jets. In the interior, stacked jets are characterized by eastward wave propagation suggesting that high baroclinic mode Kelvin waves radiate energy generated in the WBC into the interior and form the stacked jets.

  20. Marine debris ingestion by albatrosses in the southwest Atlantic Ocean.

    PubMed

    Jiménez, Sebastián; Domingo, Andrés; Brazeiro, Alejandro; Defeo, Omar; Phillips, Richard A

    2015-07-15

    Plastics and other marine debris affect wildlife through entanglement and by ingestion. We assessed the ingestion of marine debris by seven albatross species in the southwest Atlantic by analyzing stomach contents of birds killed in fisheries. Of the 128 specimens examined, including four Diomedea species (n=78) and three Thalassarche species (n=50), 21 (16.4%) contained 1-4 debris items, mainly in the ventriculus. The most common type was plastic fragments. Debris was most frequent in Diomedea species (25.6%) and, particularly, Diomedea sanfordi (38.9%) and very rare in Thalassarche species (2.0%), presumably reflecting differences in foraging behavior or distribution. Frequency of occurrence was significantly higher in male than female Diomedea albatrosses (39.3% vs. 18.0%). Although levels of accumulated debris were relatively low overall, and unlikely to result in gut blockage, associated toxins might nevertheless represent a health risk for Diomedea albatrosses, compounding the negative impact of other human activities on these threatened species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Climate change and oceanic barriers: genetic differentiation in Pomatomus saltatrix (Pisces: Pomatomidae) in the North Atlantic Ocean and the Mediterranean Sea.

    PubMed

    Pardiñas, A F; Campo, D; Pola, I G; Miralles, L; Juanes, F; Garcia-Vazquez, E

    2010-11-01

    Nucleotide variation of partial cytochrome b sequences was analysed in the bluefish Pomatomus saltatrix to investigate the population-structuring roles of climate change and oceanic barriers. Western and eastern North Atlantic Ocean populations appeared to be totally isolated, with the latter connected to the Mediterranean Sea within which further structuring occurred.

  2. The salinity signature of the cross-shelf exchanges in the Southwestern Atlantic Ocean: Satellite observations

    PubMed Central

    Guerrero, Raul A; Piola, Alberto R; Fenco, Harold; Matano, Ricardo P; Combes, Vincent; Chao, Yi; James, Corinne; Palma, Elbio D; Saraceno, Martin; Strub, P Ted

    2014-01-01

    Satellite-derived sea surface salinity (SSS) data from Aquarius and SMOS are used to study the shelf-open ocean exchanges in the western South Atlantic near 35°S. Away from the tropics, these exchanges cause the largest SSS variability throughout the South Atlantic. The data reveal a well-defined seasonal pattern of SSS during the analyzed period and of the location of the export of low-salinity shelf waters. In spring and summer, low-salinity waters over the shelf expand offshore and are transferred to the open ocean primarily southeast of the river mouth (from 36°S to 37°30′S). In contrast, in fall and winter, low-salinity waters extend along a coastal plume and the export path to the open ocean distributes along the offshore edge of the plume. The strong seasonal SSS pattern is modulated by the seasonality of the along-shelf component of the wind stress over the shelf. However, the combined analysis of SSS, satellite-derived sea surface elevation and surface velocity data suggest that the precise location of the export of shelf waters depends on offshore circulation patterns, such as the location of the Brazil Malvinas Confluence and mesoscale eddies and meanders of the Brazil Current. The satellite data indicate that in summer, mixtures of low-salinity shelf waters are swiftly driven toward the ocean interior along the axis of the Brazil/Malvinas Confluence. In winter, episodic wind reversals force the low-salinity coastal plume offshore where they mix with tropical waters within the Brazil Current and create a warmer variety of low-salinity waters in the open ocean. Key Points Satellite salinity sensors capture low-salinity detrainment events from shelves SW Atlantic low-salinity detrainments cause highest basin-scale variability In summer low-salinity detrainments cause extended low-salinity anomalies PMID:26213672

  3. The salinity signature of the cross-shelf exchanges in the Southwestern Atlantic Ocean: Satellite observations.

    PubMed

    Guerrero, Raul A; Piola, Alberto R; Fenco, Harold; Matano, Ricardo P; Combes, Vincent; Chao, Yi; James, Corinne; Palma, Elbio D; Saraceno, Martin; Strub, P Ted

    2014-11-01

    Satellite-derived sea surface salinity (SSS) data from Aquarius and SMOS are used to study the shelf-open ocean exchanges in the western South Atlantic near 35°S. Away from the tropics, these exchanges cause the largest SSS variability throughout the South Atlantic. The data reveal a well-defined seasonal pattern of SSS during the analyzed period and of the location of the export of low-salinity shelf waters. In spring and summer, low-salinity waters over the shelf expand offshore and are transferred to the open ocean primarily southeast of the river mouth (from 36°S to 37°30'S). In contrast, in fall and winter, low-salinity waters extend along a coastal plume and the export path to the open ocean distributes along the offshore edge of the plume. The strong seasonal SSS pattern is modulated by the seasonality of the along-shelf component of the wind stress over the shelf. However, the combined analysis of SSS, satellite-derived sea surface elevation and surface velocity data suggest that the precise location of the export of shelf waters depends on offshore circulation patterns, such as the location of the Brazil Malvinas Confluence and mesoscale eddies and meanders of the Brazil Current. The satellite data indicate that in summer, mixtures of low-salinity shelf waters are swiftly driven toward the ocean interior along the axis of the Brazil/Malvinas Confluence. In winter, episodic wind reversals force the low-salinity coastal plume offshore where they mix with tropical waters within the Brazil Current and create a warmer variety of low-salinity waters in the open ocean. Satellite salinity sensors capture low-salinity detrainment events from shelves SW Atlantic low-salinity detrainments cause highest basin-scale variability In summer low-salinity detrainments cause extended low-salinity anomalies.

  4. Evidence of Northeastern Atlantic Ocean Acidification Recorded by Boron Isotopes on Deep-sea Coral Madrepora oculata

    NASA Astrophysics Data System (ADS)

    Gonzalez-Roubaud, C.; Douville, E.; Bordier, L.; Louvat, P.; Gaillardet, J.; Hall-Spencer, J. M.; Juillet-Leclerc, A.

    2011-12-01

    Ocean acidification is caused by the rising levels of CO2 in the atmosphere since the industrial era. Seawater pH has already decreased 0.1 units in surface waters and will continue to drop as atmospheric CO2 levels increase. Assessing the pH variability during the last decades is essential as survival of calcifying organisms strongly depends on seawater pH. Several studies have shown the potential of boron isotopic composition in tropical corals for reconstructing for sea-surface paleo-pH at low latitudes. For highest latitudes and deeper waters (50-4500 m), cold-water corals are interesting and unique as natural archives not only because they live between 4°C and 12°C under strong currents, recording the parameters of sub-surface or intermediate currents, but also because they build their aragonite skeleton without the photosynthesis process. In order to assess if the seawater acidification has already reached the North Atlantic Ocean at high latitudes, pH reconstruction has been performed on a deep-sea coral Madrepora oculata sample from Rost Reef (67°N, 9°E, 350 m of depth). Boron isotopes have been measured on the Neptune Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MCICP-MS) with direct injection system (d-DIHEN). External reproducibility obtained here for seawater reference NASS-2 was 0.1%. The model age estimates its life-span to 40±3 years (2σ) and the Li/Mg ratio estimates a relative constant seawater temperature during the whole period of growth of the coral (7.0±0.5°C). A drop tendency is observed on boron isotopes, reflecting a potential decrease of seawater pH of approximately 0.06±0.02 pH units during the last 40 years, depending on the isotopic fractionation coefficient employed for calculations. Similarly, seawater acidification rate is 0.0012±0.00015 pH units per year. pH and temperature reconstructions revealed an influence of thermohaline circulation and surface winds on the skeleton geochemistry. Supplementary

  5. Harmonising and semantically linking key variables from in-situ observing networks of an Integrated Atlantic Ocean Observing System, AtlantOS

    NASA Astrophysics Data System (ADS)

    Darroch, Louise; Buck, Justin

    2017-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements at regional, national and international scales. The EU Horizon 2020 AtlantOS project aims to deliver an advanced framework for the development of an Integrated Atlantic Ocean Observing System that strengthens the Global Ocean Observing System (GOOS) and contributes to the aims of the Galway Statement on Atlantic Ocean Cooperation. One goal is to ensure that data from different and diverse in-situ observing networks are readily accessible and useable to a wider community, including the international ocean science community and other stakeholders in this field. To help achieve this goal, the British Oceanographic Data Centre (BODC) produced a parameter matrix to harmonise data exchange, data flow and data integration for the key variables acquired by multiple in-situ AtlantOS observing networks such as ARGO, Seafloor Mapping and OceanSITES. Our solution used semantic linking of controlled vocabularies and metadata for parameters that were "mappable" to existing EU and international standard vocabularies. An AtlantOS Essential Variables list of terms (aggregated level) based on Global Climate Observing System (GCOS) Essential Climate Variables (ECV), GOOS Essential Ocean Variables (EOV) and other key network variables was defined and published on the Natural Environment Research Council (NERC) Vocabulary Server (version 2.0) as collection A05 (http://vocab.nerc.ac.uk/collection/A05/current/). This new vocabulary was semantically linked to standardised metadata for observed properties and units that had been validated by the AtlantOS community: SeaDataNet parameters (P01), Climate and Forecast (CF) Standard Names (P07) and SeaDataNet units (P06). Observed properties were mapped to biological entities from the internationally assured AphiaID from the WOrld Register of Marine Species (WoRMS), http

  6. Deglacial Ocean Circulation Scheme at Intermediate Depths in the Tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Xie, R. C.; Marcantonio, F.; Schmidt, M. W.

    2014-12-01

    In the modern Atlantic Ocean, intermediate water circulation is largely governed by the southward flowing upper North Atlantic Deep Water (NADW) and the northward return flow Antarctic Intermediate Water (AAIW). During the last deglaciation, it is commonly accepted that the southward flow Glacial North Atlantic Intermediate Water, the glacial analogue of NADW, contributed significantly to past variations in intermediate water circulation. However, to date, there is no common consensus of the role AAIW played during the last deglaciation, especially across abrupt climate events such as the Heinrich 1 and the Younger Dryas. This study aims to reconstruct intermediate northern- and southern-sourced water circulation in the tropical North Atlantic during the past 22 kyr and attempts to confine the boundary between AAIW and northern-sourced intermediate waters in the past. High-resolution Nd isotopic compositions (ɛNd thereafter) of fish debris and bulk sediment acid-reductive leachate from the Southern Caribbean (VM12-107; 1079 m) are inconsistent, again casting concerns, as already raised by recent studies, on the reliability of the leachate method in extracting seawater ɛNd signature. This urges the need to carefully verify the seawater ɛNd integrity in sediment acid-reductive leachate in various oceanic settings. Fish debris Nd isotope record in our study displays a two-step decreasing trend from the early deglaciation to early Holocene. We interpret this as recording a two-step deglacial recovery of the upper NADW, given the assumption on a more radiogenic glacial northern-sourced water is valid. Comparing with authigenic ɛNd records in the Florida Straits [1] and the Demarara Rise [2], our new fish debris ɛNd results suggest that, in the tropical western North Atlantic, glacial and deglacial AAIW never penetrated beyond the lower depth limit of modern AAIW. [1] Xie et al., GCA (140) 2014; [2] Huang et al., EPSL (389) 2014

  7. Large-scale diversity patterns of cephalopods in the Atlantic open ocean and deep sea.

    PubMed

    Rosa, Rui; Dierssen, Heidi M; Gonzalez, Liliana; Seibel, Brad A

    2008-12-01

    Although the oceans cover 70% of the Earth's surface and the open ocean is by far the largest ecosystem on the planet, our knowledge regarding diversity patterns of pelagic fauna is very scarce. Here, we examine large-scale latitudinal and depth-related patterns of pelagic cephalopod richness in the Atlantic Ocean in relation to ambient thermal and productive energy availability. Diversity, across 17 biogeochemical regions in the open ocean, does not decline monotonically with latitude, but is positively correlated to the availability of oceanic resources. Mean net primary productivity (NPP), determined from ocean color satellite imagery, explains 37% of the variance in species richness. Outside the poles, the range in NPP explains over 40% of the variability. This suggests that cephalopods are well adapted to the spatial patchiness and seasonality of open-ocean resources. Pelagic richness is also correlated to sea surface temperature, with maximum richness occurring around 15 degrees C and decreasing with both colder and warmer temperatures. Both pelagic and benthos-associated diversities decline sharply from sublittoral and epipelagic regions to the slope and bathypelagic habitats and then steadily to abyssal depths. Thus, higher energy availability at shallow depths seems to promote diversification rates. This strong depth-related trend in diversity also emphasizes the greater influence of the sharp vertical thermal gradient than the smoother and more seasonal horizontal (latitudinal) one on marine diversity.

  8. Physiological and endocrine changes in Atlantic salmon smolts during hatchery rearing, downstream migration and ocean entry

    USGS Publications Warehouse

    McCormick, Stephen D.; Sheehan, Timothy F.; Björnsson, Björn Thrandur; Lipsky, Christine; Kocik, John F.; Regish, Amy M.; O'Dea, Michael F.

    2013-01-01

    Billions of hatchery salmon smolts are released annually in an attempt to mitigate anthropogenic impacts on freshwater habitats, often with limited success. Mortality of wild and hatchery fish is high during downstream and early ocean migration. To understand changes that occur during migration, we examined physiological and endocrine changes in Atlantic salmon (Salmo salar) smolts during hatchery rearing, downstream migration, and early ocean entry in two successive years. Gill Na+/K+-ATPase activity increased in the hatchery during spring, increased further after river release, and was slightly lower after recapture in the ocean. Plasma growth hormone levels increased in the hatchery, were higher in the river, and increased further in the ocean. Plasma IGF-I remained relatively constant in the hatchery, increased in the river, then decreased in the ocean. Plasma thyroid hormones were variable in the hatchery, but increased in both river- and ocean-captured smolts. Naturally reared fish had lower condition factor, gill NKA activity, and plasma thyroxine than hatchery fish in the river but were similar in the ocean. This novel data set provides a vital first step in understanding the role and norms of endocrine function in smolts and the metrics of successful marine entry.

  9. C : N : P stoichiometry at the Bermuda Atlantic Time-series Study station in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Singh, A.; Baer, S. E.; Riebesell, U.; Martiny, A. C.; Lomas, M. W.

    2015-11-01

    Nitrogen (N) and phosphorus (P) availability, in addition to other macro- and micronutrients, determine the strength of the ocean's carbon (C) uptake, and variation in the N : P ratio of inorganic nutrient pools is key to phytoplankton growth. A similarity between C : N : P ratios in the plankton biomass and deep-water nutrients was observed by Alfred C. Redfield around 80 years ago and suggested that biological processes in the surface ocean controlled deep-ocean chemistry. Recent studies have emphasized the role of inorganic N : P ratios in governing biogeochemical processes, particularly the C : N : P ratio in suspended particulate organic matter (POM), with somewhat less attention given to exported POM and dissolved organic matter (DOM). Herein, we extend the discussion on ecosystem C : N : P stoichiometry but also examine temporal variation in stoichiometric relationships. We have analyzed elemental stoichiometry in the suspended POM and total (POM + DOM) organic-matter (TOM) pools in the upper 100 m and in the exported POM and subeuphotic zone (100-500 m) inorganic nutrient pools from the monthly data collected at the Bermuda Atlantic Time-series Study (BATS) site located in the western part of the North Atlantic Ocean. C : N and N : P ratios in TOM were at least twice those in the POM, while C : P ratios were up to 5 times higher in TOM compared to those in the POM. Observed C : N ratios in suspended POM were approximately equal to the canonical Redfield ratio (C : N : P = 106 : 16 : 1), while N : P and C : P ratios in the same pool were more than twice the Redfield ratio. Average N : P ratios in the subsurface inorganic nutrient pool were ~ 26 : 1, squarely between the suspended POM ratio and the Redfield ratio. We have further linked variation in elemental stoichiometry to that of phytoplankton cell abundance observed at the BATS site. Findings from this study suggest that elemental ratios vary with depth in the euphotic zone, mainly due to different

  10. C : N : P stoichiometry at the Bermuda Atlantic Time-series Study station in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Singh, A.; Baer, S. E.; Riebesell, U.; Martiny, A. C.; Lomas, M. W.

    2015-06-01

    Nitrogen (N) and phosphorus (P) availability determine the strength of the ocean's carbon (C) uptake, and variation in the N : P ratio in inorganic nutrients is key to phytoplankton growth. A similarity between C : N : P ratios in the plankton biomass and deep-water nutrients was observed by Alfred C. Redfield around 80 years ago and suggested that biological processes in the surface ocean controlled deep ocean chemistry. Recent studies have emphasized the role of inorganic N : P ratios in governing biogeochemical processes, particularly the C : N : P ratio in suspended particulate organic matter (POM), with somewhat less attention given to exported POM and dissolved organic matter (DOM). Herein, we extend the discussion on ecosystem C : N : P stoichiometry but also examine temporal variation of stoichiometric relationships. We have analysed elemental stoichiometry in the suspended POM and total (POM + DOM) organic matter (TOM) pools in the upper 100 m, and in the exported POM and sub-euphotic zone (100-500 m) inorganic nutrient pools from the monthly data collected at the Bermuda Atlantic Time-series Study (BATS) site located in the western part of the North Atlantic Ocean. C : N : P ratios in the TOM pool were more than twice that in the POM pool. Observed C : N ratios in suspended POM were approximately equal to the canonical Redfield Ratio (C : N : P = 106 : 16 : 1), while N : P and C : P ratios in the same pool were more than twice the Redfield Ratio. Average N : P ratios in the subsurface inorganic nutrient pool were ~ 26 : 1, squarely between the suspended POM ratio and the Redfield ratio. We have further linked variation in elemental stoichiometry with that of phytoplankton cell abundance observed at the BATS site. Findings from this study suggest that the variation elemental ratios with depth in the euphotic zone was mainly due to different growth rates of cyanobacterial cells. These time-series data have also allowed us to examine the potential role of

  11. Dynamics of the Atlantic meridional overturning circulation and Southern Ocean in an ocean model of intermediate complexity

    NASA Astrophysics Data System (ADS)

    McCreary, Julian P.; Furue, Ryo; Schloesser, Fabian; Burkhardt, Theodore W.; Nonaka, Masami

    2016-04-01

    A steady-state, variable-density, 2-layer, ocean model (VLOM) is used to investigate basic dynamics of the Atlantic meridional overturning circulation and Southern Ocean. The domain consists of idealized (rectangular) representations of the Atlantic, Southern, and Pacific Oceans. The model equations represent the depth-averaged, layer-1 response (except for one solution in which they represent the depth-integrated flow over both layers). To allow for overturning, water can cross the bottom of layer 1 at the velocity we =wd +wm +wn , the three parts representing: interior diffusion wd that increases the layer-1 thickness h throughout the basin, mixed-layer entrainment wm that ensures h is never less than a minimum value hm , and diapycnal (cooling) processes external to the basin wn that adjust h to hn . For most solutions, horizontal mixing has the form of Rayleigh damping with coefficient ν , which we interpret to result from baroclinic instability through the closure, V∗ = - (ν /f2) ∇P , where ∇P = ∇(1/2 g‧h2) is the depth-integrated pressure gradient, g‧ is the reduced-gravity coefficient, and ν is a mixing coefficient; with this interpretation, the layer-1 flow corresponds to the sum of the Eulerian-mean and eddy-mean (V∗) transport/widths, that is, the ;residual; circulation. Finally, layer-1 temperature cools polewards in response to a surface heat flux Q, and the cooling can be strong enough in the Southern Ocean for g‧ = 0 south of a latitude y0 , in which case layer 1 vanishes and the model reduces to a single layer 2.

  12. Phylogenetic identification of marine bacteria isolated from deep-sea sediments of the eastern South Atlantic Ocean.

    PubMed

    da Silva, Marcus Adonai Castro; Cavalett, Angélica; Spinner, Ananda; Rosa, Daniele Cristina; Jasper, Regina Beltrame; Quecine, Maria Carolina; Bonatelli, Maria Letícia; Pizzirani-Kleiner, Aline; Corção, Gertrudes; Lima, André Oliveira de Souza

    2013-12-01

    The deep-sea environments of the South Atlantic Ocean are less studied in comparison to the North Atlantic and Pacific Oceans. With the aim of identifying the deep-sea bacteria in this less known ocean, 70 strains were isolated from eight sediment samples (depth range between 1905 to 5560 m) collected in the eastern part of the South Atlantic, from the equatorial region to the Cape Abyssal Plain, using three different culture media. The strains were classified into three phylogenetic groups, Gammaproteobacteria, Firmicutes and Actinobacteria, by the analysis of 16s rRNA gene sequences. Gammaproteobacteria and Firmicutes were the most frequently identified groups, with Halomonas the most frequent genus among the strains. Microorganisms belonging to Firmicutes were the only ones observed in all samples. Sixteen of the 41 identified operational taxonomic units probably represent new species. The presence of potentially new species reinforces the need for new studies in the deep-sea environments of the South Atlantic.

  13. Are South Texas Streamflow Variations Influenced by Sea Surface Temperature Changes in Pacific and Atlantic Oceans?

    NASA Astrophysics Data System (ADS)

    Murgulet, V.; Hay, R.; Ard, R.

    2013-12-01

    The impact of sea surface temperature (SST) anomalies of the Pacific and Atlantic Oceans on several major river basins in the continental U. S. has recently become well documented. Clear relationships have been identified between El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO) and continental U. S. streamflow. Because these relationships can be potentially used to predict streamflow variability, it would also be of great importance to evaluate whether these climate phenomena affect river basins at the sub-regional and/or local scale, objectives that are not usually addressed in previous studies. Therefore, this study is focused on the basin river system of South Texas, an area that encompasses approximately 30,000 km2 and is climatologically defined as subtropical subhumid. Streamflow data (1940-2011) from sixteen unimpaired U.S. Geological Survey gage stations were normalized into a South Texas streamflow data set and evaluated with respect to ENSO, PDO and AMO index time series. The comparison of South Texas annual streamflow with Pacific Decadal Oscillation and El Niño Southern Oscillation Indices shows that the warm phases of ENSO and PDO are generally associated with increased streamflow, whereas cold phases of ENSO and PDO result in lower streamflow volumes. In addition, cross-correlation analyses show a 7-8 month delayed streamflow response to sea surface temperature signals. Furthermore, annual streamflow variability in the South Texas river basins can be also due to sea surface temperature anomalies in the Atlantic Ocean. Higher streamflow values are shown during the cold phase of AMO, while relatively low streamflow values are illustrated during the warm phase of AMO. Thus, preliminary results show that SST anomalies in both Pacific and Atlantic Oceans influence the streamflow variability in the South Texas area. Current research is also focused on evaluating if these climate phenomena

  14. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean - potential impacts

    NASA Astrophysics Data System (ADS)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier van der Gon, H. A. C.

    2010-07-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates), natural (desert dust, sea salt) and chemically aged (sulphate and nitrate on dust) aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode) are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment). The sodium (sea salt related) aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  15. Chemically aged and mixed aerosols over the Central Atlantic Ocean - potential impacts

    NASA Astrophysics Data System (ADS)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier van der Gon, H. A. C.

    2010-02-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates), natural (desert dust, sea salt) and chemically aged (sulphate and nitrate on dust) aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode) are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, designating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols indicates that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud and entrainment). The sodium (sea salt related) aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  16. Coherency of late Holocene European speleothem δ18O records linked to North Atlantic Ocean circulation

    NASA Astrophysics Data System (ADS)

    Deininger, Michael; McDermott, Frank; Mudelsee, Manfred; Werner, Martin; Frank, Norbert; Mangini, Augusto

    2017-07-01

    Speleothem δ18O records provide valuable information about past continental environmental and climatic conditions, although their interpretation is often not straightforward. Here we evaluate a compilation of late Holocene speleothem δ18O records using a Monte Carlo based Principal Component Analysis (MC-PCA) method that accounts for uncertainties in individual speleothem age models and for the variable temporal resolution of each δ18O record. The MC-PCA approach permits not only the identification of temporally coherent changes in speleothem δ18O; it also facilitates their graphical depiction and evaluation of their spatial coherency. The MC-PCA method was applied to 11 Holocene speleothem δ18O records that span most of the European continent (apart from the circum-Mediterranean region). We observe a common (shared) mode of speleothem δ18O variability that suggests millennial-scale coherency and cyclicity during the last 4.5 ka. These changes are likely caused by variability in atmospheric circulation akin to that associated with the North Atlantic Oscillation, reflecting meridionally shifted westerlies. We argue that these common large-scale variations in European speleothem δ18O records are in phase with changes in the North Atlantic Ocean circulation indicated by the vigour of the Iceland Scotland Overflow Water (ISOW), the strength of the subpolar gyre (SPG) and an ocean stacked North Atlantic ice rafted debris (IRD) index. Based on a recent modelling study, we conclude that these changes in the North Atlantic circulation history may be caused by wind stress on the ocean surface driven by shifted westerlies. However, the mechanisms that ultimately force the westerlies remain unclear.

  17. Causes of Upper-Ocean Temperature Anomalies in the Tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Rugg, A.; Foltz, G. R.; Perez, R. C.

    2016-02-01

    Hurricane activity and regional rainfall are strongly impacted by upper ocean conditions in the tropical North Atlantic, defined as the region between the equator and 20°N. A previous study analyzed a strong cold sea surface temperature (SST) anomaly that developed in this region during early 2009 and was recorded by the Pilot Research Array in the Tropical Atlantic (PIRATA) moored buoy at 4°N, 23°W (Foltz et al. 2012). The same mooring shows a similar cold anomaly in the spring of 2015 as well as a strong warm anomaly in 2010, offering the opportunity for a more comprehensive analysis of the causes of these events. In this study we examine the main causes of the observed temperature anomalies between 1998 and 2015. Basin-scale conditions during these events are analyzed using satellite SST, wind, and rain data, as well as temperature and salinity profiles from the NCEP Global Ocean Data Assimilation System. A more detailed analysis is conducted using ten years of direct measurements from the PIRATA mooring at 4°N, 23°W. Results show that the cooling and warming anomalies were caused primarily by wind-driven changes in surface evaporative cooling, mixed layer depth, and upper-ocean vertical velocity. Anomalies in surface solar radiation acted to damp the wind-driven SST anomalies in the latitude bands of the ITCZ (3°-8°N). Basin-scale analyses also suggest a strong connection between the observed SST anomalies and the Atlantic Meridional Mode, a well-known pattern of SST and surface wind anomalies spanning the tropical Atlantic.

  18. On the Flow of Atlantic Water Towards the Arctic Ocean; a Synergy Between Altimetry and Hydrography.

    NASA Astrophysics Data System (ADS)

    Chafik, L.; Nilsson, J.; Skagseth, O.; Lundberg, P.

    2015-12-01

    The Arctic climate is strongly influenced by the inflow of warm Atlantic water conveyed by the Norwegian Atlantic Slope Current (NwASC); the main heat conveyor into the Arctic Ocean. Based on sea surface height (SSH) data from altimetry, we develop a dynamical measure of the NwASC transport to diagnose its spatio-temporal variability. This supports a dynamical division of the NwASC into two flow regimes; the Svinøy Branch (SvB) in the Norwegian Sea, and the Fram Strait Branch (FSB) west of Spitsbergen. The SvB transport is well correlated with the SSH and atmospheric variability within the Nordic Seas, factors that also affect the inflow to the Barents Sea. In contrast, the FSB is regulated by regional atmospheric patterns around Svalbard and northern Barents Sea. We further relate anomalous flow events to temperature fluctuations of Atlantic water. A warm anomaly is found to propagate northwards, with a tendency to amplify enroute, after events of strong flow in the Norwegian Sea. A roughly 12-months delayed temperature signal is identified in the FSB. This suggests that hydrographic anomalies both upstream from the North Atlantic, and locally generated in the Norwegian Sea, are important for the oceanic heat and salt transport that eventually enters into the Arctic. We believe that the combination of the flow from altimetry and temperature fluctuations in the Nordic Seas can be used to qualitatively predict warm anomalies towards the Arctic Ocean, which could be a valuable addition to the forecast skill of the statistical Arctic sea-ice models.

  19. Sources of Meridional Heat and Freshwater Transport Anomalies in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kelly, K. A.; Thompson, L.; Drushka, K.

    2016-02-01

    Observations of thermosteric and halosteric sea level from hydrographic data, ocean mass from GRACE and altimetric sea surface height are used to infer meridional heat transport (MHT) and freshwater convergence (FWC) anomalies for the Atlantic Ocean for 1993-2014. A Kalman filter extracts smooth estimates of heat transport convergence (HTC) and FWC from discrepancies between the sea level response to monthly surface heat and freshwater fluxes and observed heat and freshwater content in each of eight regions. Estimates of MHT anomalies are derived by summing the HTC from north to south and adding an integration constant derived from updated MHT estimates at 41N (Willis 2010). MHT estimates are relatively insensitive to the choice of heat flux products and are highly coherent spatially. Anomalies in MHT are comparable to those observed at the RAPID/MOCHA line at 26.5N and show a continued recovery from the minimum in 2010 throughout the Atlantic. MHT anomalies resemble estimates of Agulhas Leakage derived from altimeter (LeBars et al 2014) suggesting that the Indian Ocean is the source of the anomalous heat inflow. FWC estimates are also insensitive to choice of flux products. Interannual anomalies of FWC integrated from 67N to 35S resemble estimates of Atlantic river inflow (de Couet and Maurer, GRDC 2009), whereas the trend is consistent with estimates of freshwater input from Greenland. Increasing values of FWC after 2002 at a time when MHT was decreasing may indicate a feedback between the Atlantic Meridional Overturning Circulation and FWC that would accelerate the AMOC slowdown.

  20. Coherency of late Holocene European speleothem δ18O records linked to North Atlantic Ocean circulation

    NASA Astrophysics Data System (ADS)

    Deininger, Michael; McDermott, Frank; Mudelsee, Manfred; Werner, Martin; Frank, Norbert; Mangini, Augusto

    2016-09-01

    Speleothem δ18O records provide valuable information about past continental environmental and climatic conditions, although their interpretation is often not straightforward. Here we evaluate a compilation of late Holocene speleothem δ18O records using a Monte Carlo based Principal Component Analysis (MC-PCA) method that accounts for uncertainties in individual speleothem age models and for the variable temporal resolution of each δ18O record. The MC-PCA approach permits not only the identification of temporally coherent changes in speleothem δ18O; it also facilitates their graphical depiction and evaluation of their spatial coherency. The MC-PCA method was applied to 11 Holocene speleothem δ18O records that span most of the European continent (apart from the circum-Mediterranean region). We observe a common (shared) mode of speleothem δ18O variability that suggests millennial-scale coherency and cyclicity during the last 4.5 ka. These changes are likely caused by variability in atmospheric circulation akin to that associated with the North Atlantic Oscillation, reflecting meridionally shifted westerlies. We argue that these common large-scale variations in European speleothem δ18O records are in phase with changes in the North Atlantic Ocean circulation indicated by the vigour of the Iceland Scotland Overflow Water (ISOW), the strength of the subpolar gyre (SPG) and an ocean stacked North Atlantic ice rafted debris (IRD) index. Based on a recent modelling study, we conclude that these changes in the North Atlantic circulation history may be caused by wind stress on the ocean surface driven by shifted westerlies. However, the mechanisms that ultimately force the westerlies remain unclear.