WorldWideScience

Sample records for middle atlantic sea

  1. Biodiversity of polycyclic aromatic hydrocarbon-degrading bacteria from deep sea sediments of the Middle Atlantic Ridge

    OpenAIRE

    Cui, Zhisong; Lai, Qiliang; Dong, Chunming; Shao, Zongze

    2008-01-01

    The bacteria involved in the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in deep sea subsurface environments are largely unknown. In order to reveal their biodiversity, sediments from 2.2 m under the bottom surface at a water depth of 3542 m were sampled on the Middle Atlantic Ridge with a gravity column sampler. The sediments were promptly enriched with either crude oil or a mixture of PAHs (naphthalene, phenanthrene and pyrene) as the sole carbon source, and further enriched w...

  2. [Predominant strains of polycyclic aromatic hydrocarbon-degrading consortia from deep sea of the Middle Atlantic Ridge].

    Science.gov (United States)

    Cui, Zhisong; Shao, Zongze

    2009-07-01

    In order to identify the predominant strains of polycyclic aromatic hydrocarbon (PAH)-degrading consortia harboring in sea water and surface sediment collected from deep sea of the Middle Atlantic Ridge. We employed enrichment method and spread-plate method to isolate cultivable bacteria and PAHs degraders from deep sea samples. Phylogenetic analysis was conducted by 16S rRNA gene sequencing of the bacteria. Then we analyzed the dominant bacteria in the PAHs-degrading consortia by denaturing gradient gel electrophoresis (DGGE) combined with DNA sequencing. Altogether 16 cultivable bacteria were obtained, including one PAHs degrader Novosphingobium sp. 4D. Phylogenetic analysis showed that strains closely related to Alcanivorax dieselolei NO1A (5/16) and Tistrella mobilis TISTR 1108T (5/16) constituted two biggest groups among the cultivable bacteria. DGGE analysis showed that strain 4L (also 4M and 4N, Alcanivorax dieselolei NO1A, 99.21%), 4D (Novosphingobium pentaromativorans US6-1(T), 97.07%) and 4B (also 4E, 4H and 4K, Tistrella mobilis TISTR 1108T, > 99%) dominated the consortium MC2D. While in consortium MC3CO, the predominant strains were strain 5C (also 5H, Alcanivorax dieselolei NO1A, > 99%), uncultivable strain represented by band 5-8 (Novosphingobium aromaticivorans DSM 12444T, 99.41%), 5J (Tistrella mobilis TISTR 1108T, 99.52%) and 5F (also 5G, Thalassospira lucentensis DSM 14000T, degrading consortia in sea water and surface sediment of Middle Atlantic Ridge deep sea, with Novosphingobium spp. as their main PAHs degraders.

  3. Biodiversity of polycyclic aromatic hydrocarbon-degrading bacteria from deep sea sediments of the Middle Atlantic Ridge.

    Science.gov (United States)

    Cui, Zhisong; Lai, Qiliang; Dong, Chunming; Shao, Zongze

    2008-08-01

    The bacteria involved in the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in deep sea subsurface environments are largely unknown. In order to reveal their biodiversity, sediments from 2.2 m under the bottom surface at a water depth of 3542 m were sampled on the Middle Atlantic Ridge with a gravity column sampler. The sediments were promptly enriched with either crude oil or a mixture of PAHs (naphthalene, phenanthrene and pyrene) as the sole carbon source, and further enriched with the PAH mixture mentioned above in the lab. The resulting consortia were named C2CO and C2PPN respectively. Their bacterial composition was analysed with plate cultivation, PCR-DGGE and 16S rDNA library analysis. On plates, isolates belonging to Pseudoalteromonas, Halomonas, Marinobacter, Thalassospira and Tistrella dominated the culturable populations. With PCR-DGGE, five major bands closely related to Cycloclasticus, Alteromonas, Thalassospira, Alcanivorax and Rhodospirillaceae were detected in consortium C2CO, while only one major band of Cycloclasticus was detected in consortium C2PPN. In addition, the dynamics of community structure in response to aromatic substrate alterations were examined. As a result, three ribotypes of Cycloclasticus were detected by 16S rDNA library analysis, one which played a key role in phenanthrene degradation; two Alteromonas bacteria dominated the naphthalene reselected consortium. Although bacteria of the two genera grew as the main members of the communities, none of them were isolated, probably owing to their poor cultivability. These results confirm that bacteria of Cycloclasticus are important obligate PAH degraders in marine environments, and coexist with other degrading bacteria that inhabit the deep subsurface sediment of the Atlantic. This supports the view that PAH accumulation and bioattenuation occur in remote areas consistently and continuously.

  4. Continental slope sea level and flow variability induced by lateral movements of the Gulf Stream in the Middle Atlantic Bight

    Science.gov (United States)

    Böhm, E.; Hopkins, T. S.; Pietrafesa, L. J.; Churchill, J. H.

    2006-08-01

    As described by [Csanady, G.T., Hamilton, P., 1988. Circulation of slope water. Continental Shelf Research 8, 565-624], the flow regime over the slope of the southern Middle Atlantic Bight (MAB) includes a current reversal in which southwestward flow over the upper and middle slope becomes entrained in the northeastward current adjacent to the Gulf Stream. In this paper we use satellite-derived data to quantify how lateral motions of the Gulf Stream impact this current system. In our analysis, the Gulf Stream’s thermal front is delineated using a two-year time series of sea surface temperature derived from NOAA/AVHRR satellite data. Lateral motions of the Gulf Stream are represented in terms of temporal variations of the area, east of 73°W, between the Gulf Stream thermal front and the shelf edge. Variations of slope water flow within this area are represented by anomalies of geostrophic velocity as derived from the time series of the sea level anomaly determined from TOPEX/POSEIDON satellite altimeter data. A strong statistical relationship is found between Gulf Stream displacements and parabathic flow over the continental slope. It is such that the southwestward flow over the slope is accelerated when the Gulf Stream is relatively far from the shelf edge, and is decelerated (and perhaps even reversed) when the Gulf Stream is close to the shelf edge. This relationship between Gulf Stream displacements and parabathic flow is also observed in numerical simulations produced by the Miami Isopycnic Coordinate Model. In qualitative terms, it is consistent with the notion that when the Gulf Stream is closer to the 200-m isobath, it is capable of entraining a larger fraction of shelf water masses. Alternatively, when the Gulf Stream is far from the shelf-break, more water is advected into the MAB slope region from the northeast. Analysis of the diabathic flow indicates that much of the cross-slope transport by which the southwestward flow entering the study region is

  5. Assemblages of deep-sea fishes on the middle slope off Northwest Africa (26°-33° N, eastern Atlantic)

    Science.gov (United States)

    Pajuelo, J. G.; Seoane, J.; Biscoito, M.; Freitas, M.; González, J. A.

    2016-12-01

    The structure and composition of deep-sea fish assemblages living on the middle slope off NW Africa (26-33° N) were investigated. Data were collected by six commercial trawlers during experimental fishing (1027 hauls) at depths between 800 and 1515 m. A total of 1,115,727 fish specimens, belonging to 37 families and 96 species (24 Elasmobranchii, 5 Holocephali, and 67 Actinopteri) were collected with bottom trawls. The deep-sea demersal fish fauna off NW Africa is dominated by fishes of the family Macrouridae, followed by the Moridae and Alepocephalidae families. The main abundant species were Trachyrincus scabrus, Bathygadus favosus, Mora moro, Alepocephalus productus, Nezumia aequalis and Bathygadus melanobranchus. PERMANOVA analysis showed differences in demersal fish assemblages among bottom types, depth strata and between areas (north and south of parallel 30° N), with the area being the most influential factor followed by the type of substrate. PERMANOVAs computed separately for each area showed significant differences among the bottom types and depths in both areas. SIMPER analysis revealed that B. melanobranchus and B. favosus, which occurred at higher abundances in the area ≥30° N, were the species that were best discriminated between areas; whilst T. scabrus and M. moro occurred at higher abundances in the area <30° N. N. aequalis, B. favosus, B. melanobranchus, Deania hystricosa, Aphanopus intermedius, Coelorinchus labiatus and Halosaurus johnsonianus were restricted or more abundant in the area ≥30° N, and functioned as the discriminating species that most contributed to the average dissimilarity between areas. T. scabrus, M. moro, Alepocephalus productus and Alepocephalus bairdii were more abundant in the area <30° N. The standardized mean abundance (in number of individuals/km2) showed a decreasing pattern: i) with depth in both areas, north and south of parallel 30° N, and ii) with depth on each type of substrate, except on cold coral

  6. Middle Atlantic neutron therapy trail

    International Nuclear Information System (INIS)

    Rogers, C.

    1975-01-01

    A consortium of therapeutic radiologists in the Middle Atlantic States and physicists at the Naval Research Laboratory has been established to investigate the use of fast neutron beams in the control of some tumors. Many radiobiology experiments have indicated that neutron beams may have an advantage in the control of local tumors over that of conventional forms of radiotherapy. In preparation for clinical radiotherapy trials, extensive measurements have quantified the various physical characteristics of the NRL cyclotron-produced neutron beam. Techniques have been developed for the absolute determination of delivered dose at depth in tissue for this beam, accounting for the relatively small component of dose delivered by gamma rays, as well as that by the neutrons. A collimator system has been designed to allow the precise field definition necessary for optimum therapy treatment planning. A dose control and monitor unit has been engineered and has demonstrated a reproducibility of 0.2 percent. The relative biological effectiveness of this neutron bean has been studied with several biological systems to aid in determining proper radiotherapeutic dose levels. The objective of these studies is a full-scale clinical radiotherapy trial to test neutron effectiveness as compared to that of conventional radiotherapy, after a pilot study in man

  7. On the differences between early and middle winter atmospheric responses to sea surface temperature anomalies in the northwest Atlantic

    International Nuclear Information System (INIS)

    Peng, S.; Mysak, L.A.; Derome, J.; Ritchie, H.; Dugas, B.

    1994-01-01

    Using an atmospheric global spectral model at RPN with T42 horizontal resolution, we have shown that the winter atmosphere in the mid-latitude is capable of reacting to the SST anomalies prescribed in the northwest Atlantic with two different responses. The nature of the response is determined by the climatological conditions of the winter system. Experiments are conducted using either the perpetual November or January conditions, with or without the SST anomalies prescribed. Six 50-day integrations, with positive (or negative) SST anomalies prescribed, initialized from independent November analyses and similarly, four runs initialized from January analyses, have been examined in comparison with their control runs

  8. Erosional and depositional contourite features at the transition between the western Scotia Sea and southern South Atlantic Ocean: links with regional water-mass circulation since the Middle Miocene

    Science.gov (United States)

    Pérez, Lara F.; Hernández-Molina, F. Javier; Esteban, Federico D.; Tassone, Alejandro; Piola, Alberto R.; Maldonado, Andrés; Preu, Benedict; Violante, Roberto A.; Lodolo, Emanuele

    2015-08-01

    The aim of the present study was to characterise the morpho-sedimentary features and main stratigraphic stacking pattern off the Tierra del Fuego continental margin, the north-western sector of the Scotia Sea abyssal plain (Yaghan Basin) and the Malvinas/Falkland depression, based on single- and multi-channel seismic profiles. Distinct contourite features were identified within the sedimentary record from the Middle Miocene onwards. Each major drift developed in a water depth range coincident with a particular water mass, contourite terraces on top of some of these drifts being associated with interfaces between water masses. Two major palaeoceanographic changes were identified. One took place in the Middle Miocene with the onset of Antarctic Intermediate Water flow and the enhancement of Circumpolar Deep Water (CDW) flow, coevally with the onset of Weddell Sea Deep Water flow in the Scotia Sea. Another palaeoceanographic change occurred on the abyssal plain of the Yaghan Basin in the Late Miocene as a consequence of the onset of Southeast Pacific Deep Water flow and its complex interaction with the lower branch of the CDW. Interestingly, these two periods of change in bottom currents are coincident with regional tectonic episodes, as well as climate and Antarctic ice sheet oscillations. The results convincingly demonstrate that the identification of contourite features on the present-day seafloor and within the sedimentary record is the key for decoding the circulation of water masses in the past. Nevertheless, further detailed studies, especially the recovery of drill cores, are necessary to establish a more robust chronology of the evolutionary stages at the transition between the western Scotia Sea and the southern South Atlantic Ocean.

  9. 75 FR 49420 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-08-13

    .... 100513223-0289-02] RIN 0648-AY88 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In- season Adjustment AGENCY: National Marine...-sea (DAS) allocation for the Atlantic deep- sea red crab fishery that were implemented in May 2010...

  10. 75 FR 7435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-02-19

    .... 100105009-0053-01] RIN 0648-AY51 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications AGENCY: National Marine Fisheries Service (NMFS... comments. SUMMARY: NMFS proposes 2010 specifications for the Atlantic deep-sea red crab fishery, including...

  11. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  12. 75 FR 35435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-06-22

    .... 100513223-0254-01] RIN 0648-AY88 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In- season Adjustment AGENCY: National Marine... deep-sea red crab fishery, including a target total allowable catch (TAC) and a fleet-wide days-at-sea...

  13. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    The stratigraphic and tectonic evolution of the Jurassic of East Greenland, the Norwegian Shelf and the North Sea is remarkably similar. A major Middle Jurassic unconformity occurs in all three areas. In the North Sea it is commonly termed the `Mid-Cimmerian Unconformity` and is characterized by progressive truncation of the underlying section towards a centre at the triple junction between the Central Graben, Viking Graben and Moray Firth. Strata above the unconformity show a progressive Late Aalenian-Early Kimmeridgian onlap in the same direction. These relations have been interpreted as caused by Early Jurassic uplift and of a major thermal dome in the central North Sea, followed by Medial and Late Jurassic rifting, erosion, deflation and transgression of the dome. The East Greenland unconformity shows progressive truncation of underlying strata from south to north, and Bajocian to Callovian onlap in the same direction. The same pattern seems to be developed on the conjugate Norwegian margin. This suggests the possibility that the three unconformities have similar causes for their development. It is proposed that major rift domes formed in the Central North Sea and in the Greenland-Norway seaway in Early Jurassic times. The domes were eroded and gradually deflated during Medial Jurassic times and were finally submerged by the Late Oxfordian-Kimmeridgian. They were associated with volcanism and rifting which was delayed with respect to dome initiation. Roughly contemperaneous domes were present west of Britain, north of the Porcupine Seabight, and in Scania, southern Sweden, as reflected by development of asymmetrical unconformities showing progressive truncation of underlying strata, onlap of overlying Jurassic strata, and associated intrusive and extrusive volcanism. The domes are related to impingement of the heads of transient mantle plumes at the base of the lithosphere. The associated unconformities are thus of non-eustatic nature. Domal uplift and

  14. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  15. 18th Middle Atlantic Regional Meeting, American Chemical Society

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The Proceedings of the 18th Middle Atlantic Regional Meeting of the American Chemical Society held May 21-23, 1984, include information about the meeting, e.g. area map and list of exhibitors, and abstracts for most of the 397 papers. A few papers are only title listed. The papers are arranged into sections dealing with analytical chemistry, biochemistry, chemical education, environmental chemistry, fuel chemistry, history of chemistry, industrial and engineering chemistry, inorganic chemistry, photochemistry, physical chemistry, polymer chemistry, and polymeric materials. Sections are also included to highlight undergraduate research and papers by chemical technicians and younger chemists. Separate abstracts have been prepared for 36 papers

  16. Sea-ice cover in the Nordic Seas and the sensitivity to Atlantic water temperatures

    Science.gov (United States)

    Jensen, Mari F.; Nisancioglu, Kerim H.; Spall, Michael A.

    2017-04-01

    Changes in the sea-ice cover of the Nordic Seas have been proposed to play a key role for the dramatic temperature excursions associated with the Dansgaard-Oeschger events during the last glacial. However, with its proximity to the warm Atlantic water, how a sea-ice cover can persist in the Nordic Seas is not well understood. In this study, we apply an eddy-resolving configuration of the Massachusetts Institute of Technology general circulation model with an idealized topography to study the presence of sea ice in a Nordic Seas-like domain. We assume an infinite amount of warm Atlantic water present in the south by restoring the southern area to constant temperatures. The sea-surface temperatures are restored toward cold, atmospheric temperatures, and as a result, sea ice is present in the interior of the domain. However, the sea-ice cover in the margins of the Nordic Seas, an area with a warm, cyclonic boundary current, is sensitive to the amount of heat entering the domain, i.e., the restoring temperature in the south. When the temperature of the warm, cyclonic boundary current is high, the margins are free of sea ice and heat is released to the atmosphere. We show that with a small reduction in the temperature of the incoming Atlantic water, the Nordic Seas-like domain is fully covered in sea ice. Warm water is still entering the Nordic Seas, however, this happens at depths below a cold, fresh surface layer produced by melted sea ice. Consequently, the heat release to the atmosphere is reduced along with the eddy heat fluxes. Results suggest a threshold value in the amount of heat entering the Nordic Seas before the sea-ice cover disappears in the margins. We study the sensitivity of this threshold to changes in atmospheric temperatures and vertical diffusivity.

  17. Interannual variability of north Atlantic Sea surface temperatures

    International Nuclear Information System (INIS)

    Bhatt, U.S.; Battisiti, D.S.; Alexander, M.A.

    1994-01-01

    In the midlatitude north Atlantic Ocean the pattern of sea surface temperature anomalies (ssta) is characterized by a north-south dipole. Bjerknes was the first to propose that the banded structure was associated with the interannual variability. Recently, these patterns have been studied more extensively. In this study the quantitative aspects of these patterns are examined through the use of a mixed-layer model (MLM)

  18. Late Cenozoic flexural deformation of the middle U.S. Atlantic passive margin

    Science.gov (United States)

    Pazzaglia, Frank J.; Gardner, Thomas, W.

    1994-01-01

    Despite the century-long recognition of regional epeirogeny along the middle Atlantic passive margin, relatively few studies have focused on understanding postrift uplift mechanisms. Here, we demonstrate that epeirogenic uplift of the central Appalachian Piedmont and subsidence of the Salisbury Embayment represent first-order, flexural isostatic processes driven by continental denudation and offshore deposition. Our results show that regional epeirogenic processes, present on all Atlantic-type passive margins, are best resolved by specific stratigraphic and geomorphic relationships, rather than topography. A simple one-dimensional geodynamic model, constrained by well-dated Baltimore Canyon trough, Coastal Plain, and lower Susquehanna River (piedmont) stratigraphy, simulates flexural deforamtion of the U.S. Atlantic margin. The model represents the passive margin lithosphree as a uniformly thick elastic plate, without horizontal compressive stresses, that deforms flexurally under the stress of strike-averaged, vertically applied line loads. Model results illustrate a complex interaction among margin stratigraphy and geomorphology, the isostatic repsonse to denudational and depositional processes, and the modulating influence of exogenic forces such as eustasy. The current elevation, with respect to modern sea level, of fluvial terraces and correlateive Coastal Plain deposits or unconformities is successfully predicted through the synthesis of paleotopography, eustatic change, and margin flexure. Results suggest that the middle U.S. Atlantic margin landward of East Coast Magnetic Anomaly is underlain by lithoshpere with an average elastic thickness of 40 km (flexural rigidity, D = 4 X 10(exp 23) N m), the margin experience an average, long-term denudation rate of approximately 10m/m.y., and the Piedmont has been flexurally upwaped between 35 and 130 meters in the last 15 m.y. Long term isostatic continental uplift resulting rom denudation and basin subsidence

  19. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T.

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  20. Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea ice

    Science.gov (United States)

    Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.

    2017-08-01

    Arctic sea ice over the last few decades has experienced a significant decline in coverage both in summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea ice in the Nordic Seas (including the Barents Sea). More open water combined with the prevailing atmospheric pattern of airflow from the southeast, and persistent North Atlantic storms such as the recent extremely strong Storm Frank in December 2015, lead to increased energy transport to the high Arctic. Each of these storms brings sizeable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, Franz Joseph Land and Novaya Zemlya, and the associated heat release from open water into the atmosphere, contributed significantly to the increase in the downward longwave radiation throughout the entire Arctic. Added to other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W m-2, which can result in thinner (up to at least 15-20 cm) Arctic ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea ice.

  1. Estimating sea-level allowances for Atlantic Canada under conditions of uncertain sea-level rise

    Directory of Open Access Journals (Sweden)

    B. Greenan

    2015-03-01

    Full Text Available This paper documents the methodology of computing sea-level rise allowances for Atlantic Canada in the 21st century under conditions of uncertain sea-level rise. The sea-level rise allowances are defined as the amount by which an asset needs to be raised in order to maintain the same likelihood of future flooding events as that site has experienced in the recent past. The allowances are determined by combination of the statistics of present tides and storm surges (storm tides and the regional projections of sea-level rise and associated uncertainty. Tide-gauge data for nine sites from the Canadian Atlantic coast are used to derive the scale parameters of present sea-level extremes using the Gumbel distribution function. The allowances in the 21st century, with respect to the year 1990, were computed for the Intergovernmental Panel on Climate Change (IPCC A1FI emission scenario. For Atlantic Canada, the allowances are regionally variable and, for the period 1990–2050, range between –13 and 38 cm while, for the period 1990–2100, they range between 7 and 108 cm. The negative allowances in the northern Gulf of St. Lawrence region are caused by land uplift due to glacial isostatic adjustment (GIA.

  2. Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

  3. Millennial-scale northern Hemisphere Atlantic-Pacific climate teleconnections in the earliest Middle Pleistocene.

    Science.gov (United States)

    Hyodo, Masayuki; Bradák, Balázs; Okada, Makoto; Katoh, Shigehiro; Kitaba, Ikuko; Dettman, David L; Hayashi, Hiroki; Kumazawa, Koyo; Hirose, Kotaro; Kazaoka, Osamu; Shikoku, Kizuku; Kitamura, Akihisa

    2017-08-30

    Suborbital-scale climate variations, possibly caused by solar activity, are observed in the Holocene and last-glacial climates. Recently published bicentennial-resolution paleoceanic environmental records reveal millennial-scale high-amplitude oscillations postdating the last geomagnetic reversal in the Marine Isotope Stage (MIS) 19 interglacial. These oscillations, together with decoupling of post-reversal warming from maximum sea-level highstand in mid-latitudes, are key features for understanding the climate system of MIS 19 and the following Middle Pleistocene. It is unclear whether the oscillations are synchronous, or have the same driver as Holocene cycles. Here we present a high resolution record of western North Pacific submarine anoxia and sea surface bioproductivity from the Chiba Section, central Japan. The record reveals many oxic events in MIS 19, coincident with cold intervals, or with combined cold and sea-level fall events. This allows detailed correlations with paleoceanic records from the mid-latitude North Atlantic and Osaka Bay, southwest Japan. We find that the millennial-scale oscillations are synchronous between East and West hemispheres. In addition, during the two warmest intervals, bioproductivity follows the same pattern of change modulated by bicentennial cycles that are possibly related to solar activity.

  4. Sea Spray Aerosol Production over the North Atlantic

    Science.gov (United States)

    Bates, T. S.; Quinn, P.

    2017-12-01

    Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

  5. Impact of North Atlantic Current changes on the Nordic Seas and the Arctic Ocean

    OpenAIRE

    Kauker, Frank; Gerdes, Rüdiger; Karcher, Michael; Köberle, Cornelia

    2005-01-01

    The impact of North Atlantic Current (NAC) volume, heat, and salt transport variability onto the NordicSeas and the Arctic Ocean is investigated using numerical hindcast and sensitivity experiments. Theocean-sea ice model reproduces observed propagation pathways and speeds of SST anomalies.Part of the signal reaching the entrance to the Nordic Seas between Iceland and Scotland originatesin the lower latitude North Atlantic. Response experiments with different prescribed conditionsat 50N show ...

  6. Sea Ice and Hydrographic Variability in the Northwest North Atlantic

    Science.gov (United States)

    Fenty, I. G.; Heimbach, P.; Wunsch, C. I.

    2010-12-01

    Sea ice anomalies in the Northwest North Atlantic's Labrador Sea are of climatic interest because of known and hypothesized feedbacks with hydrographic anomalies, deep convection/mode water formation, and Northern Hemisphere atmospheric patterns. As greenhouse gas concentrations increase, hydrographic anomalies formed in the Arctic Ocean associated with warming will propagate into the Labrador Sea via the Fram Strait/West Greenland Current and the Canadian Archipelago/Baffin Island Current. Therefore, understanding the dynamical response of sea ice in the basin to hydrographic anomalies is essential for the prediction and interpretation of future high-latitude climate change. Historically, efforts to quantify the link between the observed sea ice and hydrographic variability in the region has been limited due to in situ observation paucity and technical challenges associated with synthesizing ocean and sea ice observations with numerical models. To elaborate the relationship between sea ice and ocean variability, we create three one-year (1992-1993, 1996-1997, 2003-2004) three-dimensional time-varying reconstructions of the ocean and sea ice state in Labrador Sea and Baffin Bay. The reconstructions are syntheses of a regional coupled 32 km ocean-sea ice model with a suite of contemporary in situ and satellite hydrographic and ice data using the adjoint method. The model and data are made consistent, in a least-squares sense, by iteratively adjusting several model control variables (e.g., ocean initial and lateral boundary conditions and the atmospheric state) to minimize an uncertainty-weighted model-data misfit cost function. The reconstructions reveal that the ice pack attains a state of quasi-equilibrium in mid-March (the annual sea ice maximum) in which the total ice-covered area reaches a steady state -ice production and dynamical divergence along the coasts balances dynamical convergence and melt along the pack’s seaward edge. Sea ice advected to the

  7. Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

    Directory of Open Access Journals (Sweden)

    M. Wary

    2017-06-01

    Full Text Available Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.

  8. Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation

    NARCIS (Netherlands)

    Yang, Qian; Dixon, Timothy H.; Myers, Paul G.; Bonin, Jennifer; Chambers, Don; Van Den Broeke, M. R.|info:eu-repo/dai/nl/073765643

    2016-01-01

    The Atlantic Meridional Overturning Circulation (AMOC) is an important component of ocean thermohaline circulation. Melting of Greenland's ice sheet is freshening the North Atlantic; however, whether the augmented freshwater flux is disrupting the AMOC is unclear. Dense Labrador Sea Water (LSW),

  9. Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

    Science.gov (United States)

    Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

    2017-12-31

    Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and

  10. 75 FR 27219 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-05-14

    .... Whereas a limited market has been responsible for the shortfall in landings compared to the target TAC... final specifications for the 2010 Atlantic deep- sea red crab fishery, including a target total... specify the target TAC and other management measures in order to manage the red crab resource for fishing...

  11. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  12. Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

    Science.gov (United States)

    Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

    2014-01-23

    In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

  13. Predation on Atlantic salmon and sea trout during their first days as postsmolts

    DEFF Research Database (Denmark)

    Dieperink, C.; Bak, B.D.; Pedersen, Lars-Flemming

    2002-01-01

    Radio-tagged smolts of Atlantic salmon Salmo salar and sea trout Salmo trutta were predated heavily by sea birds after crossing the saline limit in the estuary of the River Skjern, Denmark. Most predation took place within the first 9 h after estuarine entry. The field data do not contradict...

  14. Scottish Sea Lochs: High Resolution Archives of North Atlantic Climate

    Science.gov (United States)

    Norgaard-Pedersen, N.; Austin, W. E.; Cage, A. G.; Shimmield, T. M.; Gillibrand, P. A.

    2002-12-01

    The sea lochs (fjords) of NW Scotland bridge the land-ocean interface in a region of Europe which is particularly well situated to monitor changes in westerly air flow. Inter-annual atmospheric circulation changes at this latitude are largely governed by the North Atlantic Oscillation (NAO), in turn influencing both westerlies and precipitation. Comparing two extreme recent NAO years, circulation modelling results from Loch Sunart, NW Scotland, reveal a clear response to freshwater runoff and wind forcing in both magnitude and rate of deep-water renewal events. Scottish fjords, because of the relatively small impact which salinity has on d18Owater (0.18 % per salinity unit), potentially provide NW Europe's most useful study sites in coastal palaeoclimate research, particularly where palaeotemperature is the primary record of interest. New data from a high-resolution record (7 yr sample resolution), spanning the last two millennia, from the deepest part of the main basin of Loch Sunart illustrate significant multi-decadal to centennial scale variability in the sedimentary and stable isotope record of epibenthic foraminifera Cibicides lobatulus. The long-term pattern in benthic d18O appears to reflect bottom water temperature differences of 1-2§C, resolving climatic periods such as the Medieval Warm Period and the Little Ice Age. Since the core site is connected with shelf waters (i.e. no shallow sill) it seems likely that this paleotemperature reflects changing shelf water, not the exchange process as a function of long-term runoff/wind forcing. Grain size data and XRF data point to catchment-wide responses (weathering and erosion) which appear to show the largest variability during the last millennium, driven either by rainfall and temperature and/or land-use. Pb-isotope data, constraining the modern and industrial period, suggest accelerated sedimentation rates over this interval. On-going work attempts to calibrate proxy data with instrumental historical data.

  15. Middle Range Sea Ice Prediction System of Voyage Environmental Information System in Arctic Sea Route

    Science.gov (United States)

    Lim, H. S.

    2017-12-01

    Due to global warming, the sea ice in the Arctic Ocean is melting dramatically in summer, which is providing a new opportunity to exploit the Northern Sea Route (NSR) connecting Asia and Europe ship route. Recent increases in logistics transportation through NSR and resource development reveal the possible threats of marine pollution and marine transportation accidents without real-time navigation system. To develop a safe Voyage Environmental Information System (VEIS) for vessels operating, the Korea Institute of Ocean Science and Technology (KIOST) which is supported by the Ministry of Oceans and Fisheries, Korea has initiated the development of short-term and middle range prediction system for the sea ice concentration (SIC) and sea ice thickness (SIT) in NSR since 2014. The sea ice prediction system of VEIS consists of AMSR2 satellite composite images (a day), short-term (a week) prediction system, and middle range (a month) prediction system using a statistical method with re-analysis data (TOPAZ) and short-term predicted model data. In this study, the middle range prediction system for the SIC and SIT in NSR is calibrated with another middle range predicted atmospheric and oceanic data (NOAA CFSv2). The system predicts one month SIC and SIT on a daily basis, as validated with dynamic composite SIC data extracted from AMSR2 L2 satellite images.

  16. Recent increases in Arctic freshwater flux affects Labrador Sea convection and Atlantic overturning circulation

    Science.gov (United States)

    Yang, Qian; Dixon, Timothy H.; Myers, Paul G.; Bonin, Jennifer; Chambers, Don; van den Broeke, M. R.

    2016-01-01

    The Atlantic Meridional Overturning Circulation (AMOC) is an important component of ocean thermohaline circulation. Melting of Greenland's ice sheet is freshening the North Atlantic; however, whether the augmented freshwater flux is disrupting the AMOC is unclear. Dense Labrador Sea Water (LSW), formed by winter cooling of saline North Atlantic water and subsequent convection, is a key component of the deep southward return flow of the AMOC. Although LSW formation recently decreased, it also reached historically high values in the mid-1990s, making the connection to the freshwater flux unclear. Here we derive a new estimate of the recent freshwater flux from Greenland using updated GRACE satellite data, present new flux estimates for heat and salt from the North Atlantic into the Labrador Sea and explain recent variations in LSW formation. We suggest that changes in LSW can be directly linked to recent freshening, and suggest a possible link to AMOC weakening.

  17. Late Quaternary Palaeoceanographic Changes in Sea Surface Conditions in the Tropical Atlantic

    Science.gov (United States)

    Fischel, Andrea; Seidenkrantz, Marit-Solveig; Kuijpers, Antoon; Nürnberg, Dirk

    2013-04-01

    Palaeoceanographic changes and the variability in surface water mass hydrography are reconstructed in order to track tropical ocean and climate variability and inter-hemispheric heat exchange through the last 42,000 year BP. Our studies are based on the relative abundance of planktonic foraminifera combined with sea surface temperature approximation based Mg/Ca measurements, XRF scanning and stable oxygen isotope analyses in a 5 m long gravity core Ga307-Win-12GC (17°50.80N, 64°48.7290W), retrieved in the Virgin Island Basin in approx. 3,960 m water depth. The Virgin Island Basin is the deepest part of the Anegada-Jungfern Passage in the northeast Caribbean, one of the most important pathways for water mass exchange between the Central Atlantic and the Caribbean Sea. Due to its bathymetry surface waters as well as deep water mass strata from the northern and southern hemisphere enter the basin, comprising Caribbean Surface Water (CSW), Antarctic Intermediate Water (AAIW), Atlantic Intermediate Water (AIW) and North Atlantic Deep Water (NADW). The planktonic foraminiferal assemblage suggests rather stable sea-surface conditions during the Holocene in the NE Caribbean. However, major changes in the hydrographic setting could be identified within the glacial period. During the glacial period, clear millennial-scale variability in sea-surface temperature and productivity are present. Fluctuations in the relative abundance of Globigerinoides ruber in the sediment core may be correlated to Dansgaard-Oeschger events in the northern North Atlantic. Furthermore an increase in relative abundance of Globorotalia rubescens occurs synchronous with ice rafted debris layers described from the North Atlantic. The faunal changes in the tropical Atlantic may thus be correlated to major climate changes in the North Atlantic, mainly D-O cyclicity as well as Heinrich events. Thus, the synchronous change in water mass distribution and hydrographic cyclicity suggests a possible linkage

  18. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    OpenAIRE

    Morato, T.; Kvile, K. Ø.; Taranto, G. H.; Tempera, F.; Narayanaswamy, B. E.; Hebbeln, D.; Menezes, G. M.; Wienberg, C.; Santos, R. S.; Pitcher, T. J.

    2013-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic) and in the Medite...

  19. Seamount physiography and biology in North-East Atlantic and Mediterranean Sea

    OpenAIRE

    T. Morato; K. Ø. Kvile; G. H. Taranto; F. Tempera; B. E. Narayanaswamy; D. Hebbeln; G. Menezes; C. Wienberg; R. S. Santos; T. J. Pitcher

    2012-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (North-East Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in-situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (North-East Atlantic) and in Mediterran...

  20. Distribution by origin and sea age of Atlantic salmon (Salmo salar) in the sea around the Faroe Islands based on analysis of historical tag recoveries

    DEFF Research Database (Denmark)

    Jacobsen, Jan Arge; Hansen, Lars P.; Bakkestuen, Vegar

    2012-01-01

    Distribution by origin and sea age of Atlantic salmon (Salmo salar) in the sea around the Faroe Islands based on analysis of historical tag recoveries. – ICES Journal of Marine Science, 69: 1598–1608.A database of 2651 tags applied to Atlantic salmon (Salmo salar) smolts in 13 countries...

  1. Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; TeSlaa, Joshua L.; Jónsson, Jón Eínar; Ballard, Jennifer R.; Harms, Naomi Jane; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology. PMID:26677841

  2. Avian influenza ecology in North Atlantic sea ducks: Not all ducks are created equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; Teslaa, Joshua L.; Jónsson, Jón Einar; Ballard, Jennifer R.; Harms, Naomi Jnae; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

  3. Contrasting trends in North Atlantic deep-water formation in the Labrador Sea and Nordic Seas during the Holocene

    NARCIS (Netherlands)

    Renssen, H.; Goosse, H.; Fichefet, T.

    2005-01-01

    The Holocene North Atlantic deep-water formation is studied in a 9,000-year long simulation with a coupled climate model of intermediate complexity, forced by changes in orbital forcing and atmospheric trace gas concentrations. During the experiment, deep-water formation in the Nordic Seas is

  4. Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

    Science.gov (United States)

    Xiao, Ziniu; Li, Delin

    2016-06-01

    The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

  5. A nested Atlantic-Mediterranean Sea general circulation model for operational forecasting

    Directory of Open Access Journals (Sweden)

    P. Oddo

    2009-10-01

    Full Text Available A new numerical general circulation ocean model for the Mediterranean Sea has been implemented nested within an Atlantic general circulation model within the framework of the Marine Environment and Security for the European Area project (MERSEA, Desaubies, 2006. A 4-year twin experiment was carried out from January 2004 to December 2007 with two different models to evaluate the impact on the Mediterranean Sea circulation of open lateral boundary conditions in the Atlantic Ocean. One model considers a closed lateral boundary in a large Atlantic box and the other is nested in the same box in a global ocean circulation model. Impact was observed comparing the two simulations with independent observations: ARGO for temperature and salinity profiles and tide gauges and along-track satellite observations for the sea surface height. The improvement in the nested Atlantic-Mediterranean model with respect to the closed one is particularly evident in the salinity characteristics of the Modified Atlantic Water and in the Mediterranean sea level seasonal variability.

  6. Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic meridional overturning circulation

    NARCIS (Netherlands)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; van Werkhoven, B.J.C.; Bal, H. E.; Seinstra, F.; Maassen, J.; van Meersbergen, M.

    2014-01-01

    As an extreme scenario of dynamical sea level changes, regional sea surface height (SSH) changes that occur in the North Atlantic due to an abrupt weakening of the Atlantic meridional overturning circulation (AMOC) are simulated. Two versions of the same ocean-only model are used to study the effect

  7. 76 FR 36511 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3

    Science.gov (United States)

    2011-06-22

    ...-BA22 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3 AGENCY... the Atlantic Deep-Sea Red Crab Fishery Management Plan (FMP) (Amendment 3), incorporating a draft... current trap limit regulations state that red crab may not be harvested from gear other than a marked red...

  8. 76 FR 60379 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab; Amendment 3

    Science.gov (United States)

    2011-09-29

    .... 100903433-1531-02] RIN 0648-BA22 Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab... approved in Amendment 3 to the Atlantic Deep-Sea Red Crab Fishery Management Plan (FMP). The New England... ABC control rule.'' The NS1 guidelines further state that ``ABC may not exceed OFL,'' and that ``the...

  9. Environmental change studies in the Caspian Sea and the north-east Atlantic Ocean

    International Nuclear Information System (INIS)

    Povinec, P.; Oregioni, B.; GASTAUD, J.

    2002-01-01

    Caspian Sea and NE Atlantic water profiles were investigated for radionuclide content. Radionuclide data on the water samples collected in 1995 and 1996 in the Caspian Sea show a rapid exchange of water masses in the two deep basins (the Central and Southern Basins). The main source of radionuclides is global fallout. In the NE Atlantic Ocean elevated concentrations of 3 H and 4 C were observed at medium depths (2000-3000 m) which could be explained by high latitude injection processes. (author)

  10. Evolution of Interhemispheric Sea-Surface Temperature Contrast in the Tropical Atlantic During Termination I

    Science.gov (United States)

    Kim, J.

    2001-12-01

    Meteorological and oceanographic studies show that interannual and decadal variability in tropical Atlantic sea-surface temperature (SST) strongly influences the climates over northeast Brazil, sub-Saharan Africa, as well as the Central American and Caribbean regions. In this context, it is worthwhile to reconstruct spatial temperature patterns for the longer-term tropical Atlantic SST history. In this study, a high-resolution alkenone-derived SST record from the subtropical eastern South Atlantic (core GeoB 1023-5) is compared with one from the tropical western North Atlantic (core M35003-4). This comparison reveals synchronous SST variations between both near equatorial Atlantic regions during the Heinrich Event 1 (H1) (18-15.5 cal kyr B.P.), but dipole-like SST variations during the Younger Dryas (YD) (13-11.5 cal kyr B.P.). To assess the relationship of SST variations between both regions, we calculated SST differences between cores GeoB 1023-5 and M35003-4, and compared it with the coccolithophorid Florisphaera profunda abundance record from the equatorial eastern Atlantic (core RC24-08) as an indicator of variations in intensity of south-easterly trade winds [McIntyre and Molfino, 1996]. This comparison suggests that synchronous warming in both regions during the H1 can be attributed to a reduced northward heat transport from the warm equatorial Atlantic to the cold high-latitude North Atlantic linked to the slowdown of thermohaline circulation overturning during cold events under full glacial conditions. However, dipole-like SST variations during the YD is probably more associated with strengthened south-easterly trade winds, which led to a strong upwelling-related cooling in the eastern South Atlantic region and concurrently enhanced advection of warm subtropical South Atlantic waters to the tropical western Atlantic during that time. Accordingly, a coupled oceanic-atmospheric process created a warm pool in the tropical western Atlantic and thus a dipole

  11. Climate drift of AMOC, North Atlantic salinity and arctic sea ice in CFSv2 decadal predictions

    Science.gov (United States)

    Huang, Bohua; Zhu, Jieshun; Marx, Lawrence; Wu, Xingren; Kumar, Arun; Hu, Zeng-Zhen; Balmaseda, Magdalena A.; Zhang, Shaoqing; Lu, Jian; Schneider, Edwin K.; Kinter, James L., III

    2015-01-01

    There are potential advantages to extending operational seasonal forecast models to predict decadal variability but major efforts are required to assess the model fidelity for this task. In this study, we examine the North Atlantic climate simulated by the NCEP Climate Forecast System, version 2 (CFSv2), using a set of ensemble decadal hindcasts and several 30-year simulations initialized from realistic ocean-atmosphere states. It is found that a substantial climate drift occurs in the first few years of the CFSv2 hindcasts, which represents a major systematic bias and may seriously affect the model's fidelity for decadal prediction. In particular, it is noted that a major reduction of the upper ocean salinity in the northern North Atlantic weakens the Atlantic meridional overturning circulation (AMOC) significantly. This freshening is likely caused by the excessive freshwater transport from the Arctic Ocean and weakened subtropical water transport by the North Atlantic Current. A potential source of the excessive freshwater is the quick melting of sea ice, which also causes unrealistically thin ice cover in the Arctic Ocean. Our sensitivity experiments with adjusted sea ice albedo parameters produce a sustainable ice cover with realistic thickness distribution. It also leads to a moderate increase of the AMOC strength. This study suggests that a realistic freshwater balance, including a proper sea ice feedback, is crucial for simulating the North Atlantic climate and its variability.

  12. Trophic impact of Atlantic bluefin tuna migrations in the North Sea

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Andersen, Ken Haste; Lindegren, Martin

    2017-01-01

    and the stability of the fish community. The impact of a migrating top-predator is investigated here for Atlantic bluefin tuna in the North Sea. Bluefin tuna has been absent from the region for half-century, but recent years have seen recovery of migrations and a return of bluefin tuna in the area. We use a size...

  13. 76 FR 23940 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 22

    Science.gov (United States)

    2011-04-29

    ... the LA fleet, Amendment 15 proposes a management uncertainty buffer based on the F associated with a... to implement Framework Adjustment 22 (Framework 22) to the Atlantic Sea Scallop Fishery Management Plan (FMP), which was developed and adopted by the New England Fishery Management Council (Council) and...

  14. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    T. Morato

    2013-05-01

    Full Text Available This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km2 in the OSPAR region and of about 89 500 km2 in the Mediterranean Sea. The presence of seamounts in the north-east Atlantic has been known since the late 19th century, but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5% of all seamounts in the region, 22 in the Mediterranean Sea (9.2% of all seamounts in the region and 25 in the north-east Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.

  15. Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

    DEFF Research Database (Denmark)

    Salt, Lesley A.; Thomas, Helmuth; Prowe, Friederike

    2013-01-01

    [1] High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO2 system...... of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive...... observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead...

  16. Astronomically paced middle Eocene deepwater circulation in the western North Atlantic

    Science.gov (United States)

    Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Lohmann, Gerrit; Pälike, Heiko; Zachos, James C.

    2017-04-01

    The role of the Atlantic Meridional Overturning Circulation (AMOC) as a key player for abrupt climatic changes (e.g. Heinrich Stadials) during the Pleistocene is relatively well constrained. However, the timing of the onset of a „modern" North Atlantic Deepwater (NADW) formation are still debated: Recent estimates range from the middle Miocene to the Early Eocene [Davies et al., 2001, Stoker et al., 2005, Hohbein et al., 2012] and are mainly based on the seismic interpretation contourite drifts. Another understudied aspect of the AMOC is its behavior during climatic variations on orbital time scales and under different climatic boundary conditions (icehouse vs hothouse). IODP Expedition 342 drilled carbonate-rich sequences from sediment drifts offshore Newfoundland that cover the middle Eocene with high sedimentation rates ( 3 cm/ kyr). We present a 2 Myr long stable carbon and oxygen isotope record of benthic foraminifera nuttalides truempyi spanning magnetochron C20r in unprecedented resolution (Petroleum Geology, v. 22, no. 9, p. 977-1005. Hohbein, M. W., Sexton, P. F., and Cartwright, J. A., 2012, Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend: Geology, v. 40, no. 3, p. 255-258.

  17. Interannual-to-decadal air-sea interactions in the tropical Atlantic region

    Science.gov (United States)

    Ruiz-Barradas, Alfredo

    2001-09-01

    The present research identifies modes of atmosphere-ocean interaction in the tropical Atlantic region and the mechanisms by which air-sea interactions influence the regional climate. Novelties of the present work are (1)the use of relevant ocean and atmosphere variables important to identity coupled variability in the system. (2)The use of new data sets, including realistic diabatic heating. (3)The study of interactions between ocean and atmosphere relevant at interannual-to-decadal time scales. Two tropical modes of variability are identified during the period 1958-1993, the Atlantic Niño mode and the Interhemispheric mode. Those modes have defined structures in both ocean and atmosphere. Anomalous sea surface temperatures and winds are associated to anomalous placement of the Intertropical Convergence Zone (ITCZ). They develop maximum amplitude during boreal summer and spring, respectively. The anomalous positioning of the ITCZ produces anomalous precipitation in some places like Nordeste, Brazil and the Caribbean region. Through the use of a diagnostic primitive equation model, it is found that the most important terms controlling local anomalous surface winds over the ocean are boundary layer temperature gradients and diabatic heating anomalies at low levels (below 780 mb). The latter is of particular importance in the deep tropics in producing the anomalous meridional response to the surface circulation. Simulated latent heat anomalies indicate that a thermodynamic feedback establishes positive feedbacks at both sides of the equator and west of 20°W in the deep tropics and a negative feedback in front of the north west coast of Africa for the Interhemispheric mode. This thermodynamic feedback only establishes negative feedbacks for the Atlantic Niño mode. Transients establish some connection between the tropical Atlantic and other basins. Interhemispheric gradients of surface temperature in the tropical Atlantic influence winds in the midlatitude North

  18. Influence of Atlantic on the warming and reduction of sea ice in the Arctic

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2017-01-01

    Full Text Available Influence of anomalies of the sea surface temperature (SST in low latitudes of the North Atlantic on the sea ice cover and the near-surface air temperature in the marine Arctic is discussed in the article. Data on the SST in the Atlantic Ocean from the HadISST dataset, climatic series of the water temperature at the section along the Kola meridian together with mean monthly data on the sea ice extent and the air surface temperature in the Maritime Arctic and the Northern hemisphere were analyzed. Multivariate cross-correlation analysis was applied to determine the maximum correlation coefficients between the SST anomalies, climate characteristics and their corresponding delays within time limits of 33 to 38 months. Existence of intimate link had been found between changes of the Atlantic SST in low latitudes and the sea ice extent in the Arctic with correlation coefficients up to 0.90 and delays up to 3 years. A mechanism of formation of the remote influence of low-latitude SST anomalies on the sea ice anomalies in the Arctic Ocean is proposed. The interpretation of this mechanism includes into consideration the interaction between atmospheric and oceanic circulation modes.

  19. Variations of Sea Surface Temperature, Wind Stress, and Rainfall over the Tropical Atlantic and South America.

    Science.gov (United States)

    Nobre, Paulo; Srukla, J.

    1996-10-01

    Empirical orthogonal functions (E0Fs) and composite analyses are used to investigate the development of sea surface temperature (SST) anomaly patterns over the tropical Atlantic. The evolution of large-scale rainfall anomaly patterns over the equatorial Atlantic and South America are also investigated. 71e EOF analyses revealed that a pattern of anomalous SST and wind stress asymmetric relative to the equator is the dominant mode of interannual and longer variability over the tropical Atlantic. The most important findings of this study are as follows.Atmospheric circulation anomalies precede the development of basinwide anomalous SST patterns over the tropical Atlantic. Anomalous SST originate off the African coast simultaneously with atmospheric circulation anomalies and expand westward afterward. The time lag between wind stress relaxation (strengthening) and maximum SST warming (cooling) is about two months.Anomalous atmospheric circulation patterns over northern tropical Atlantic are phase locked to the seasonal cycle. Composite fields of SLP and wind stress over northern tropical Atlantic can be distinguished from random only within a few months preceding the March-May (MAM) season. Observational evidence is presented to show that the El Niño-Southern Oscillation phenomenon in the Pacific influences atmospheric circulation and SST anomalies over northern tropical Atlantic through atmospheric teleconnection patterns into higher latitudes of the Northern Hemisphere.The well-known droughts over northeastern Brazil (Nordeste) are a local manifestation of a much larger-scale rainfall anomaly pattern encompassing the whole equatorial Atlantic and Amazon region. Negative rainfall anomalies to the south of the equator during MAM, which is the rainy season for the Nordeste region, are related to an early withdrawal of the intertropical convergence zone toward the warm SST anomalies over the northern tropical Atlantic. Also, it is shown that precipitation anomalies

  20. Sea surface temperature and sea ice variability in the subpolar North Atlantic from explosive volcanism of the late thirteenth century

    DEFF Research Database (Denmark)

    Sicre, M. -A.; Khodri, M.; Mignot, J.

    2013-01-01

    In this study, we use IP25 and alkenone biomarker proxies to document the subdecadal variations of sea ice and sea surface temperature in the subpolar North Atlantic induced by the decadally paced explosive tropical volcanic eruptions of the second half of the thirteenth century. The short-and long......-term evolutions of both variables were investigated by cross analysis with a simulation of the IPSL-CM5A LR model. Our results show short-term ocean cooling and sea ice expansion in response to each volcanic eruption. They also highlight that the long response time of the ocean leads to cumulative surface cooling...... and subsurface heat buildup due to sea ice capping. As volcanic forcing relaxes, the surface ocean rapidly warms, likely amplified by subsurface heat, and remains almost ice free for several decades....

  1. 2 - 4 million years of sedimentary processes in the Labrador Sea: implication for North Atlantic stratigraphy

    Science.gov (United States)

    Mosher, D. C.; Saint-Ange, F.; Campbell, C.; Piper, D. J.

    2012-12-01

    Marine sedimentary records from the western North Atlantic show that a significant portion of sediment deposited since the Pliocene originated from the Canadian Shield. In the Labrador Sea, previous studies have shown that bottom currents .strongly influenced sedimentation during the Pliocene, while during the Quaternary, intensification of turbidity current flows related to meltwater events were a dominant factor in supplying sediment to the basin and in the development of the North Atlantic Mid-Ocean Channel (NAMOC). Despite understanding this general pattern of sediment flux, details regarding the transfer of sediment from the Labrador Shelf to deep water and from the Labrador Sea to the North Atlantic remain poorly understood. Our study focuses on sedimentary processes occurring along the Labrador margin since the Pliocene and their consequences on the margin architecture, connection to the NAMOC, and role in sediment flux from the Labrador basin to the Sohm Abyssal Plain. Piston core and high resolution seismic data reveal that during the Pliocene to mid Pleistocene, widespread slope failures led to mass transport deposition along the entire Labrador continental slope. After the mid Pleistocene, sedimentation along the margin was dominated by the combined effects of glaciation and active bottom currents. On the shelf, prograded sedimentary wedges filled troughs and agraded till sheets form intervening banks. On the slope, stacked glaciogenic fans developed seaward of transverse troughs between 400 and 2800 mbsl. On the lower slope, seismic data show thick sediment drifts capped by glacio-marine mud. This unit is draped by well stratified sediment and marks a switch from a contourite dominated regime to a turbidite dominated regime. This shift occurred around 0.5 - 0.8 ka and correlates to the intensification of glaciations. Late Pleistocene sediments on the upper slope consist of stratified sediments related to proglacial plume fall-out. Coarse grained

  2. Geochemistry of Slow-Growing Corals: Reconstructing Sea Surface Temperature, Salinity and the North Atlantic Oscillation

    Science.gov (United States)

    2007-06-01

    Number 8, October 1989) The island of Bermuda (64°W, 32°N) (Fig. 1.3) located in the western sub- tropical Atlantic is an excellent location for examining...lobata at Clipperton Atoll, Coral Reefv, 18, 13-27, 1999. Lough, J. M., A strategy to improve the contribution of coral data to high-resolution...to evaluate winter Sr/Ca. The island of Bermuda (64°W, 32°N) is located in the Sargasso Sea in the sub-tropical North Atlantic. This site is

  3. Temperature, salinity, oxygen and nutrients bottle and CTD data collected in the northern North Atlantic, Nordic and Arctic Seas from 1901 to 2011 (NODC Accession 0105532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen and nutrients bottle and CTD data collected in the Arctic Ocean, Barents Sea, Greenland Sea, Kara Sea, North Atlantic Ocean,...

  4. Bacterial diversity and biogeography in deep-sea sediments of the South Atlantic Ocean

    DEFF Research Database (Denmark)

    Schauer, Regina; Bienhold, Christina; Ramette, Alban

    2010-01-01

    in 1051 sequences. Phylotypes affiliated with Gammaproteobacteria, Deltaproteobacteria and Acidobacteria were present in all three basins. The distribution of these shared phylotypes seemed to be influenced neither by the Walvis Ridge nor by different deep water masses, suggesting a high dispersal......Microbial biogeographic patterns in the deep sea depend on the ability of microorganisms to disperse. One possible limitation to microbial dispersal may be the Walvis Ridge that separates the Antarctic Lower Circumpolar Deep Water from the North Atlantic Deep Water. We examined bacterial...... communities in three basins of the eastern South Atlantic Ocean to determine diversity and biogeography of bacterial communities in deep-sea surface sediments. The analysis of 16S ribosomal RNA (rRNA) gene clone libraries in each basin revealed a high diversity, representing 521 phylotypes with 98% identity...

  5. Simulated North Atlantic-Nordic Seas water mass exchanges in an isopycnic coordinate OGCM

    OpenAIRE

    Nilsen, Jan Even Øie; Gao, Yongqi; Drange, Helge; Furevik, Tore; Bentsen, Mats

    2003-01-01

    The variability in the volume exchanges between the North Atlantic and the Nordic Seas during the last 50 years is investigated using a synoptic forced, global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The simulated volume fluxes agree with the existing observations. The net volume flux across the Faroe-Shetland Channel (FSC) is positively correlated with the net flux through the Denmark Strait (DS; R = 0.74 for 3 years low pass filtering), but negatively correlated with ...

  6. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic

    Science.gov (United States)

    Bjorndal, Karen A.; Bolten, Alan B.; Chaloupka, Milani; Saba, Vincent S.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Santos, Armando J.B.; Bortolon, Luis Felipe Wurdig; Meylan, Anne B.; Meylan, Peter A.; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C.; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E.; van Dam, Robert P.; Willis, Sue; Nava, Mabel; Hart, Kristen M.; Cherkiss, Michael S.; Crowder, Andrew; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A.; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M.; Foley, Allen M.; Bailey, Rhonda; Carthy, Raymond R.; Scarpino, Russell; McMichael, Erin; Provancha, Jane A.; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M.; Boulon, Ralf H.; Collazo, Jaime; Wershoven, Robert; Hernández, Vicente Guzmán; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Metz, Tasha L.; Gordon, Amanda L.; Landry, Andre M.; Shaver, Donna J.; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J.; McGowan, Andrew; Witt, Matthew J.; Campbell, Cathi L.; Lagueux, Cynthia J.; Bethel, Thomas L.; Kenyon, Lory

    2017-01-01

    Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles – hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta – exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO) – the strongest on record – combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -0.94) and the Multivariate ENSO Index (MEI) for all years (r = 0.74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study

  7. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic.

    Science.gov (United States)

    Bjorndal, Karen A; Bolten, Alan B; Chaloupka, Milani; Saba, Vincent S; Bellini, Cláudio; Marcovaldi, Maria A G; Santos, Armando J B; Bortolon, Luis Felipe Wurdig; Meylan, Anne B; Meylan, Peter A; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E; van Dam, Robert P; Willis, Sue; Nava, Mabel; Hart, Kristen M; Cherkiss, Michael S; Crowder, Andrew G; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M; Foley, Allen M; Bailey, Rhonda; Carthy, Raymond R; Scarpino, Russell; McMichael, Erin; Provancha, Jane A; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M; Boulon, Ralf H; Collazo, Jaime A; Wershoven, Robert; Guzmán Hernández, Vicente; Stringell, Thomas B; Sanghera, Amdeep; Richardson, Peter B; Broderick, Annette C; Phillips, Quinton; Calosso, Marta; Claydon, John A B; Metz, Tasha L; Gordon, Amanda L; Landry, Andre M; Shaver, Donna J; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J; McGowan, Andrew; Witt, Matthew J; Campbell, Cathi L; Lagueux, Cynthia J; Bethel, Thomas L; Kenyon, Lory

    2017-11-01

    Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the

  8. Oceanic fronts in the Sargasso Sea control the early life and drift of Atlantic eels

    DEFF Research Database (Denmark)

    Munk, Peter; Hansen, Michael Møller; Maas, Gregory E.

    2010-01-01

    Anguillid freshwater eels show remarkable life histories. In the Atlantic, the European eel (Anguilla anguilla) and American eel (Anguilla rostrata) undertake extensive migrations to spawn in the oceanic Sargasso Sea, and subsequently the offspring drift to foraging areas in Europe and North......, during a field expedition to the eel spawning sites in the Sargasso Sea, we carried out a wide range of dedicated bio-physical studies across areas of eel larval distribution. Our findings suggest a key role of oceanic frontal processes, retaining eel larvae within a zone of enhanced feeding conditions...

  9. A field efficacy evaluation of emamectin benzoate for the control of sea lice on Atlantic salmon.

    Science.gov (United States)

    Armstrong, R; MacPhee, D; Katz, T; Endris, R

    2000-08-01

    This study evaluated the efficacy of emamectin benzoate, 0.2% aquaculture premix, against sea lice on Atlantic salmon in eastern Canada. Salmon pens received either emamectin benzoate, orally, in feed at 50 micrograms/kg body weight/day for 7 consecutive days, or the same diet with no added medication. The site veterinarian had the option of administering a bath treatment with azamethiphos to any pen in the trial. The mean number of lice per fish was lower (P emamectin benzoate was palatable and highly effective for control of sea lice on salmon.

  10. North Atlantic teleconnection patterns signature on sea level from satellite altimetry

    Science.gov (United States)

    Iglesias, Isabel; Lázaro, Clara; Joana Fernandes, M.; Bastos, Luísa

    2015-04-01

    Presently, satellite altimetry record is long enough to appropriately study inter-annual signals in sea level anomaly and ocean surface circulation, allowing the association of teleconnection patterns of low-frequency variability with the response of sea level. The variability of the Atlantic Ocean at basin-scale is known to be complex in space and time, with the dominant mode occurring on annual timescales. However, interannual and decadal variability have already been documented in sea surface temperature. Both modes are believed to be linked and are known to influence sea level along coastal regions. The analysis of the sea level multiannual variability is thus essential to understand the present climate and its long-term variability. While in the open-ocean sea level anomaly from satellite altimetry currently possesses centimetre-level accuracy, satellite altimetry measurements become invalid or of lower accuracy along the coast due to the invalidity of the wet tropospheric correction (WTC) derived from on-board microwave radiometers. In order to adequately analyse long-term changes in sea level in the coastal regions, satellite altimetry measurements can be recovered by using an improved WTC computed from recent algorithms that combine wet path delays from all available observations (remote sensing scanning imaging radiometers, GNSS stations, microwave radiometers on-board satellite altimetry missions and numerical weather models). In this study, a 20-year (1993-2013) time series of multi-mission satellite altimetry (TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1/2, ENVISAT, CryoSat-2 and SARAL), are used to characterize the North Atlantic (NA) long-term variability on sea level at basin-scale and analyse its response to several atmospheric teleconnections known to operate on the NA. The altimetry record was generated using an improved coastal WTC computed from either the GNSS-derived path Delay or the Data Combination methodologies developed by University of

  11. The Sea Stacks Project: Enhancing the Use of Regional Literature in Atlantic Canadian Schools

    Directory of Open Access Journals (Sweden)

    Vivian Howard

    2012-06-01

    Full Text Available Research over the past two decades has amply demonstrated the importance of literature to the formation of both regional and national cultural identity, particularly in the face of mass market globalization of children’s book publishing in the 21st century as well as the predominance of non-Canadian content from television, movies, books, magazines and internet media. However, Canadian children appear to have only very limited exposure to Canadian authors and illustrators. In Atlantic Canada, regional Atlantic Canadian authors and illustrators for children receive very limited critical attention, and resources for the study and teaching of Atlantic Canadian children’s literature are few. Print and digital information sources on regional children’s books, publishing, authors and illustrators are scattered and inconsistent in quality and currency. This research project directly addresses these key concerns by summarizing the findings of a survey of Atlantic Canadian teachers on their use of regional books. In response to survey findings, the paper concludes by describing the creation of the Sea Stacks Project an authoritative web-delivered information resource devoted to contemporary Atlantic Canadian literature for children and teens.

  12. Topex-Poseidon analysis of sea level variability over the Atlantic Ocean

    Science.gov (United States)

    Catalan P-U, M.; Villares, P.; Catalan, M.; Gomez-Enri, J.

    2003-04-01

    The variability of sea level and surface geostrophic currents in Atlantic Ocean is investigated using 333 cycles of altimeter information obtained by TOPEX-POSEIDON satellite. After the improvements of orbit accuracy, the most important concern to studies of sea level variability from altimeter height data are related with the formalism used for modelling the altimetric measurement corrections. Presently, one of the main sources of potential error is the correction for atmospheric pressure loading, the so-called ‘inverse barometer effect’. As is well known, this correction is intended to adjust the sea surface elevation for the static effects of the downward force of the mass of the atmosphere on the sea surface, adjusted, in this oversimplified model in 1cm/mbar. The exact response of the sea surface to atmospheric pressure loading depends on the space and time scales of the pressure field and must be specially a concern at high latitudes where atmospheric pressure fluctuations are large due to the intensity of low pressure fields at these latitudes and the additional uncertainty in the model estimates of the local sea level pressure. To study these effects over the whole Atlantic Ocean we compute a linear regression adjustment and an Empirical Orthogonal Functions Decomposition (EOFD), between sea level variation without inverse barometer correction and the atmospheric pressure, in all the Topex-Poseidon cross points over the whole Atlantic, including both the Artic and Antarctic Oceans. We use the barometric factor computed from the linear regression to correct the satellite mean sea level variation, comparing the correlation with the pressure. Our results show an important improvement in the decorrelation between sea level and atmospheric pressure time series, compared with the use of Inverse Barometer model, at most of the satellite cross points. The complicated nature of sea level variability at high latitudes justify that EOFD analysis conclusions

  13. Algorithm Development and Validation for Satellite-Derived Distributions of DOC and CDOM in the US Middle Atlantic Bight

    Science.gov (United States)

    Mannino, Antonio; Russ, Mary E.; Hooker, Stanford B.

    2007-01-01

    In coastal ocean waters, distributions of dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) vary seasonally and interannually due to multiple source inputs and removal processes. We conducted several oceanographic cruises within the continental margin of the U.S. Middle Atlantic Bight (MAB) to collect field measurements in order to develop algorithms to retrieve CDOM and DOC from NASA's MODIS-Aqua and SeaWiFS satellite sensors. In order to develop empirical algorithms for CDOM and DOC, we correlated the CDOM absorption coefficient (a(sub cdom)) with in situ radiometry (remote sensing reflectance, Rrs, band ratios) and then correlated DOC to Rrs band ratios through the CDOM to DOC relationships. Our validation analyses demonstrate successful retrieval of DOC and CDOM from coastal ocean waters using the MODIS-Aqua and SeaWiFS satellite sensors with mean absolute percent differences from field measurements of cdom)(355)1,6 % for a(sub cdom)(443), and 12% for the CDOM spectral slope. To our knowledge, the algorithms presented here represent the first validated algorithms for satellite retrieval of a(sub cdom) DOC, and CDOM spectral slope in the coastal ocean. The satellite-derived DOC and a(sub cdom) products demonstrate the seasonal net ecosystem production of DOC and photooxidation of CDOM from spring to fall. With accurate satellite retrievals of CDOM and DOC, we will be able to apply satellite observations to investigate interannual and decadal-scale variability in surface CDOM and DOC within continental margins and monitor impacts of climate change and anthropogenic activities on coastal ecosystems.

  14. Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic

    Science.gov (United States)

    Gardner, B.; Sullivan, P.J.; Epperly, S.; Morreale, S.J.

    2008-01-01

    Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water temperature, region, bottom depth, and target species are all significant predictors of the number of loggerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit. ?? Inter-Research 2008.

  15. The Caspian Sea Catchment influenced by Atlantic Teleconnections in CESM1.2.2 and Observations

    Science.gov (United States)

    Nandini, S. D.; Prange, M.; Schulz, M.

    2017-12-01

    The Caspian Sea (CS) is the world's largest inland sea and located within a closed (endorheic) drainage basin [ 37°-47N, 47°-54°E]. It has undergone dynamic variations (>3 m) during the past century with huge impacts on the economy, ecosystem and livelihood of coastal people. The origin of these variations as well as future changes are disputable. Here, we examine the impact of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO) and the East Atlantic pattern (EA) on Caspian hydroclimate variability from 1850-2100 CE. Five Numerical experiments at different atmospheric grid resolutions (2° and 1°) and atmospheric model versions (CAM4 and CAM5) are carried out with the coupled Community Earth System Model (CESM1.2.2). Results reveal the 1° CESM1.2.2 CAM5 captures DJF NAO (46.5%) and EA (13.4%), agreeing well with observational data (1850-2000). The DJF NAO has a strong influence on the DJF temperature, rainfall and evaporation minus precipitation (E-P) over the Caspian sub-basins (Volga, Ural, Terek and Kura). Furthermore, 1° model climate projections (2020-2100 CE) are performed with different Representative Concentration Pathways (RCP4.5 and RCP8.5) to examine likely changes in the NAO and EA and their influence on the Caspian catchment. The NAO under the RCP4.5 and RCP8.5 scenarios remains the leading mode with the highest variance and influences E-P with increased precipitation over the Volga basin and increased evaporation over the Caspian Sea. The above canceling effects act on the hydroclimate variability in the Caspian sub-basins. Moreover, it is indicated that no substantial change is predicted in the CSL by the year 2100. Keywords: North Atlantic Oscillation (NAO), CESM1.2.2 resolutions, Evaporation minus Precipitation (E-P), RCP4.5, RCP8.5

  16. Bathymetric controls on Pliocene North Atlantic and Arctic sea surface temperature and deepwater production

    Science.gov (United States)

    Robinson, M.M.; Valdes, P.J.; Haywood, A.M.; Dowsett, H.J.; Hill, D.J.; Jones, S.M.

    2011-01-01

    The mid-Pliocene warm period (MPWP; ~. 3.3 to 3.0. Ma) is the most recent interval in Earth's history in which global temperatures reached and remained at levels similar to those projected for the near future. The distribution of global warmth, however, was different than today in that the high latitudes warmed more than the tropics. Multiple temperature proxies indicate significant sea surface warming in the North Atlantic and Arctic Oceans during the MPWP, but predictions from a fully coupled ocean-atmosphere model (HadCM3) have so far been unable to fully predict the large scale of sea surface warming in the high latitudes. If climate proxies accurately represent Pliocene conditions, and if no weakness exists in the physics of the model, then model boundary conditions may be in error. Here we alter a single boundary condition (bathymetry) to examine if Pliocene high latitude warming was aided by an increase in poleward heat transport due to changes in the subsidence of North Atlantic Ocean ridges. We find an increase in both Arctic sea surface temperature and deepwater production in model experiments that incorporate a deepened Greenland-Scotland Ridge. These results offer both a mechanism for the warming in the North Atlantic and Arctic Oceans indicated by numerous proxies and an explanation for the apparent disparity between proxy data and model simulations of Pliocene northern North Atlantic and Arctic Ocean conditions. Determining the causes of Pliocene warmth remains critical to fully understanding comparisons of the Pliocene warm period to possible future climate change scenarios. ?? 2011.

  17. The sea-level budget along the Northwest Atlantic coast : GIA, mass changes, and large-scale ocean dynamics

    NARCIS (Netherlands)

    Frederikse, T.; Simon, K.M.; Katsman, C.A.; Riva, R.E.M.

    2017-01-01

    Sea-level rise and decadal variability along the northwestern coast of the North Atlantic Ocean are studied in a self-consistent framework that takes into account the effects of solid-earth deformation and geoid changes due to large-scale mass redistribution processes. Observations of sea and

  18. 77 FR 28305 - Temporary Rule To Delay Start Date of 2012-2013 South Atlantic Black Sea Bass Commercial Fishing...

    Science.gov (United States)

    2012-05-14

    .... 120501426-2426-01] RIN 0648-BB98 Temporary Rule To Delay Start Date of 2012-2013 South Atlantic Black Sea... this temporary rule to delay the start date of the 2012-2013 fishing season for the commercial black... temporary rule delays the start date of the 2012-2013 commercial fishing season for black sea bass from June...

  19. Marketing Strategies Used to Promote Master of Business Administration Programs in Colleges and Universities in the Middle Atlantic Region.

    Science.gov (United States)

    Sable, Paul F.

    Enrollments in Masters of Business Administration (MBA) programs and the use and effectiveness of marketing techniques for managing MBA enrollments were investigated in 1984. A 94-item questionnaire completed by 56 MBA programs offered at colleges and universities in the Middle Atlantic States addressed administration, awareness of marketing and…

  20. Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr

    Directory of Open Access Journals (Sweden)

    C. V. Dylmer

    2013-07-01

    Full Text Available Three marine sediment cores distributed along the Norwegian (MD95-2011, Barents Sea (JM09-KA11-GC, and Svalbard (HH11-134-BC continental margins have been investigated in order to reconstruct changes in the poleward flow of Atlantic waters (AW and in the nature of upper surface water masses within the eastern Nordic Seas over the last 3000 yr. These reconstructions are based on a limited set of coccolith proxies: the abundance ratio between Emiliania huxleyi and Coccolithus pelagicus, an index of Atlantic vs. Polar/Arctic surface water masses; and Gephyrocapsa muellerae, a drifted coccolith species from the temperate North Atlantic, whose abundance changes are related to variations in the strength of the North Atlantic Current. The entire investigated area, from 66 to 77° N, was affected by an overall increase in AW flow from 3000 cal yr BP (before present to the present. The long-term modulation of westerlies' strength and location, which are essentially driven by the dominant mode of the North Atlantic Oscillation (NAO, is thought to explain the observed dynamics of poleward AW flow. The same mechanism also reconciles the recorded opposite zonal shifts in the location of the Arctic front between the area off western Norway and the western Barents Sea–eastern Fram Strait region. The Little Ice Age (LIA was governed by deteriorating conditions, with Arctic/Polar waters dominating in the surface off western Svalbard and western Barents Sea, possibly associated with both severe sea ice conditions and a strongly reduced AW strength. A sudden short pulse of resumed high WSC (West Spitsbergen Current flow interrupted this cold spell in eastern Fram Strait from 330 to 410 cal yr BP. Our dataset not only confirms the high amplitude warming of surface waters at the turn of the 19th century off western Svalbard, it also shows that such a warming was primarily induced by an excess flow of AW which stands as unprecedented over the last 3000 yr.

  1. Linking The Atlantic Gyres: Warm, Saline Intrusions From Subtropical Atlantic to the Nordic Seas

    Science.gov (United States)

    Hakkinen, Sirpa M.; Rhines, P. B.

    2010-01-01

    Ocean state estimates from SODA assimilation are analyzed to understand how major shifts in the North Atlantic Current path relate to AMOC, and how these shifts are related to large scale ocean circulation and surface forcing. These complement surface-drifter and altimetry data showing the same events. SODA data indicate that the warm water limb of AMOC, reaching to at least 600m depth, expanded in density/salinity space greatly after 1995, and that Similar events occurred in the late 1960s and around 1980. While there were large changes in the upper limb, there was no immediate response in the dense return flow, at least not in SODA, however one would expect a delayed response of increasing AMOC due to the positive feedback from increased salt transport. These upper limb changes are winddriven, involving changes in the eastern subpolar gyre, visible in the subduction of low potential vorticity waters. The subtropical gyre has been weak during the times of the northward intrusions of the highly saline subtropical waters, while the NAO index has been neutral or in a negative phase. The image of subtropical/subpolar gyre exchange through teleconnections within the AMOC overturning cell will be described.

  2. Post-Glacial Development of Western North Atlantic - Labrador Sea Oceanographic Circulation

    DEFF Research Database (Denmark)

    Sheldon, Christina

    2015-01-01

    The subpolar North Atlantic Ocean – Labrador Sea region is an important site for both oceanographic and atmospheric circulation. The convergence of ocean currents causes downwelling of cold, saline water in the subpolar gyre, helping to drive the world-wide thermohaline circulation system. The main......, the subpolar gyre weakened, which carried less Gulf Stream-derived water to the western North Atlantic Ocean via the West Greenland Current and the Slopewater Current, south of Newfoundland. Changes in the subpolar gyre circulation had developed to be analogous to the modern climate by approximately 2 cal kyr...... surface currents involved in the gyre are the south-flowing, cold and relatively fresh Labrador Current and the north-flowing, warm and relatively saline Gulf Stream. The oceanic front between these two major currents moves north and south, dependent on the relative strengths of the currents, impacting...

  3. Splitting of Atlantic water transport towards the Arctic Ocean into the Fram Strait and Barents Sea Branches - mechanisms and consequences

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Skagseth, Øystein; von Appen, Wilken-Jon; Walczowski, Waldemar; Lien, Vidar

    2016-04-01

    The heat content in the Arctic Ocean is to a large extent determined by oceanic advection from the south. During the last two decades the extraordinary warm Atlantic water (AW) inflow has been reported to progress through the Nordic Seas into the Arctic Ocean. Warm anomalies can result from higher air temperatures (smaller heat loss) in the Nordic Seas, and/or from an increased oceanic advection. But the ultimate fate of warm anomalies of Atlantic origin depends strongly on their two possible pathways towards the Arctic Ocean. The AW temperature changes from 7-10°C at the entrance to the Nordic Seas, to 6-6.5°C in the Barents Sea opening and 3-3.5°C as the AW leaving Fram Strait enters the Arctic Ocean. When AW passes through the shallow Barents Sea, nearly all its heat is lost due to atmospheric cooling and AW looses its signature. In the deep Fram Strait the upper part of Atlantic water becomes transformed into a less saline and colder surface layer and thus AW preserves its warm core. A significant warming and high variability of AW volume transport was observed in two recent decades in the West Spitsbergen Current, representing the Fram Strait Branch of Atlantic inflow. The AW inflow through Fram Strait carries between 26 and 50 TW of heat into the Arctic Ocean. While the oceanic heat influx to the Barents Sea is of a similar order, the heat leaving it through the northern exit into the Arctic Ocean is negligible. The relative strength of two Atlantic water branches through Fram Strait and the Barents Sea governs the oceanic heat transport into the Arctic Ocean. According to recently proposed mechanism, the Atlantic water flow in the Barents Sea Branch is controlled by the strength of atmospheric low over the northern Barents Sea, acting through a wind-induced Ekman divergence, which intensifies eastward AW flow. The Atlantic water transport in the Fram Strait Branch is mainly forced by the large-scale low-pressure system over the eastern Norwegian and

  4. PBDEs in the atmosphere over the Asian marginal seas, and the Indian and Atlantic oceans

    Science.gov (United States)

    Li, Jun; Li, Qilu; Gioia, Rosalinda; Zhang, Yanlin; Zhang, Gan; Li, Xiangdong; Spiro, Baruch; Bhatia, Ravinder S.; Jones, Kevin C.

    2011-12-01

    Air samples were collected from Jan 16 to Mar 14, 2008 onboard the Oceanic II- The Scholar Ship which navigated an east-west transect from Shanghai to Cape Verde, and polybrominated diphenyl ethers (PBDEs) were analyzed in these samples. PBDE concentrations in the atmosphere over the open seas were influenced by proximity to source areas and land, and air mass origins. The concentrations of Σ 21PBDEs over the East and South China Seas, the Bay of Bengal and the Andaman Sea, the Indian Ocean, and the Atlantic Ocean were 10.8 ± 6.13, 3.22 ± 1.57, 5.12 ± 3.56, and 2.87 ± 1.81 pg m -3, respectively. BDE-47 and -99 were the dominant congeners in all the samples, suggesting that the widely used commercial penta-BDE products were the original sources. Over some parts of Atlantic and Indian Ocean, daytime concentrations of BDE-47 and BDE-99 were higher than the concentrations at night. The strong atmospheric variability does not always coincide with a diurnal cycle, but the variability in air concentrations in such remote areas of the ocean remains strong. No significant trends were found for each of PBDE congener with latitude.

  5. The influence of the Atlantic Warm Pool on the Florida panhandle sea breeze

    Science.gov (United States)

    Misra, Vasubandhu; Moeller, Lauren; Stefanova, Lydia; Chan, Steven; O'Brien, James J.; Smith, Thomas J.; Plant, Nathaniel

    2011-01-01

    In this paper we examine the variations of the boreal summer season sea breeze circulation along the Florida panhandle coast from relatively high resolution (10 km) regional climate model integrations. The 23 year climatology (1979–2001) of the multidecadal dynamically downscaled simulations forced by the National Centers for Environmental Prediction–Department of Energy (NCEP-DOE) Reanalysis II at the lateral boundaries verify quite well with the observed climatology. The variations at diurnal and interannual time scales are also well simulated with respect to the observations. We show from composite analyses made from these downscaled simulations that sea breezes in northwestern Florida are associated with changes in the size of the Atlantic Warm Pool (AWP) on interannual time scales. In large AWP years when the North Atlantic Subtropical High becomes weaker and moves further eastward relative to the small AWP years, a large part of the southeast U.S. including Florida comes under the influence of relatively strong anomalous low-level northerly flow and large-scale subsidence consistent with the theory of the Sverdrup balance. This tends to suppress the diurnal convection over the Florida panhandle coast in large AWP years. This study is also an illustration of the benefit of dynamic downscaling in understanding the low-frequency variations of the sea breeze.

  6. GHRSST Level 2P Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-16 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A regional Level 2P Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the Atlantic Ocean and nearby regions based on multi-channel sea surface...

  7. GHRSST Level 2P Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-17 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A regional Level 2P Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the Atlantic Ocean and nearby regions based on multi-channel sea surface...

  8. TOPAZ4: an ocean-sea ice data assimilation system for the North Atlantic and Arctic

    Directory of Open Access Journals (Sweden)

    P. Sakov

    2012-08-01

    Full Text Available We present a detailed description of TOPAZ4, the latest version of TOPAZ – a coupled ocean-sea ice data assimilation system for the North Atlantic Ocean and Arctic. It is the only operational, large-scale ocean data assimilation system that uses the ensemble Kalman filter. This means that TOPAZ features a time-evolving, state-dependent estimate of the state error covariance. Based on results from the pilot MyOcean reanalysis for 2003–2008, we demonstrate that TOPAZ4 produces a realistic estimate of the ocean circulation in the North Atlantic and the sea-ice variability in the Arctic. We find that the ensemble spread for temperature and sea-level remains fairly constant throughout the reanalysis demonstrating that the data assimilation system is robust to ensemble collapse. Moreover, the ensemble spread for ice concentration is well correlated with the actual errors. This indicates that the ensemble statistics provide reliable state-dependent error estimates – a feature that is unique to ensemble-based data assimilation systems. We demonstrate that the quality of the reanalysis changes when different sea surface temperature products are assimilated, or when in-situ profiles below the ice in the Arctic Ocean are assimilated. We find that data assimilation improves the match to independent observations compared to a free model. Improvements are particularly noticeable for ice thickness, salinity in the Arctic, and temperature in the Fram Strait, but not for transport estimates or underwater temperature. At the same time, the pilot reanalysis has revealed several flaws in the system that have degraded its performance. Finally, we show that a simple bias estimation scheme can effectively detect the seasonal or constant bias in temperature and sea-level.

  9. Coastal Sea Level along the North Eastern Atlantic Shelf from Delay Doppler Altimetry

    Science.gov (United States)

    Fenoglio-Marc, L.; Benveniste, J.; Andersen, O. B.; Gravelle, M.; Dinardo, S.; Uebbing, B.; Scharroo, R.; Kusche, J.; Kern, M.; Buchhaupt, C.

    2017-12-01

    Satellite altimetry data of the CryoSat-2 and Sentinel-3 missions processed with Delay Doppler methodology (DDA) provide improved coastal sea level measurements up to 2-4 km from coast, thanks to an along-track resolution of about 300m and a higher signal to noise ratio. We investigate the 10 Kilometre stripe along the North-Eastern Atlantic shelf from Lisbon to Bergen to detect the possible impacts in sea level change studies of this enhanced dataset. We consider SAR CryoSat-2 and Sentinel-3 altimetry products from the ESA GPOD processor and in-house reduced SAR altimetry (RDSAR) products. Improved processing includes in RDSAR the application of enhanced retrackers for the RDSAR waveform. Improved processing in SAR includes modification both in the generation of SAR waveforms, (as Hamming weighting window on the burst data prior to the azimuth FFT, zero-padding prior to the range FFT, doubling of the extension for the radar range swath) and in the SAMOSA2 retracker. Data cover the full lifetime of CryoSat-2 (6 years) and Sentinel-3 (1 year). Conventional altimetry are from the sea level CCI database. First we analyse the impact of these SAR altimeter data on the sea level trend and on the estimation of vertical motion from the altimeter minus tide gauge differences. VLM along the North-Eastern Atlantic shelf is generally small compared to the North-Western Atlantic Coast VLM, with a smaller signal to noise ratio. Second we investigate impact on the coastal mean sea level surface and the mean dynamic topography. We evaluate a mean surface from the new altimeter data to be combined to state of the art geoid models to derive the mean dynamic topography. We compare the results to existing oceanographic and geodetic mean dynamic topography solutions, both on grid and pointwise at the tide gauge stations. This study is supported by ESA through the Sea Level CCI and the GOCE++DYCOT projects

  10. Support of Publication Costs, Atlantic Meridional Overturning Circulation Special Issue of Deep Sea Research II Journal

    Energy Technology Data Exchange (ETDEWEB)

    Amy Honchar

    2012-11-12

    The contribution of funds from DOE supported publication costs of a special issue of Deep Sea Research arising from presentations at the First U.S. Atlantic Meridional Overturning Circulation (AMOC) Meeting held 4-6 May, 2009 to review the US implementation plan and its coordination with other monitoring activities. The special issue includes a total of 16 papers, including publications from three DOE-supported investigators (ie Sevellec, F., and A.V. Fedorov; Hu et. al., and Wan et. al.,). The special issue addresses DOE interests in understanding and simulation/modeling of abrupt climate change.

  11. A field efficacy evaluation of emamectin benzoate for the control of sea lice on Atlantic salmon.

    OpenAIRE

    Armstrong, R; MacPhee, D; Katz, T; Endris, R

    2000-01-01

    This study evaluated the efficacy of emamectin benzoate, 0.2% aquaculture premix, against sea lice on Atlantic salmon in eastern Canada. Salmon pens received either emamectin benzoate, orally, in feed at 50 micrograms/kg body weight/day for 7 consecutive days, or the same diet with no added medication. The site veterinarian had the option of administering a bath treatment with azamethiphos to any pen in the trial. The mean number of lice per fish was lower (P < 0.05) in the experimental group...

  12. Marine environmental monitoring related to sea disposal of radioactive waste in the NE Atlantic Ocean

    International Nuclear Information System (INIS)

    Bettencourt, A.O.; Elias, M.D.T.; Ferrador, G.C.

    1988-01-01

    Reference is made to the sea disposal of packaged radioactive waste in the NE Atlantic and to the role of the OCDE Nuclear Energy Agency (NEA) since 1967, in the dumping operations. The objectives of marine environmental monitoring in relation to sea disposal of radioactive wastes are described as well as the coordinated research and environmental surveillance programme (CRESP) developed within NEA frame. The Portuguese on-going programme in this field is presented and the results concerning measurements of 239+240 Pu, 238 Pu, 241 Am and 137 Cs in samples of water, sediments and fish collected at Madeira and Continental Portuguese coasts, are discussed. It was observed that these radionuclides concentrations are lower for deep-sea fishes than for the shallow-water ones. The obtained results are compared with those found in the literature. From the observation of the large spectrum of results available, it can be concluded that no generalized contamination of the marine environment due to the sea dumping of radioactive wastes if observed at present. On the other hand, there is an interest in pursuing analyses of deep-sea fish with the aim of early detection of any possible modifications in the actual levels of radioactivity in the marine environment. (author) [pt

  13. Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted debris.

    Science.gov (United States)

    Stickley, Catherine E; St John, Kristen; Koç, Nalân; Jordan, Richard W; Passchier, Sandra; Pearce, Richard B; Kearns, Lance E

    2009-07-16

    Oceanic sediments from long cores drilled on the Lomonosov ridge, in the central Arctic, contain ice-rafted debris (IRD) back to the middle Eocene epoch, prompting recent suggestions that ice appeared in the Arctic about 46 million years (Myr) ago. However, because IRD can be transported by icebergs (derived from land-based ice) and also by sea ice, IRD records are restricted to providing a history of general ice-rafting only. It is critical to differentiate sea ice from glacial (land-based) ice as climate feedback mechanisms vary and global impacts differ between these systems: sea ice directly affects ocean-atmosphere exchanges, whereas land-based ice affects sea level and consequently ocean acidity. An earlier report assumed that sea ice was prevalent in the middle Eocene Arctic on the basis of IRD, and although somewhat preliminary supportive evidence exists, these data are neither comprehensive nor quantified. Here we show the presence of middle Eocene Arctic sea ice from an extraordinary abundance of a group of sea-ice-dependent fossil diatoms (Synedropsis spp.). Analysis of quartz grain textural characteristics further supports sea ice as the dominant transporter of IRD at this time. Together with new information on cosmopolitan diatoms and existing IRD records, our data strongly suggest a two-phase establishment of sea ice: initial episodic formation in marginal shelf areas approximately 47.5 Myr ago, followed approximately 0.5 Myr later by the onset of seasonally paced sea-ice formation in offshore areas of the central Arctic. Our data establish a 2-Myr record of sea ice, documenting the transition from a warm, ice-free environment to one dominated by winter sea ice at the start of the middle Eocene climatic cooling phase.

  14. Wintertime re-ventilation of the East Greenland Current's Atlantic-origin Overflow Water in the western Iceland Sea

    Science.gov (United States)

    Våge, Kjetil; Håvik, Lisbeth; Papritz, Lukas; Spall, Michael; Moore, Kent

    2017-04-01

    The Deep Western Boundary Current constitutes the lower limb of the Atlantic Meridional Overturning Circulation, and, as such, is a crucial component of the Earth's climate system. The largest and densest contribution to the current stems from the overflow plume that passes through Denmark Strait. A main source of Denmark Strait Overflow Water (DSOW) is the East Greenland Current (EGC). The DSOW transported by the EGC originates from the Atlantic inflow into the Nordic Seas. This is then transformed into Atlantic-origin Overflow Water while progressing northward through the eastern part of the Nordic Seas. Here we show, using measurements from autonomous gliders deployed from fall 2015 to spring 2016, that the Atlantic-origin Overflow Water transported toward Denmark Strait by the EGC was re-ventilated while transiting the western Iceland Sea in winter. In summer, this region is characterized by an upper layer of cold, fresh Polar Surface Water that is thought to prevent convection. But in fall and winter this fresh water mass is diverted toward the Greenland shelf by enhanced northerly winds, which results in a water column that is preconditioned for convection. Severe heat loss from the ocean to the atmosphere offshore of the ice edge subsequently causes the formation of deep mixed layers. This further transforms the Atlantic-origin Overflow Water and impacts the properties of the DSOW, and hence the deepest and densest component of the lower limb of the Atlantic Meridional Overturning Circulation.

  15. Surfactant control of air-sea gas exchange from North Sea coastal waters and the Atlantic Meridional Transect

    Science.gov (United States)

    Pereira, R.

    2016-02-01

    Suppression of gas transfer velocity (kw) by surfactants are well established, both in laboratory wind flumes and purposeful oceanic releases. However, the effects on kw of time and space varying concentrations of natural surfactant are inadequately studied. We have developed an automated gas exchange tank for simultaneous high precision measurement of kw in unmodified seawater samples. Here we present data from two studies along a coastal North Sea transect during 2012-2013 and the Atlantic Meridional Transect (AMT) 24 from September to November 2014. Measurements of surfactant activity (SA), CDOM absorbance and chlorophyll-a have enabled us to characterize the effects of variable amounts of natural surfactant on kw. North Sea coastal waters range in k660 (kw normalized to the value for CO2 in freshwater at 20oC) was 6.8-24.5 cm hr-1 (n=20), with the ranges of SA, total CDOM absorbance (200-450 nm) and chlorophyll-a measured in the surface microlayer (SML) of our seawater samples were 0.08-0.38 mg l-1 T-X-100, 0.13-4.7 and 0.09-1.54 µg l-1, respectively. The AMT k660 ranged from 7.0-23.9 cm hr-1 (n=22), with SA measured in the SML and subsurface water (SSW) of our seawater samples ranging from 0.15-1.08 mg l-1 T-X-100 and 0.07-0.43 mg l-1 T-X-100, respectively. Importantly, we found 12-45% (North Sea) and 1-43% (AMT) k660 suppression relative to Milli-Q water that relate to seasonal and spatial differences in SA. The North Sea demonstrated notable seasonal influences on k660 suppression that were related to CDOM absorbance and chlorophyll-a. The degree of k660 suppression was highest in summer consistent with k660 control by natural surfactant. The degree of k660 suppression decreased with distance offshore in the North Sea and displayed a strong relationship with SA (r2 = 0.51-0.64, p = 0.02, n = 20). The AMT demonstrated notable differences in k660 suppression between hemispheres and across the Longhurst Provinces but the overall relationship between k660

  16. Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years.

    Science.gov (United States)

    Thornalley, David J R; Oppo, Delia W; Ortega, Pablo; Robson, Jon I; Brierley, Chris M; Davis, Renee; Hall, Ian R; Moffa-Sanchez, Paola; Rose, Neil L; Spooner, Peter T; Yashayaev, Igor; Keigwin, Lloyd D

    2018-04-01

    The Atlantic meridional overturning circulation (AMOC) is a system of ocean currents that has an essential role in Earth's climate, redistributing heat and influencing the carbon cycle 1, 2 . The AMOC has been shown to be weakening in recent years 1 ; this decline may reflect decadal-scale variability in convection in the Labrador Sea, but short observational datasets preclude a longer-term perspective on the modern state and variability of Labrador Sea convection and the AMOC 1, 3-5 . Here we provide several lines of palaeo-oceanographic evidence that Labrador Sea deep convection and the AMOC have been anomalously weak over the past 150 years or so (since the end of the Little Ice Age, LIA, approximately AD 1850) compared with the preceding 1,500 years. Our palaeoclimate reconstructions indicate that the transition occurred either as a predominantly abrupt shift towards the end of the LIA, or as a more gradual, continued decline over the past 150 years; this ambiguity probably arises from non-AMOC influences on the various proxies or from the different sensitivities of these proxies to individual components of the AMOC. We suggest that enhanced freshwater fluxes from the Arctic and Nordic seas towards the end of the LIA-sourced from melting glaciers and thickened sea ice that developed earlier in the LIA-weakened Labrador Sea convection and the AMOC. The lack of a subsequent recovery may have resulted from hysteresis or from twentieth-century melting of the Greenland Ice Sheet 6 . Our results suggest that recent decadal variability in Labrador Sea convection and the AMOC has occurred during an atypical, weak background state. Future work should aim to constrain the roles of internal climate variability and early anthropogenic forcing in the AMOC weakening described here.

  17. Conservation hotspots for the turtles on the high seas of the Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Hsiang-Wen Huang

    Full Text Available Understanding the distribution of bycaught sea turtles could inform conservation strategies and priorities. This research analyses the distribution of turtles caught as longline fisheries bycatch on the high seas of the Atlantic Ocean. This research collected 18,142 bycatch observations and 47.1 million hooks from large-scale Taiwanese longline vessels in the Atlantic Ocean from June 2002 to December 2013. The coverage rates were ranged from 0.48% to 17.54% by year. Seven hundred and sixty-seven turtles were caught, and the major species were leatherback (59.8%, olive ridley (27.1% and loggerhead turtles (8.7%. Most olive ridley (81.7% and loggerhead (82.1% turtles were hooked, while the leatherbacks were both hooked (44.0% and entangled (31.8%. Depending on the species, 21.4% to 57.7% were dead when brought onboard. Most of the turtles were caught in tropical areas, especially in the Gulf of Guinea (15°N-10°S, 30°W-10°E, but loggerheads were caught in the south Atlantic Ocean (25°S-35°S, 40°W-10°E and 30°S-40°S, 55°W-45°W. The bycatch rate was the highest at 0.030 per 1000 hooks for leatherbacks in the tropical area. The bycatch rates of olive ridley ranged from 0 to 0.010 per thousand hooks. The loggerhead bycatch rates were higher in the northern and southern Atlantic Ocean and ranged from 0.0128 to 0.0239 per thousand hooks. Due to the characteristics of the Taiwanese deep-set longline fleet, bycatch rates were lower than those of coastal longline fisheries, but mortality rates were higher because of the long hours of operation. Gear and bait modification should be considered to reduce sea turtle bycatch and increase survival rates while reducing the use of shallow hooks would also be helpful.

  18. Conservation hotspots for the turtles on the high seas of the Atlantic Ocean.

    Science.gov (United States)

    Huang, Hsiang-Wen

    2015-01-01

    Understanding the distribution of bycaught sea turtles could inform conservation strategies and priorities. This research analyses the distribution of turtles caught as longline fisheries bycatch on the high seas of the Atlantic Ocean. This research collected 18,142 bycatch observations and 47.1 million hooks from large-scale Taiwanese longline vessels in the Atlantic Ocean from June 2002 to December 2013. The coverage rates were ranged from 0.48% to 17.54% by year. Seven hundred and sixty-seven turtles were caught, and the major species were leatherback (59.8%), olive ridley (27.1%) and loggerhead turtles (8.7%). Most olive ridley (81.7%) and loggerhead (82.1%) turtles were hooked, while the leatherbacks were both hooked (44.0%) and entangled (31.8%). Depending on the species, 21.4% to 57.7% were dead when brought onboard. Most of the turtles were caught in tropical areas, especially in the Gulf of Guinea (15°N-10°S, 30°W-10°E), but loggerheads were caught in the south Atlantic Ocean (25°S-35°S, 40°W-10°E and 30°S-40°S, 55°W-45°W). The bycatch rate was the highest at 0.030 per 1000 hooks for leatherbacks in the tropical area. The bycatch rates of olive ridley ranged from 0 to 0.010 per thousand hooks. The loggerhead bycatch rates were higher in the northern and southern Atlantic Ocean and ranged from 0.0128 to 0.0239 per thousand hooks. Due to the characteristics of the Taiwanese deep-set longline fleet, bycatch rates were lower than those of coastal longline fisheries, but mortality rates were higher because of the long hours of operation. Gear and bait modification should be considered to reduce sea turtle bycatch and increase survival rates while reducing the use of shallow hooks would also be helpful.

  19. Data-adaptive harmonic analysis and prediction of sea level change in North Atlantic region

    Science.gov (United States)

    Kondrashov, D. A.; Chekroun, M.

    2017-12-01

    This study aims to characterize North Atlantic sea level variability across the temporal and spatial scales. We apply recently developed data-adaptive Harmonic Decomposition (DAH) and Multilayer Stuart-Landau Models (MSLM) stochastic modeling techniques [Chekroun and Kondrashov, 2017] to monthly 1993-2017 dataset of Combined TOPEX/Poseidon, Jason-1 and Jason-2/OSTM altimetry fields over North Atlantic region. The key numerical feature of the DAH relies on the eigendecomposition of a matrix constructed from time-lagged spatial cross-correlations. In particular, eigenmodes form an orthogonal set of oscillating data-adaptive harmonic modes (DAHMs) that come in pairs and in exact phase quadrature for a given temporal frequency. Furthermore, the pairs of data-adaptive harmonic coefficients (DAHCs), obtained by projecting the dataset onto associated DAHMs, can be very efficiently modeled by a universal parametric family of simple nonlinear stochastic models - coupled Stuart-Landau oscillators stacked per frequency, and synchronized across different frequencies by the stochastic forcing. Despite the short record of altimetry dataset, developed DAH-MSLM model provides for skillful prediction of key dynamical and statistical features of sea level variability. References M. D. Chekroun and D. Kondrashov, Data-adaptive harmonic spectra and multilayer Stuart-Landau models. HAL preprint, 2017, https://hal.archives-ouvertes.fr/hal-01537797

  20. The North Atlantic Oscillation and sea surface temperature affect loggerhead abundance around the Strait of Gibraltar

    Directory of Open Access Journals (Sweden)

    José C. Báez

    2011-04-01

    Full Text Available The aim of this study was to explore the possible link between variations in the North Atlantic Oscillation (NAO and sea surface temperature (SST and the abundance of loggerhead turtles around the Strait of Gibraltar, using stranding data for the Andalusian coastal area as a proxy for abundance. The annual average SST (from November to October in the Gulf of Cadiz was negatively associated with the total number of loggerhead strandings each year from November 1997 to October 2006 in the Gulf of Cadiz and the Alboran Sea. The average NAO index was positively associated with the number of strandings in the Gulf of Cadiz in the following year. Prevailing westerly winds during positive NAO phases and the subsequent delayed decrease in SST may lead to turtles from the west Atlantic accumulating in the Gulf of Cadiz and unsuccessfully attempting to return. Secondary causes, such as buoyancy, cold stunning, longline fisheries, net fisheries, debilitated turtle syndrome, and trauma may also increase the number of turtle strandings.

  1. Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics

    Science.gov (United States)

    Zipkin, Elise F.; Gardner, Beth; Gilbert, Andrew T.; O'Connell, Allan F.; Royle, J. Andrew; Silverman, Emily D.

    2010-01-01

    Twelve species of North American sea ducks (Tribe Mergini) winter off the eastern coast of the United States and Canada. Yet, despite their seasonal proximity to urbanized areas in this region, there is limited information on patterns of wintering sea duck habitat use. It is difficult to gather information on sea ducks because of the relative inaccessibility of their offshore locations, their high degree of mobility, and their aggregated distributions. To characterize environmental conditions that affect wintering distributions, as well as their geographic ranges, we analyzed count data on five species of sea ducks (black scoters Melanitta nigra americana, surf scoters M. perspicillata, white-winged scoters M. fusca, common eiders Somateria mollissima, and long-tailed ducks Clangula hyemalis) that were collected during the Atlantic Flyway Sea Duck Survey for ten years starting in the early 1990s. We modeled count data for each species within ten-nautical-mile linear survey segments using a zero-inflated negative binomial model that included four local-scale habitat covariates (sea surface temperature, mean bottom depth, maximum bottom slope, and a variable to indicate if the segment was in a bay or not), one broad-scale covariate (the North Atlantic Oscillation), and a temporal correlation component. Our results indicate that species distributions have strong latitudinal gradients and consistency in local habitat use. The North Atlantic Oscillation was the only environmental covariate that had a significant (but variable) effect on the expected count for all five species, suggesting that broad-scale climatic conditions may be directly or indirectly important to the distributions of wintering sea ducks. Our results provide critical information on species-habitat associations, elucidate the complicated relationship between the North Atlantic Oscillation, sea surface temperature, and local sea duck abundances, and should be useful in assessing the impacts of climate

  2. Interannual to Decadal Variability of Atlantic Water in the Nordic and Adjacent Seas

    Science.gov (United States)

    Carton, James A.; Chepurin, Gennady A.; Reagan, James; Haekkinen, Sirpa

    2011-01-01

    Warm salty Atlantic Water is the main source water for the Arctic Ocean and thus plays an important role in the mass and heat budget of the Arctic. This study explores interannual to decadal variability of Atlantic Water properties in the Nordic Seas area where Atlantic Water enters the Arctic, based on a reexamination of the historical hydrographic record for the years 1950-2009, obtained by combining multiple data sets. The analysis shows a succession of four multi-year warm events where temperature anomalies at 100m depth exceed 0.4oC, and three cold events. Three of the four warm events lasted 3-4 years, while the fourth began in 1999 and persists at least through 2009. This most recent warm event is anomalous in other ways as well, being the strongest, having the broadest geographic extent, being surface-intensified, and occurring under exceptional meteorological conditions. Three of the four warm events were accompanied by elevated salinities consistent with enhanced ocean transport into the Nordic Seas, with the exception of the event spanning July 1989-July 1993. Of the three cold events, two lasted for four years, while the third lasted for nearly 14 years. Two of the three cold events are associated with reduced salinities, but the cold event of the 1960s had elevated salinities. The relationship of these events to meteorological conditions is examined. The results show that local surface heat flux variations act in some cases to reinforce the anomalies, but are too weak to be the sole cause.

  3. Astronomically paced changes in deep-water circulation in the western North Atlantic during the middle Eocene

    Science.gov (United States)

    Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Kirtland Turner, Sandra; Lohmann, Gerrit; Sexton, Philip; Zachos, James; Pälike, Heiko

    2018-02-01

    North Atlantic Deep Water (NADW) currently redistributes heat and salt between Earth's ocean basins, and plays a vital role in the ocean-atmosphere CO2 exchange. Despite its crucial role in today's climate system, vigorous debate remains as to when deep-water formation in the North Atlantic started. Here, we present datasets from carbonate-rich middle Eocene sediments from the Newfoundland Ridge, revealing a unique archive of paleoceanographic change from the progressively cooling climate of the middle Eocene. Well-defined lithologic alternations between calcareous ooze and clay-rich intervals occur at the ∼41-kyr beat of axial obliquity. Hence, we identify obliquity as the driver of middle Eocene (43.5-46 Ma) Northern Component Water (NCW, the predecessor of modern NADW) variability. High-resolution benthic foraminiferal δ18O and δ13C suggest that obliquity minima correspond to cold, nutrient-depleted, western North Atlantic deep waters. We thus link stronger NCW formation with obliquity minima. In contrast, during obliquity maxima, Deep Western Boundary Currents were weaker and warmer, while abyssal nutrients were more abundant. These aspects reflect a more sluggish NCW formation. This obliquity-paced paleoceanographic regime is in excellent agreement with results from an Earth system model, in which obliquity minima configurations enhance NCW formation.

  4. Atlantic Water transformation in the Nordic Seas and its influence on the export rate of the Overflow Waters

    Science.gov (United States)

    Garcia Quintana, Yarisbel; Wiesner, Pia; Hu, Xianmin; Myers, Paul

    2017-04-01

    The Nordic Seas (NS) are the main gateway between the Arctic and the Atlantic Oceans. The basin can be considered as the headwaters for the Meridional Overturning Circulation (MOC), for it is there that the Denmark Strait Overflow Water (DSOW) and the Iceland-Scotland Overflow Water (ISOW) acquire their properties. Their inflow into the North Atlantic Ocean occurs across the Greenland-Scotland ridge. Together with Labrador Sea Water, DSOW and ISOW are the main components of the North Atlantic Deep Water (NADW), which ventilates the lower limb of the Atlantic MOC. In spite recent studies exploring the export rate and later pathways of the overflows, the question about what drives them, remains. Here we explore the transformation of the Atlantic Water (AW) as it enters the NS through Denmark Strait, Iceland Faroe Ridge and Faroe Schotland Channel, as well as its pathways within the basin. To do so, we use an eddy-permitting ocean general circulation model run over the period 2002 to 2015. Two different approaches are used to track the AW transformation in the NS: the well-tested off-line Lagrangian tool ARIANE and on-line passive tracers. In both cases we use the same definition of AW to tag its inflow through the three entering sections. The overflows directly impact circulation and water properties in much of the deep Atlantic Ocean, thus a better understanding of the physical processes behind their variability is crucial a asset.

  5. Somatic growth dynamics of West Atlantic hawksbill sea turtles: a spatio-temporal perspective

    Science.gov (United States)

    Bjorndal, Karen A.; Chaloupka, Milani; Saba, Vincent S.; Diez, Carlos E.; van Dam, Robert P.; Krueger, Barry H.; Horrocks, Julia A.; Santos, Armando J.B.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Nava, Mabel; Willis, Sue; Godley, Brendan J.; Gore, Shannon; Hawkes, Lucy A.; McGowan, Andrew; Witt, Matthew J.; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Blumenthal, Janice; Moncada, Felix; Nodarse, Gonzalo; Medina, Yosvani; Dunbar, Stephen G.; Wood, Lawrence D.; Lagueux, Cynthia J.; Campbell, Cathi L.; Meylan, Anne B.; Meylan, Peter A.; Burns Perez, Virginia R.; Coleman, Robin A.; Strindberg, Samantha; Guzmán-H, Vicente; Hart, Kristen M.; Cherkiss, Michael S.; Hillis-Starr, Zandy; Lundgren, Ian; Boulon, Ralf H.; Connett, Stephen; Outerbridge, Mark E.; Bolten, Alan B.

    2016-01-01

    Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long-lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio-temporal effects on hawksbill growth dynamics over a 33-yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio-temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region-wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0- or 1-yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs. Main

  6. Atlantic Region

    NARCIS (Netherlands)

    Elands, B.H.M.; Bell, S.; Blok, J.

    2010-01-01

    Chapter 2 explores recreation and tourism practices in forest areas in the Atlantic region, which refers to the geographical area close to the North Sea and the Atlantic Ocean. The Atlantic countries described in this section are Belgium (Flanders and Wallonia), Denmark, Iceland, Ireland, the

  7. Holocene North Atlantic Overturning in an atmosphere-ocean-sea-ice model compared to proxy-based reconstructions

    NARCIS (Netherlands)

    Blaschek, M.; Renssen, H.; Kissel, C.; Thornalley, D.

    2015-01-01

    Climate and ocean circulation in the North Atlantic region changed over the course of the Holocene, partly because of disintegrating ice sheets and partly because of an orbital-induced insolation trend. In the Nordic Seas, this impact was accompanied by a rather small, but significant, amount of

  8. Deep-sea benthic community and environmental impact assessment at the Atlantic Frontier

    Science.gov (United States)

    Gage, John D.

    2001-05-01

    The seabed community provides a sensitive litmus for environmental change. North Sea analysis of benthic populations provides an effective means for monitoring impacts from man's interventions, such as offshore oil exploitation and fishing, against baseline knowledge of the environment. Comparable knowledge of the benthic biology in the deep waters of the Atlantic Frontier beyond the N.E. Atlantic shelf edge is poorly developed. But uncertainties should not encourage assumptions and extrapolations from the better-known conditions on the continental shelf. While sampling at present still provides the best means to assess the health of the deepwater benthic habitat, protocols developed for deep-sea fauna should be applied. These are necessary because of (a) lower faunal densities, (b) higher species richness, (c) smaller body size, and (d) to ensure comparability with other deep-sea data. As in the North Sea, species richness and relative abundance can be analysed from quantitative samples in order to detect impacts. But analysis based on taxonomic sufficiency above species level is premature, even if arguably possible for coastal communities. Measures also need to ensure identifications are not forced to more familiar coastal species without proper study. Species-level analysis may be applied to seabed photographs of megafauna in relation to data on bottom environment, such as currents and the sediment, to monitor the health of the deep-water community. Although the composition of higher taxa in the benthic community is broadly similar to soft sediments on the shelf, concordance in sensitivities is speculative. Moreover, new organisms occur, such as giant protozoan xenophyophores, unknown on the continental shelf, whose sensitivities remain conjectural. Past knowledge of the benthic biology of the deep-water areas off Scotland is based on scattered stations and some more focussed, multidisciplinary studies, and should be significantly augmented by the results from

  9. Sea-water/groundwater interactions along a small catchment of the European Atlantic coast

    International Nuclear Information System (INIS)

    Einsiedl, Florian

    2012-01-01

    The geochemistry and isotopic composition of a karstic coastal aquifer in western Ireland has shed light on the effect of sea-water/groundwater interactions on the water quality of Ireland’s Atlantic coastal zone. The use of stable isotope data from the IAEA precipitation station in Valentia, located in SW Ireland has facilitated the characterization of groundwater recharge conditions in the western part of Ireland and suggests that groundwater is mostly replenished by the isotopically light winter precipitation. The dissolved SO 4 2- in the karstic groundwater that was collected during baseflow conditions with δ 34 S values between 4.6‰ and 18‰ may be composed of S stemming from three principal sources: SO 4 2- derived from precipitation which is composed of both sea-spray S (δ 34 S: 20‰) and an isotopically light anthropogenic source (δ 34 S: 1–5‰), SO 4 2- stemming from animal slurries (δ 34 S: ∼5‰), and intruding sea-water SO 4 2- (δ 34 S: 20.2‰). The isotopic composition of δ 18 O in dissolved groundwater SO 4 2- collected during baseflow conditions is interpreted as reflecting sea-water intrusion to the karstic coastal groundwater system. The highest δ 18 O values in dissolved groundwater SO 4 2- were in samples collected near the coast (4.8 ± 0.4‰) and the lowest (2 ± 0.5‰) were collected further inland. The δ 15 N and δ 18 O values of groundwater NO 3 - were between 3.4‰ and 11.4‰ and approximately 7.7‰, respectively, and reflect geochemical conditions in the aquifer that do not promote attenuation of NO 3 - through denitrification. As a result N loading to Kinvara Bay that is controlled by submarine groundwater discharge (SGD) was calculated as 5 tons/day on average compared to an estimated N-input that derives from precipitation of approximately 2.5 tons/a. SGD into the bay may result in near coastal sea-water quality changes. These results represent one of the first studies addressing the effect of groundwater

  10. Terrestrially derived dissolved organic matter in the chesapeake bay and the middle atlantic bight

    Science.gov (United States)

    Mitra, Siddhartha; Bianchi, Thomas S.; Guo, Laodong; Santschi, Peter H.

    2000-10-01

    Concentrations of lignin-phenols were analyzed in high molecular weight dissolved organic matter (0.2 μm > HMW DOM > 1 kDa) isolated from surface waters of the Chesapeake Bay (C. Bay), and surface and bottom waters of the Middle Atlantic Bight (MAB). The abundance of lignin-phenols in HMW DOM was higher in the C. Bay (0.128 ± 0.06 μg L -1) compared to MAB surface waters (0.016 ± 0.004 μg L -1) and MAB bottom waters (0.005 ± 0.003 μg L -1). On an organic carbon-normalized basis, lignin-phenol abundances in the HMW DOM (i.e., Λ 6), were significantly higher ( p vanillin (Ad/Al) V in HMW DOM, indicative of lignin decay, ranged from 0.611 to 1.37 in C. Bay, 0.534 to 2.62 in MAB surface waters, and 0.435 to 1.96 in MAB bottom water. Ratios of S/V and (Ad/Al) V showed no significant differences between each environment, providing no evidence of any compositionally distinct input of terrestrial organic matter into each environment. When considering depth profiles of suspended particulate matter in the MAB, with C:N ratios, and bulk radiocarbon ages and stable carbon isotopic values in HMW DOM isolated from these areas, two scenarios present themselves regarding the sources and transport of terrestrially derived HMW DOM in the MAB. Scenario #1 assumes that a low amount of refractory terrestrial organic matter and old DOC are uniformly distributed in the oceans, both in surface and bottom waters, and that primary production in surface waters increases DOC with low lignin and younger DOC which degrades easily. In this case, many of the trends in age and biomarker composition likely reflect general patterns of Atlantic Ocean surface and bottom water circulation in the area of the MAB. Scenario 2 assumes terrestrial organic matter in bottom waters of the MAB may have originated from weathered shelf and slope sediments in nearshore areas via a combination of mechanisms (e.g., diffusion, recent resuspension events, and/or desorption of DOM from riverine POM buried deep

  11. The distribution of deep-sea sponge aggregations in the North Atlantic and implications for their effective spatial management

    Science.gov (United States)

    Howell, Kerry-Louise; Piechaud, Nils; Downie, Anna-Leena; Kenny, Andrew

    2016-09-01

    Sponge aggregations have been recognised as key component of shallow benthic ecosystems providing several important functional roles including habitat building and nutrient recycling. Within the deep-sea ecosystem, sponge aggregations may be extensive and available evidence suggests they may also play important functional roles, however data on their ecology, extent and distribution in the North Atlantic is lacking, hampering conservation efforts. In this study, we used Maximum Entropy Modelling and presence data for two deep-sea sponge aggregation types, Pheronema carpenteri aggregations and ostur aggregations dominated by geodid sponges, to address the following questions: 1) What environmental factors drive the broad-scale distribution of these selected sponge grounds? 2) What is the predicted distribution of these grounds in the northern North Atlantic, Norwegian and Barents Sea? 3) How are these sponge grounds distributed between Exclusive Economic Zones (EEZs) and High Seas areas? 4) What percentage of these grounds in High Seas areas are protected by the current High Seas MPA network? Our results suggest that silicate concentration, temperature, depth and amount of particulate organic carbon are the most important drivers of sponge distribution. Most of the sponge grounds are located within national EEZs rather than in the High Seas. Coordinated conservation planning between nations with significant areas of sponge grounds such as Iceland, Greenland and Faroes (Denmark), Norway (coastal Norway and Svalbard), Portugal and the UK, should be implemented in order to effectively manage these communities in view of the increasing level of human activity within the deep-sea environment.

  12. Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic

    Directory of Open Access Journals (Sweden)

    S. GARCIA-SANZ

    2014-03-01

    Full Text Available Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula at Gran Canaria Island (eastern Atlantic via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula with the most conspicuous species (D. africanum in the study area.

  13. Plasma Vitellogenin in Free-Ranging Loggerhead Sea Turtles (Caretta caretta of the Northwest Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Kimberly Smelker

    2014-01-01

    Full Text Available Vitellogenin is the egg yolk precursor protein produced by oviparous vertebrates. As endogenous estrogen increases during early reproductive activity, hepatic production of vitellogenin is induced and is assumed to be complete in female sea turtles before the first nesting event. Until the present study, innate production of vitellogenin has not been described in free-ranging sea turtles. Our study describes circulating concentrations of vitellogenin in loggerhead sea turtles (Caretta caretta from the Northwest Atlantic Ocean. We collected blood samples from juveniles and adults via in-water captures off the coast of the Southeast USA from May to August, and from nesting females in June and July at Hutchinson Island, Florida. All samples were analyzed using an in-house ELISA developed specifically to measure Caretta caretta vitellogenin concentration. As expected, plasma vitellogenin declined in nesting turtles as the nesting season progressed, although it still remained relatively elevated at the end of the season. In addition, mean vitellogenin concentration in nesting turtles was 1,000 times greater than that measured in samples from in-water captures. Our results suggest that vitellogenesis may continue throughout the nesting season, albeit at a decreasing rate. Further, vitellogenin detected in turtles captured in-water may have resulted from exposure to endocrine disrupting chemicals.

  14. Genetic homogeneity in the deep-sea grenadier Macrourus berglax across the North Atlantic Ocean

    Science.gov (United States)

    Coscia, Ilaria; Castilho, Rita; Massa-Gallucci, Alexia; Sacchi, Carlotta; Cunha, Regina L.; Stefanni, Sergio; Helyar, Sarah J.; Knutsen, Halvor; Mariani, Stefano

    2018-02-01

    Paucity of data on population structure and connectivity in deep sea species remains a major obstacle to their sustainable management and conservation in the face of ever increasing fisheries pressure and other forms of impacts on deep sea ecosystems. The roughhead grenadier Macrourus berglax presents all the classical characteristics of a deep sea species, such as slow growth and low fecundity, which make them particularly vulnerable to anthropogenic impact, due to their low resilience to change. In this study, the population structure of the roughhead grenadier is investigated throughout its geographic distribution using two sets of molecular markers: a partial sequence of the Control Region of mitochondrial DNA and species-specific microsatellites. No evidence of significant structure was found throughout the North Atlantic, with both sets of molecular markers yielding the same results of overall homogeneity. We posit two non-mutually exclusive scenarios that can explain such outcome: i) substantial high gene flow among locations, possibly maintained by larval stages, ii) very large effective size of post-glacially expanded populations. The results can inform management strategies in this by-caught species, and contribute to the broader issue of biological connectivity in the deep ocean.

  15. Retrospective analysis of seasonal ocean growth rates of two sea winter Atlantic Salmon in eastern Maine using historic scales

    Science.gov (United States)

    Izzo, Lisa K.; Zydlewski, Joseph D.

    2017-01-01

    Substantial declines of anadromous Atlantic Salmon Salmo salar have occurred throughout its range, with many populations at the southern extent of the distribution currently extirpated or endangered. While both one sea winter (1SW) and two sea winter (2SW) spawner numbers for the North American stocks have declined since the 1950s, the decline has been most severe in 2SW spawners. The first months at sea are considered a period of high mortality. However, early ocean mortality alone cannot explain the more pronounced decline of 2SW spawners, suggesting that the second year at sea may be more critical than previously thought. Atlantic Salmon scales collected by anglers and the state agency from 1946 to 2013 from five rivers in eastern Maine were used to estimate smolt age and ocean age of returning adults. Additionally, seasonal growth rates of maiden 2SW spawners were estimated using intercirculi measurements and linear back-calculation methods. Generalized linear mixed models (Gaussian family, log link function) were used to investigate the influence of average sea surface temperature, accumulated thermal units, the Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation indices, smolt age, smolt length, postsmolt growth, and river of origin on growth rate during the oceanic migration of North American Atlantic Salmon. Results suggest that different factors influence salmon growth throughout their oceanic migration, and previous growth can be a strong predictor of future size. Growth was negatively impacted by the phase of the AMO, which has been linked to salmon abundance trends, in early spring following the postsmolt period. This is likely when the 1SW and 2SW stock components separate, and our results suggest that this period may be of interest in future work examining the disproportionate decline in 2SW spawners.

  16. Contrasting records of sea-level change in the eastern and western North Atlantic during the last 300 years

    Science.gov (United States)

    Long, A. J.; Barlow, N. L. M.; Gehrels, W. R.; Saher, M. H.; Woodworth, P. L.; Scaife, R. G.; Brain, M. J.; Cahill, N.

    2014-02-01

    We present a new 300-year sea-level reconstruction from a salt marsh on the Isle of Wight (central English Channel, UK) that we compare to other salt-marsh and long tide-gauge records to examine spatial and temporal variability in sea-level change in the North Atlantic. Our new reconstruction identifies an overall rise in relative sea level (RSL) of c. 0.30 m since the start of the eighteenth century at a rate of 0.9±0.3 mm yr. Error-in-variables changepoint analysis indicates that there is no statistically significant deviation from a constant rate within the dataset. The reconstruction is broadly comparable to other tide-gauge and salt-marsh records from the European Atlantic, demonstrating coherence in sea level in this region over the last 150-300 years. In contrast, we identify significant differences in the rate and timing of RSL with records from the east coast of North America. The absence of a strong late 19th/early 20th century RSL acceleration contrasts with that recorded in salt marsh sediments along the eastern USA coastline, in particular in a well-dated and precise sea-level reconstruction from North Carolina. This suggests that this part of the North Carolina sea level record represents a regionally specific sea level acceleration. This is significant because the North Carolina record has been used as if it were globally representative within semi-empirical parameterisations of past and future sea-level change. We conclude that regional-scale differences of sea-level change highlight the value of using several, regionally representative RSL records when calibrating and testing semi-empirical models of sea level against palaeo-records. This is because by using records that potentially over-estimate sea-level rise in the past such models risk over-estimating sea-level rise in the future.

  17. The Effect of Seasonal Variability of Atlantic Water on the Arctic Sea Ice Cover

    Science.gov (United States)

    Ivanov, V. V.; Repina, I. A.

    2018-01-01

    Under the influence of global warming, the sea ice in the Arctic Ocean (AO) is expected to reduce with a transition toward a seasonal ice cover by the end of this century. A comparison of climate-model predictions with measurements shows that the actual rate of ice cover decay in the AO is higher than the predicted one. This paper argues that the rapid shrinking of the Arctic summer ice cover is due to its increased seasonality, while seasonal oscillations of the Atlantic origin water temperature create favorable conditions for the formation of negative anomalies in the ice-cover area in winter. The basis for this hypothesis is the fundamental possibility of the activation of positive feedback provided by a specific feature of the seasonal cycle of the inflowing Atlantic origin water and the peaking of temperature in the Nansen Basin in midwinter. The recently accelerated reduction in the summer ice cover in the AO leads to an increased accumulation of heat in the upper ocean layer during the summer season. The extra heat content of the upper ocean layer favors prerequisite conditions for winter thermohaline convection and the transfer of heat from the Atlantic water (AW) layer to the ice cover. This, in turn, contributes to further ice thinning and a decrease in ice concentration, accelerated melting in summer, and a greater accumulation of heat in the ocean by the end of the following summer. An important role is played by the seasonal variability of the temperature of AW, which forms on the border between the North European and Arctic basins. The phase of seasonal oscillation changes while the AW is moving through the Nansen Basin. As a result, the timing of temperature peak shifts from summer to winter, additionally contributing to enhanced ice melting in winter. The formulated theoretical concept is substantiated by a simplified mathematical model and comparison with observations.

  18. Aspects of Remote Sensing in the GEOid and Sea level Of the North Atlantic Region (GEOSONAR) Project

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Nielsen, Allan Aasbjerg; Knudsen, Per

    1999-01-01

    The general objectives of the GEOid and Sea level Of the North Atlantic Region (GEOSONAR) project are presented. These include analyses of the dynamics of the ocean and its characteristics. The analyses are mainly based on remote sensing. As an example a data set obtained by the multi-channel Sea-viewing...... Wide Field-of-view Sensor (SeaWiFs) is analysed. The presentation results include the computed principal components (PC) and the maximum autocorrelation factors (MAF). Both methods are expected to be incorporated into future analyses of the state of the ocean....

  19. Temporal energy partitions of Florida extreme sea level events as a function of Atlantic multidecadal oscillation

    Directory of Open Access Journals (Sweden)

    J. Park

    2010-06-01

    Full Text Available An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic (shorter duration timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics might be consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.

  20. Stock structure of Atlantic herring Clupea harengus in the Norwegian Sea and adjacent waters

    DEFF Research Database (Denmark)

    Pampoulie, Christophe; Slotte, Aril; Oskarsson, Guomundur J.

    2015-01-01

    The genetic structure of Atlantic herring Clupea harengus L. was investigated in its north-easterly distribution in the Norwegian Sea and adjacent waters, using 23 neutral and one non-neutral (Cpa111) microsatellite loci. Fish from the suspected 2 main populations-the Norwegian spring......-spawning herring (NSSH) and the Icelandic summer-spawning herring (ISSH)-were collected at spawning locations in their respective spawning seasons from 2009 to 2012. Samples were also collected from Norwegian autumn spawning locations, from different local Norwegian fjords such as the inner part...... of Trondheimsfjorden, Lindas pollene, Landvikvannet and Lusterfjorden, as well as from suspected Faroese spawning components. The observed level of genetic differentiation was significant but low (F-ST = 0.007) and mostly attributable to the differentiation of the local Norwegian fjord populations. The locus Cpa111...

  1. Microbial processes in North Atlantic pelagic sediments, and potential risks of deep-sea waste disposal

    International Nuclear Information System (INIS)

    Bolliger, R.; Hanselmann, K.W.; Bachofen, R.

    1989-01-01

    From the results for waste disposal on deep sea sediments, it was concluded: As waste canisters are buried in the sediment to a depth of 15 to 20 cm, they are in contact with the zone that contains the highest potential bacterial activity through a relatively large surface. An input of oxidizable organic matter to the sediment surface zone will stimulate microbial activity and therefore increase the risk for solubilization and redistribution of elements in the ocean water. Waste canisters lying on the sediment surface cut off the oxygen supply from the ocean water and ease the shift to anaerobiosis. This initiates microbial activities through which metals are changed into their mobile species as a consequence of the altered environmental redox potential. The risk for steel corrosion by hydrogen sulfide, which could be produced by sulfate reducing bacteria, is minimal since this physiological group is not active in the North Atlantic sediments examined

  2. Into the deep blue sea: Commons theory and international governance of Atlantic Bluefin Tuna

    Directory of Open Access Journals (Sweden)

    Graham Epstein

    2014-08-01

    Full Text Available The need to understand how to sustainably govern oceanic fisheries has become increasingly urgent as their contribution to global food security and livelihoods are threatened by declining stocks. Atlantic Bluefin Tuna (ABFT is a prominent example of the complexities associated with widely distributed oceanic resources, extending in this case to include much of the North-Atlantic and Mediterranean Sea. This distribution has led to limited attention from commons theorists that tend to focus on small-scale social ecological systems. Therefore in order to explore the fit between theories of the commons developed in small-scale systems, we apply the Social-Ecological Systems Meta-Analysis Database (SESMAD to systematically analyze ABFT governance over a 22 year period. The results, which focus on the effects of resource characteristics, broadly correspond to the expectations of commons theory. Interestingly, however, the addition of resource storage in the form of ABFT ranches appears to be contributing to unsustainable harvests. This stands in contrast to previous findings in the commons literature that storage tends to enhance prospects for sustainable governance. Therefore several alternative hypotheses are developed by comparing and contrasting attributes of ABFT and canal irrigation storage. These hypotheses may be used in future research to evaluate the conditions in which storage enhances prospects for sustainable governance.

  3. Characterizing wave- and current- induced bottom shear stress: U.S. middle Atlantic continental shelf

    Science.gov (United States)

    Dalyander, P. Soupy; Butman, Bradford; Sherwood, Christopher R.; Signell, Richard P.; Wilkin, John L.

    2013-01-01

    Waves and currents create bottom shear stress, a force at the seabed that influences sediment texture distribution, micro-topography, habitat, and anthropogenic use. This paper presents a methodology for assessing the magnitude, variability, and driving mechanisms of bottom stress and resultant sediment mobility on regional scales using numerical model output. The analysis was applied to the Middle Atlantic Bight (MAB), off the U.S. East Coast, and identified a tidally-dominated shallow region with relatively high stress southeast of Massachusetts over Nantucket Shoals, where sediment mobility thresholds are exceeded over 50% of the time; a coastal band extending offshore to about 30 m water depth dominated by waves, where mobility occurs more than 20% of the time; and a quiescent low stress region southeast of Long Island, approximately coincident with an area of fine-grained sediments called the “Mud Patch”. The regional high in stress and mobility over Nantucket Shoals supports the hypothesis that fine grain sediment winnowed away in this region maintains the Mud Patch to the southwest. The analysis identified waves as the driving mechanism for stress throughout most of the MAB, excluding Nantucket Shoals and sheltered coastal bays where tides dominate; however, the relative dominance of low-frequency events varied regionally, and increased southward toward Cape Hatteras. The correlation between wave stress and local wind stress was lowest in the central MAB, indicating a relatively high contribution of swell to bottom stress in this area, rather than locally generated waves. Accurate prediction of the wave energy spectrum was critical to produce good estimates of bottom shear stress, which was sensitive to energy in the long period waves.

  4. The air-sea equilibrium and time trend of hexachlorocyclohexanes in the Atlantic Ocean between the Arctic and Antarctica.

    Science.gov (United States)

    Lakaschus, Sonke; Weber, Kurt; Wania, Frank; Bruhn, Regina; Schrems, Otto

    2002-01-15

    Hexachlorocyclohexanes (HCHs) were determined simultaneously in air and seawater during two cruises across the Atlantic Ocean between the Arctic Ocean (Ny-Alesund/ Svalbard, 79 degrees N; 12 degrees E) and the Antarctic Continent (Neumayer Station/ Ekstroem Ice Shelf, 70 degrees S; 8.2 degrees W) in 1999/ 2000. The concentrations of alpha-HCH and gamma-HCH in air and surface waters of the Arctic exceeded those in Antarctica by 1-2 orders of magnitude. The gaseous concentrations of gamma-HCH were highest above the North Sea and between 20 degrees N and 30 degrees S. Fugacity fractions were used to estimate the direction of the air-sea gas exchange. These showed for alpha-HCH thatthe measured concentrations in both phases were close to equilibrium in the North Atlantic (78 degrees N-40 degrees N), slightly undersaturated between 30 degrees N and 10 degrees S and again close to equilibrium between 20 degrees S and 50 degrees S. Y-HCH has reached phase equilibrium in the North Atlantic as alpha-HCH, but the surface waters of the tropical and southern Atlantic were strongly undersaturated with y-HCH, especially between 30 degrees N and 20 degrees S. These findings are significantly different from two earlier estimates around 1990 as a result of global emission changes within the past decade. Therefore, we investigated the time trend of the HCHs in the surface waters of the Atlantic between 50 degrees N and 60 degrees S on the basis of archived samples taken in 1987-1997 and those from 1999. A decrease of alpha-HCH by a factor of approximately 4 is observed at all sampling locations. No decrease of gamma-HCH occurred between 30 degrees N and 30 degrees S, but there was a decrease in the North Atlantic, North Sea, and in the South Atlantic south of 40 degrees S. The constant level of gamma-HCH in the tropical Atlantic confirms the conclusion that the tropical Atlantic acts as a sink for y-HCH at present time. The measured alpha-HCH seawater concentrations were compared

  5. Regional Effects of the Mount Pinatubo Eruption on the Middle East and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2017-10-26

    The 1991 eruption of Mount Pinatubo had dramatic effects on the regional climate in the Middle East. Though acknowledged, these effects have not been thoroughly studied. To fill this gap and to advance understanding of the mechanisms that control variability in the Middle East\\'s regional climate, we simulated the impact of the 1991 Pinatubo eruption using a regional coupled ocean-atmosphere modeling system set for the Middle East and North Africa (MENA) domain. We used the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) framework, which couples the Weather Research and Forecasting Model (WRF) model with the Regional Oceanic Modeling System (ROMS). We modified the WRF model to account for the radiative effect of volcanic aerosols. Our coupled ocean-atmosphere simulations verified by available observations revealed strong perturbations in the energy balance of the Red Sea, which drove thermal and circulation responses. Our modeling approach allowed us to separate changes in the atmospheric circulation caused by the impact of the volcano from direct regional radiative cooling from volcanic aerosols. The atmospheric circulation effect was significantly stronger than the direct volcanic aerosols effect. We found that the Red Sea response to the Pinatubo eruption was stronger and qualitatively different from that of the global ocean system. Our results suggest that major volcanic eruptions significantly affect the climate in the Middle East and the Red Sea and should be carefully taken into account in assessments of long-term climate variability and warming trends in MENA and the Red Sea.

  6. Regional Effects of the Mount Pinatubo Eruption on the Middle East and the Red Sea

    Science.gov (United States)

    Osipov, Sergey; Stenchikov, Georgiy

    2017-11-01

    The 1991 eruption of Mount Pinatubo had dramatic effects on the regional climate in the Middle East. Though acknowledged, these effects have not been thoroughly studied. To fill this gap and to advance understanding of the mechanisms that control variability in the Middle East's regional climate, we simulated the impact of the 1991 Pinatubo eruption using a regional coupled ocean-atmosphere modeling system set for the Middle East and North Africa (MENA) domain. We used the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) framework, which couples the Weather Research and Forecasting Model (WRF) model with the Regional Oceanic Modeling System (ROMS). We modified the WRF model to account for the radiative effect of volcanic aerosols. Our coupled ocean-atmosphere simulations verified by available observations revealed strong perturbations in the energy balance of the Red Sea, which drove thermal and circulation responses. Our modeling approach allowed us to separate changes in the atmospheric circulation caused by the impact of the volcano from direct regional radiative cooling from volcanic aerosols. The atmospheric circulation effect was significantly stronger than the direct volcanic aerosols effect. We found that the Red Sea response to the Pinatubo eruption was stronger and qualitatively different from that of the global ocean system. Our results suggest that major volcanic eruptions significantly affect the climate in the Middle East and the Red Sea and should be carefully taken into account in assessments of long-term climate variability and warming trends in MENA and the Red Sea.

  7. Tracing Atlantic Water Signature in the Arctic Sea Ice Cover East of Svalbard

    Directory of Open Access Journals (Sweden)

    Vladimir V. Ivanov

    2012-01-01

    Full Text Available We focus on the Arctic Ocean between Svalbard and Franz Joseph Land in order to elucidate the possible role of Atlantic water (AW inflow in shaping ice conditions. Ice conditions substantially affect the temperature regime of the Spitsbergen archipelago, particularly in winter. We test the hypothesis that intensive vertical mixing at the upper AW boundary releases substantial heat upwards that eventually reaches the under-ice water layer, thinning the ice cover. We examine spatial and temporal variation of ice concentration against time series of wind, air temperature, and AW temperature. Analysis of 1979–2011 ice properties revealed a general tendency of decreasing ice concentration that commenced after the mid-1990s. AW temperature time series in Fram Strait feature a monotonic increase after the mid-1990s, consistent with shrinking ice cover. Ice thins due to increased sensible heat flux from AW; ice erosion from below allows wind and local currents to more effectively break ice. The winter spatial pattern of sea ice concentration is collocated with patterns of surface heat flux anomalies. Winter minimum sea ice thickness occurs in the ice pack interior above the AW path, clearly indicating AW influence on ice thickness. Our study indicates that in the AW inflow region heat flux from the ocean reduces the ice thickness.

  8. Air-Sea CO2 fluxes in the Atlantic as measured during boreal spring and autumn

    Directory of Open Access Journals (Sweden)

    A. F. Ríos

    2010-05-01

    Full Text Available A total of fourteen hydrographic cruises from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean under the framework of the Spanish research project FICARAM. The underway measurements were processed and analysed to describe the meridional air-sea CO2 fluxes (FCO2 in the covered sector of the Atlantic Ocean. The data has been grouped into different biogeochemical oceanographic provinces based on thermohaline characteristics. The spatial and temporal distributions of FCO2 followed expected distributions and annual trends reproducing the recent climatological ΔfCO2 estimations with a mean difference of −3 ± 18 μatm (Takahashi et al., 2009. The reduction in the CO2 saturation along the meridional FICARAM cruises represented an increase of 0.02 ± 0.14 mol m−2 yr−1 in the ocean uptake of atmospheric CO2. The subtropical waters in both Hemispheres acted as a sink of atmospheric CO2 during the successive spring seasons and as a source in autumn. The coarse reduction of the ocean uptake of atmospheric CO2 observed in the North Atlantic Ocean was linked to conditions of negative phase of the North Atlantic Oscillation that prevailed during the FICARAM period. Surface waters in the North Equatorial Counter Current revealed a significant long-term decrease of sea surface salinity of −0.16 ± 0.01 yr−1 coinciding with a declination of −3.5 ± 0.9 μatm yr−1 in the air–sea disequilibrium of CO2 fugacity and a rise of oceanic CO2 uptake of −0.09 ± 0.03 mol m−2 yr−1. The largest CO2 source was located in the equatorial upwelling system. These tropical waters that reached emissions of 0.7 ± 0.5 and 1.0 ± 0.7 mol m−2 y−1 in spring and autumn, respectively, showed an interannual warming of 0.11 ± 0.03 °C yr−1 and a wind speed decrease of −0.58 ± 0.14 m s−1 yr−1 in spring cruises which suggest the weakening of upwelling events associated with warm El Niño – Southern

  9. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Science.gov (United States)

    Duperron, S.; Gaudron, S. M.; Rodrigues, C. F.; Cunha, M. R.; Decker, C.; Olu, K.

    2013-05-01

    Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae). Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

  10. An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    S. Duperron

    2013-05-01

    Full Text Available Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria that ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, eastern Americas, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous, more easily accessible shallow marine species have been studied. Herein we provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east from the Gulf of Mexico to the Sea of Marmara, and north-to-south from the Arctic to the Gulf of Guinea. Characteristics of symbioses in 53 species from the area are summarized for each of the five bivalve families documented to harbor chemosynthetic symbionts (Mytilidae, Vesicomyidae, Solemyidae, Thyasiridae and Lucinidae. Comparisons are made between the families, with special emphasis on ecology, life cycle, and connectivity. Chemosynthetic symbioses are a major adaptation to ecosystems and habitats exposed to reducing conditions. However, relatively little is known regarding their diversity and functioning, apart from a few "model species" on which effort has focused over the last 30 yr. In the context of increasing concern about biodiversity and ecosystems, and increasing anthropogenic pressure on oceans, we advocate a better assessment of the diversity of bivalve symbioses in order to evaluate the capacities of these remarkable ecological and evolutionary units to withstand environmental change.

  11. Chlorophyll-a profiles collected by various vessels in the Atlantic Ocean and adjoining seas from 03/02/1961 to 10/21/1992 (NODC Accession 9300147)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chlorophyll-a profiles were collected in the Atlantic Ocean and adjoining seas from March 2, 1961 to October 21, 1992. The data were collected by multiple...

  12. GHRSST Level 3P North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on NOAA-19 (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  13. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-18 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  14. GHRSST Level 3C North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on NOAA-19 (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  15. Underway sea surface temperature and salinity data from thermosalinographs collected from multiple platforms assembled by NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection contains sea surface oceanographic data in netCDF and ASCII formatted files assembled by the NOAA Atlantic Oceanographic and Meteorological...

  16. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from SNPP/VIIRS (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A regional Group for High Resolution Sea Surface Temperature (GHRSST) Level 3 Collated (L3C) dataset for the North Atlantic Region (NAR) based on retrievals from the...

  17. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-17 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  18. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-16 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  19. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from Metop/AVHRR (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) derived from the Advanced Very High Resolution Radiometer...

  20. Horizontal and vertical distribution of Chaetognatha in the upper 1000 m of the western Sargasso Sea and the Central and South-east Atlantic.

    Digital Repository Service at National Institute of Oceanography (India)

    Pierrot-Bultsa, A.C.; Nair, V.R.

    The chaetognath abundance, species richness and bathymetric distribution in the upper 1000 m in two regions of the Atlantic Ocean is discussed based on samples collected on two cruises, one to the Sargasso Sea (Northwest Atlantic) on board the R/V R...

  1. Obliquity-driven expansion of North Atlantic sea ice controls structure of the last glacial

    Science.gov (United States)

    Turney, Chris; Thomas, Zoe; Hutchinson, David; Bradshaw, Corey; Brook, Barry; England, Matthew; Fogwill, Christopher; Jones, Richard; Palmer, Jonathan; Hughen, Konrad; Cooper, Alan

    2015-04-01

    North Atlantic late-Pleistocene climate was characterised by a series of abrupt climate changes, the most extreme of which were the Dansgaard-Oeschger (D-O) events; millennial-scale oscillations that switched rapidly between cold and warm atmospheric conditions of up to Δ16°C, most strongly expressed during the period 60-30 ka. Time series analysis of palaeoclimate ice core records is one of the best ways to detect threshold behaviour in the climate system; however, some of these techniques can be age model dependent. Spectral analysis of a new Greenland-Cariaco GICC05 age model (GICC05-CB), generated by combining the GICC05 and Cariaco ∂18O chronologies, reveals a change in the dominant periodicities at ~31 ka, consistent with the cessation of the D-O events. While the GICC05-CB has the same ∂18O structure as GICC05, the different periodicity profile reveals a change in the climate system at 31 ka. Stability analysis of the ∂18O time series over the last 60 ka determines the number of states the climate experienced over time, and reveals a bifurcation in the climate system at 31 ka, switching from a bistable to a monostable state. Early warning signals of this bifurcation are also detected starting 10,000 years before the shift in the form of increasing autocorrelation and variance. This is consistent with the climate system experiencing a slow forcing towards a critical threshold. These signals are found in both the GICC05-CB and GICC05 chronologies, though the timing of the bifurcation point varies slightly. We suggest that this bifurcation is linked to a minima in obliquity, causing greatly expanded sea ice in the Labrador sea. Modelling runs from the CSIRO Mk3L Earth-system model indicates that extensive sea ice cover is established in the Labrador Sea and North Pacific at the obliquity minima centred on 28.5 ka. This expanded sea ice is thus responsible for shifting the Northern Hemisphere westerlies southwards and reducing the strength of the AMOC

  2. Natural and anthropogenic decadal pH decrease in the North Atlantic and Mediterranean Sea waters

    Science.gov (United States)

    Huertas, E.; Flecha, S.; Murata, A.; Garcia Lafuente, J.; Pérez, F. F.

    2017-12-01

    Seawater pH is undergoing a decreasing trend due to atmospheric CO2 absorption, a phenomenon known as Ocean Acidification (OA) that has been documented in different ocean regions. Certain marine basins are more vulnerable to OA, such as the Mediterranean Sea (MS), which is attributed to particular water circulation processes and biogeochemical features. Considering previous studies on OA in Mediterranean and Atlantic water masses, the main aim of this work was to identify for the first time the natural and anthropogenic contribution to decadal pH variations. Therefore, an archetypal analysis was applied to pH measurements and other biogeochemical variables collected in the Strait of Gibraltar during 10 years. Our results reveal that the biological component of the pH change in the Western Mediterranean Deep Water (WMDW) (ΔpHWMDW) represents around 56% of the total decadal pH decrease observed, highlighting the relevance of the remineralization occurring in the Alboran basin, where the WMDW resides before leaving the MS. On the other hand, neither natural nor anthropogenic forcing on the pH change in the Levantine Intermediate Water (ΔpHLIW) was detected, as pH variation was negligible. As for the North Atlantic Central Water (NACW), atmospheric CO2 uptake was responsible of 58% of the ΔpHNACW, likely related to permanent contact with the atmosphere. Additionally, estimations of the approximated ages of the NACW, LIW and WMDW in the SG of about 8, 34 and 32 years respectively have been obtained. Our results show that Mediterranean waters undergo changes in their biogeochemical characteristics during transit through the SG and gives insights on the main mechanisms affecting pH variations occurring from their formation sites to the SG.

  3. The air-sea exchange of mercury in the low latitude Pacific and Atlantic Oceans

    Science.gov (United States)

    Mason, Robert P.; Hammerschmidt, Chad R.; Lamborg, Carl H.; Bowman, Katlin L.; Swarr, Gretchen J.; Shelley, Rachel U.

    2017-04-01

    Air-sea exchange is an important component of the global mercury (Hg) cycle as it mediates the rate of increase in ocean Hg, and therefore the rate of change in levels of methylmercury (MeHg), the most toxic and bioaccumulative form of Hg in seafood and the driver of human health concerns. Gas evasion of elemental Hg (Hg0) from the ocean is an important sink for ocean Hg with previous studies suggesting that evasion is not uniform across ocean basins. To understand further the factors controlling Hg0 evasion, and its relationship to atmospheric Hg deposition, we made measurements of dissolved Hg0 (DHg0) in surface waters, along with measurements of Hg in precipitation and on aerosols, and Hg0 in marine air, during two GEOTRACES cruises; GP16 in the equatorial South Pacific and GA03 in the North Atlantic. We contrast the concentrations and estimated evasion fluxes of Hg0 during these cruises, and the factors influencing this exchange. Concentrations of DHg0 and fluxes were lower during the GP16 cruise than during the GA03 cruise, and likely reflect the lower atmospheric deposition in the South Pacific. An examination of Hg/Al ratios for aerosols from the cruises suggests that they were anthropogenically-enriched relative to crustal material, although to a lesser degree for the South Pacific than the aerosols over the North Atlantic. Both regions appear to be net sources of Hg0 to the atmosphere (evasion>deposition) and the reasons for this are discussed. Overall, the studies reported here provide further clarification on the factors controlling evasion of Hg0 from the ocean surface, and the role of anthropogenic inputs in influencing ocean Hg concentrations.

  4. Simulating the Regional Impact of Dust on the Middle East Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2018-01-19

    The Red Sea is located between North Africa and the Arabian Peninsula, the largest sources of dust in the world. Satellite retrievals show very high aerosol optical depth in the region, which increases during the summer season, especially over the southern Red Sea. Previously estimated and validated radiative effect from dust is expected to have a profound thermal and dynamic impact on the Red Sea, but that impact has not yet been studied or evaluated. Due to the strong dust radiative effect at the sea surface, uncoupled ocean modeling approaches with prescribed atmospheric boundary conditions result in an unrealistic ocean response. Therefore, to study the impact of dust on the regional climate of the Middle East and the Red Sea, we employed the Regional Ocean Modeling System fully coupled with the Weather Research and Forecasting model. We modified the atmospheric model to account for the radiative effect of dust. The simulations show that, in the equilibrium response, dust cools the Red Sea, reduces the surface wind speed, and weakens both the exchange at the Bab-el-Mandeb strait and the overturning circulation. The salinity distribution, freshwater, and heat budgets are significantly altered. A validation of the simulations against satellite products indicates that accounting for radiative effect from dust almost completely removes the bias and reduces errors in the top of the atmosphere fluxes and sea surface temperature. Our results suggest that dust plays an important role in the energy balance, thermal, and circulation regimes in the Red Sea.

  5. Simulating the Regional Impact of Dust on the Middle East Climate and the Red Sea

    Science.gov (United States)

    Osipov, Sergey; Stenchikov, Georgiy

    2018-02-01

    The Red Sea is located between North Africa and the Arabian Peninsula, the largest sources of dust in the world. Satellite retrievals show very high aerosol optical depth in the region, which increases during the summer season, especially over the southern Red Sea. Previously estimated and validated radiative effect from dust is expected to have a profound thermal and dynamic impact on the Red Sea, but that impact has not yet been studied or evaluated. Due to the strong dust radiative effect at the sea surface, uncoupled ocean modeling approaches with prescribed atmospheric boundary conditions result in an unrealistic ocean response. Therefore, to study the impact of dust on the regional climate of the Middle East and the Red Sea, we employed the Regional Ocean Modeling System fully coupled with the Weather Research and Forecasting model. We modified the atmospheric model to account for the radiative effect of dust. The simulations show that, in the equilibrium response, dust cools the Red Sea, reduces the surface wind speed, and weakens both the exchange at the Bab-el-Mandeb strait and the overturning circulation. The salinity distribution, freshwater, and heat budgets are significantly altered. A validation of the simulations against satellite products indicates that accounting for radiative effect from dust almost completely removes the bias and reduces errors in the top of the atmosphere fluxes and sea surface temperature. Our results suggest that dust plays an important role in the energy balance, thermal, and circulation regimes in the Red Sea.

  6. Assessing extreme sea levels due to tropical cyclones in the Atlantic basin

    Science.gov (United States)

    Muis, Sanne; Lin, Ning; Verlaan, Martin; Winsemius, Hessel; Vatvani, Deepak; Ward, Philip; Aerts, Jeroen

    2017-04-01

    provide reliable probabilities of surge levels for the entire Atlantic basin. References Demuth, J., DeMaria, M., and Knaff, J.A. (2006). Improvement of advanced microwave sounder unit tropical cyclone intensity and size estimation algorithms. Journal of Applied Meteorology., 45, pp. 1573-1581. Emanuel, K., Ravela, S., Vivant, E. and Risi, C. (2006). A statistical deterministic approach to hurricane risk assessment. Bulletin of the American Meteorological Society, 87(3), pp.299-314. Holland, G.J. (1980). An analytic model of the wind and pressure profiles in hurricanes. Monthly Weather Review, 108(8), pp.1212-1218. Lin, N. and D. Chavas (2012). On hurricane parametric wind and applications in storm surge modeling. Journal of Geophysical Research - Atmospheres. 117. doi:10.1029/2011jd017126. Muis, S., Verlaan, M., Winsemius, H. C., Aerts, J. C. J. H., & Ward, P. J. (2016). A global reanalysis of storm surge and extreme sea levels. Nature Communications, 7(7:11969), 1-11.

  7. Geological and Structural evolution of the Eurasia Africa plate boundary in the Gulf of Cadiz Central Eastern Atlantic Sea.

    OpenAIRE

    D’Oriano, Filippo

    2010-01-01

    Iberia Africa plate boundary, cross, roughly W-E, connecting the eastern Atlantic Ocean from Azores triple junction to the Continental margin of Morocco. Relative movement between the two plate change along the boundary, from transtensive near the Azores archipelago, through trascurrent movement in the middle at the Gloria Fracture Zone, to transpressive in the Gulf of Cadiz area. This study presents the results of geophysical and geological analysis on the plate boundary area offshore Gibral...

  8. Potential contribution of surface-dwelling Sargassum algae to deep-sea ecosystems in the southern North Atlantic

    Science.gov (United States)

    Baker, Philip; Minzlaff, Ulrike; Schoenle, Alexandra; Schwabe, Enrico; Hohlfeld, Manon; Jeuck, Alexandra; Brenke, Nils; Prausse, Dennis; Rothenbeck, Marcel; Brix, Saskia; Frutos, Inmaculada; Jörger, Katharina M.; Neusser, Timea P.; Koppelmann, Rolf; Devey, Colin; Brandt, Angelika; Arndt, Hartmut

    2018-02-01

    Deep-sea ecosystems, limited by their inability to use primary production as a source of carbon, rely on other sources to maintain life. Sedimentation of organic carbon into the deep sea has been previously studied, however, the high biomass of sedimented Sargassum algae discovered during the VEMA Transit expedition in 2014/2015 to the southern North Atlantic, and its potential as a regular carbon input, has been an underestimated phenomenon. To determine the potential for this carbon flux, a literature survey of previous studies that estimated the abundance of surface water Sargassum was conducted. We compared these estimates with quantitative analyses of sedimented Sargassum appearing on photos taken with an autonomous underwater vehicle (AUV) directly above the abyssal sediment during the expedition. Organismal communities associated to Sargassum fluitans from surface waters were investigated and Sargassum samples collected from surface waters and the deep sea were biochemically analyzed (fatty acids, stable isotopes, C:N ratios) to determine degradation potential and the trophic significance within deep-sea communities. The estimated Sargassum biomass (fresh weight) in the deep sea (0.07-3.75 g/m2) was several times higher than that estimated from surface waters in the North Atlantic (0.024-0.84 g/m2). Biochemical analysis showed degradation of Sargassum occurring during sedimentation or in the deep sea, however, fatty acid and stable isotope analysis did not indicate direct trophic interactions between the algae and benthic organisms. Thus, it is assumed that components of the deep-sea microbial food web form an important link between the macroalgae and larger benthic organisms. Evaluation of the epifauna showed a diverse nano- micro-, meio, and macrofauna on surface Sargassum and maybe transported across the Atlantic, but we had no evidence for a vertical exchange of fauna components. The large-scale sedimentation of Sargassum forms an important trophic link

  9. The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

    Science.gov (United States)

    Hand, Ralf; Keenlyside, Noel S.; Omrani, Nour-Eddine; Bader, Jürgen; Greatbatch, Richard J.

    2018-03-01

    Beside its global effects, climate change is manifested in many regionally pronounced features mainly resulting from changes in the oceanic and atmospheric circulation. Here we investigate the influence of the North Atlantic SST on shaping the winter-time response to global warming. Our results are based on a long-term climate projection with the Max Planck Institute Earth System Model (MPI-ESM) to investigate the influence of North Atlantic sea surface temperature pattern changes on shaping the atmospheric climate change signal. In sensitivity experiments with the model's atmospheric component we decompose the response into components controlled by the local SST structure and components controlled by global/remote changes. MPI-ESM simulates a global warming response in SST similar to other climate models: there is a warming minimum—or "warming hole"—in the subpolar North Atlantic, and the sharp SST gradients associated with the Gulf Stream and the North Atlantic Current shift northward by a few a degrees. Over the warming hole, global warming causes a relatively weak increase in rainfall. Beyond this, our experiments show more localized effects, likely resulting from future SST gradient changes in the North Atlantic. This includes a significant precipitation decrease to the south of the Gulf Stream despite increased underlying SSTs. Since this region is characterised by a strong band of precipitation in the current climate, this is contrary to the usual case that wet regions become wetter and dry regions become drier in a warmer climate. A moisture budget analysis identifies a complex interplay of various processes in the region of modified SST gradients: reduced surface winds cause a decrease in evaporation; and thermodynamic, modified atmospheric eddy transports, and coastal processes cause a change in the moisture convergence. The changes in the the North Atlantic storm track are mainly controlled by the non-regional changes in the forcing. The impact of

  10. Structural geology of the North and Middle Caspian sea on the new geophysical data interpretation

    International Nuclear Information System (INIS)

    Boris, V.S; Rais, V.Sh; Victor, L.U

    2002-01-01

    Full text:A structural and tectonic map of the North and Middle Caspian Sea is made on the basis of seismic and other geological and geophysical data analysis. According to the plotting results the total amplitude range of the heterogeneous basement depths are in the North Caspian Sea (Ukatnensky depression-over 12 km and Prorva depression-over 16 km). In the middle Caspian Sea the deppest basement point is supposed in Sulak basin (over 12 km). The least basement depths are marked in Karpinsky ridge,Buzachinky and Karabogazsky arches (1-3 km). On the whole the morphology and structure of the basement confirms the conclusion previously made by many researches that the Caspian Sea is a heterogeneous depression superimposed on the junction of regional tectonic elements of various ages.The ancient East-European platform represented by Pricaspiisky depression (Donetsko-Astrakhanskaya fault system limits the latter in the south) is situated on the North. The middle Caspian Sea is occupied with the offshore continuation of Terek-Caspian foredeep is represented by Sulak basin clearly limited in the south by a system of upthrusts and thrusts falling under North Caucasus foreland.Geological interpretation of the Yuzhmorgeologiya Center new geophysical data allows making an assumption about the biohermexistence within TriassicSea sediments on Kuma-Manychsky depression offshore continuation. Seismic exploration works show strike-slip faults and thrust structure development within the sedimentary cover on the offshore continuation of Karpinsky ridge.Some strike-slipped blocks are separated by left-side shifts of the northeast stretch.The pool location at the left-side (east) blocks of the shift areas is marked.

  11. Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic.

    Science.gov (United States)

    Murillo, F J; Kenchington, E; Lawson, J M; Li, G; Piper, D J W

    Recent studies on deep-sea sponges have focused on mapping contemporary distributions while little work has been done to map historical distributions; historical distributions can provide valuable information on the time frame over which species have co-evolved and may provide insight into the reasons for their persistence or decline. Members of the sponge family Geodiidae are dominant members of deep-sea sponge assemblages in the northwestern Atlantic. They possess unique spicules called sterrasters, which undergo little transport in sediment and can therefore indicate the Geodiidae sponge historical presence when found in sediment cores. This study focuses on the slopes of Flemish Cap and Grand Bank, important fishing grounds off the coast of Newfoundland, Canada, in international waters. Sediment cores collected in 2009 and 2010 were visually inspected for sponge spicules. Cores containing spicules were sub-sampled and examined under a light microscope for the presence of sterrasters. These cores were also dated using X-radiographs and grouped into five time categories based on known sediment horizons, ranging from 17,000 years BP to the present. Chronological groupings identified Geodiidae sponges in four persistent sponge grounds. The oldest sterrasters were concentrated in the eastern region of the Flemish Cap and on the southeastern slope of the Grand Bank. Opportunistic sampling of a long core in the southeastern region of the Flemish Cap showed the continuous presence of sponge spicules to more than 130 ka BP. Our results indicate that the geodiids underwent a significant range expansion following deglaciation, and support a contemporary distribution that is not shaped by recent fishing activity.

  12. Influence of Tropical South Atlantic Sea Surface Temperatures on the Indian Summer monsoon in CMIP5 models

    Science.gov (United States)

    Kucharski, Fred; Joshi, Manish K.

    2017-04-01

    In this study the teleconnection from the tropical south Atlantic to the Indian monsoon has been assessed in observations and in 32 models from the World Climate Research Program (WCRP) Coupled Model Intercomparison Project Phase 5 (CMIP5). All models show that the regression pattern of tropics-wide Atlantic sea surface temperature (SST) anomalies onto the tropical south Atlantic index correlates well with that in observations, even though with varying spatial standard deviations. However, only about half of the 32 models considered show the correct sign of rainfall response over India to a warm anomaly in the south tropical Atlantic, which is a reduction of rainfall. On the other hand, models generally do show large-scale responses broadly consistent with the observations, and the signal over India depends on relatively subtle changes in the response. This response to a tropical south Atlantic warm (cold) anomaly is a low-level quadrupole in streamfunction with an anticyclonic (cyclonic) anomaly over the Arabian Sea and India. This anticyclonic (cyclonic) anomaly leads to a weakening (strengthening) of the Somali jet and low-level divergence (convergence) over India, both inducing a reduction (increase) of Indian rainfall. The models which do not show the correct rainfall response over India also show a response similar to the one indicated above, but with maximum of the anticyclonic (cyclonic) response shifted to the western Pacific. The large-scale Walker circulation adjustment to the tropical south Atlantic SST anomalies is identified as one of the factors which account for the differences in the low-level streamfunction response. Models (and the observations) with the correct sign of the rainfall signal over India show the dominant upper-level convergence (divergence) as response to a warm (cold) tropical south Atlantic in the western Pacific region, whereas models with the wrong sign of the rainfall signal show it predominantly in the central-eastern Pacific

  13. Summer Sea Ice Motion from the 18 GHz Channel of AMSR-E and the Exchange of Sea Ice between the Pacific and Atlantic Sectors

    Science.gov (United States)

    Kwok, Ronald

    2008-01-01

    We demonstrate that sea ice motion in summer can be derived reliably from the 18GHz channel of the AMSR-E instrument on the EOS Aqua platform. The improved spatial resolution of this channel with its lower sensitivity to atmospheric moisture seems to have alleviated various issues that have plagued summer motion retrievals from shorter wavelength observations. Two spatial filters improve retrieval quality: one reduces some of the microwave signatures associated with synoptic-scale weather systems and the other removes outliers. Compared with daily buoy drifts, uncertainties in motion are approx.3-4 km/day. Using the daily motion fields, we examine five years of summer ice area exchange between the Pacific and Atlantic sectors of the Arctic Ocean. With the sea-level pressure patterns during the summer of 2006 and 2007 favoring the export of sea ice into the Atlantic Sector, the regional outflow is approx.21% and approx.15% of the total sea ice retreat in the Pacific sector.

  14. Deepwater Horizon oil spill impacts on sea turtles could span the Atlantic.

    Science.gov (United States)

    Putman, Nathan F; Abreu-Grobois, F Alberto; Iturbe-Darkistade, Iñaky; Putman, Emily M; Richards, Paul M; Verley, Philippe

    2015-12-01

    We investigated the extent that the 2010 Deepwater Horizon oil spill potentially affected oceanic-stage sea turtles from populations across the Atlantic. Within an ocean-circulation model, particles were backtracked from the Gulf of Mexico spill site to determine the probability of young turtles arriving in this area from major nesting beaches. The abundance of turtles in the vicinity of the oil spill was derived by forward-tracking particles from focal beaches and integrating population size, oceanic-stage duration and stage-specific survival rates. Simulations indicated that 321 401 (66 199-397 864) green (Chelonia mydas), loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtles were likely within the spill site. These predictions compared favourably with estimates from in-water observations recently made available to the public (though our initial predictions for Kemp's ridley were substantially lower than in-water estimates, better agreement was obtained with modifications to mimic behaviour of young Kemp's ridley turtles in the northern Gulf). Simulations predicted 75.2% (71.9-76.3%) of turtles came from Mexico, 14.8% (11-18%) from Costa Rica, 5.9% (4.8-7.9%) from countries in northern South America, 3.4% (2.4-3.5%) from the United States and 1.6% (0.6-2.0%) from West African countries. Thus, the spill's impacts may extend far beyond the current focus on the northern Gulf of Mexico. © 2015 The Authors.

  15. Caribbean Sea rainfall variability during the rainy season and relationship to the equatorial Pacific and tropical Atlantic SST

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Renguang [Institute of Global Environment and Society, Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Kirtman, Ben P. [University of Miami, Rosenstiel School of Marine and Atmospheric Sciences, Miami, FL (United States)

    2011-10-15

    The present study investigates the Caribbean Sea rainfall variability during the early and late rainy seasons and its association with sea surface temperature (SST) and air-sea interaction based on observational estimates, the NCEP Climate Forecast System (CFS) and Global Forecast System (GFS) simulations, and the CFS retrospective forecasts. Analysis of the observational estimates indicates that air-sea interaction is important over the Caribbean Sea, whereas the atmospheric forcing of SST dominates over the Gulf of Mexico. The CFS simulation captures the basic elements of this observed air-sea relationship. The GFS simulation produces spurious SST forcing of the atmosphere over the Gulf of Mexico largely due to prescribing SST. The CFS forecasts capture the air-sea relationship in the late rainy season (August-October), but cannot reproduce the SST forcing of atmosphere over the Caribbean Sea in the early rainy season (May-July). An empirical orthogonal function (EOF) analysis indicates that the leading modes of percent anomalies of the rainy season precipitation have the largest loading in the southern Caribbean Sea in observations. The model simulations and forecasts skillfully reproduce the spatial pattern, but not the temporal evolution. The Caribbean Sea rainfall variability in the early rainy season is mainly due to the tropical North Atlantic (TNA) SST anomalies in observations, is contributed by both the TNA and eastern equatorial Pacific (EEP) SST anomalies in the CFS simulation, and has an overly large impact from the EEP SST anomalies in the GFS simulation and the CFS forecasts. The observed Caribbean Sea rainfall variability in the late rainy season has a leading impact from the EEP SST anomalies, with a secondary contribution from the TNA SST anomalies. In comparison, the model simulations and forecasts overestimate the impacts of the EEP SST anomalies due to an earlier development and longer duration of the El Nino-Southern Oscillation in the CFS

  16. Inter-Relationship Between Subtropical Pacific Sea Surface Temperature, Arctic Sea Ice Concentration, and the North Atlantic Oscillation in Recent Summers and Winters

    Science.gov (United States)

    Lim, Young-Kwon; Cullather, Richard I.; Nowicki, Sophie M.; Kim, Kyu-Myong

    2017-01-01

    The inter-relationship between subtropical western-central Pacific sea surface temperatures (STWCPSST), sea ice concentration in the Beaufort Sea (SICBS), and the North Atlantic Oscillation (NAO) are investigated for the last 37 summers and winters (1980-2016). Lag-correlation of the STWCPSST×(-1) in spring with the NAO phase and SICBS in summer increases over the last two decades, reaching r = 0.4-0.5 with significance at 5 percent, while winter has strong correlations in approximately 1985-2005. Observational analysis and the atmospheric general circulation model experiments both suggest that STWCPSST warming acts to increase the Arctic geopotential height and temperature in the following season. This atmospheric response extends to Greenland, providing favorable conditions for developing the negative phase of the NAO. SIC and surface albedo tend to decrease over the Beaufort Sea in summer, linked to the positive surface net shortwave flux. Energy balance considering radiative and turbulent fluxes reveal that available energy that can heat surface is larger over the Arctic and Greenland and smaller over the south of Greenland, in response to the STWCPSST warming in spring. XXXX Arctic & Atlantic: Positive upper-level height/T anomaly over the Arctic and Greenland, and a negative anomaly over the central-eastern Atlantic, resembling the (-) phase of the NAO. Pacific: The negative height/T anomaly over the mid-latitudes, along with the positive anomaly over the STWCP, where 1degC warming above climatology is prescribed. Discussion: It is likely that the Arctic gets warm and the NAO is in the negative phase in response to the STWCP warming. But, there are other factors (e.g., internal variability) that contribute to determination of the NAO phase: not always the negative phase of the NAO in the event of STWCP warming (e.g.: recent winters and near neutral NAO in 2017 summer).

  17. Correlation of Brunhes detrital-layer stratigraphy into the North Atlantic from Orphan Knoll (Labrador Sea)

    Science.gov (United States)

    Channell, J. E.; Hodell, D. A.; Romero, O. E.; Hillaire-Marcel, C.; de Vernal, A.; Stoner, J. S.; Mazaud, A.; Roehl, U.

    2011-12-01

    IODP Site U1302-U1303, on the SE flank of Orphan Knoll (Labrador Sea), has a record of detrital layers that extends through most of the Brunhes Chron. The age model is built by tandem matching of relative paleointensity (RPI) and oxygen isotope data (δ18O) from Neogloboquadrina pachyderma (sin.) to reference records, indicating a mean Brunhes sedimentation rate of 14 cm/kyr. Sedimentation back to marine isotope stage (MIS) 18 is characterized by detrital layers that are detected by higher than background gamma-ray attenuation (GRA) density, peaks in X-ray fluorescence (XRF) indicators for detrital carbonate (Ca/Sr) and detrital silicate (Si/Sr), an ice-rafted debris (IRD) proxy (>106 μm), magnetic susceptibility, and magnetic grain-size peaks. The age model enables correlation of Site U1302/03 to IODP Site U1308 (re-drill of DSDP Site 609) in the heart of the central Atlantic IRD belt where an age model and a similar set of detrital-layer proxies have already been derived. Ages of Heinrich layers H1, H2, H4, H5 and H6 are within ~2 kyr at the two sites (H0, H3 and H5a are not observed at Site U1308), and agree with previous work at Orphan Knoll within ~3 kyr. At Site U1308, Brunhes detrital layers are restricted to peak glacials and glacial terminations back to MIS16, however, these same proxies at Site U1302/03 indicate detrital layers distributed throughout the record in both glacial and most interglacial stages. At Site U1302/03, we distinguish Heinrich-type layers in glacial stages, which are associated with IRD (some of which have near-synchronous analogues at Site U1308), from detrital layers within interglacial stages manifested by multiple detrital layer proxies (including Ca/Sr) but usually not associated with IRD, that may be attributed to a distinct depositional process, namely drainage and debris-flow events funneled down the nearby NAMOC (North Atlantic Mid-Ocean Channel).

  18. Diversity, distribution and nature of faunal associations with deep-sea pennatulacean corals in the Northwest Atlantic.

    Directory of Open Access Journals (Sweden)

    Sandrine Baillon

    Full Text Available Anthoptilum grandiflorum and Halipteris finmarchica are two deep-sea corals (Octocorallia: Pennatulacea common on soft bottoms in the North Atlantic where they are believed to act as biogenic habitat. The former also has a worldwide distribution. To assist conservation efforts, this study examines spatial and temporal patterns in the abundance, diversity, and nature of their faunal associates. A total of 14 species were found on A. grandiflorum and 6 species on H. finmarchica during a multi-year and multi-site sampling campaign in eastern Canada. Among those, 7 and 5 species, respectively, were attached to the sea pens and categorized as close associates or symbionts. Rarefaction analyses suggest that the most common associates of both sea pens have been sampled. Biodiversity associated with each sea pen is analyzed according to season, depth and region using either close associates or the broader collection of species. Associated biodiversity generally increases from northern to southern locations and does not vary with depth (∼ 100-1400 m. Seasonal patterns in A. grandiflorum show higher biodiversity during spring/summer due to the transient presence of early life stages of fishes and shrimps whereas it peaks in fall for H. finmarchica. Two distinct endoparasitic species of highly modified copepods (families Lamippidae and Corallovexiidae commonly occur in the polyps of A. grandiflorum and H. finmarchica, and a commensal sea anemone frequently associates with H. finmarchica. Stable isotope analyses (δ(13C and δ(15N reveal potential trophic interactions between the parasites and their hosts. Overall, the diversity of obligate/permanent associates of sea pens is moderate; however the presence of mobile/transient associates highlights an ecological role that has yet to be fully elucidated and supports their key contribution to the enhancement of biodiversity in the Northwest Atlantic.

  19. Development of the Wintertime Sr/Ca-SST Record from Red Sea Corals as a Proxy for the North Atlantic Oscillation

    Science.gov (United States)

    Bernstein, W. N.; Hughen, K. A.

    2009-12-01

    The North Atlantic Oscillation (NAO) is one of the most pronounced and influential patterns in winter atmospheric circulation variability. This meridional redistribution of atmospheric mass across the Atlantic Ocean produces large changes in the intensity, number and direction of storms generated within the basin, and the regional climate of surrounding continents. The NAO exerts a significant impact on society, through influences on agriculture, fisheries, water management, energy generation and coastal development. NAO effects on climate extend from eastern North America across Europe to the eastern Mediterranean and Middle East. Changes in NAO behavior during the late 20th century have been linked to global warming; yet despite its importance, the causes and long-term patterns of NAO variability in the past remain poorly understood. In order to better predict the influence of the NAO on climate in the future, it is critical to examine multi-century NAO variability. The Red Sea is an excellent location from which to generate long NAO records for two reasons. First, patterns of wintertime sea surface temperature (SST) and salinity (SSS) in the Red Sea are highly correlated with NAO variability (Visbeck et al. 2001; Hurrell et al. 2003). Second, the tropical/subtropical Red Sea region contains fast growing long-lived massive Porites spp. corals with annually banded skeletons. These corals are ideal for generating well-dated high-resolution paleoclimatic records that extend well beyond the instrumental period. Here we present a study of winter SST and NAO variability in the Red sea region based on coral Sr/Ca data. In 2008, we collected multiple drill cores ranging in length from 1 to 4.1 meters from Porites corals at six sites spanning a large SST gradient. Sr/Ca measurements from multiple corals will be regressed against 23 years of satellite SST data, expanding the SST range over which we calibrate. A sampling resolution of 0.5mm will yield greater than bi

  20. Can preferred atmospheric circulation patterns over the North-Atlantic-Eurasian region be associated with arctic sea ice loss?

    Science.gov (United States)

    Crasemann, Berit; Handorf, Dörthe; Jaiser, Ralf; Dethloff, Klaus; Nakamura, Tetsu; Ukita, Jinro; Yamazaki, Koji

    2017-12-01

    In the framework of atmospheric circulation regimes, we study whether the recent Arctic sea ice loss and Arctic Amplification are associated with changes in the frequency of occurrence of preferred atmospheric circulation patterns during the extended winter season from December to March. To determine regimes we applied a cluster analysis to sea-level pressure fields from reanalysis data and output from an atmospheric general circulation model. The specific set up of the two analyzed model simulations for low and high ice conditions allows for attributing differences between the simulations to the prescribed sea ice changes only. The reanalysis data revealed two circulation patterns that occur more frequently for low Arctic sea ice conditions: a Scandinavian blocking in December and January and a negative North Atlantic Oscillation pattern in February and March. An analysis of related patterns of synoptic-scale activity and 2 m temperatures provides a synoptic interpretation of the corresponding large-scale regimes. The regimes that occur more frequently for low sea ice conditions are resembled reasonably well by the model simulations. Based on those results we conclude that the detected changes in the frequency of occurrence of large-scale circulation patterns can be associated with changes in Arctic sea ice conditions.

  1. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from the Atlantic Companion in the Inner Sea - West Coast Scotland, Irish Sea and St. George's Channel and North Atlantic Ocean from 2006-06-11 to 2007-11-05 (NODC Accession 0115226)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115226 includes chemical, meteorological, physical and underway - surface data collected from Atlantic Companion in the Inner Sea - West Coast...

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Atlantic Cartier in the Inner Sea - West Coast Scotland, Irish Sea and St. George's Channel and North Atlantic Ocean from 2015-09-12 to 2015-12-22 (NCEI Accession 0157236)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157236 includes Surface underway, chemical, meteorological and physical data collected from Atlantic Cartier in the Inner Sea - West Coast Scotland,...

  3. Trans-Atlantic application of the Baltic Middle and Upper Ordovician carbon isotope zonation

    Directory of Open Access Journals (Sweden)

    Stig M. Bergström

    2015-02-01

    Full Text Available Application of the recently introduced Baltic d13C isotope zonation to a composite North American Darriwilian through Hirnantian succession shows that in most intervals there is good trans-Atlantic agreement not only between the isotope zones but also with the available biostratigraphic data. This indicates that this isotope zonation is a useful tool for improving previously uncertain long-distance correlations.

  4. Mechanisms of decadal variability in the Labrador Sea and the wider North Atlantic in a high-resolution climate model

    Science.gov (United States)

    Ortega, Pablo; Robson, Jon; Sutton, Rowan T.; Andrews, Martin B.

    2017-10-01

    A necessary step before assessing the performance of decadal predictions is the evaluation of the processes that bring memory to the climate system, both in climate models and observations. These mechanisms are particularly relevant in the North Atlantic, where the ocean circulation, related to both the Subpolar Gyre and the Meridional Overturning Circulation (AMOC), is thought to be important for driving significant heat content anomalies. Recently, a rapid decline in observed densities in the deep Labrador Sea has pointed to an ongoing slowdown of the AMOC strength taking place since the mid 90s, a decline also hinted by in-situ observations from the RAPID array. This study explores the use of Labrador Sea densities as a precursor of the ocean circulation changes, by analysing a 300-year long simulation with the state-of-the-art coupled model HadGEM3-GC2. The major drivers of Labrador Sea density variability are investigated, and are characterised by three major contributions. First, the integrated effect of local surface heat fluxes, mainly driven by year-to-year changes in the North Atlantic Oscillation, which accounts for 62% of the total variance. Additionally, two multidecadal-to-centennial contributions from the Greenland-Scotland Ridge outflows are quantified; the first associated with freshwater exports via the East Greenland Current, and the second with density changes in the Denmark Strait Overflow. Finally, evidence is shown that decadal trends in Labrador Sea densities are followed by important atmospheric impacts. In particular, a positive winter NAO response appears to follow the negative Labrador Sea density trends, and provides a phase reversal mechanism.

  5. Were sea level changes during the Pleistocene in the South Atlantic Coastal Plain a driver of speciation in Petunia (Solanaceae)?

    Science.gov (United States)

    Ramos-Fregonezi, Aline M C; Fregonezi, Jeferson N; Cybis, Gabriela B; Fagundes, Nelson J R; Bonatto, Sandro L; Freitas, Loreta B

    2015-05-20

    Quaternary climatic changes led to variations in sea level and these variations played a significant role in the generation of marine terrace deposits in the South Atlantic Coastal Plain. The main consequence of the increase in sea level was local extinction or population displacement, such that coastal species would be found around the new coastline. Our main goal was to investigate the effects of sea level changes on the geographical structure and variability of genetic lineages from a Petunia species endemic to the South Atlantic Coastal Plain. We employed a phylogeographic approach based on plastid sequences obtained from individuals collected from the complete geographic distribution of Petunia integrifolia ssp. depauperata and its sister group. We used population genetics tests to evaluate the degree of genetic variation and structure among and within populations, and we used haplotype network analysis and Bayesian phylogenetic methods to estimate divergence times and population growth. We observed three major genetic lineages whose geographical distribution may be related to different transgression/regression events that occurred in this region during the Pleistocene. The divergence time between the monophyletic group P. integrifolia ssp. depauperata and its sister group (P. integrifolia ssp. integrifolia) was compatible with geological estimates of the availability of the coastal plain. Similarly, the origin of each genetic lineage is congruent with geological estimates of habitat availability. Diversification of P. integrifolia ssp. depauperata possibly occurred as a consequence of the marine transgression/regression cycles during the Pleistocene. In periods of high sea level, plants were most likely restricted to a refuge area corresponding to fossil dunes and granitic hills, from which they colonized the coast once the sea level came down. The modern pattern of lineage geographical distribution and population variation was established by a range

  6. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from KNORR in the North Atlantic Ocean, North Greenland Sea and others from 1972-07-18 to 1973-04-01 (NCEI Accession 0143398)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0143398 includes discrete sample and profile data collected from KNORR in the North Atlantic Ocean, North Greenland Sea, Norwegian Sea, South Atlantic...

  7. Reconstruction of middle-west Pangaea in and around Mediterranean Sea : A proposal of Pangaea model A3

    Science.gov (United States)

    Kwon, O.-hyeok; Cheong, Hyeong-Bin

    2017-04-01

    , which looks better than that presented by Bullard who succeeded in fitting almost seamlessly the west and east coastal lines of the Atlantic ocean. Such an elaborate fit was also done for most of middle-west part of Pangaea including Mediterranean Sea. Secondly, the Pangaea A3 appeared to be in strong support of the paleomagnetism observation. Though not perfect agreement with the paleomagnetism, the present model seems to be in better agreement than any other previous models. Thirdly, the Pangaea A3 model has brought a settlement to several unsolved problems such as overlapping of north- and south- America continent and the Europe and northern edge of the Africa. Fourthly, the Pangaea A3 model is also in good agreement with the paleo-geological survey, because it shows almost perfect match in the climate, biological distribution, and position of glaciers at those times. Fifthly, the Pangaea model clearly explains why the gap between the Gondwana and Laurasia becomes broader toward the east. Lastly, the present study was performed using an elaborate software, G-plate, to produce accurate and reliable results.

  8. State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast

    International Nuclear Information System (INIS)

    Titus, J G; Hudgens, D E; Kassakian, J M; Trescott, D L; Craghan, M; Nuckols, W H; Hershner, C H; Linn, C J; Merritt, P G; McCue, T M; O'Connell, J F; Tanski, J; Wang, J

    2009-01-01

    Rising sea level threatens existing coastal wetlands. Overall ecosystems could often survive by migrating inland, if adjacent lands remained vacant. On the basis of 131 state and local land use plans, we estimate that almost 60% of the land below 1 m along the US Atlantic coast is expected to be developed and thus unavailable for the inland migration of wetlands. Less than 10% of the land below 1 m has been set aside for conservation. Environmental regulators routinely grant permits for shore protection structures (which block wetland migration) on the basis of a federal finding that these structures have no cumulative environmental impact. Our results suggest that shore protection does have a cumulative impact. If sea level rise is taken into account, wetland policies that previously seemed to comply with federal law probably violate the Clean Water Act.

  9. Effects of the North Atlantic Oscillation and wind waves on salt marsh dynamics in the Danish Wadden Sea

    DEFF Research Database (Denmark)

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

    2013-01-01

    Long-term eustatic sea-level variation has been recognized as a primary factor affecting the hydrological and geomorphic dynamics of salt marshes. However, recent studies suggest that wind waves influenced by atmospheric oscillations also may play an important role in many coastal areas. Although...... this notion has been conceptually introduced for the Wadden Sea, no modeling attempts have been made yet. As a proof of concept, this study developed a simulation model using the commercially available STELLAA (R) software, based on long-term data on water level and sedimentation collected at a back......-barrier marsh on the Skallingen peninsula in Denmark. In the model, the frequency (number year(-1)) of wind-driven extreme high water level (HWL) events (> 130 cm Danish Ordnance Zero) was simulated in terms of the North Atlantic Oscillation (NAO) index. Then, surface accretion (cm year(-1)) and submergence...

  10. Aerosol Radiative Impact on the Middle East Regional Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2017-10-01

    The climate in the Middle East is complex and remains poorly understood. Due to the vast Arabian Desert, it is very sensitive to radiative forcing. Mineral dust is the dominant aerosol in this region. High background dust loading and frequent dust outbreaks significantly perturb the radiative balance and contribute to climate variability in the Middle East. To assess the climatological impact of dust in the region, we derived the aerosol optical properties and used a standalone column model to quantify radiative forcing sensitivity to a range of parameters representative of the Arabian Peninsula and the Red Sea. Simulations and modeling assumptions were validated using available in situ observations and satellite retrievals for fair weather and dust storm conditions. We incorporated the optical properties into the regional coupled ocean-atmosphere model and conducted simulations that represent the regional climate. The analysis shows that dust cools the Earth-atmosphere system and thus offsets the warming due to greenhouse gases. Dust reduces the sea surface temperature by 0.4 K, significantly perturbs energy balance, overturning circulation, and its purely dynamical impact reduces biological productivity in the Red Sea. In the real world, dust is present permanently and this does not allow to directly observe the climate response to the dust forcing. Volcanic eruptions produce a transient radiative impact that causes a detectable climate response that could be evaluated from observations and compared with simulations. Large equatorial eruptions are known to significantly perturb the Earth’s climate on the global scale, but their regional impact on the Middle East has not been thoroughly investigated. For example, the 1991 Mount Pinatubo eruption had a profound effect on the MENA and caused extensive coral bleaching in the Gulf of Aqaba. The analysis shows that observed cooling in the Middle East was mostly driven by changes in the atmospheric large

  11. Climate aberrations during the middle Miocene: evidence from the eastern North Atlantic Ocean

    NARCIS (Netherlands)

    Quaijtaal, W.; Donders, T.H.; Schouten, S.; Louwye, S.

    2013-01-01

    During the Middle Miocene Climatic Optimum (MMCO; 17-14.5 Ma) the relatively warm climate of the Miocene reached peak temperatures. After the MMCO, the global climate started cooling through several short-lived cooling events, represented by positive oxygen isotope excursions: the Mi-events (Miocene

  12. Characterization of Carbonate Crust from Deep-sea Methane Seeps on the Northern US Atlantic Margin.

    Science.gov (United States)

    Gabitov, R. I.; Borrelli, C.; Buettner, J.; Testa, M.; Garner, B.; Weremeichik, J.; Thomas, J. B.; Wahidi, M.; Thirumalai, R. V. K. G.; Kirkland, B. L.; Skarke, A. D.

    2017-12-01

    Authigenic carbonate minerals widely occur at the seafloor as carbonate crusts and are often directly linked to microbial activity, about which promotion of carbonate crystal growth and geochemistry are not entirely understood. To evaluate a potential metabolic contribution, studies were conducted on carbonate crust collected from a methane seep and on precipitation experiments which produced inorganic aragonite crystallized at high pressure. Among the samples collected during a NSF sponsored cruise to the North Atlantic Continental Margin of the United States (off of New England) in July-August 2016, we analyzed one carbonate crust sample (AD4835 BB-4522) collected at 39.805860; -69.592593 and at a depth of 1419.6 m. In this crust sample, two textural types of aragonite were identified: 1) groundmass consisting of fine grey crystals (100 µm, 24.9 wt%), feldspar (5.6 wt%), and dolomite (3.6 wt%), and trace amount of troilite were identified using XRD, SEM, and optical microscopy. The sample was cut into slabs parallel to crust growth assuming the crust grew in a downward direction. Concentrations of Na, Mg, Al, Si, S, K, Ca, Mn, Fe, Sr, Zr, Ba, and U were measured in the direction parallel to growth of the crust using LA-ICP-MS. Proportions of Si, Al, (Na+K), Mg, S, and Fe in the groundmass suggest the occurrence of sub-micron inclusions of alkali feldspar, and potentially pyroxene, Fe oxide, and Fe sulfide, which were impossible to avoid with the instrument's spatial resolution. The occurrence of micro non-carbonate inclusions causes high elemental concentrations compared to the values expected for aragonite crystallized from seawater. White aragonite acicular crystals were free of silicate and sulfide inclusions, and therefore, yielded lower concentrations of all measured elements except Sr compared to the groundmass. Analyzed Mg and Sr are consistent with published data for deep-sea corals. Also, Sr is similar to experimental data on inorganic aragonite. Mg

  13. The annual cycle of satellite derived sea surface temperature on the western South Atlantic shelf

    Directory of Open Access Journals (Sweden)

    Carlos A. D. Lentini

    2000-01-01

    Full Text Available In this article, thirteen years of weekly sea surface temperature (SST fields derived from NOAA Advanced Very High Resolution Radiometer global area coverage infrared satellite data, from January 1982 to December 1994, are used to investigate spatial and temporal variabilities of SST seasonal cycle in the Southwest Atlantic Oceano This work addresses large scale variations over the eastem South American continental shelf and slope regions limited offshore by the 1000-m isobath, between 42° and 22°S. SST time series are fit with annual and semi-annual harmonics to describe the annual variation of sea surface temperatures. The annual harmonic explains a large proportion of the SST variability. The coefficient of determination is highest (> 90% on the continental shelf, decreasing offshore. The estimated amplitude of the seasonal cycle ranges between 4° and 13°e throughout the study area, with minima in August­September and maxima in February-March. After the identification and removal of the dominant annual components ofSST variability, models such as the one presented here are an attractive tool to study interannual SST variability.Neste artigo, treze anos de imagens semanais da temperatura da superfície do mar (TSM obtidas através do sensor infravermelho Advanced Very High Resolution Radiometer a bordo dos satélites NOAA, de janeiro de 1982 a dezembro de 1994, são utlilizadas para investigar as variabilidades espacial e temporal do cicIo sazonal de TSM no Oceano Atlântico Sudoeste. Este trabalho objetiva as variações de larga escala sobre a plataforma continental e o talude leste da América do Sul limitados ao largo pela isóbata de 1000 metros, entre 42°5 e 22°S. As séries temporais de TSM são ajustadas aos .harmônicos anual e sem i-anual para descrever a variação anual das temperaturas da superfície do mar. O harmônico anual explica a maior parte da variabilidade da TSM. O coeficiente de determinação é alto (> 90

  14. The morphology of saccular otoliths as a tool to identify different mugilid species from the Northeastern Atlantic and Mediterranean Sea

    Science.gov (United States)

    Callicó Fortunato, Roberta; Benedito Durà, Vicent; Volpedo, Alejandra

    2014-06-01

    In the Northeastern Atlantic and Mediterranean Sea there are 8 species of the Mugilidae family: Mugil cephalus, Liza aurata, Liza ramada, Oedalechilus labeo, Chelon labrosus, Liza saliens, Liza carinata and Liza haematocheila. The identification of mugilids is very important for local fisheries management and regulations, but it is difficult using gross morphological characters. This work aims to contribute to the identification of mullets present in the Northeastern Atlantic Ocean and Mediterranean Sea using saccular otolith features of each species. Specimens of C. labrosus, L. aurata, L. ramada, L. saliens and M. cephalus were obtained from Delta del Ebro (40°38'N-0°44'E) in artisanal catches. For L. carinata and O. labeo photographs extracted from AFORO online database were used. L. haematocheila was not studied for lack of otolith samples. A general pattern of the saccular otoliths for this family was identified: the shape of the otoliths are rectangular to oblong with irregular margins; they present a heterosulcoid, ostial sulcus acusticus, with an open funnel-like ostium to the anterior margin and a closed, tubular cauda, ending towards the posterior ventral corner, always larger than the ostium. In the present study, the mugilid species could be recognized using their saccular otolith morphology. Here we give the first key to identify Northeastern Atlantic and Mediterranean mullets. The distinctive features between the species were the position and centrality of the sulcus, the curvature of the cauda, the presence of areal depositions and plateaus, and the type of anterior and posterior regions. These features could be used not only to reinforce the identification keys through morphological and meristic characters of the species, but also to identify the species consumed by piscivores, being the otoliths the only identifiable remains of the individuals.

  15. North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation

    Directory of Open Access Journals (Sweden)

    I. Medhaug

    2011-06-01

    Full Text Available Output from a total of 24 state-of-the-art Atmosphere-Ocean General Circulation Models is analyzed. The models were integrated with observed forcing for the period 1850–2000 as part of the Intergovernmental Panel on Climate Change (IPCC Fourth Assessment Report. All models show enhanced variability at multi-decadal time scales in the North Atlantic sector similar to the observations, but with a large intermodel spread in amplitudes and frequencies for both the Atlantic Multidecadal Oscillation (AMO and the Atlantic Meridional Overturning Circulation (AMOC. The models, in general, are able to reproduce the observed geographical patterns of warm and cold episodes, but not the phasing such as the early warming (1930s–1950s and the following colder period (1960s–1980s. This indicates that the observed 20th century extreme in temperatures are due to primarily a fortuitous phasing of intrinsic climate variability and not dominated by external forcing. Most models show a realistic structure in the overturning circulation, where more than half of the available models have a mean overturning transport within the observed estimated range of 13–24 Sverdrup. Associated with a stronger than normal AMOC, the surface temperature is increased and the sea ice extent slightly reduced in the North Atlantic. Individual models show potential for decadal prediction based on the relationship between the AMO and AMOC, but the models strongly disagree both in phasing and strength of the covariability. This makes it difficult to identify common mechanisms and to assess the applicability for predictions.

  16. Genetic diversity of the NE Atlantic sea urchin Strongylocentrotus droebachiensis unveils chaotic genetic patchiness possibly linked to local selective pressure.

    Science.gov (United States)

    Norderhaug, K M; Anglès d'Auriac, M B; Fagerli, C W; Gundersen, H; Christie, H; Dahl, K; Hobæk, A

    We compared the genetic differentiation in the green sea urchin Strongylocentrotus droebachiensis from discrete populations on the NE Atlantic coast. By using eight recently developed microsatellite markers, genetic structure was compared between populations from the Danish Strait in the south to the Barents Sea in the north (56-79°N). Urchins are spread by pelagic larvae and may be transported long distances by northwards-going ocean currents. Two main superimposed patterns were identified. The first showed a subtle but significant genetic differentiation from the southernmost to the northernmost of the studied populations and could be explained by an isolation by distance model. The second pattern included two coastal populations in mid-Norway (65°N), NH and NS, as well as the northernmost population of continental Norway (71°N) FV. They showed a high degree of differentiation from all other populations. The explanation to the second pattern is most likely chaotic genetic patchiness caused by introgression from another species, S. pallidus, into S. droebachiensis resulting from selective pressure. Ongoing sea urchin collapse and kelp forests recovery are observed in the area of NH, NS and FV populations. High gene flow between populations spanning more than 22° in latitude suggests a high risk of new grazing events to occur rapidly in the future if conditions for sea urchins are favourable. On the other hand, the possibility of hybridization in association with collapsing populations may be used as an early warning indicator for monitoring purposes.

  17. Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    Science.gov (United States)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-05-01

    Shipboard measurements of eddy covariance DMS air/sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air/sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near surface water side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air/sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  18. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages

    Directory of Open Access Journals (Sweden)

    Schaefer Hanno

    2012-12-01

    middle Miocene and spread from there across Eurasia, into Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years. Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.

  19. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages.

    Science.gov (United States)

    Schaefer, Hanno; Hechenleitner, Paulina; Santos-Guerra, Arnoldo; Menezes de Sequeira, Miguel; Pennington, R Toby; Kenicer, Gregory; Carine, Mark A

    2012-12-25

    Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years). Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.

  20. Acropora palmata reef framework: A reliable indicator of sea level in the western atlantic for the past 10,000 years

    Science.gov (United States)

    Lighty, R. G.; MacIntyre, I. G.; Stuckenrath, R.

    1982-10-01

    A minimum sea-level curve for the past 10,000 years has been constructed on the basis of radiocarbon dates of Acropora palmata (Lamarck) samples from the shallow-water framework of both relict and modern reefs of the tropical western Atlantic. A. palmata framework is a reliable reference for reconstructing the history of late Quaternary sea levels owing to its restricted depth range (palmata framework, the ease of obtaining uncontaminated samples, and the minimal compaction of A. palmata reef facies. The minimum sea-level curve constructed in this study is useful not only in evaluating the reliability of present and future Holocene sea-level curves for the western Atlantic, but also in estimating paleo-water depths in the study of Holocene reef history of this area.

  1. Potential for shoreline changes due to sea-level rise along the U.S. mid-Atlantic region

    Science.gov (United States)

    Gutierrez, Benjamin T.; Williams, S. Jeffress; Thieler, E. Robert

    2007-01-01

    Sea-level rise over the next century is expected to contribute significantly to physical changes along open-ocean shorelines. Predicting the form and magnitude of coastal changes is important for understanding the impacts to humans and the environment. Presently, the ability to predict coastal changes is limited by the scientific understanding of the many variables and processes involved in coastal change, and the lack of consensus regarding the validity of existing conceptual, analytical, or numerical models. In order to assess potential future coastal changes in the mid-Atlantic U.S. for the U.S. Climate Change Science Program (CCSP), a workshop was convened by the U.S. Geological Survey. Assessments of future coastal change were made by a committee of coastal scientists with extensive professional experience in the mid-Atlantic region. Thirteen scientists convened for a two-day meeting to exchange information and develop a consensus opinion on potential future coastal changes for the mid-Atlantic coast in response to sea-level rise. Using criteria defined in past work, the mid-Atlantic coast was divided into four geomorphic compartments: spits, headlands, wave-dominated barriers, and mixed-energy barriers. A range of potential coastal responses was identified for each compartment based on four sea-level rise scenarios. The four scenarios were based on the assumptions that: a) the long-term sea-level rise rate observed over the 20th century would persist over the 21st century, b) the 20th century rate would increase by 2 mm/yr, c) the 20th century rate would increase by 7 mm/yr, or d) sea-level would rise by 2 m over the next few hundred years. Potential responses to these sea-level rise scenarios depend on the landforms that occur within a region and include increased likelihood for erosion and shoreline retreat for all coastal types, increased likelihood for erosion, overwash and inlet breaching for barrier islands, as well as the possibility of a threshold

  2. Other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from unknown platforms in the North Atlantic Ocean, North Sea and Norwegian Sea from 1874-01-01 to 2005-12-31 (NCEI Accession 0144342)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144342 includes discrete sample and profile data collected from unknown platforms in the North Atlantic Ocean, North Sea and Norwegian Sea from...

  3. Distribution of Polycystine Radiolarians in Bottom Surface Sediments and Its Relation to Summer Sea Temperature in the High-Latitude North Atlantic

    Directory of Open Access Journals (Sweden)

    Alexander Matul

    2017-10-01

    Full Text Available An objective of the study is to get new biogeographic information on the modern polycystine radiolarians from the high-latitude North Atlantic. The quantitative radiolarian dataset was compiled from publications and own micropaleontological counts from samples of the bottom surface sediments of the North Atlantic north of 40°N and Nordic Seas. Standard statistical treatment of micropaleontological data by factor analysis reveals five radiolarian assemblages which have their highest load at the specific temperature range in agreement with the oceanographic setting. An occurrence of radiolarian assemblages reflects extension and interaction of the warm North Atlantic and cold Polar/Arctic waters. Radiolarian distribution exhibits good correlation with the climatically averaged summer sea temperature on depth level of 200 m.

  4. Development of temporal trends of radioactivity in benthic organisms and in water from the deep sea (Atlantic)

    International Nuclear Information System (INIS)

    Kanisch, G.; Kellermann, H.-J.; Vobach, M.; Krueger, A.

    2003-01-01

    Since 20 years the Federal Research Centre for Fisheries is performing radioecological studies in the deep sea of the Northeast Atlantic, especially in the area north-west of Spain used for dumping of radioactive waste until 1982. Until 1998/2000, in Benthos some decrease was observed for 137 Cs, however, almost not for 238 Pu, 239,240 Pu and 241 Am. In the dumpsite area the ratio 238 Pu/ 239,240 Pu, about 0.072, showed higher values than in comparison sites, about 0,044. Alpha spectrometric measurements of the atom based ratio 240 Pu/ 239 Pu in Benthos, due to slight deviations from the global fallout value of 0.18, indicated a special impact of the ''Nevada Test Site'' fallout. In rat-tailed fish (Macrouridae) from the deep sea 137Cs decreased since 1989 with an effective half-live of 14.5 years, comparable to that of 16.2 years in the surface water. Related to the concentration in the surface water a 137 Cs concentration factor of 83 was obtained. It is concluded that the dominant source for 137 Cs in deep sea fish is the global fallout. For plutonium isotopes measured in sea water samples from the deep the values of 238 Pu/ 239,240 Pu and 238 Pu, being higher for the dumpsite area, were interpreted as impact of leaking radioactive drums. For this leakage acting as a plutonium source a 238 Pu/ 239,240 Pu ratio of 0.17 was estimated. However, the total plutonium inventory in the deep sea thereby increased by only about 20 %. (orig.)

  5. The Teleconnection of the Tropical Atlantic to Indo-Pacific Sea Surface Temperatures on Inter-Annual to Centennial Time Scales: A Review of Recent Findings

    Directory of Open Access Journals (Sweden)

    Fred Kucharski

    2016-02-01

    Full Text Available In this paper, the teleconnections from the tropical Atlantic to the Indo-Pacific region from inter-annual to centennial time scales will be reviewed. Identified teleconnections and hypotheses on mechanisms at work are reviewed and further explored in a century-long pacemaker coupled ocean-atmosphere simulation ensemble. There is a substantial impact of the tropical Atlantic on the Pacific region at inter-annual time scales. An Atlantic Niño (Niña event leads to rising (sinking motion in the Atlantic region, which is compensated by sinking (rising motion in the central-western Pacific. The sinking (rising motion in the central-western Pacific induces easterly (westerly surface wind anomalies just to the west, which alter the thermocline. These perturbations propagate eastward as upwelling (downwelling Kelvin-waves, where they increase the probability for a La Niña (El Niño event. Moreover, tropical North Atlantic sea surface temperature anomalies are also able to lead La Niña/El Niño development. At multidecadal time scales, a positive (negative Atlantic Multidecadal Oscillation leads to a cooling (warming of the eastern Pacific and a warming (cooling of the western Pacific and Indian Ocean regions. The physical mechanism for this impact is similar to that at inter-annual time scales. At centennial time scales, the Atlantic warming induces a substantial reduction of the eastern Pacific warming even under CO2 increase and to a strong subsurface cooling.

  6. Growth studies on Norway lobster, Nephrops norvegicus (L., in different areas of the Mediterranean Sea and the adjacent Atlantic

    Directory of Open Access Journals (Sweden)

    Chryssi Mytilineou

    1998-12-01

    Full Text Available A comparative study of the growth of Nephrops norvegicus among different areas in the Mediterranean Sea and the adjacent Atlantic was conducted. MIX and Bhattacharya´s length-based methods were used for age determination. Both methods were used for all the studied areas. For the estimation of the growth parameters two non-linear methods, based on the results of the length frequency analysis, were used; the Gauss-Newton method, implemented by the SAS program, was applied using the results of the MIX and the FISHPARM program using the results of the Bhattacharya´s method. The identification of the age groups and their mean lengths-at-age as well as the estimation of the growth parameters proved to be difficult. A question regarding the adequacy of the von Bertalanffy model was also posed. Remarkable differences were obvious between sexes in the number of identified age groups and their mean lengths-at-age as well as in their growth parameters in all areas. The comparison of the results obtained for the studied areas showed differences, which could not be considered very important except in the case of the Nephrops population of the Alboran Sea, which was characterised by a high growth rate. All other areas seemed to be close; among them the populations from Euboikos Gulf and Catalan Sea being the most different.

  7. Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas

    OpenAIRE

    van Ginneken, Vincent JT; Helsper, Johannes PFG; de Visser, Willem; van Keulen, Herman; Brandenburg, Willem A

    2011-01-01

    Abstract Background In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. Methods The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (...

  8. Coastal sensitivity to sea level rise : a focus on the mid-atlantic region

    Science.gov (United States)

    2009-01-15

    The focus of this product is to identify and review the potential impacts of future sea-level rise based on present scientific understanding. To do so, this product evaluates : several aspects of sea-level rise impacts to the natural environment and ...

  9. Sea-to-air and diapycnal nitrous oxide fluxes in the eastern tropical North Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    A. Kock

    2012-03-01

    Full Text Available Sea-to-air and diapycnal fluxes of nitrous oxide (N2O into the mixed layer were determined during three cruises to the upwelling region off Mauritania. Sea-to-air fluxes as well as diapycnal fluxes were elevated close to the shelf break, but elevated sea-to-air fluxes reached further offshore as a result of the offshore transport of upwelled water masses. To calculate a mixed layer budget for N2O we compared the regionally averaged sea-to-air and diapycnal fluxes and estimated the potential contribution of other processes, such as vertical advection and biological N2O production in the mixed layer. Using common parameterizations for the gas transfer velocity, the comparison of the average sea-to-air and diapycnal N2O fluxes indicated that the mean sea-to-air flux is about three to four times larger than the diapycnal flux. Neither vertical and horizontal advection nor biological production were found sufficient to close the mixed layer budget. Instead, the sea-to-air flux, calculated using a parameterization that takes into account the attenuating effect of surfactants on gas exchange, is in the same range as the diapycnal flux. From our observations we conclude that common parameterizations for the gas transfer velocity likely overestimate the air-sea gas exchange within highly productive upwelling zones.

  10. An assessment of the radiological impact of sea-dumping at the North East Atlantic dump site

    International Nuclear Information System (INIS)

    Delow, C.E.; Mobbs, S.F.; Hill, M.D.

    1985-04-01

    This report describes the models and methodology developed for the assessment of the radiological impact of disposal of low and intermediate level waste on the seabed. The development of the waste package model and the combined model of radionuclide dispersion and interactions with sediments in the world's ocean is outlined. This integrated set of models was used for the radiological assessment of sea dumping at the North-East Atlantic site, which formed part of the recent NEA review of the continued suitability of this site. The predicted radiation doses to man are presented, together with the results of the analysis of the sensitivity of the annual individual doses to critical groups to variations in model parameters. (author)

  11. Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre.

    Science.gov (United States)

    Pham, Christopher K; Rodríguez, Yasmina; Dauphin, Axelle; Carriço, Rita; Frias, João P G L; Vandeperre, Frederic; Otero, Vanessa; Santos, Marco R; Martins, Helen R; Bolten, Alan B; Bjorndal, Karen A

    2017-08-15

    Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2007-01-01

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

  13. Deep-sea dives reveal an unexpected hexactinellid sponge garden on the Rio Grande Rise (SW Atlantic). A mimicking habitat?

    Science.gov (United States)

    Hajdu, Eduardo; Castello-Branco, Cristiana; Lopes, Daniela A.; Sumida, Paulo Yukio Gomes; Perez, Jose Angel Alvarez

    2017-12-01

    Long overlooked, sponge grounds are now recognised as important habitats which support high biodiversity. Some of these deep-sea sponge aggregations are formed by hexactinellids, in varying densities, which can occur on both soft and hard substrates. Despite their ecological importance as habitat framework building taxa, hexactinellids have been little studied and only 33 species in this Class were reported from the entire South Atlantic until now. Most of this knowledge was gained from studies conducted on the eastern South America continental slope. Here we report a new hexactinellid sponge garden found by the Shinkai 6500 manned submersible on the Rio Grande Rise, a prominent topographic feature of the deep SW Atlantic. This is the first sponge garden worldwide found to be dominated by the stiff, often dichotomously branching, Sarostegia oculata which may occur in densities of over 5 individuals per square meter. This sponge, of uncertain familial allocation, seems to always carry epibiotic zoanthids, thus mimicking the 3D skeletal framework of actual coral gardens

  14. Risk assessment reveals high exposure of sea turtles to marine debris in French Mediterranean and metropolitan Atlantic waters

    Science.gov (United States)

    Darmon, Gaëlle; Miaud, Claude; Claro, Françoise; Doremus, Ghislain; Galgani, François

    2017-07-01

    Debris impact on marine wildlife has become a major issue of concern. Mainy species have been identified as being threatened by collision, entanglement or ingestion of debris, generally plastics, which constitute the predominant part of the recorded marine debris. Assessing sensitive areas, where exposure to debris are high, is thus crucial, in particular for sea turtles which have been proposed as sentinels of debris levels for the Marine Strategy Framework Directive and for the Unep-MedPol convention. Our objective here was to assess sea turtle exposure to marine debris in the 3 metropolitan French fronts. Using aerial surveys performed in the Channel, the Atlantic and the Mediterranean regions in winter and summer 2011-2012, we evaluated exposure areas and magnitude in terms of spatial overlap, encounter probability and density of surrounding debris at various spatial scales. Major overlapping areas appeared in the Atlantic and Mediterranean fronts, concerning mostly the leatherback and the loggerhead turtles respectively. The probability for individuals to be in contact with debris (around 90% of individuals within a radius of 2 km) and the density of debris surrounding individuals (up to 16 items with a radius of 2 km, 88 items within a radius of 10 km) were very high, whatever the considered spatial scale, especially in the Mediterranean region and during the summer season. The comparison of the observed mean debris density with random distribution suggested that turtles selected debris areas. This may occur if both debris and turtles drift to the same areas due to currents, if turtles meet debris accidentally by selecting high food concentration areas, and/or if turtles actively seek debris out, confounding them with their preys. Various factors such as species-specific foraging strategies or oceanic features which condition the passive diffusion of debris, and sea turtles in part, may explain spatio-temporal variations in sensitive areas. Further research

  15. Importance of flexure in response to sedimentation and erosion along the US Atlantic passive margin in reconciling sea level change and paleoshorelines

    Science.gov (United States)

    Moucha, R.; Ruetenik, G.; de Boer, B.

    2017-12-01

    Reconciling elevations of paleoshorelines along the US Atlantic passive margin with estimates of eustatic sea level have long posed to be a challenge. Discrepancies between shoreline elevation and sea level have been attributed to combinations of tectonics, glacial isostatic adjustment, mantle convection, gravitation and/or errors, for example, in the inference of eustatic sea level from the marine 18O record. Herein we present a numerical model of landscape evolution combined with sea level change and solid Earth deformations to demonstrate the importance of flexural effects in response to erosion and sedimentation along the US Atlantic passive margin. We quantify these effects using two different temporal models. One reconciles the Orangeburg scarp, a well-documented 3.5 million-year-old mid-Pliocene shoreline, with a 15 m mid-Pliocene sea level above present-day (Moucha and Ruetenik, 2017). The other model focuses on the evolution of the South Carolina and northern Georgia margin since MIS 11 ( 400 Ka) using a fully coupled ice sheet, sea level and solid Earth model (de Boer et al, 2014) while relating our results to a series of enigmatic sea level high stand markers. de Boer, B., Stocci, P., and van de Wal, R. (2014). A fully coupled 3-d ice-sheet-sea-level model: algorithm and applications. Geoscientific Model Development, 7:2141-2156. Moucha, R. and Ruetenik, G. A. (2017). Interplay between dynamic topography and flexure along the US Atlantic passive margin: Insights from landscape evolution modeling. Global and Planetary Change, 149: 72-78

  16. North sea: a quarter of total's reserves (excluding the Middle East)

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    In 1994, for the fifth successive year, Total increased its proven reserves of hydrocarbons which reach 4.3 Gboe (+ 6% compared to 1993). Outside the Middle East, the reserves show a development of 9% and reach the threshold of 2 Gboe. In 1994, Total's production of hydrocarbons reached 633,000 boe/d (+ 4%), despite a fall of 3% in oil production in the Middle East. Excluding the Middle East, production was increased to 345,000 boe/d (+ 12%), including 212,000 boe/d for gas (+ 20%). Exploration/production investments were 5.8 GF in 1994 (excluding labour) and the development program for reserves and production for the coming years is based on yearly investments of some 6 GF. Total's production in Europe, essentially in the North Sea, was 154,000 boe/d in 1994 (+ 12%). This zone has potential for significant growth for the group which has undertaken exploration surveys in the Western Shetlands and in Haltenbanken. In the British zone, the Dunbar field and its neighbour Ellon were brought into production in December 1994. In the Norwegian zone, the Froy field, was brought into production last June. In the Lille-Frigg field, whose production started in May, initial reserves are estimated at 6,7 Bcm of gas. Total Norge AS also has interests in the producing fields of Ekofisk, Frigg, East-Frigg, Heimdal, Sleipner East, Veslefrikk, Oseberg, Brage, in those of Sleipner West and Huldra (start-up scheduled for 1997) and in Troll (phase 1) which should be producing in 1996. In the Dutch zone, the K4b and K5a blocks brought into production last November hold reserves estimated at 20 Bcm; their production could reach 2 Bcm/year as from 1995. (authors). 1 tab., 1 photo

  17. Coccolithophore surface distributions in the North Atlantic and their modulation of the air-sea flux of CO2 from 10 years of satellite Earth observation data

    Directory of Open Access Journals (Sweden)

    J. D. Shutler

    2013-04-01

    Full Text Available Coccolithophores are the primary oceanic phytoplankton responsible for the production of calcium carbonate (CaCO3. These climatically important plankton play a key role in the oceanic carbon cycle as a major contributor of carbon to the open ocean carbonate pump (~50% and their calcification can affect the atmosphere-to-ocean (air-sea uptake of carbon dioxide (CO2 through increasing the seawater partial pressure of CO2 (pCO2. Here we document variations in the areal extent of surface blooms of the globally important coccolithophore, Emiliania huxleyi, in the North Atlantic over a 10-year period (1998–2007, using Earth observation data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS. We calculate the annual mean sea surface areal coverage of E. huxleyi in the North Atlantic to be 474 000 ± 104 000 km2, which results in a net CaCO3 carbon (CaCO3-C production of 0.14–1.71 Tg CaCO3-C per year. However, this surface coverage (and, thus, net production can fluctuate inter-annually by −54/+8% about the mean value and is strongly correlated with the El Niño/Southern Oscillation (ENSO climate oscillation index (r=0.75, pE. huxleyi blooms in the North Atlantic can increase the pCO2 and, thus, decrease the localised air-sea flux of atmospheric CO2. In regions where the blooms are prevalent, the average reduction in the monthly air-sea CO2 flux can reach 55%. The maximum reduction of the monthly air-sea CO2 flux in the time series is 155%. This work suggests that the high variability, frequency and distribution of these calcifying plankton and their impact on pCO2 should be considered if we are to fully understand the variability of the North Atlantic air-to-sea flux of CO2. We estimate that these blooms can reduce the annual N. Atlantic net sink atmospheric CO2 by between 3–28%.

  18. A new species of brooding Psolidae (Echinodermata: Holothuroidea) from deep-sea off Argentina, Southwestern Atlantic Ocean

    Science.gov (United States)

    Martinez, Mariano I.; Penchaszadeh, Pablo E.

    2017-12-01

    This paper describes a new species of Psolus (Holothuroidea, Echinodermata), P. lawrencei sp. nov., (19 specimens) found in the deep sea (308-1398 m) in the Southwestern Atlantic Ocean (SWAO) (around 38°S-54°W) with brooders (up to 3.15 mm) in the tentacles of females and a penis-like genital papilla on males. The presence of dorsal scales, the concave shape of the ossicles with a bridge, the distribution of podia on the dorsal side and the absence of large and conspicuous oral and anal valves are unique for this species. Furthermore, this is the first species of this genus found outside Antarctica that broods between its tentacles. The paper also reviews the reproductive, brooding development and morphological characteristics of P. lawrencei sp. nov. and compares them with those of several members of the family Psolidae. Finally, a possible connectivity between the deep-sea populations in the SWAO and in Antarctica is considered based on the appearance of a similar reproductive pattern in populations found in both areas, which suggests a past or present connection between these regions.

  19. Temporal, spatial, and body size effects on growth rates of loggerhead sea turtles (Caretta caretta) in the Northwest Atlantic

    Science.gov (United States)

    Bjorndal, Karen A.; Schroeder, Barbara A.; Foley, Allen M.; Witherington, Blair E.; Bresette, Michael; Clark, David; Herren, Richard M.; Arendt, Michael D.; Schmid, Jeffrey R.; Meylan, Anne B.; Meylan, Peter A.; Provancha, Jane A.; Hart, Kristen M.; Lamont, Margaret M.; Carthy, Raymond R.; Bolten, Alan B.

    2013-01-01

    In response to a call from the US National Research Council for research programs to combine their data to improve sea turtle population assessments, we analyzed somatic growth data for Northwest Atlantic (NWA) loggerhead sea turtles (Caretta caretta) from 10 research programs. We assessed growth dynamics over wide ranges of geography (9–33°N latitude), time (1978–2012), and body size (35.4–103.3 cm carapace length). Generalized additive models revealed significant spatial and temporal variation in growth rates and a significant decline in growth rates with increasing body size. Growth was more rapid in waters south of the USA (productivity to a common environmental change should be explored to determine whether somatic growth rates can help interpret population trends based on annual counts of nests or nesting females. Because of the significant spatial and temporal variation in growth rates, population models of NWA loggerheads should avoid employing growth data from restricted spatial or temporal coverage to calculate demographic metrics such as age at sexual maturity.

  20. Modeling Biogeochemical-Physical Interactions and Carbon Flux in the Sargasso Sea (Bermuda Atlantic Time-series Study site)

    Science.gov (United States)

    Signorini, Sergio R.; McClain, Charles R.; Christian, James R.

    2001-01-01

    An ecosystem-carbon cycle model is used to analyze the biogeochemical-physical interactions and carbon fluxes in the Bermuda Atlantic Time-series Study (BATS) site for the period of 1992-1998. The model results compare well with observations (most variables are within 8% of observed values). The sea-air flux ranges from -0.32 to -0.50 mol C/sq m/yr, depending upon the gas transfer algorithm used. This estimate is within the range (-0.22 to -0.83 mol C/sq m/yr) of previously reported values which indicates that the BATS region is a weak sink of atmospheric CO2. The overall carbon balance consists of atmospheric CO2 uptake of 0.3 Mol C/sq m/yr, upward dissolved inorganic carbon (DIC) bottom flux of 1.1 Mol C/sq m/yr, and carbon export of 1.4 mol C/sq m/yr via sedimentation. Upper ocean DIC levels increased between 1992 and 1996 at a rate of approximately 1.2 (micro)mol/kg/yr, consistent with observations. However, this trend was reversed during 1997-1998 to -2.7 (micro)mol/kg/yr in response to hydrographic changes imposed by the El Nino-La Nina transition, which were manifested in the Sargasso Sea by the warmest SST and lowest surface salinity of the period (1992-1998).

  1. Bathymetric and geographic population structure in the pan-Atlantic deep-sea bivalve Deminucula atacellana (Schenck, 1939).

    Science.gov (United States)

    Zardus, John D; Etter, Ron J; Chase, Michael R; Rex, Michael A; Boyle, Elizabeth E

    2006-03-01

    The deep-sea soft-sediment environment hosts a diverse and highly endemic fauna of uncertain origin. We know little about how this fauna evolved because geographic patterns of genetic variation, the essential information for inferring patterns of population differentiation and speciation are poorly understood. Using formalin-fixed specimens from archival collections, we quantify patterns of genetic variation in the protobranch bivalve Deminucula atacellana, a species widespread throughout the Atlantic Ocean at bathyal and abyssal depths. Samples were taken from 18 localities in the North American, West European and Argentine basins. A hypervariable region of mitochondrial 16S rDNA was amplified by polymerase chain reaction (PCR) and sequenced from 130 individuals revealing 21 haplotypes. Except for several important exceptions, haplotypes are unique to each basin. Overall gene diversity is high (h = 0.73) with pronounced population structure (Phi(ST) = 0.877) and highly significant geographic associations (P < 0.0001). Sequences cluster into four major clades corresponding to differences in geography and depth. Genetic divergence was much greater among populations at different depths within the same basin, than among those at similar depths but separated by thousands of kilometres. Isolation by distance probably explains much of the interbasin variation. Depth-related divergence may reflect historical patterns of colonization or strong environmental selective gradients. Broadly distributed deep-sea organisms can possess highly genetically divergent populations, despite the lack of any morphological divergence.

  2. Sea-Level Rise Implications for Coastal Protection from Southern Mediterranean to the U.S.A. Atlantic Coast

    Science.gov (United States)

    Ismail, Nabil; Williams, Jeffress

    2013-04-01

    This paper presents an assessment of global sea level rise and the need to incorporate projections of rise into management plans for coastal adaptation. It also discusses the performance of a shoreline revetment; M. Ali Seawall, placed to protect the land against flooding and overtopping at coastal site, within Abu Qir Bay, East of Alexandria, Egypt along the Nile Delta coast. The assessment is conducted to examine the adequacy of the seawall under the current and progressive effects of climate change demonstrated by the anticipated sea level rise during this century. The Intergovernmental Panel on Climate Change (IPCC, 2007) predicts that the Mediterranean will rise 30 cm to 1 meter this century. Coastal zone management of the bay coastline is of utmost significance to the protection of the low agricultural land and the industrial complex located in the rear side of the seawall. Moreover this joint research work highlights the similarity of the nature of current and anticipated coastal zone problems, at several locations around the world, and required adaptation and protection measures. For example many barrier islands in the world such as that in the Atlantic and Gulf of Mexico coasts of the U.S., lowland and deltas such as in Italy and the Nile Delta, and many islands are also experiencing significant levels of erosion and flooding that are exacerbated by sea level rise. Global Climatic Changes: At a global scale, an example of the effects of accelerated climate changes was demonstrated. In recent years, the impacts of natural disasters are more and more severe on coastal lowland areas. With the threats of climate change, sea level rise storm surge, progressive storm and hurricane activities and potential subsidence, the reduction of natural disasters in coastal lowland areas receives increased attention. Yet many of their inhabitants are becoming increasingly vulnerable to flooding, and conversions of land to open ocean. These global changes were recently

  3. Historical versus contemporary climate forcing on the annual nesting variability of loggerhead sea turtles in the Northwest Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Michael D Arendt

    Full Text Available A recent analysis suggested that historical climate forcing on the oceanic habitat of neonate sea turtles explained two-thirds of interannual variability in contemporary loggerhead (Caretta caretta sea turtle nest counts in Florida, where nearly 90% of all nesting by this species in the Northwest Atlantic Ocean occurs. Here, we show that associations between annual nest counts and climate conditions decades prior to nest counts and those conditions one year prior to nest counts were not significantly different. Examination of annual nest count and climate data revealed that statistical artifacts influenced the reported 31-year lag association with nest counts. The projected importance of age 31 neophytes to annual nest counts between 2020 and 2043 was modeled using observed nest counts between 1989 and 2012. Assuming consistent survival rates among cohorts for a 5% population growth trajectory and that one third of the mature female population nests annually, the 41% decline in annual nest counts observed during 1998-2007 was not projected for 2029-2038. This finding suggests that annual nest count trends are more influenced by remigrants than neophytes. Projections under the 5% population growth scenario also suggest that the Peninsular Recovery Unit could attain the demographic recovery criteria of 106,100 annual nests by 2027 if nest counts in 2019 are at least comparable to 2012. Because the first year of life represents only 4% of the time elapsed through age 31, cumulative survival at sea across decades explains most cohort variability, and thus, remigrant population size. Pursuant to the U.S. Endangered Species Act, staggered implementation of protection measures for all loggerhead life stages has taken place since the 1970s. We suggest that the 1998-2007 nesting decline represented a lagged perturbation response to historical anthropogenic impacts, and that subsequent nest count increases since 2008 reflect a potential recovery response.

  4. Cloud amount/frequency, NITRATE and other data from POISK, FRITJOF NANSEN and other platforms in the NE Atlantic and Norwegian Sea from 1969-04-17 to 1980-09-28 (NODC Accession 9000077)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Russian Ocean Station data was collected in Norwegian Sea and NE Atlantic (limit-40 W) using four different Ships by Polar Research and Designing Institute of...

  5. Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the Northwest Atlantic Ocean and Caribbean Sea from 30 April 1988 to 31 May 1988 (NODC Accession 8800173)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC HARRIOT LANE in the Northwest Atlantic Ocean and Caribbean Sea. Data...

  6. GHRSST Level 3P North Atlantic Regional Subskin Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the MetOp-A satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for HIgh Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) from the Advanced Very High Resolution Radiometer (AVHRR) on...

  7. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-18 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  8. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-19 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  9. GHRSST Level 2P North Atlantic Regional Bulk Sea Surface Temperature from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-17 satellite produced by NEODAAS (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Level 2P swath-based Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic area from the Advanced Very High Resolution...

  10. GHRSST Level 3C Atlantic sub-skin Sea Surface Temperature from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on MSG at 0 degree longitude (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the Eastern Atlantic Region from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI)...

  11. Temperature profile and water depth data from BT and XBT casts in the Atlantic Ocean from USCGC POLAR SEA from 14 December 1983 to 06 May 1984 (NODC Accession 8600108)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC POLAR SEA in the Atlantic Ocean. Data were collected from 14 December...

  12. Temperature profile and water depth data collected from USS JOHN RODGERS using BT and XBT casts in the NE/NW Atlantic Ocean and other seas from 03 August 1988 to 03 October 1988 (NODC Accession 8900041)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS JOHN RODGERS in the Northeast / Northwest Atlantic Ocean, Ionian Sea,...

  13. GHRSST Level 3C North Atlantic Regional (NAR) subskin Sea Surface Temperature from SNPP/VIIRS and Metop-A/AVHRR (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) dataset for the North Atlantic Region (NAR) derived from the Advanced Very High Resolution Radiometer...

  14. The relative importance of ENSO and tropical Atlantic sea surface temperature anomalies for seasonal precipitation over South America: a numerical study

    Science.gov (United States)

    Pezzi, L. P.; Cavalcanti, I. F. A.

    The role of tropical Atlantic sea surface temperature (SST) anomalies during ENSO episodes over northeast Brazil (Nordeste) is investigated using the CPTEC/COLA Atmospheric General Circulation Model (AGCM). Four sets of integrations are performed using SST in El Niño and La Niña (ENSO) episodes, changing the SST of the Atlantic Ocean. A positive dipole (SST higher than normal in the tropical North Atlantic and below normal in the tropical South Atlantic) and a negative dipole (opposite conditions), are set as the boundary conditions of SST in the Atlantic Ocean. The four experiments are performed using El Niño or La Niña SST in all oceans, except in the tropical Atlantic where the two phases of the SST dipole are applied. Five initial conditions were integrated in each case in order to obtain four ensemble results. The positive SST dipole over the tropical Atlantic Ocean and El Niño conditions over the Pacific Ocean resulted in dry conditions over the Nordeste. When the negative dipole and El Niño conditions over the Pacific Ocean were applied, the results showed precipitation above normal over the north of Nordeste. When La Niña conditions over Pacific Ocean were tested together with a negative dipole, positive precipitation anomalies occurred over the whole Nordeste. Using the positive dipole over the tropical Atlantic, the precipitation over Nordeste was below average. During La Niña episodes, the Atlantic Ocean conditions have a larger effect on the precipitation of Nordeste than the Pacific Ocean. In El Niño conditions, only the north region of Nordeste is affected by the Atlantic SST. Other tropical areas of South America show a change only in the intensity of anomalies. Central and southeast regions of South America are affected by the Atlantic conditions only during La Niña conditions, whereas during El Niño these regions are influenced only by conditions in the Pacific Ocean.

  15. Aspects on gametogenesis, fertilization and embryogenesis of two deep-sea polychaetes from Eastern Atlantic cold seeps

    Science.gov (United States)

    Gaudron, S. M.; Hourdez, S.; Olu, K.

    2017-11-01

    We investigated two gonochoristic species of annelid polychaetes (one siboglinid and one polynoid) from cold seeps that ranged from 525 m to 3300 m in depth (Guiness, Worm Hole and Regab pockmarks) on the Gabon and Congo continental margins (Gulf of Guinea). Different aspects of gametogenesis (oocyte diameter, presence of ovisac, spermatozoa shape, and fecundity), fertilization (in vitro fertilization experiments: IVF) and embryogenesis (cleavage rate) were studied. The sampled siboglinid was a new species of Lamellibrachia and the second population of this genus in the Eastern Atlantic. Mean oocyte diameter was about 100 μm and fully-grown primary oocytes were stored in an ovisac, as in other studied siboglinids. The presence of a single spermatozoon was noted within an oviduct, indicating a possible internal fertilization. The rate of cell division at 6 °C was one cleavage every 20 h. Embryos developed normally to the blastula stage after 5-d post-fertilization at atmospheric pressure suggesting some pressure tolerance. The second polychaete was the scale-worm Branchipolynoe cf. seepensis that lives in commensalism in the mantle cavity of Bathymodiolus aff. boomerang. Anatomical reproductive features were similar to those described in B. seepensis from hydrothermal vents on Mid-Atlantic Ridge, with lecithotrophic larval development and continuous gametogenesis. We performed the first IVF carried out on gametes for any deep-sea polynoid species. Fertilization and development occurred but a number of abnormalities were observed demonstrating a limitation to embryogenesis at atmospheric pressure. The rate of cell division was three times faster at 8 °C than at 4 °C with a maximum stage of 8-cells reached after 72 h post-fertilization. We surprisingly observed some oocytes from the negative seawater control during IVF experiments cleaved to the 2-cell stage, demonstrating the possible occurrence of internal fertilization prior to IVF experiment or the accidental

  16. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Caribbean Sea, North Atlantic Ocean and South Atlantic Ocean from 2002-06-07 to 2002-07-04 (NODC Accession 0115586)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115586 includes chemical, discrete sample, physical and profile data collected from METEOR in the Caribbean Sea, North Atlantic Ocean and South...

  17. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the KNORR in the Caribbean Sea, North Atlantic Ocean and South Atlantic Ocean from 1982-12-01 to 1983-02-18 (NODC Accession 0116706)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116706 includes chemical, discrete sample, physical and profile data collected from KNORR in the Caribbean Sea, North Atlantic Ocean and South...

  18. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the SONNE in the Caribbean Sea, North Atlantic Ocean and South Atlantic Ocean from 2003-05-25 to 2003-06-13 (NODC Accession 0116705)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116705 includes chemical, discrete sample, physical and profile data collected from SONNE in the Caribbean Sea, North Atlantic Ocean and South...

  19. Wave inhibition by sea ice enables trans-Atlantic ice rafting of debris during Heinrich Events

    Science.gov (United States)

    Wagner, T. J. W.; Dell, R.; Eisenman, I.; Keeling, R. F.; Padman, L.; Severinghaus, J. P.

    2017-12-01

    The thickness of the ice-rafted debris (IRD) layers that signal Heinrich Events declines far more gradually with distance from the iceberg sources than would be expected based on present-day iceberg trajectories. Here we model icebergs as passive Lagrangian tracers driven by ocean currents, winds, and sea surface temperatures. The icebergs are released in a comprehensive climate model simulation of the last glacial maximum (LGM), as well as a simulation of the modern climate. The two simulated climates result in qualitatively similar distributions of iceberg meltwater and hence debris, with the colder temperatures of the LGM having only a relatively small effect on meltwater spread. In both scenarios, meltwater flux falls off rapidly with zonal distance from the source, in contrast with the more uniform spread of IRD in sediment cores. In order to address this discrepancy, we propose a physical mechanism that could have prolonged the lifetime of icebergs during Heinrich events. The mechanism involves a surface layer of cold and fresh meltwater formed from, and retained around, densely packed armadas of icebergs. This leads to wintertime sea ice formation even in relatively low latitudes. The sea ice in turn shields the icebergs from wave erosion, which is the main source of iceberg ablation. We find that allowing sea ice to form around all icebergs during four months each winter causes the model to approximately agree with the distribution of IRD in sediment cores.

  20. Eddy covariance measurements of sea spray particles over the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    S. J. Norris

    2008-02-01

    Full Text Available Most estimates of sea spray aerosol source functions have used indirect means to infer the rate of production as a function of wind speed. Only recently has the technology become available to make high frequency measurements of aerosol spectra suitable for direct eddy correlation determination of the sea spray particle flux. This was accomplished in this study by combining a newly developed fast aerosol particle counter with an ultrasonic anemometer which allowed for eddy covariance measurements of size-segregated particle fluxes. The aerosol instrument is the Compact Lightweight Aerosol Spectrometer Probe (CLASP – capable of measuring 8-channel size spectra for mean radii between 0.15 and 3.5 µm at 10 Hz. The first successful measurements were made during the Waves, Air Sea Fluxes, Aerosol and Bubbles (WASFAB field campaign in October 2005 in Duck (NC, USA. The method and initial results are presented and comparisons are made with recent sea spray source functions from the literature.

  1. Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas

    NARCIS (Netherlands)

    Ginneken, van V.J.T.; Helsper, J.P.F.G.; Visser, de W.; Keulen, van H.; Brandenburg, W.A.

    2011-01-01

    Background - In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. Methods - The fatty acid (FA) composition in lipids from seven sea

  2. 75 FR 36559 - Fisheries of the Northeastern United States; Atlantic Sea Scallop Fishery; Framework Adjustment 21

    Science.gov (United States)

    2010-06-28

    ... of the fishing year (FY). Framework 21 specifies measures only for FY 2010. Amendment 15 to the FMP... trips in the Elephant Trunk Access Area (ETAA), and one trip in the Delmarva Access Area (Delmarva). A... through October 31 into other areas and times of year when sea turtle interactions are less likely. This...

  3. The influence of sea surface temperature anomalies on low-frequency variability of the North Atlantic Oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Manganello, Julia V. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States)

    2008-05-15

    The influence of sea surface temperature anomalies (SSTA) on multi-year persistence of the North Atlantic Oscillation (NAO) during the second half of the twentieth century is investigated using the Center for Ocean-Land-Atmosphere Studies (COLA) Atmospheric GCM (AGCM) with an emphasis on isolating the geographic location of the SSTA that produce this influence. The present study focuses on calculating the atmospheric response to the SSTA averaged over 1988-1995 (1961-1968) corresponding to the observed period of strong persistence of the positive (negative) phase of the decadal NAO. The model response to the global 1988-1995 average SSTA shows a statistically significant large-scale pattern characteristic of the positive phase of the NAO. Forcing with the global 1961-1968 average SSTA generates a NAO of the opposite polarity compared to observations. However, all large-scale features both in the model and observations during this period are weaker in magnitude and less significant compared to 1988-1995. Additional idealized experiments show that over the northern center of the NAO the non-linear component of the forced response appears to be quite important and acts to enhance the positive NAO signal. On the other hand, over the southern center where the model response is the strongest, it is also essentially linear. The 1988-1995 average SSTA restricted to the western tropical Pacific region produce a positive NAO remarkably similar in structure but stronger in magnitude than the model response to the global and tropical Indo-Pacific 1988-1995 forcing. A 200-hPa geopotential height response in these experiments shows a positive anomaly over the southern center of the NAO embedded in the Rossby wave trains propagating from the western tropical Pacific. Indian Ocean SSTA lead to much weaker positive NAO primarily through the effect on its northern center. SST forcing confined to the North Atlantic north of equator does not produce a response statistically different

  4. Decadal variability of extreme wave height representing storm severity in the northeast Atlantic and North Sea since the foundation of the Royal Society

    Science.gov (United States)

    Santo, H.; Taylor, P. H.; Gibson, R.

    2016-09-01

    Long-term estimation of extreme wave height remains a key challenge because of the short duration of available wave data, and also because of the possible impact of climate variability on ocean waves. Here, we analyse storm-based statistics to obtain estimates of extreme wave height at locations in the northeast Atlantic and North Sea using the NORA10 wave hindcast (1958-2011), and use a 5 year sliding window to examine temporal variability. The decadal variability is correlated to the North Atlantic oscillation and other atmospheric modes, using a six-term predictor model incorporating the climate indices and their Hilbert transforms. This allows reconstruction of the historic extreme climate back to 1661, using a combination of known and proxy climate indices. Significant decadal variability primarily driven by the North Atlantic oscillation is observed, and this should be considered for the long-term survivability of offshore structures and marine renewable energy devices. The analysis on wave climate reconstruction reveals that the variation of the mean, 99th percentile and extreme wave climates over decadal time scales for locations close to the dominant storm tracks in the open North Atlantic are comparable, whereas the wave climates for the rest of the locations including the North Sea are rather different.

  5. Inventory, distribution, and origin of aliphatic and polyaromatic hydrocarbons in sea water, the surface microlayer, and the aerosols in the tropical Eastern Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Marty, J C; Saliot, A; Tissier, M J

    1978-03-20

    Hydrocarbons have been analyzed in several samples from ''Midlante'' cruise, Cape Verde islands-Canary islands, in the Eastern tropical Atlantic: subsurface water, sea surface microlayer collected by a metallic screen and aerosols collected by filtration of large air volumes at about 12 m. above the sea surface. Detailed analysis of aliphatic and polyaromatic hydrocarbons has been made by computerized gas chromatography/mass spectrometry. This study of the air/sea interface indicates a discontinuity in hydrocarbon composition between the underlying water and the microlayer and a similarity between the surface microlayer and the aerosols. The origin of the collected aerosols is essentially marine with a minor terrestrial contribution. The hydrocarbon pattern shows that, superimposed on the typical marine components, a contribution from smokes of natural and industrial origin and/or from pollution associated with crude oil sea slicks is present.

  6. A new species of dwarf sea bass, genus Serranus (Serranidae: Actinopterygii, from the southwestern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Alfredo Carvalho Filho

    Full Text Available Serranus aliceae n. sp. is described from Rio de Janeiro and Espírito Santo States, southeastern Brazilian coast. The species is readily distinguished from its congeners by the following combination of characters: scales around the caudal peduncle 20 or 21; total gill rakers on first branchial arch 23-29; cheek-scales rows 5 or 6; and by the coloration of live specimens, which are reddish with a broad, conspicuous, white stripe from post-orbital region to the caudal-fin base and a white abdomen. The new species apparently inhabits the deeper (30 or more meters portions of reef environments along the subtropical Brazilian coast, and is possibly associated with upwelling cold-water masses. The species was observed hovering above rocky bottoms, feeding on micro-crustaceans, squid larvae, and zooplankton. This new species increases to eight the number of valid Serranus species recorded in the southwestern Atlantic.

  7. Commercial trials using emamectin benzoate to control sea lice Lepeophtheirus salmonis infestations in Atlantic salmon Salmo salar.

    Science.gov (United States)

    Stone, J; Sutherland, I H; Sommerville, C; Richards, R H; Varma, K J

    2000-06-19

    Two trials were conducted at commercial salmon farms to evaluate the efficacy of emamectin benzoate (Slice, 0.2% aquaculture pre-mix, Schering-Plough Animal Health) as a treatment for sea lice Lepeophtheirus salmonis (Krøyer) and Caligus elongatus Nordmann infestations in Atlantic salmon Salmo salar L. Trials were carried out in 15 m2 commercial sea pens, at temperatures of 5.5 to 7.5 degrees C and 10.8 to 13.8 degrees C. Each pen was stocked with 14,000 to 17,500 fish with mean weights of 0.44 to 0.74 and 1.33 to 1.83 kg. Fish were naturally infested with sea lice at the start of each trial. At Day -1, samples of 10 or 15 fish were taken from each pen to determine pre-treatment numbers of lice. Emamectin benzoate was administered in feed, to 4 replicate pens, at a dose of 50 micrograms kg-1 biomass d-1 for 7 consecutive days (Days 0 to 6). Sea lice were counted again, between Days 7 and 77, and comparisons made with untreated control fish. Despite adverse weather conditions, wide variations in fish weights and exposure to new infestations, treatment was effective against chalimus and motile stages of L. salmonis. In the autumn trial, efficacy at Day 27 was 89%, and lice numbers remained lower on treated fish than on control fish 64 d from the start of treatment. In the winter trial, reductions in lice numbers at low temperatures were slower but good efficacy was achieved by Day 35. Although control fish had to be treated with hydrogen peroxide at Day 21, fish treated only with emamectin benzoate on Days 0 to 6 still had 89% fewer lice than control fish at Day 35. There were very few C. elongatus present, but at the end of both trials numbers were lower on treated fish. No adverse effects were associated with treatment of fish with emamectin benzoate.

  8. Sea Salt Aerosol, Atmospheric Radon and Meteorological Observations in the Western South Atlantic Ocean (February 1981).

    Science.gov (United States)

    1983-09-28

    approximately isokinetic sampling conditions. The blower motor for the hi-vol was separated from the filter holder unit by a one- meter length of flexible...bridge bulkhead about 15 m above sea level and within 3 meters of the ARCAS inlet. The flow rate through the 20 cm x 25 cm glass fiber filters was...materials, atmospheric pressure, soil moisture and vegetative cover (Larson and Bressan, 1980). Radon concentrations measured a few meters above

  9. The effects of sea surface temperature anomalies on oceanic coral reef systems in the southwestern tropical Atlantic

    Science.gov (United States)

    Ferreira, B. P.; Costa, M. B. S. F.; Coxey, M. S.; Gaspar, A. L. B.; Veleda, D.; Araujo, M.

    2013-06-01

    In 2010, high sea surface temperatures that were recorded in several parts of the world and caused coral bleaching and coral mortality were also recorded in the southwest Atlantic Ocean, between latitudes 0°S and 8°S. This paper reports on coral bleaching and diseases in Rocas Atoll and Fernando de Noronha archipelago and examines their relationship with sea surface temperature (SST) anomalies recorded by PIRATA buoys located at 8°S30°W, 0°S35°W, and 0°S23°W. Adjusted satellite data were used to derive SST climatological means at buoy sites and to derive anomalies at reef sites. The whole region was affected by the elevated temperature anomaly that persisted through 2010, reaching 1.67 °C above average at reef sites and 1.83 °C above average at buoys sites. A significant positive relationship was found between the percentage of coral bleaching that was observed on reef formations and the corresponding HotSpot SST anomaly recorded by both satellite and buoys. These results indicate that the warming observed in the ocean waters was followed by a warming at the reefs. The percentage of bleached corals persisting after the subsidence of the thermal stress, and disease prevalence increased through 2010, after two periods of thermal stress. The in situ temperature anomaly observed during the 2009-2010 El Niño event was equivalent to the anomaly observed during the 1997-1998 El Niño event, explaining similar bleaching intensity. Continued monitoring efforts are necessary to further assess the relationship between bleaching severity and PIRATA SST anomalies and improve the use of this new dataset in future regional bleaching predictions.

  10. Characterization of natural variation in North American Atlantic Salmon populations (Salmonidae: Salmo salar) at a locus with a major effect on sea age.

    Science.gov (United States)

    Kusche, Henrik; Côté, Guillaume; Hernandez, Cécilia; Normandeau, Eric; Boivin-Delisle, Damien; Bernatchez, Louis

    2017-08-01

    Age at maturity is a key life-history trait of most organisms. In anadromous salmonid fishes such as Atlantic Salmon ( Salmo salar ), age at sexual maturity is associated with sea age, the number of years spent at sea before the spawning migration. For the first time, we investigated the presence of two nonsynonymous vgll3 polymorphisms in North American Atlantic Salmon populations that relate to sea age in European salmon and quantified the natural variation at these and two additional candidate SNPs from two other genes. A targeted resequencing assay was developed and 1,505 returning adult individuals of size-inferred sea age and sex from four populations were genotyped. Across three of four populations sampled in Québec, Canada, the late-maturing component (MSW) of the population of a given sex exhibited higher proportions of SNP genotypes 54Thr vgll3 and 323Lys vgll3 compared to early-maturing fish (1SW), for example, 85% versus 53% of females from Trinité River carried 323Lys vgll3 ( n MSW  = 205 vs. n 1SW  = 30; p 66%) to be female. In summary, two nonsynonymous vgll3 polymorphisms were confirmed in North American populations of Atlantic Salmon and our results suggest that variation at those loci correlates with sea age and sex. Our results also suggest that this correlation varies among populations. Future work would benefit from a more balanced sampling and from adding data on juvenile riverine life stages to contrast our data.

  11. The importance of ship log data: reconstructing North Atlantic, European and Mediterranean sea level pressure fields back to 1750

    Energy Technology Data Exchange (ETDEWEB)

    Kuettel, M.; Wanner, H. [University of Bern, Oeschger Centre for Climate Change Research (OCCR), and Institute of Geography, Climatology and Meteorology, Bern (Switzerland); Xoplaki, E. [University of Bern, Oeschger Centre for Climate Change Research (OCCR), and Institute of Geography, Climatology and Meteorology, Bern (Switzerland); EEWRC, The Cyprus Institute, Nicosia (Cyprus); Gallego, D. [Universidad Pablo de Olavide de Sevilla, Departamento de Sistemas Fisicos, Quimicos y Naturales, Sevilla (Spain); Luterbacher, J. [University of Bern, Oeschger Centre for Climate Change Research (OCCR), and Institute of Geography, Climatology and Meteorology, Bern (Switzerland); Justus-Liebig University of Giessen, Department of Geography, Climatology, Climate Dynamics and Climate Change, Giessen (Germany); Garcia-Herrera, R. [Universidad Complutense de Madrid, Departamento de Fisica de la Tierra II, Facultad de CC Fisicas, Madrid (Spain); Allan, R. [Met Office Hadley Centre, Exeter (United Kingdom); Barriendos, M. [University of Barcelona, Department of Modern History, Barcelona (Spain); Jones, P.D. [University of East Anglia, Climatic Research Unit, School of Environmental Sciences, Norwich (United Kingdom); Wheeler, D. [University of Sunderland, Faculty of Applied Sciences, Sunderland (United Kingdom)

    2010-06-15

    Local to regional climate anomalies are to a large extent determined by the state of the atmospheric circulation. The knowledge of large-scale sea level pressure (SLP) variations in former times is therefore crucial when addressing past climate changes across Europe and the Mediterranean. However, currently available SLP reconstructions lack data from the ocean, particularly in the pre-1850 period. Here we present a new statistically-derived 5 x 5 resolved gridded seasonal SLP dataset covering the eastern North Atlantic, Europe and the Mediterranean area (40 W-50 E; 20 N-70 N) back to 1750 using terrestrial instrumental pressure series and marine wind information from ship logbooks. For the period 1750-1850, the new SLP reconstruction provides a more accurate representation of the strength of the winter westerlies as well as the location and variability of the Azores High than currently available multiproxy pressure field reconstructions. These findings strongly support the potential of ship logbooks as an important source to determine past circulation variations especially for the pre-1850 period. This new dataset can be further used for dynamical studies relating large-scale atmospheric circulation to temperature and precipitation variability over the Mediterranean and Eurasia, for the comparison with outputs from GCMs as well as for detection and attribution studies. (orig.)

  12. Deep-sea benthic habitats modeling and mapping in a NE Atlantic seamount (Galicia Bank)

    Science.gov (United States)

    Serrano, A.; González-Irusta, J. M.; Punzón, A.; García-Alegre, A.; Lourido, A.; Ríos, P.; Blanco, M.; Gómez-Ballesteros, M.; Druet, M.; Cristobo, J.; Cartes, J. E.

    2017-08-01

    This study presents the results of seafloor habitat identification and mapping of a NE Atlantic deep seamount. An ;assemble first, predict later; approach has been followed to identify and map the benthic habitats of the Galicia Bank (NW Iberian). Biotic patterns inferred from the survey data have been used to drive the definition of benthic assemblages using multivariate tools. Eight assemblages, four hard substrates and four sedimentary ones, have been described from a matrix of structural species. Distribution of these assemblages was correlated with environmental factors (multibeam and backscatter data) using binomial GAMs. Finally, the distribution model of each assemblage was applied to produce continuous maps and pooled in a final map with the distribution of the main benthic habitats. Depth and substrate type are key factors when determining soft bottom communities, whereas rocky habitat distribution is mainly explained by rock slope and orientation. Enrichment by northern water masses (LSW) arriving to GB and possible zooplankton biomass increase at vertical-steep walls by ;bottom trapping; can explain the higher diversity of habitat providing filter-feeders at slope rocky breaks. These results concerning vulnerable species and habitats, such as Lophelia and Madrepora communities and black and bamboo coral aggregations were the basis of the Spanish proposal of inclusion within the Natura 2000 network. The aim of the present study was to establish the scientific criteria needed for managing and protecting those environmental values.

  13. Lower Crstal Reflectity bands and Magma Emplacement in Norweigian sea, NE Atlantic

    Science.gov (United States)

    Rai, A.; Breivik, A. J.; Mjelde, R.

    2013-12-01

    In this study we present the OBS data collected along seismic profiles in the norweigian sea. The traveltime modelling of the OBS data provides first-hand information about seismic structure of the subsurface. However, waveform modelling is used to further constrain the fine scale structure, velocity constrast and velocity gradients. By forward modelling and inversion of the seismic waveforms, we show that the multiple bands of reflectivity could be due to multiple episodes of magma emplacements that might have frozen in the form of sills. These mafic intrusions probably intruded into the ductile lower crust during the main rifting phase of Europe and Greenland.

  14. Regional Effects of the Mount Pinatubo Eruption on the Middle East and the Red Sea

    KAUST Repository

    Osipov, Sergey; Stenchikov, Georgiy L.

    2017-01-01

    variability in the Middle East's regional climate, we simulated the impact of the 1991 Pinatubo eruption using a regional coupled ocean-atmosphere modeling system set for the Middle East and North Africa (MENA) domain. We used the Coupled Ocean

  15. A new Liopropoma sea bass (Serranidae, Epinephelinae, Liopropomini) from deep reefs off Curaçao, southern Caribbean, with comments on depth distributions of western Atlantic liopropomins

    Science.gov (United States)

    Baldwin, Carole C.; Robertson, D. Ross

    2014-01-01

    Collecting reef-fish specimens using a manned submersible diving to 300 m off Curaçao, southern Caribbean, is resulting in the discovery of numerous new fish species. The new Liopropoma sea bass described here differs from other western Atlantic members of the genus in having VIII, 13 dorsal-fin rays; a moderately indented dorsal-fin margin; a yellow-orange stripe along the entire upper lip; a series of approximately 13 white, chevron-shaped markings on the ventral portion of the trunk; and a reddish-black blotch on the tip of the lower caudal-fin lobe. The new species, with predominantly yellow body and fins, closely resembles the other two “golden basses” found together with it at Curaçao: L. aberransand L. olneyi. It also shares morphological features with the other western Atlantic liopropomin genus,Bathyanthias. Preliminary phylogenetic data suggest that western Atlantic liopropomins, includingBathyanthias, are monophyletic with respect to Indo-Pacific Liopropoma, and that Bathyanthias is nested within Liopropoma, indicating a need for further study of the generic limits of Liopropoma. The phylogenetic data also suggest that western Atlantic liopropomins comprise three monophyletic clades that have overlapping depth distributions but different depth maxima (3–135 m, 30–150 m, 133–411 m). The new species has the deepest depth range (182–241 m) of any known western Atlantic Liopropomaspecies. Both allopatric and depth-mediated ecological speciation may have contributed to the evolution of western Atlantic Liopropomini.

  16. The role of the Strait of Gibraltar in shaping the genetic structure of the Mediterranean Grenadier, Coryphaenoides mediterraneus, between the Atlantic and Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Diana Catarino

    Full Text Available Population genetic studies of species inhabiting the deepest parts of the oceans are still scarce and only until recently we started to understand how oceanographic processes and topography affect dispersal and gene flow patterns. The aim of this study was to investigate the spatial population genetic structure of the bathyal bony fish Coryphaenoides mediterraneus, with a focus on the Atlantic-Mediterranean transition. We used nine nuclear microsatellites and the mitochondrial cytochrome c oxidase I gene from 6 different sampling areas. No population genetic structure was found within Mediterranean with both marker types (mean ΦST = 0.0960, FST = -0.0003, for both P > 0.05. However, within the Atlantic a contrasting pattern of genetic structure was found for the mtDNA and nuclear markers (mean ΦST = 0.2479, P 0.05. When comparing samples from Atlantic and Mediterranean they exhibited high and significant levels of genetic divergence (mean ΦST = 0.7171, FST = 0.0245, for both P < 0.001 regardless the genetic marker used. Furthermore, no shared haplotypes were found between Atlantic and Mediterranean populations. These results suggest very limited genetic exchange between Atlantic and Mediterranean populations of C. mediterraneus, likely due to the shallow bathymetry of the Strait of Gibraltar acting as a barrier to gene flow. This physical barrier not only prevents the direct interactions between the deep-living adults, but also must prevent interchange of pelagic early life stages between the two basins. According to Bayesian simulations it is likely that Atlantic and Mediterranean populations of C. mediterraneus were separated during the late Pleistocene, which is congruent with results for other deep-sea fish from the same region.

  17. Polyunsaturated fatty acids in various macroalgal species from North Atlantic and tropical seas.

    Science.gov (United States)

    van Ginneken, Vincent J T; Helsper, Johannes P F G; de Visser, Willem; van Keulen, Herman; Brandenburg, Willem A

    2011-06-22

    In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species. Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed. Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.

  18. Notes on the zoogeography of the Atlantic sea turtles of the genus Lepidochelys

    Directory of Open Access Journals (Sweden)

    Archie Carr

    2002-06-01

    Full Text Available The sea turtle Lepidochelys kempi has an extensive range in coastal waters of the United States, and in parts of Florida is abundant as a seasonal resident. All known populations are sexually immature, and the breeding area of the species is not known. The present paper suggests the necessity of assuming a distant origin for the North American population, examines fragmentary evidence bearing on the coronary assumption of migratory movement, and somewhat hesitantly proposes the coast of northwestern Africa as a possible site of nesting. Spreading into American waters may occur via the Gulf Stream system. New records extend the range of the genus to northern Mauretania and into the MediterraneanLa tortuga marina Lepidochelys kempi tiene amplia distribución en el litoral de los Estados Unidos, y abunda como visitante en la costa occidental de Florida, si bien en la costa oriental hay un trecho desde Melbourne hasta Miami en que no ha sido registrada. Tampoco ha sido registrada en las Bahamas ni en las Antillas, aunque un ejemplar recogido en Cuba, mencionado por AGUAYO (1 parece ser la especie africana L. olivacea, que se debe considerar como visitante y ocasional de esas islas; también existe por 10 menos un ejemplar registrado en las cercanías de Bermuda, y queda la posibilidad de que la "batalí" de Trinidad sea una u otra especie de Lepidochelys. L. olivacea, que se debe considerar como visitante y ocasional de esas islas; también existe por lo menos un ejemplar registrado en las cercanías de Bermuda, y queda la posibilidad de que la "batalí" de Trinidad sea una u otra especie de Lepidochelys. Todas las poblaciones conocidas en aguas norteamericanas son sexualmente inmaturas, y no se conoce el criadero de la especie. En este trabajo el autor sugiere la necesidad de suponer un punto de origen distante para estas poblaciones; examina los fragmentos disponibles de evidencia que apoyan la suposición corolaria de movimientos migratorios, y

  19. Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas

    Directory of Open Access Journals (Sweden)

    van Keulen Herman

    2011-06-01

    Full Text Available Abstract Background In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. Methods The fatty acid (FA composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum and two from tropical seas (Caulerpa taxifolia, Sargassum natans was determined using GCMS. Four independent replicates were taken from each seaweed species. Results Omega-3 (n-3 and omega-6 (n-6 polyunsaturated fatty acids (PUFAs, were in the concentration range of 2-14 mg/g dry matter (DM, while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6 and/or eicosapentaenoic acids (EPA, C20:5, n-3, the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3 at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed. Conclusion Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6 FA: (n-3 FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3, while in S. natans also docosahexaenoic acid (DHA, C

  20. Multigene phylogeny of the scyphozoan jellyfish family Pelagiidae reveals that the common U.S. Atlantic sea nettle comprises two distinct species (Chrysaora quinquecirrha and C. chesapeakei

    Directory of Open Access Journals (Sweden)

    Keith M. Bayha

    2017-10-01

    Full Text Available Background Species of the scyphozoan family Pelagiidae (e.g., Pelagia noctiluca, Chrysaora quinquecirrha are well-known for impacting fisheries, aquaculture, and tourism, especially for the painful sting they can inflict on swimmers. However, historical taxonomic uncertainty at the genus (e.g., new genus Mawia and species levels hinders progress in studying their biology and evolutionary adaptations that make them nuisance species, as well as ability to understand and/or mitigate their ecological and economic impacts. Methods We collected nuclear (28S rDNA and mitochondrial (cytochrome c oxidase I and 16S rDNA sequence data from individuals of all four pelagiid genera, including 11 of 13 currently recognized species of Chrysaora. To examine species boundaries in the U.S. Atlantic sea nettle Chrysaora quinquecirrha, specimens were included from its entire range along the U.S. Atlantic and Gulf of Mexico coasts, with representatives also examined morphologically (macromorphology and cnidome. Results Phylogenetic analyses show that the genus Chrysaora is paraphyletic with respect to other pelagiid genera. In combined analyses, Mawia, sampled from the coast of Senegal, is most closely related to Sanderia malayensis, and Pelagia forms a close relationship to a clade of Pacific Chrysaora species (Chrysaora achlyos, Chrysaora colorata, Chrysaora fuscescens, and Chrysaora melanaster. Chrysaora quinquecirrha is polyphyletic, with one clade from the U.S. coastal Atlantic and another in U.S. Atlantic estuaries and Gulf of Mexico. These genetic differences are reflected in morphology, e.g., tentacle and lappet number, oral arm length, and nematocyst dimensions. Caribbean sea nettles (Jamaica and Panama are genetically similar to the U.S. Atlantic estuaries and Gulf of Mexico clade of Chrysaora quinquecirrha. Discussion Our phylogenetic hypothesis for Pelagiidae contradicts current generic definitions, revealing major disagreements between DNA-based and

  1. Evidence for a Middle Pleistocene glaciation of MIS 8 age in the southern North Sea

    NARCIS (Netherlands)

    Beets, C.J.

    2005-01-01

    In the coresof borehole 89/2, situated at 541 00 010N and 51 00 040E about 70 km north of the Frisian Islands in the southern North Sea, two diamictonsle vels are found at 770 and 100m below sea floor (i.e. 7110 and 140 below present sea level), respectively. Both diamictonsap pear to be older than

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HUDSON in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1982-02-28 to 1982-04-04 (NODC Accession 0113889)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113889 includes chemical, discrete sample, physical and profile data collected from HUDSON in the North Atlantic Ocean, North Greenland Sea and...

  3. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1992-07-12 to 1992-07-28 (NODC Accession 0113558)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113558 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

  4. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from Atlantic Companion in the Inner Sea - West Coast Scotland, Irish Sea and St. George's Channel and others from 2012-03-17 to 2012-12-06 (NCEI Accession 0157280)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157280 includes Surface underway, chemical, meteorological and physical data collected from Atlantic Companion in the Inner Sea - West Coast...

  5. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HAKON MOSBY in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 2001-05-27 to 2001-06-19 (NODC Accession 0113754)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113754 includes chemical, discrete sample, physical and profile data collected from HAKON MOSBY in the North Atlantic Ocean, North Greenland Sea and...

  6. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the G.O. SARS in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 2003-09-22 to 2003-10-13 (NODC Accession 0113752)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113752 includes chemical, discrete sample, physical and profile data collected from G.O. SARS in the North Atlantic Ocean, North Greenland Sea and...

  7. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1994-10-29 to 1994-11-23 (NODC Accession 0115681)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115681 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

  8. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and Norwegian Sea from 1994-07-23 to 1994-08-16 (NODC Accession 0113560)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113560 includes chemical, discrete sample, physical and profile data collected from JOHAN HJORT in the North Atlantic Ocean, North Greenland Sea and...

  9. Lessons derived from two high-frequency sea level events in the Atlantic: implications for coastal risk analysis and tsunami detection

    Directory of Open Access Journals (Sweden)

    Begoña Pérez-Gómez

    2016-11-01

    Full Text Available The upgrade and enhancement of sea level networks worldwide for integration in sea level hazard warning systems have significantly increased the possibilities for measuring and analyzing high frequency sea level oscillations, with typical periods ranging from a few minutes to a few hours. Many tide gauges now afford 1 min or more frequent sampling and have shown such events to be a common occurrence. Their origins and spatial distribution are diverse and must be well understood in order to correctly design and interpret, for example, the automatic detection algorithms used by tsunami warning centers. Two events recorded recently in European Atlantic waters are analyzed here: possible wave-induced seiches that occurred along the North coast of Spain during the storms of January and February of 2014, and oscillations detected after an earthquake in the mid-Atlantic the 13th of February of 2015. The former caused significant flooding in towns and villages and a huge increase in wave-induced coastal damage that was reported in the media for weeks. The second was a smaller signal present in several tide gauges along the Atlantic coast that, that coincided with the occurrence of this earthquake, leading to a debate on the potential detection of a very small tsunami and how it might yield significant information for tsunami wave modelers and for the development of tsunami detection software. These kinds of events inform us about the limitations of automatic algorithms for tsunami warning and help to improve the information provided to tsunami warning centers, whilst also emphasizing the importance of other forcings in generating extreme sea levels and their associated potential for causing damage to infrastructure.

  10. Influences of sediment redistribution on sea-level changes along the U.S. Atlantic margin since the mid-Pliocene

    Science.gov (United States)

    Li, Q.; Ferrier, K.; Austermann, J.; Mitrovica, J. X.

    2017-12-01

    The Orangeburg Scarp is a paleo-shoreline formed along the southeastern U.S. Atlantic coast during the mid-Pliocene warm period (MPWP; 3.3 - 2.9 Ma). The MPWP is a time of interest because it is often cited as an analog for modern climate and thus an important target for understanding sea-level responses to climate change. The present Orangeburg Scarp exhibits 40-meter variations in elevation along its length, implying that it has been warped since its formation, which complicates efforts to infer global ice volume at the MPWP. Previous studies have shown that the effects of glacial isostatic adjustment (GIA) and dynamic topography (DT) on sea level can explain a significant fraction of the observed variability in elevation along the Orangeburg Scarp. Here we build on these studies by using a gravitationally self-consistent ice age sea-level model to compute the effects of sediment loading and unloading on paleo-shoreline elevation since the mid-Pliocene. To constrain the sediment loading history in this region, we present a new compilation of erosion and deposition rates along the U.S. Atlantic margin, from which we generate a range of sediment redistribution scenarios since the MPWP. We simultaneously drive the sea-level model with these sediment redistribution histories and existing ice and dynamic topography histories. Our results show that sediment loading and unloading is capable of warping the elevation of this paleo-shoreline by 20 meters since its formation, similar in magnitude to the contributions from GIA and DT over the same time period. These results demonstrate that sediment redistribution can induce significant perturbations in sea-level markers from the MPWP, and thus accounting for its influence will improve reconstructions of sea level and global ice volume during the MPWP and perhaps other periods of relative ice age warmth.

  11. Spawn in two deep-sea volute gastropods (Neogastropoda: Volutidae) from southwestern Atlantic waters

    Science.gov (United States)

    Penchaszadeh, Pablo E.; Teso, Valeria; Pastorino, Guido

    2017-12-01

    The gastropods Odontocymbiola pescalia and Provocator corderoi and their egg capsules were collected by the R/V Puerto Deseado from the Mar del Plata Submarine Canyon ( 37°53‧S, at depths of 291-1404 m) and from Burdwood Bank ( 54°27‧S, 128-785 m). Odontocymbiola pescalia egg capsules measured 15.67 ± 3.38 mm in diameter. They were subspherical in shape with an external calcareous layer. Each egg capsule contained 3-5 embryos and white material as extra embryonic food. Embryos grew to a size of up to 9.3 ± 1.1 mm in mean shell length before hatching as crawling juveniles. The spawn of P. corderoi consisted of a single dome shaped egg capsule of 14.17 ± 1.5 mm in diameter, attached to hard substrata by a basal membrane with a rounded outline. A curved semilunar furrow (seam) on one side of the capsules was always present. The number of embryos per capsule was 2-6. Embryos hatched as crawling juveniles with a shell length of 5.9 ± 0.6 mm. The size and number of whorls in the hatchling shell suggested a slow rate of development, akin to many other deep-sea invertebrates. The egg capsules and reproductive development strategies of both species were compared with those from other congeneric representatives.

  12. Sequence stratigraphy and a revised sea-level curve for the Middle Devonian of eastern North America

    Science.gov (United States)

    Brett, Carlton E.; Baird, G.C.; Bartholomew, A.J.; DeSantis, M.K.; Ver Straeten, C.A.

    2011-01-01

    The well-exposed Middle Devonian rocks of the Appalachian foreland basin (Onondaga Formation; Hamilton Group, Tully Formation, and the Genesee Group of New York State) preserve one of the most detailed records of high-order sea-level oscillation cycles for this time period in the world. Detailed examination of coeval units in distal areas of the Appalachian Basin, as well as portions of the Michigan and Illinois basins, has revealed that the pattern of high-order sea-level oscillations documented in the New York-Pennsylvania section can be positively identified in all areas of eastern North America where coeval units are preserved. The persistence of the pattern of high-order sea-level cycles across such a wide geographic area suggests that these cycles are allocyclic in nature with primary control on deposition being eustatic sea-level oscillation, as opposed to autocylic controls, such as sediment supply, which would be more local in their manifestation. There is strong evidence from studies of cyclicity and spectral analysis that these cycles are also related to Milankovitch orbital variations, with the short and long-term eccentricity cycles (100. kyr and 405. kyr) being the dominant oscillations in many settings. Relative sea-level oscillations of tens of meters are likely and raise considerable issues about the driving mechanism, given that the Middle Devonian appears to record a greenhouse phase of Phanerozoic history. These new correlations lend strong support to a revised high-resolution sea-level oscillation curve for the Middle Devonian for the eastern portion of North America. Recognized third-order sequences are: Eif-1 lower Onondaga Formation, Eif-2: upper Onondaga and Union Springs formations; Eif-Giv: Oatka Creek Formation; Giv-1: Skaneateles, Giv-2: Ludlowville, Giv-3: lower Moscow, Giv-4: upper Moscow-lower Tully, and Giv-5: middle Tully-Geneseo formations. Thus, in contrast with the widely cited eustatic curve of Johnson et al. (1985), which

  13. Middle Holocene Organic Carbon and Biomarker Records from the South Yellow Sea: Relationship to the East Asian Monsoon

    Science.gov (United States)

    Zou, Liang; Hu, Bangqi; Li, Jun; Dou, Yanguang; Xie, Luhua; Dong, Liang

    2018-03-01

    The East Asian monsoon system influences the sedimentation and transport of organic matter in East Asian marginal seas that is derived from both terrestrial and marine sources. In this study, we determined organic carbon (OC) isotope values, concentrations of marine biomarkers, and levels of OC and total nitrogen (TN) in core YSC-1 from the central South Yellow Sea (SYS). Our objectives were to trace the sources of OC and variations in palaeoproductivity since the middle Holocene, and their relationships with the East Asian monsoon system. The relative contributions of terrestrial versus marine organic matter in core sediments were estimated using a two-end-member mixing model of OC isotopes. Results show that marine organic matter has been the main sediment constituent since the middle Holocene. The variation of terrestrial organic carbon concentration (OCter) is similar to the EASM history. However, the variation of marine organic carbon concentration (OCmar) is opposite to that of the EASM curve, suggesting OCmar is distinctly influenced by terrestrial material input. Inputs of terrestrial nutrients into the SYS occur in the form of fluvial and aeolian dust, while concentrations of nutrients in surface water are derived mainly from bottom water via the Yellow Sea circulation system, which is controlled by the East Asian winter monsoon (EAWM). Variations in palaeoproductivity represented by marine organic matter and biomarker records are, in general, consistent with the recent EAWM intensity studies, thus, compared with EASM, EAWM may play the main role to control the marine productivity variations in the SYS.

  14. Feeding Ecology of Northeast Atlantic Mackerel, Norwegian Spring-Spawning Herring and Blue Whiting in the Norwegian Sea.

    Directory of Open Access Journals (Sweden)

    Eneko Bachiller

    Full Text Available The Norwegian spring-spawning (NSS herring (Clupea harengus, blue whiting (Micromesistius poutassou and Northeast Atlantic (NEA mackerel (Scomber scombrus are extremely abundant pelagic planktivores that feed in the Norwegian Sea (NS during spring and summer. This study investigated the feeding ecology and diet composition of these commercially important fish stocks on the basis of biological data, including an extensive set of stomach samples in combination with hydrographical data, zooplankton samples and acoustic abundance data from 12 stock monitoring surveys carried out in 2005-2010. Mackerel were absent during the spring, but had generally high feeding overlap with herring in the summer, with a diet mainly based on calanoid copepods, especially Calanus finmarchicus, as well as a similar diet width. Stomach fullness in herring diminished from spring to summer and feeding incidence was lower than that of mackerel in summer. However, stomach fullness did not differ between the two species, indicating that herring maintain an equally efficient pattern of feeding as mackerel in summer, but on a diet that is less dominated by copepods and is more reliant on larger prey. Blue whiting tended to have a low dietary overlap with mackerel and herring, with larger prey such as euphausiids and amphipods dominating, and stomach fullness and feeding incidence increasing with length. For all the species, feeding incidence increased with decreasing temperature, and for mackerel so did stomach fullness, indicating that feeding activity is highest in areas associated with colder water masses. Significant annual effects on diet composition and feeding-related variables suggested that the three species are able to adapt to different food and environmental conditions. These annual effects are likely to have an important impact on the predation pressure on different plankton groups and the carrying capacity of individual systems, and emphasise the importance of

  15. Extreme total solar irradiance due to cloud enhancement at sea level of the NE Atlantic coast of Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Piacentini, Ruben D. [Instituto de Fisica Rosario (CONICET-Universidad Nacional de Rosario), 27 de Febrero 210bis, 2000 Rosario (Argentina); Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Pellegrini 250, 2000 Rosario (Argentina); Salum, Graciela M. [Instituto de Fisica Rosario (CONICET-Universidad Nacional de Rosario), 27 de Febrero 210bis, 2000 Rosario (Argentina); Facultad Regional Concepcion del Uruguay, Universidad Tecnologica Nacional, Concepcion del Uruguay (Argentina); Fraidenraich, Naum; Tiba, Chigueru [Grupo de Pesquisas em Fontes Alternativas de Energia, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, 1000 - 50.740-540, Recife, PE (Brazil)

    2011-01-15

    Extraterrestrial total solar irradiance, usually called Solar Constant, is attenuated by the atmosphere in different proportions, depending mainly on solar zenith angle and altitude of the measurement point. In this work, it is presented very high and extreme horizontal plane measurements of global solar irradiance that in some days overpassed the Solar Constant corrected by the actual Sun-Earth distance (CSC). They were obtained at sea level of the intertropical Atlantic coast, in the city of Recife, Brazil, in the period February 2008-January 2009. Extreme total solar irradiance values larger than CSC were measured during 3.4% of the days of the total registered period. This percentage increases to 7.4% for global solar irradiance within 95.1-100% of the CSC and to 15.3% within 90.1-95% of the CSC. The largest extreme total solar irradiance value, 1477 {+-} 30 W/m{sup 2}, was registered the 28th of March 2008 at 11:34 local time (UT - 3h). It overpassed by 7.9% the CSC value for this day (1369.4 W/m{sup 2}) and by 42.3% the estimated value of the clear sky Iqbal C radiation model (1037.7 W/m{sup 2}). The observation of extreme values should be taken into account in the study of solar radiation effects related to materials exposed to the outside, UV index and biological effects, among others. Also, the detailed knowledge of this interesting effect may contribute significantly to clarify physical aspects about the interaction of global solar radiation with the ecosystem and climate change. (author)

  16. Feeding Ecology of Northeast Atlantic Mackerel, Norwegian Spring-Spawning Herring and Blue Whiting in the Norwegian Sea.

    Science.gov (United States)

    Bachiller, Eneko; Skaret, Georg; Nøttestad, Leif; Slotte, Aril

    2016-01-01

    The Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesistius poutassou) and Northeast Atlantic (NEA) mackerel (Scomber scombrus) are extremely abundant pelagic planktivores that feed in the Norwegian Sea (NS) during spring and summer. This study investigated the feeding ecology and diet composition of these commercially important fish stocks on the basis of biological data, including an extensive set of stomach samples in combination with hydrographical data, zooplankton samples and acoustic abundance data from 12 stock monitoring surveys carried out in 2005-2010. Mackerel were absent during the spring, but had generally high feeding overlap with herring in the summer, with a diet mainly based on calanoid copepods, especially Calanus finmarchicus, as well as a similar diet width. Stomach fullness in herring diminished from spring to summer and feeding incidence was lower than that of mackerel in summer. However, stomach fullness did not differ between the two species, indicating that herring maintain an equally efficient pattern of feeding as mackerel in summer, but on a diet that is less dominated by copepods and is more reliant on larger prey. Blue whiting tended to have a low dietary overlap with mackerel and herring, with larger prey such as euphausiids and amphipods dominating, and stomach fullness and feeding incidence increasing with length. For all the species, feeding incidence increased with decreasing temperature, and for mackerel so did stomach fullness, indicating that feeding activity is highest in areas associated with colder water masses. Significant annual effects on diet composition and feeding-related variables suggested that the three species are able to adapt to different food and environmental conditions. These annual effects are likely to have an important impact on the predation pressure on different plankton groups and the carrying capacity of individual systems, and emphasise the importance of regular

  17. Comparative biology and population mixing among local, coastal and offshore Atlantic herring (Clupea harengus) in the North Sea, Skagerrak, Kattegat and western Baltic

    Science.gov (United States)

    Slotte, Aril; Johannessen, Arne; Kvamme, Cecilie; Clausen, Lotte Worsøe; Nash, Richard D. M.

    2017-01-01

    The population structure of Atlantic herring (Clupea harengus) from 13 local, coastal and offshore areas of the North Sea, Skagerrak, Kattegat and western Baltic (northeast Atlantic) was studied using biological and environmental data from 1970–2015. The objective was to identify distinct populations by comparing variability in the temporal and spatial phenotypic characteristics and evaluate the potential for mixing of populations in time and space. The populations varied in biological characteristics such as mean vertebral counts (VS), growth and maturity ogives. Generalized additive models indicated temporally stable VS in the North Sea and western Baltic, whereas intra-annual temporal variation of VS occurred in other areas. High variability of VS within a population was not affected by environmental factors such as temperature and salinity. Consequently, seasonal VS variability can be explained by the presence or absence of herring populations as they migrate between areas. The three main populations identified in this paper correspond to the three managed stocks in this area: Norwegian spring spawners (NSS), western Baltic spring spawners (WBSS) and North Sea autumn spawners (NSAS). In addition, several local populations were identified in fjords or lakes along the coast, but our analyses could not detect direct mixing of local populations with the three main populations. Our results highlight the importance of recognizing herring dynamics and understanding the mixing of populations as a challenge for management of herring. PMID:29084258

  18. Evaluation and identification of histamine-forming bacteria on fish products of middle Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Rocco Mancusi

    2013-04-01

    Full Text Available Regulation EU 2073/2005 sets maximum concentration for histamine in fish and products thereof. To meet these criteria, manufacturers have to define performance objectives, such as the maximum allowed prevalence and number/activity of histamine-producing bacteria at relevant stage of production. In order to assess the presence and decarboxylase activity of contaminant bacteria we examined 51 samples of blue fish caught and processed in Emilia Romagna region. We collected 50 gr of fish (skin and gills or the entire product from 10 sample units from every lot. Analytical samples were cultured in Trypticase Soy Broth supplemented with histidine and pyridoxal HCl. Histamine was measured with an electrochemical biosensor after incubation at both 37°C for 24 h and 18-22°C for 48 h. Enrichments that showed relevant enzymatic activity were seeded on Niven agar to isolate suspected colonies and DNA extracts from these bacteria were analyzed by polymerase chain reaction (PCR for detecting specific sequences of the gene encoding pyridoxaldependent histidine decarboxylase (HDC. Overall, 29.4% samples showed relevant production of histamine in broth cultures (above a cut-off value set at 250 ng/mL and 53.3% of them (8 out of 15 samples allowed detection of HDC positive strains. All of them were typed as Morganella, which appears to be the most common of fish caught in middle Adriatic sea. Ten out of the twelve positive samples with enrichment cultures incubated at both 37 and 18-22°C (83% showed higher decarboxylase activity at room temperature, suggesting the presence of psychrotolerant strains. In addition, the prevalence of histamine-producing bacteria was higher at retail than at production level, probably as a consequence of manipulations and cross-contamination. The risk correlated to development of histamine-producing psychrotolerans bacteria cannot be controlled only with storage temperature: it is necessary for the food business operators to

  19. Nitrous oxide and methane in the Atlantic Ocean between 50°N and 52°S: Latitudinal distribution and sea-to-air flux

    Science.gov (United States)

    Forster, Grant; Upstill-Goddard, Rob C.; Gist, Niki; Robinson, Carol; Uher, Gunther; Woodward, E. Malcolm S.

    2009-07-01

    We discuss nitrous oxide (N 2O) and methane (CH 4) distributions in 49 vertical profiles covering the upper ˜300 m of the water column along two ˜13,500 km transects between ˜50°N and ˜52°S during the Atlantic Meridional Transect (AMT) programme (AMT cruises 12 and 13). Vertical N 2O profiles were amenable to analysis on the basis of common features coincident with Longhurst provinces. In contrast, CH 4 showed no such pattern. The most striking feature of the latitudinal depth distributions was a well-defined "plume" of exceptionally high N 2O concentrations coincident with very low levels of CH 4, located between ˜23.5°N and ˜23.5°S; this feature reflects the upwelling of deep waters containing N 2O derived from nitrification, as identified by an analysis of N 2O, apparent oxygen utilization (AOU) and NO 3-, and presumably depleted in CH 4 by bacterial oxidation. Sea-to-air emissions fluxes for a region equivalent to ˜42% of the Atlantic Ocean surface area were in the range 0.40-0.68 Tg N 2O yr -1 and 0.81-1.43 Tg CH 4 yr -1. Based on contemporary estimates of the global ocean source strengths of atmospheric N 2O and CH 4, the Atlantic Ocean could account for ˜6-15% and 4-13%, respectively, of these source totals. Given that the Atlantic Ocean accounts for around 20% of the global ocean surface, on unit area basis it appears that the Atlantic may be a slightly weaker source of atmospheric N 2O than other ocean regions but it could make a somewhat larger contribution to marine-derived atmospheric CH 4 than previously thought.

  20. Biogeochemical and Optical Analysis of Coastal DOM for Satellite Retrieval of Terrigenous DOM in the U.S. Middle Atlantic Bight

    Science.gov (United States)

    Mannino, A.; Dyda, R. Y.; Hernes, P. J.; Hooker, Stan; Hyde, Kim; Novak, Mike

    2012-01-01

    Estuaries and coastal ocean waters experience a high degree of variability in the composition and concentration of particulate and dissolved organic matter (DOM) as a consequence of riverine/estuarine fluxes of terrigenous DOM, sediments, detritus and nutrients into coastal waters and associated phytoplankton blooms. Our approach integrates biogeochemical measurements (elemental content, molecular analyses), optical properties (absorption) and remote sensing to examine terrestrial DOM contributions into the U.S. Middle Atlantic Bight (MAB). We measured lignin phenol composition, DOC and CDOM absorption within the Chesapeake and Delaware Bay mouths, plumes and adjacent coastal ocean waters to derive empirical relationships between CDOM and biogeochemical measurements for satellite remote sensing application. Lignin ranged from 0.03 to 6.6 ug/L between estuarine and outer shelf waters. Our results demonstrate that satellite-derived CDOM is useful as a tracer of terrigenous DOM in the coastal ocean

  1. Low levels of very-long-chain n-3 PUFA in Atlantic salmon (Salmo salar) diet reduce fish robustness under challenging conditions in sea cages.

    Science.gov (United States)

    Bou, Marta; Berge, Gerd M; Baeverfjord, Grete; Sigholt, Trygve; Østbye, Tone-Kari; Ruyter, Bente

    2017-01-01

    The present study aimed to determine the minimum requirements of the essential n -3 fatty acids EPA and DHA in Atlantic salmon ( Salmo salar ) that can secure their health under challenging conditions in sea cages. Individually tagged Atlantic salmon were fed 2, 10 and 17 g/kg of EPA + DHA from 400 g until slaughter size (about 3·5 kg). The experimental fish reared in sea cages were subjected to the challenging conditions typically experienced under commercial production. Salmon receiving the lowest EPA + DHA levels showed lower growth rates in the earlier life stages, but no significant difference in final weights at slaughter. The fatty acid composition of various tissues and organs had remarkably changed. The decreased EPA + DHA in the different tissue membrane phospholipids were typically replaced by pro-inflammatory n -6 fatty acids, most markedly in the skin. The EPA + DHA levels were maintained at a higher level in the liver and erythrocytes than in the muscle, intestine and skin. After delousing at high water temperatures, the mortality rates were 63, 52 and 16 % in the salmon fed 2, 10 and 17 g/kg EPA + DHA. Low EPA + DHA levels also increased the liver, intestinal and visceral fat amount, reduced intervertebral space and caused mid-intestinal hyper-vacuolisation. Thus, 10 g/kg EPA + DHA in the Atlantic salmon diet, a level previously regarded as sufficient, was found to be too low to maintain fish health under demanding environmental conditions in sea cages.

  2. Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua)—Implications for environmental monitoring in the Barents Sea

    International Nuclear Information System (INIS)

    Nahrgang, J.; Brooks, S.J.; Evenset, A.; Camus, L.; Jonsson, M.; Smith, T.J.; Lukina, J.; Frantzen, M.; Giarratano, E.; Renaud, P.E.

    2013-01-01

    In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

  3. Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua)-Implications for environmental monitoring in the Barents Sea

    Energy Technology Data Exchange (ETDEWEB)

    Nahrgang, J., E-mail: jasmine.m.nahrgang@uit.no [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Brooks, S.J. [Norwegian Institute for Water Research (NIVA), NO-0349 Oslo (Norway); Evenset, A. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Camus, L. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway); Jonsson, M.; Smith, T.J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Lukina, J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University of Tromso, Faculty of Biosciences, Fisheries and Economics, Department of Arctic and Marine Biosciences, NO-9037 Tromso (Norway); Frantzen, M. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Giarratano, E. [Centro Nacional Patagonico (CENPAT-CONICET), AR-9120 Puerto Madryn (Argentina); Renaud, P.E. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway)

    2013-02-15

    In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

  4. Sea-level records from the U.S. mid-Atlantic constrain Laurentide Ice Sheet extent during Marine Isotope Stage 3.

    Science.gov (United States)

    Pico, T; Creveling, J R; Mitrovica, J X

    2017-05-30

    The U.S. mid-Atlantic sea-level record is sensitive to the history of the Laurentide Ice Sheet as the coastline lies along the ice sheet's peripheral bulge. However, paleo sea-level markers on the present-day shoreline of Virginia and North Carolina dated to Marine Isotope Stage (MIS) 3, from 50 to 35 ka, are surprisingly high for this glacial interval, and remain unexplained by previous models of ice age adjustment or other local (for example, tectonic) effects. Here, we reconcile this sea-level record using a revised model of glacial isostatic adjustment characterized by a peak global mean sea level during MIS 3 of approximately -40 m, and far less ice volume within the eastern sector of the Laurentide Ice Sheet than traditional reconstructions for this interval. We conclude that the Laurentide Ice Sheet experienced a phase of very rapid growth in the 15 kyr leading into the Last Glacial Maximum, thus highlighting the potential of mid-field sea-level records to constrain areal extent of ice cover during glacial intervals with sparse geological observables.

  5. Interannual rainfall variability in the Amazon basin and sea-surface temperatures in the equatorial Pacific and the tropical Atlantic Oceans

    Science.gov (United States)

    Ronchail, Josyane; Cochonneau, Gérard; Molinier, Michel; Guyot, Jean-Loup; Chaves, Adriana Goretti De Miranda; Guimarães, Valdemar; de Oliveira, Eurides

    2002-11-01

    Rainfall variability in the Amazon basin is studied in relation to sea-surface temperatures (SSTs) in the equatorial Pacific and the northern and southern tropical Atlantic during the 1977-99 period, using the HiBAm original rainfall data set and complementary cluster and composite analyses.The northeastern part of the basin, north of 5 °S and east of 60 °W, is significantly related with tropical SSTs: a rainier wet season is observed when the equatorial Pacific and the northern (southern) tropical Atlantic are anomalously cold (warm). A shorter and drier wet season is observed during El Niño events and negative rainfall anomalies are also significantly associated with a warm northern Atlantic in the austral autumn and a cold southern Atlantic in the spring. The northeastern Amazon rainfall anomalies are closely related with El Niño-southern oscillation during the whole year, whereas the relationships with the tropical Atlantic SST anomalies are mainly observed during the autumn. A time-space continuity is observed between El Niño-related rainfall anomalies in the northeastern Amazon, those in the northern Amazon and south-eastern Amazon, and those in northern South America and in the Nordeste of Brazil.A reinforcement of certain rainfall anomalies is observed when specific oceanic events combine. For instance, when El Niño and cold SSTs in the southern Atlantic are associated, very strong negative anomalies are observed in the whole northern Amazon basin. Nonetheless, the comparison of the cluster and the composite analyses results shows that the rainfall anomalies in the northeastern Amazon are not always associated with tropical SST anomalies.In the southern and western Amazon, significant tropical SST-related rainfall anomalies are very few and spatially variable. The precipitation origins differ from those of the northeastern Amazon: land temperature variability, extratropical perturbations and moisture advection are important rainfall factors, as well

  6. Evidence for an autumn downstream migration of Atlantic salmon Salmo salar (Linnaeus) and brown trout Salmo trutta (Linnaeus) parr to the Baltic Sea

    Science.gov (United States)

    Taal, Imre; Kesler, Martin; Saks, Lauri; Rohtla, Mehis; Verliin, Aare; Svirgsden, Roland; Jürgens, Kristiina; Vetemaa, Markus; Saat, Toomas

    2014-06-01

    In the eastern Baltic rivers, anadromous salmonid parr are known to smoltify and migrate to the sea from March until June, depending on latitude, climate and hydrological conditions. In this study, we present the first records of autumn descent of brown trout Salmo trutta and Atlantic salmon Salmo salar from the Baltic Sea Basin. Otolith microchemistry analyses revealed that these individuals hatched in freshwater and had migrated to the brackish water shortly prior to capture. The fish were collected in 2006, 2008, 2009 and 2013 from Eru Bay (surface salinity 4.5-6.5 ‰), Gulf of Finland. This relatively wide temporal range of observations indicates that the autumn descent of anadromous salmonids is not a random event. These results imply that autumn descent needs more consideration in the context of the effective stock management, assessment and restoration of Baltic salmonid populations and their habitats.

  7. Revision of Chone Krøyer, 1856 (Polychaeta: Sabellidae from the eastern central Atlantic and Mediterranean Sea with descriptions of two new species

    Directory of Open Access Journals (Sweden)

    María Ana Tovar-Hernández

    2007-06-01

    Full Text Available A neotype specimen is designated for Chone acustica (Claparède, 1870 with a full description. The original descriptions of Chone arenicola Langerhans, 1880 and Chone collaris Langerhans, 1880, both from Madeira, did not include some details and incomplete or misleading information was provided, so both species are redescribed. Amendments to the description of Chone longiseta Giangrande, 1992 are also given together with the methyl green staining pattern of Chone usticensis Giangrande et al. 2006. Two new species are described: Chone gambiae sp. nov., from the Gulf of Naples and Chone dunerificta sp. nov., from the Gulf of Salerno. This study shows the distribution of Chone duneri Krøyer, 1856, and Chone filicaudata Southern, 1914, to be restricted to the Arctic seas and North Atlantic Ocean, respectively. Records from the Mediterranean Sea are found to be erroneous.

  8. The influence of physical factors on kelp and sea urchin distribution in previously and still grazed areas in the NE Atlantic.

    Science.gov (United States)

    Rinde, Eli; Christie, Hartvig; Fagerli, Camilla W; Bekkby, Trine; Gundersen, Hege; Norderhaug, Kjell Magnus; Hjermann, Dag Ø

    2014-01-01

    The spatial distribution of kelp (Laminaria hyperborea) and sea urchins (Strongylocentrotus droebachiensis) in the NE Atlantic are highly related to physical factors and to temporal changes in temperature. On a large scale, we identified borders for kelp recovery and sea urchin persistence along the north-south gradient. Sea urchin persistence was also related to the coast-ocean gradient. The southern border corresponds to summer temperatures exceeding about 10°C, a threshold value known to be critical for sea urchin recruitment and development. The outer border along the coast-ocean gradient is related to temperature, wave exposure and salinity. On a finer scale, kelp recovery occurs mainly at ridges in outer, wave exposed, saline and warm areas whereas sea urchins still dominate in inner, shallow and cold areas, particularly in areas with optimal current speed for sea urchin foraging. In contrast to other studies in Europe, we here show a positive influence of climate change to presence of a long-lived climax canopy-forming kelp. The extent of the coast-ocean gradient varies within the study area, and is especially wide in the southern part where the presence of islands and skerries increases the area of the shallow coastal zone. This creates a large area with intermediate physical conditions for the two species and a mosaic of kelp and sea urchin dominated patches. The statistical models (GAM and BRT) show high performance and indicate recovery of kelp in 45-60% of the study area. The study shows the value of combining a traditional (GAM) and a more complex (BRT) modeling approach to gain insight into complex spatial patterns of species or habitats. The results, methods and approaches are of general ecological relevance regardless of ecosystems and species, although they are particularly relevant for understanding and exploring the corresponding changes between algae and grazers in different coastal areas.

  9. The influence of physical factors on kelp and sea urchin distribution in previously and still grazed areas in the NE Atlantic.

    Directory of Open Access Journals (Sweden)

    Eli Rinde

    Full Text Available The spatial distribution of kelp (Laminaria hyperborea and sea urchins (Strongylocentrotus droebachiensis in the NE Atlantic are highly related to physical factors and to temporal changes in temperature. On a large scale, we identified borders for kelp recovery and sea urchin persistence along the north-south gradient. Sea urchin persistence was also related to the coast-ocean gradient. The southern border corresponds to summer temperatures exceeding about 10°C, a threshold value known to be critical for sea urchin recruitment and development. The outer border along the coast-ocean gradient is related to temperature, wave exposure and salinity. On a finer scale, kelp recovery occurs mainly at ridges in outer, wave exposed, saline and warm areas whereas sea urchins still dominate in inner, shallow and cold areas, particularly in areas with optimal current speed for sea urchin foraging. In contrast to other studies in Europe, we here show a positive influence of climate change to presence of a long-lived climax canopy-forming kelp. The extent of the coast-ocean gradient varies within the study area, and is especially wide in the southern part where the presence of islands and skerries increases the area of the shallow coastal zone. This creates a large area with intermediate physical conditions for the two species and a mosaic of kelp and sea urchin dominated patches. The statistical models (GAM and BRT show high performance and indicate recovery of kelp in 45-60% of the study area. The study shows the value of combining a traditional (GAM and a more complex (BRT modeling approach to gain insight into complex spatial patterns of species or habitats. The results, methods and approaches are of general ecological relevance regardless of ecosystems and species, although they are particularly relevant for understanding and exploring the corresponding changes between algae and grazers in different coastal areas.

  10. First insights into genus level diversity and biogeography of deep sea benthopelagic calanoid copepods in the South Atlantic and Southern Ocean

    Science.gov (United States)

    Renz, Jasmin; Markhaseva, Elena L.

    2015-11-01

    Calanoid copepods constitute the most numerous organisms not only in the pelagic realm, but also in the benthic boundary layer, which gives them an important role in the turnover of organic matter in the benthopelagic habitat. During seven expeditions to the South Atlantic and Southern Ocean, the diversity and biogeography of deep-sea benthopelagic calanoid copepods were studied. The communities of calanoids living in the vicinity of the seabed were characterized by high diversity comparable to many pelagic habitats, but low abundance of individuals. Members of the taxon Clausocalanoidea dominated the communities, and within this taxon most individuals belonged to detritivore calanoids characterized by sensory setae on the second maxillae or aetideid copepods. 73% of all genera classified as obligate or predominantly benthopelagic copepods detected during these expeditions were new to science and a vast number of genera and species have been described since then. Comparing the communities of calanoid genera between different regions, the assemblages in the Southern Ocean differed significantly from the Southeast and Southwest Atlantic. A latitudinal diversity gradient could be observed, with highest numbers of genera in the Southwest Atlantic and low numbers at stations in the Southern Ocean. Reviewing the literature, endemism for benthopelagic calanoids appeared to be low on a latitudinal range caused by connectivity in benthopelagic habitats through spreading water masses. However, considering the habitats structuring the water column vertically, a high number of genera are endemic in the benthopelagial and specialized to living within the vicinity of the seabed.

  11. Environmental contaminants in fillets of sea-run Atlantic salmon (Salmo salar) from the Gulf of Maine Distinct Population Segment

    Data.gov (United States)

    Department of the Interior — Between 2008 and 2010, skin‐on fillets from seven dead adult sea‐run Atlantic salmon from the Gulf of Maine Distinct Population Segment (GOM DPS) were analyzed for...

  12. Simulating the Regional Impact of Dust on the Middle East Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey; Stenchikov, Georgiy L.

    2018-01-01

    the Regional Ocean Modeling System fully coupled with the Weather Research and Forecasting model. We modified the atmospheric model to account for the radiative effect of dust. The simulations show that, in the equilibrium response, dust cools the Red Sea

  13. Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge

    Science.gov (United States)

    McCollom, Thomas M.; Seewald, Jeffrey S.; German, Christopher R.

    2015-05-01

    The possibility that deep-sea hydrothermal vents may contain organic compounds produced by abiotic synthesis or by microbial communities living deep beneath the surface has led to numerous studies of the organic composition of vent fluids. Most of these studies have focused on methane and other light hydrocarbons, while the possible occurrence of more complex organic compounds in the fluids has remained largely unstudied. To address this issue, the presence of higher molecular weight organic compounds in deep-sea hydrothermal fluids was assessed at three sites along the Mid-Atlantic Ridge that span a range of temperatures (51 to >360 °C), fluid compositions, and host-rock lithologies (mafic to ultramafic). Samples were obtained at several sites within the Lucky Strike, Rainbow, and Lost City hydrothermal fields. Three methods were employed to extract organic compounds for analysis, including liquid:liquid extraction, cold trapping on the walls of a coil of titanium tubing, and pumping fluids through cartridges filled with solid phase extraction (SPE) sorbents. The only samples to consistently yield high amounts of extractable organic compounds were the warm (51-91 °C), highly alkaline fluids from Lost City, which contained elevated concentrations of C8, C10, and C12n-alkanoic acids and, in some cases, trithiolane, hexadecanol, squalene, and cholesterol. Collectively, the C8-C12 acids can account for about 15% of the total dissolved organic carbon in the Lost City fluids. The even-carbon-number predominance of the alkanoic acids indicates a biological origin, but it is unclear whether these compounds are derived from microbial activity occurring within the hydrothermal chimney proximal to the site of fluid discharge or are transported from deeper within the system. Hydrothermal fluids from the Lucky Strike and Rainbow fields were characterized by an overall scarcity of extractable dissolved organic compounds. Trace amounts of aromatic hydrocarbons including

  14. Efficacy of emamectin benzoate against sea lice infestations of Atlantic salmon, Salmo salar L.: evaluation in the absence of an untreated contemporary control.

    Science.gov (United States)

    Gustafson, L; Ellis, S; Robinson, T; Marenghi, F; Endris, R

    2006-10-01

    The efficacy of emamectin benzoate (SLICE) against sea lice infestations of Atlantic salmon, Salmo salar L., is typically assessed using untreated fish, or fish treated with alternative therapeutants, as controls. The State of Maine, USA, is currently under active management for the OIE-notifiable pathogen, infectious salmon anaemia virus (ISAV); consequently, neither control group is feasible in this region. Untreated salmon risk extensive damage from the ectoparasites, and threaten to increase vector-borne exposure or susceptibility of farms to ISAV; and the only treatment presently available in Maine is SLICE. However, because sea lice infestations are unlikely to resolve spontaneously, and response to treatment occurs within weeks, use of a pretreatment baseline is a reasonable alternative for confirmatory studies. We evaluated SLICE efficacy on Atlantic salmon farms in Cobscook Bay 2002-2005, in the absence of untreated controls, using pretreatment lice loads as a reference for calculation. Maximum efficacy ranged from 68% to 100% reduction from initial levels. Time-to-maximum efficacy ranged from 1 to 8 weeks after treatment initiation. Efficacy duration, measured between first reduction and first progressive rise in counts, ranged from 4 to 16 weeks.

  15. MICROSTRUCTURE OF THE MID-INTESTINE OF CERTAIN CARP FISH (CIPRINIDAE IN THE WESTERN PART OF THE MIDDLE CASPIAN SEA

    Directory of Open Access Journals (Sweden)

    N. I. Rabazanov

    2016-01-01

    Full Text Available Aim. The aim of the study was an attempt to expand on the findings about the structure of the anterior part of the mid-intestine of three species of carp fish: Rutelus frisii kutum (Kamenski, Abramis brama orientalis and Ciprinus caprio (Linne in connection with the feeding habits in the changed conditions of the western coast of the Middle Caspian sea. Studies of the digestive tract can extend the idea of the specifics of the mid-intestine structure due to the feeding of fish in certain environmental conditions of habitat.Methods. Investigations of the digestive tract were carried out, guided by the "Methodological manual" by I.V. Verigina.Findings and discussion. It is shown that in the anatomical and histological structure of the middle intestine was affected by the feeding habits of these types of fish; feeding upon small and soft invertebrates leads to a relatively simple structure of the intestinal wall: mucous layer covers a small part of the total thickness of the wall; there are no collagen structures that perform the function of the mechanical frame and capsules around blood vessels.Conclusion. Simplification of the digestive system emphasizes adaptive capacity appearing in periodic fluctuation of sea water level. The absence of food of a bigger size in the diet of fish results in a relatively simple anatomical and histological structure of the mid-intestine wall. None of the species under study has a differentiated stomach; instead its role is taken by an expanded portion of the fore intestine, similar is the microstructure of the middle part of the intestines of all three species.

  16. Air-sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    Science.gov (United States)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-11-01

    Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air-sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air-sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  17. Vertical water mass structure in the North Atlantic influences the bathymetric distribution of species in the deep-sea coral genus Paramuricea

    Science.gov (United States)

    Radice, Veronica Z.; Quattrini, Andrea M.; Wareham, Vonda E.; Edinger, Evan N.; Cordes, Erik E.

    2016-10-01

    Deep-sea corals are the structural foundation of their ecosystems along continental margins worldwide, yet the factors driving their broad distribution are poorly understood. Environmental factors, especially depth-related variables including water mass properties, are thought to considerably affect the realized distribution of deep-sea corals. These factors are governed by local and regional oceanographic conditions that directly influence the dispersal of larvae, and therefore affect the ultimate distribution of adult corals. We used molecular barcoding of mitochondrial and nuclear sequences to identify species of octocorals in the genus Paramuricea collected from the Labrador Sea to the Grand Banks of Newfoundland, Canada at depths of 150-1500 m. The results of this study revealed overlapping bathymetric distributions of the Paramuricea species present off the eastern Canadian coast, including the presence of a few cryptic species previously designated as Paramuricea placomus. The distribution of Paramuricea species in the western North Atlantic differs from the Gulf of Mexico, where five Paramuricea species exhibit strong segregation by depth. The different patterns of Paramuricea species in these contrasting biogeographic regions provide insight into how water mass structure may shape species distribution. Investigating Paramuricea prevalence and distribution in conjunction with oceanographic conditions can help demonstrate the factors that generate and maintain deep-sea biodiversity.

  18. Impact of early salmon louse, Lepeophtheirus salmonis, infestation and differences in survival and marine growth of sea-ranched Atlantic salmon, Salmo salar L., smolts 1997–2009

    Science.gov (United States)

    Skilbrei, O T; Finstad, B; Urdal, K; Bakke, G; Kroglund, F; Strand, R

    2013-01-01

    The impact of salmon lice on the survival of migrating Atlantic salmon smolts was studied by comparing the adult returns of sea-ranched smolts treated for sea lice using emamectin benzoate or substance EX with untreated control groups in the River Dale in western Norway. A total of 143 500 smolts were released in 35 release groups in freshwater from 1997 to 2009 and in the fjord system from 2007 to 2009. The adult recaptures declined gradually with release year and reached minimum levels in 2007. This development corresponded with poor marine growth and increased age at maturity of ranched salmon and in three monitored salmon populations and indicated unfavourable conditions in the Norwegian Sea. The recapture rate of treated smolts was significantly higher than the controls in three of the releases performed: the only release in 1997, one of three in 2002 and the only group released in sea water in 2007. The effect of treating the smolts against salmon lice was smaller than the variability in return rates between release groups, and much smaller that variability between release years, but its overall contribution was still significant (P < 0.05) and equivalent to an odds ratio of the probability of being recaptured of 1.17 in favour of the treated smolts. Control fish also tended to be smaller as grilse (P = 0.057), possibly due to a sublethal effect of salmon lice. PMID:23311746

  19. Global Climate Change Consequences Changing the Middle Sea Level in the Brazilian Coast: Impacts on Ceará State

    Science.gov (United States)

    Lacerda, E. G.; Pires, L. B. M.; Pinto, V. K. E.

    2015-12-01

    Since the Industrial Revolution, man started to generate increasing amounts of waste and pollutants, which on a large scale in the long term is causing a series of climate change consequences, both globally as well as locally. One of the many effects of these changes has been reflected in the ocean levels, depending on various factors. Thus, the population living in coastal areas suffers from the negative effects of the advancement of ocean waters. The coast of northeastern Brazil is an example of this, especially the state of Ceará coast. The state of Ceará has 573 km of coastline, a region that has suffered extensive erosion, in which the Middle Sea Level (MSL) changes exert a significant influence. The coastal plain is a strip of land of small extent, with an average width of 2.5 km, formed depending on the availability of high sediment stocks provided through the action of wind, marine, or river processes, individually in combination with each other. In many beaches it is observed that the strip of beach is narrow due to the presence of topographic elevations carved into sharp cliffs. Between periods of high tide and low tide, often rocky beach features are observed that have recently formed. The waves control the stretches of beach which are mostly sandy. This paper presents a survey about the evidence already apparent on the rise in the MSL and correlates it with the advance of the sea on the coast of Ceará, as well as assesses the possible consequences of this process. Therefore, a literature search was conducted in relevant scientific publications. The data used are from the station "Global Sea Level Observing System - GLOSS" which maintains a tide gauge installed in Ceará in Fortaleza. The analyses show that the phenomenon has caused a lot of inconvenience to the people, streets have disappeared, as well as several buildings located along the coast. The sea advances destroyed beaches and have promoted an accelerated level of erosion, changing the

  20. Sea turtle acoustic and radio telemetry data in the Atlantic Ocean from 2013-2014 (NCEI Accession 0160089)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains acoustic tag readings that were attached to sea turtles captured in various fishing gears. These sea turtles were either actively or passively...

  1. Concentrations and distributions of metals in tissues of stranded green sea turtles (Chelonia mydas) from the southern Atlantic coast of Brazil

    International Nuclear Information System (INIS)

    da Silva, Cinthia Carneiro; Varela, Antonio Sergio; Barcarolli, Indianara Fernanda; Bianchini, Adalto

    2014-01-01

    Silver (Ag), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) concentrations were analyzed in tissues of juvenile green sea turtles (Chelonia mydas) found stranded along the southern Atlantic coast in Brazil. Green sea turtles were collected (n = 29), measured (curved carapace length: CCL) and had their muscle, liver, and kidney dissected for metal concentration measurements. Sex was identified in 18 individuals (10 females and 8 males) through gonad histology. No gender differences in CCL and tissue metal concentrations were observed. In the muscle, there was a negative correlation between CCL and Cd and Cu concentrations. Metal concentrations were lower in the muscle than in the liver and kidney. Zn concentration in the muscle was the highest of all metals analyzed (16.6 mg/kg). The kidney showed the highest concentrations of Pb, Cd and Zn (5.4, 28.3 and 54.3 mg/kg, respectively), while the liver had the highest values of Ag and Cu (0.8 and 100.9 mg/kg, respectively). Tissue Ag, Zn and Cd concentrations were similar to those found in green sea turtles from other regions while Cu and Pb values were elevated, likely due to the metal-rich water and sediment reported in the collection area. In the liver and kidney, concentrations of non-essential (Ag, Cd and Pb) and essential (Cu or Zn) metals were positively correlated, likely due to an induced metallothionein synthesis to protect tissue against the toxic effect of metals. This is the first study to report and correlate the concentrations of essential and non-essential metals in tissues of green sea turtles in the Brazilian southern Atlantic coast, an important feeding and developing area for this turtle species. - Highlights: •Juvenile female and male green sea turtles have similar concentrations of metals. •Kidney accumulated more Cd, Pb and Zn while liver accumulated more Ag and Cu. •Cu and Pb concentrations are elevated in liver of sea turtles from southern Brazil. •Concentrations of Cd and Cu in

  2. Concentrations and distributions of metals in tissues of stranded green sea turtles (Chelonia mydas) from the southern Atlantic coast of Brazil

    Energy Technology Data Exchange (ETDEWEB)

    da Silva, Cinthia Carneiro [Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália km 8, 96203-900, Rio Grande, Rio Grande do Sul (Brazil); Varela, Antonio Sergio; Barcarolli, Indianara Fernanda [Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália km 8, 96203-900, Rio Grande, Rio Grande do Sul (Brazil); Bianchini, Adalto, E-mail: adaltobianchini@furg.br [Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália km 8, 96203-900, Rio Grande, Rio Grande do Sul (Brazil); Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália km 8, 96203-900, Rio Grande, Rio Grande do Sul (Brazil)

    2014-01-01

    Silver (Ag), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) concentrations were analyzed in tissues of juvenile green sea turtles (Chelonia mydas) found stranded along the southern Atlantic coast in Brazil. Green sea turtles were collected (n = 29), measured (curved carapace length: CCL) and had their muscle, liver, and kidney dissected for metal concentration measurements. Sex was identified in 18 individuals (10 females and 8 males) through gonad histology. No gender differences in CCL and tissue metal concentrations were observed. In the muscle, there was a negative correlation between CCL and Cd and Cu concentrations. Metal concentrations were lower in the muscle than in the liver and kidney. Zn concentration in the muscle was the highest of all metals analyzed (16.6 mg/kg). The kidney showed the highest concentrations of Pb, Cd and Zn (5.4, 28.3 and 54.3 mg/kg, respectively), while the liver had the highest values of Ag and Cu (0.8 and 100.9 mg/kg, respectively). Tissue Ag, Zn and Cd concentrations were similar to those found in green sea turtles from other regions while Cu and Pb values were elevated, likely due to the metal-rich water and sediment reported in the collection area. In the liver and kidney, concentrations of non-essential (Ag, Cd and Pb) and essential (Cu or Zn) metals were positively correlated, likely due to an induced metallothionein synthesis to protect tissue against the toxic effect of metals. This is the first study to report and correlate the concentrations of essential and non-essential metals in tissues of green sea turtles in the Brazilian southern Atlantic coast, an important feeding and developing area for this turtle species. - Highlights: •Juvenile female and male green sea turtles have similar concentrations of metals. •Kidney accumulated more Cd, Pb and Zn while liver accumulated more Ag and Cu. •Cu and Pb concentrations are elevated in liver of sea turtles from southern Brazil. •Concentrations of Cd and Cu in

  3. Modeling the Middle Jurassic ocean circulation

    Directory of Open Access Journals (Sweden)

    Maura Brunetti

    2015-10-01

    Full Text Available We present coupled ocean–sea-ice simulations of the Middle Jurassic (∼165 Ma when Laurasia and Gondwana began drifting apart and gave rise to the formation of the Atlantic Ocean. Since the opening of the Proto-Caribbean is not well constrained by geological records, configurations with and without an open connection between the Proto-Caribbean and Panthalassa are examined. We use a sea-floor bathymetry obtained by a recently developed three-dimensional (3D elevation model which compiles geological, palaeogeographical and geophysical data. Our original approach consists in coupling this elevation model, which is based on detailed reconstructions of oceanic realms, with a dynamical ocean circulation model. We find that the Middle Jurassic bathymetry of the Central Atlantic and Proto-Caribbean seaway only allows for a weak current of the order of 2 Sv in the upper 1000 m even if the system is open to the west. The effect of closing the western boundary of the Proto-Caribbean is to increase the transport related to barotropic gyres in the southern hemisphere and to change water properties, such as salinity, in the Neo-Tethys. Weak upwelling rates are found in the nascent Atlantic Ocean in the presence of this superficial current and we discuss their compatibility with deep-sea sedimentological records in this region.

  4. Quantifying the ocean, freshwater and human effects on year-to-year variability of one-sea-winter Atlantic salmon angled in multiple Norwegian rivers.

    Science.gov (United States)

    Otero, Jaime; Jensen, Arne J; L'Abée-Lund, Jan Henning; Stenseth, Nils Chr; Storvik, Geir O; Vøllestad, Leif Asbjørn

    2011-01-01

    Many Atlantic salmon, Salmo salar, populations are decreasing throughout the species' distributional range probably due to several factors acting in concert. A number of studies have documented the influence of freshwater and ocean conditions, climate variability and human impacts resulting from impoundment and aquaculture. However, most previous research has focused on analyzing single or only a few populations, and quantified isolated effects rather than handling multiple factors in conjunction. By using a multi-river mixed-effects model we estimated the effects of oceanic and river conditions, as well as human impacts, on year-to-year and between-river variability across 60 time series of recreational catch of one-sea-winter salmon (grilse) from Norwegian rivers over 29 years (1979-2007). Warm coastal temperatures at the time of smolt entrance into the sea and increased water discharge during upstream migration of mature fish were associated with higher rod catches of grilse. When hydropower stations were present in the course of the river systems the strength of the relationship with runoff was reduced. Catches of grilse in the river increased significantly following the reduction of the harvesting of this life-stage at sea. However, an average decreasing temporal trend was still detected and appeared to be stronger in the presence of salmon farms on the migration route of smolts in coastal/fjord areas. These results suggest that both ocean and freshwater conditions in conjunction with various human impacts contribute to shape interannual fluctuations and between-river variability of wild Atlantic salmon in Norwegian rivers. Current global change altering coastal temperature and water flow patterns might have implications for future grilse catches, moreover, positioning of aquaculture facilities as well as the implementation of hydropower schemes or other encroachments should be made with care when implementing management actions and searching for solutions to

  5. Quantifying the ocean, freshwater and human effects on year-to-year variability of one-sea-winter Atlantic salmon angled in multiple Norwegian rivers.

    Directory of Open Access Journals (Sweden)

    Jaime Otero

    Full Text Available Many Atlantic salmon, Salmo salar, populations are decreasing throughout the species' distributional range probably due to several factors acting in concert. A number of studies have documented the influence of freshwater and ocean conditions, climate variability and human impacts resulting from impoundment and aquaculture. However, most previous research has focused on analyzing single or only a few populations, and quantified isolated effects rather than handling multiple factors in conjunction. By using a multi-river mixed-effects model we estimated the effects of oceanic and river conditions, as well as human impacts, on year-to-year and between-river variability across 60 time series of recreational catch of one-sea-winter salmon (grilse from Norwegian rivers over 29 years (1979-2007. Warm coastal temperatures at the time of smolt entrance into the sea and increased water discharge during upstream migration of mature fish were associated with higher rod catches of grilse. When hydropower stations were present in the course of the river systems the strength of the relationship with runoff was reduced. Catches of grilse in the river increased significantly following the reduction of the harvesting of this life-stage at sea. However, an average decreasing temporal trend was still detected and appeared to be stronger in the presence of salmon farms on the migration route of smolts in coastal/fjord areas. These results suggest that both ocean and freshwater conditions in conjunction with various human impacts contribute to shape interannual fluctuations and between-river variability of wild Atlantic salmon in Norwegian rivers. Current global change altering coastal temperature and water flow patterns might have implications for future grilse catches, moreover, positioning of aquaculture facilities as well as the implementation of hydropower schemes or other encroachments should be made with care when implementing management actions and searching

  6. Aerosol Radiative Impact on the Middle East Regional Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2017-01-01

    The climate in the Middle East is complex and remains poorly understood. Due to the vast Arabian Desert, it is very sensitive to radiative forcing. Mineral dust is the dominant aerosol in this region. High background dust loading and frequent dust

  7. Aerosol-driven increase in Arctic sea ice over the middle of the twentieth century

    Science.gov (United States)

    Gagné, Marie-Ève; Fyfe, John C.; Gillett, Nathan P.; Polyakov, Igor V.; Flato, Gregory M.

    2017-07-01

    Updated observational data sets without climatological infilling show that there was an increase in sea ice concentration in the eastern Arctic between 1950 and 1975, contrary to earlier climatology infilled observational data sets that show weak interannual variations during that time period. We here present climate model simulations showing that this observed sea ice concentration increase was primarily a consequence of cooling induced by increasing anthropogenic aerosols and natural forcing. Indeed, sulphur dioxide emissions, which lead to the formation of sulphate aerosols, peaked around 1980 causing a sharp increase in the burden of sulphate between the 1950s and 1970s; but since 1980, the burden has dropped. Our climate model simulations show that the cooling contribution of aerosols offset the warming effect of increasing greenhouse gases over the midtwentieth century resulting in the expansion of the Arctic sea ice cover. These results challenge the perception that Arctic sea ice extent was unperturbed by human influence until the 1970s, suggesting instead that it exhibited earlier forced multidecadal variations, with implications for our understanding of impacts and adaptation in human and natural Arctic systems.

  8. ZOOBENTHOS OF THE MIDDLE CASPIAN. BENTHOS COMMUNITIES OF THE CASPIAN SEA

    Directory of Open Access Journals (Sweden)

    S. A. Guseinova

    2014-01-01

    Full Text Available Abstract. Aim. Industrialization of Caspian oil and gas supplies requires a serious approach to the problem of protecting and preserving the region’s unique environment that, in fact, represents a property of international commons. The article studies into the impact of the Caspian modified waters on the benthos faunistic composition.Methods. Zooplancton and zoobenthos hydrobiology material was collected in the Central Caspian survey loop. Samples were collected in spring and summer in 2002 – 2007 in the western part of the Caspian Sea (Dagestan offshore location of the Caspian Sea from Smirnovsky Midstream Sandbank and Pearl Bank till Derbent latitude on “Tsada” vessel. They were collected from 25 stations located on ten standard parallel latitude logs with depth scope of 8–100 m from 0, 10, 25, 100 m horizons. These samples were used as a material for characterizing phyto- and zooplankton.Results. The benthic can be considered the most stable communities of the marine environment as they are the most resilient to quantity and modifications. Heterogeneous and variable ecosystem (biotope is typical of the areas with strong currents as the organic quality, quantity and physic-chemical properties are marked by variability.Location. The Caspian zoobenthos state as well as the features of the Caspian Sea benthos communities characterize the ecology of the Caspian Sea and give a true view of the situation in the drilling sites. This will help predict and avert negative effect of hydrocarbon production on the Caspian Sea ecosystem. Main conclusions. Water modification must be intensive, long-lasting and frequent for it to have an impact on benthos.

  9. WATER TEMPERATURE and other data from LEWIS B. PULLER, ELLIOT and USS DE WERT in the TOGA Area - Pacific, Caribbean Sea and NW Atlantic from 1986-11-07 to 1987-05-31 (NCEI Accession 9400029)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession were collected in Caribbean Sea, NW Atlantic (limit-40 W), and TOGA Area - Pacific (30 N to 30 S) from ship ELLIOT, USS DE WERT, and LEWIS...

  10. Detection of emamectin benzoate tolerance emergence in different life stages of sea lice, Lepeophtheirus salmonis, on farmed Atlantic salmon, Salmo salar L.

    Science.gov (United States)

    Jones, P G; Hammell, K L; Gettinby, G; Revie, C W

    2013-03-01

    Emamectin benzoate has been used to treat sea lice, Lepeophtheirus salmonis, infestations on farmed Atlantic salmon, Salmo salar. Recent evidence suggests a reduction in effectiveness in some locations. A major challenge in the detection of tolerance emergence can be the typically low proportion of resistant individuals in a population during the early phases. The objectives of this study were to develop a method for determining differences in temporal development of tolerance between sea lice life stages and to explore how these differences might be used to improve the monitoring of treatment effectiveness in a clinical setting. This study examined two data sets based on records of sea lice abundance following emamectin benzoate treatments from the west coast of Scotland (2002-2006) and from New Brunswick, Canada (2004-2008). Life stages were categorized into two groups (adult females and the remaining mobile stages) to examine the trends in mean abundance and treatment effectiveness. Differences in emamectin benzoate effectiveness were found between the two groups by year and location, suggesting that an important part of monitoring drug resistance development in aquatic ectoparasites may be the need to focus on key life stages. © 2013 Blackwell Publishing Ltd.

  11. THE ATMOSPHERIC CYCLING AND AIR-SEA EXCHANGE OF MERCURY SPECIES IN THE SOUTH AND EQUATORIAL ATLANTIC OCEAN. (R829796)

    Science.gov (United States)

    Measurements of gas-, particle- and precipitation-phases of atmospheric mercury(Hg) were made in the South and equatorial Atlantic Ocean as part of the 1996IOC Trace Metal Baseline Study (Montevideo, Uruguay to Barbados). Total gaseousmercury (TGM) ranged from ...

  12. The Pitfalls of Picturing Atlantic Slavery: Steven Spielberg’s Amistad vs Guy Deslauriers’s The Middle Passage

    Directory of Open Access Journals (Sweden)

    Lars Eckstein

    2011-04-01

    On the one hand, the arts are particularly called for in this situation to fill the documentary gaps and silences through acts of experiment and imagination, and they may indeed have a redemptive effect by offering, in Hayden White’s terms, successful ‘emplotments’ of a traumatic past. One the other hand, this redemptive potential simultaneously poses a serious ethical challenge: As Theodor W. Adorno has warned with reference to the Holocaust, it is precisely by making ‘sense’ of human suffering, and by making accessible to the ‘senses’ what is utterly senseless and incomprehensible, that injustice may be done to the victims. In this paper, I will try to illustrate this problematic by looking at two recent films that have attempted to represent the horrors of the middle passage – Steven Spielberg’s canonical Amistad (a terrible failure, in my view, and Guy Deslauriers’ film The Middle Passage [Passage du Milieu]. Based on a script by the Martiniquean novelist and poet Patrick Chamoiseau, the latter example uses an aesthetic approach which may point at a way out of the dilemma outlined above.

  13. Evidence for ephemeral middle Eocene to early Oligocene Greenland glacial ice and pan-Arctic sea ice.

    Science.gov (United States)

    Tripati, Aradhna; Darby, Dennis

    2018-03-12

    Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO 2 , with a potential threshold for glacial ice stability near ~500 p.p.m.v. The middle Eocene represents the Cenozoic onset of a dynamic cryosphere, with ice in both hemispheres during transient glacials and substantial regional climate heterogeneity. A more stable cryosphere developed at the Eocene-Oligocene transition, and is now threatened by anthropogenic emissions.

  14. 77 FR 60945 - 2012-2013 Accountability Measure and Closure for Commercial Black Sea Bass in the South Atlantic

    Science.gov (United States)

    2012-10-05

    ... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 622 [Docket No. 0907271173-0629-03] RIN 0648-XC152 2012-2013 Accountability Measure and Closure for Commercial Black Sea Bass... accountability measure (AM) for the commercial sector of black sea bass in the exclusive economic zone (EEZ) of...

  15. Meat Composition and Quality Assessment of King Scallops (Pecten maximus) and Frozen Atlantic Sea Scallops (Placopecten magellanicus) on a Retail Level

    Science.gov (United States)

    Manthey-Karl, Monika; Lehmann, Ines; Ostermeyer, Ute; Rehbein, Hartmut; Schröder, Ute

    2015-01-01

    An enlarged range of scallop products on the market allows the consumer to buy lower priced alternatives, which often raises the question of quality and control. Frozen meat of king scallops (Pecten maximus) and Atlantic sea scallops (Placopecten magellanicus) were purchased on the German market and compared with fresh shell-on king scallops of various origin. The approximate composition, inclusive citric acid and phosphates, minerals, free amino acids (FAA) and fatty acid profiles were examined in the muscle to identify changes as a result of processing. The FAA glycine and taurine as well the fatty acids 20:5n-3 (EPA) and 22:6n-3 (DHA) were the most abundant, but were reduced in processed samples. Di- and triphosphate contents were not detectable (additives. Labelling does not readily allow the consumer to recognize the extent of processing effects. PMID:28231221

  16. Organic storage of CO/sub 2/ on the continental slope off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru coast

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J.; Premuzic, E.T.; Gaffney, J.S.; Rowe, G.T.; Harbottle, G.; Stoenner, R.W.; Balsam, W.L.; Betzer, P.R.; Macko, S.A.

    1985-01-01

    A comparison is made of organic content, sedimentation rates derived from /sup 14/C and /sup 210/Pb analyses, /sup 13/C and /sup 15/N isotope ratios, amorphous silica, particle size, and calcium carbonate within sediments from slopes off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru coast. These sediments are mainly marine, diatom-rich, and about one-third of the organic carbon is recent, reflecting a possible transient of shelf export in response to man's increased activities since the industrial revolution. Using a combination of sedimentation and mixing rates of carbon, the C:N ratio of sediments within the upper 50 cm, and the amount of nitrogen thought to be released from the coastal zone, independent estimates suggest a carbon loading to world slopes of approx. 0.3 to 0.5 x 10/sup 9/ tons C y/sup -1/. The Bering slope exhibits no anthropogenic transients, however, while increased carbon loading may have occurred off Peru in response to overfishing and off the mid-Atlantic bight in response to eutrophication. The generality of their results depends on which of the three systems is most representative of world slopes.

  17. A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-Eastern Tropical Upwelling System.

    Directory of Open Access Journals (Sweden)

    Saliou eFaye

    2015-09-01

    Full Text Available The climatological seasonal cycle of the sea surface temperature (SST in the north-eastern tropical Atlantic (7-25°N, 26-12°W is studied using a mixed layer heat budget in a regional ocean general circulation model. The region, which experiences one of the larger SST cycle in the tropics, forms the main part of the Guinea Gyre. It is characterized by a seasonally varying open ocean and coastal upwelling system, driven by the movements of the intertropical convergence zone (ITCZ. The model annual mean heat budget has two regimes schematically. South of roughly 12°N, advection of equatorial waters, mostly warm, and warming by vertical mixing, is balanced by net air-sea flux. In the rest of the domain, a cooling by vertical mixing, reinforced by advection at the coast, is balanced by the air-sea fluxes. Regarding the seasonal cycle, within a narrow continental band, in zonal mean, the SST early decrease (from September, depending on latitude, until December is driven by upwelling dynamics off Senegal and Mauritania (15°-20°N, and instead by air-sea fluxes north and south of these latitudes. Paradoxically, the later peaks of upwelling intensity (from March to July, with increasing latitude essentially damp the warming phase, driven by air-sea fluxes. The open ocean cycle to the west, is entirely driven by the seasonal net air-sea fluxes. The oceanic processes significantly oppose it, but for winter north of ~18°N. Vertical mixing in summer-autumn tends to cool (warm the surface north (south of the ITCZ, and advective cooling or warming by the geostrophic Guinea Gyre currents and the Ekman drift. This analysis supports previous findings on the importance of air-sea fluxes offshore. It mainly offers quantitative elements on the modulation of the SST seasonal cycle by the ocean circulation, and particularly by the upwelling dynamics.Keywords: SST, upwelling, circulation, heat budget, observations, modeling

  18. First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: from kelp forests to the deep sea

    Science.gov (United States)

    Hamilton, Scott L.; Davis, Kathryn; Thompson, Christopher D. H.; Turchik, Alan; Jenkinson, Ryan; Simpson, Doug; Sala, Enric

    2018-01-01

    Tristan da Cunha Islands, an archipelago of four rocky volcanic islands situated in the South Atlantic Ocean and part of the United Kingdom Overseas Territories (UKOTs), present a rare example of a relatively unimpacted temperate marine ecosystem. We conducted the first quantitative surveys of nearshore kelp forests, offshore pelagic waters and deep sea habitats. Kelp forests had very low biodiversity and species richness, but high biomass and abundance of those species present. Spatial variation in assemblage structure for both nearshore fish and invertebrates/algae was greatest between the three northern islands and the southern island of Gough, where sea temperatures were on average 3-4o colder. Despite a lobster fishery that provides the bulk of the income to the Tristan islands, lobster abundance and biomass are comparable to or greater than many Marine Protected Areas in other parts of the world. Pelagic camera surveys documented a rich biodiversity offshore, including large numbers of juvenile blue sharks, Prionace glauca. Species richness and abundance in the deep sea is positively related to hard rocky substrate and biogenic habitats such as sea pens, crinoids, whip corals, and gorgonians were present at 40% of the deep camera deployments. We observed distinct differences in the deep fish community above and below ~750 m depth. Concurrent oceanographic sampling showed a discontinuity in temperature and salinity at this depth. While currently healthy, Tristan’s marine ecosystem is not without potential threats: shipping traffic leading to wrecks and species introductions, pressure to increase fishing effort beyond sustainable levels and the impacts of climate change all could potentially increase in the coming years. The United Kingdom has committed to protection of marine environments across the UKOTs, including Tristan da Cunha and these results can be used to inform future management decisions as well as provide a baseline against which future

  19. First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: from kelp forests to the deep sea.

    Science.gov (United States)

    Caselle, Jennifer E; Hamilton, Scott L; Davis, Kathryn; Thompson, Christopher D H; Turchik, Alan; Jenkinson, Ryan; Simpson, Doug; Sala, Enric

    2018-01-01

    Tristan da Cunha Islands, an archipelago of four rocky volcanic islands situated in the South Atlantic Ocean and part of the United Kingdom Overseas Territories (UKOTs), present a rare example of a relatively unimpacted temperate marine ecosystem. We conducted the first quantitative surveys of nearshore kelp forests, offshore pelagic waters and deep sea habitats. Kelp forests had very low biodiversity and species richness, but high biomass and abundance of those species present. Spatial variation in assemblage structure for both nearshore fish and invertebrates/algae was greatest between the three northern islands and the southern island of Gough, where sea temperatures were on average 3-4o colder. Despite a lobster fishery that provides the bulk of the income to the Tristan islands, lobster abundance and biomass are comparable to or greater than many Marine Protected Areas in other parts of the world. Pelagic camera surveys documented a rich biodiversity offshore, including large numbers of juvenile blue sharks, Prionace glauca. Species richness and abundance in the deep sea is positively related to hard rocky substrate and biogenic habitats such as sea pens, crinoids, whip corals, and gorgonians were present at 40% of the deep camera deployments. We observed distinct differences in the deep fish community above and below ~750 m depth. Concurrent oceanographic sampling showed a discontinuity in temperature and salinity at this depth. While currently healthy, Tristan's marine ecosystem is not without potential threats: shipping traffic leading to wrecks and species introductions, pressure to increase fishing effort beyond sustainable levels and the impacts of climate change all could potentially increase in the coming years. The United Kingdom has committed to protection of marine environments across the UKOTs, including Tristan da Cunha and these results can be used to inform future management decisions as well as provide a baseline against which future monitoring

  20. North Atlantic Coast Comprehensive Study Phase I: Statistical Analysis of Historical Extreme Water Levels with Sea Level Change

    Science.gov (United States)

    2014-09-01

    14-7 ii Abstract The U.S. North Atlantic coast is subject to coastal flooding as a result of both severe extratropical storms (e.g., Nor’easters...Products and Services, excluding any kind of high-resolution hydrodynamic modeling. Tropical and extratropical storms were treated as a single...joint probability analysis and high-fidelity modeling of tropical and extratropical storms

  1. Changes in North Atlantic deep-sea temperature during climatic fluctuations of the last 25,000 years based on ostracode Mg/Ca ratios

    Science.gov (United States)

    Dwyer, Gary S.; Cronin, Thomas M.; Baker, Paul A.; Rodriguez-Lazaro, Julio

    2000-01-01

    We reconstructed three time series of last glacial-to-present deep-sea temperature from deep and intermediate water sediment cores from the western North Atlantic using Mg/Ca ratios of benthic ostracode shells. Although the Mg/Ca data show considerable variability (“scatter”) that is common to single-shell chemical analyses, comparisons between cores, between core top shells and modern bottom water temperatures (BWT), and comparison to other paleo-BWT proxies, among other factors, suggest that multiple-shell average Mg/Ca ratios provide reliable estimates of BWT history at these sites. The BWT records show not only glacial-to-interglacial variations but also indicate BWT changes during the deglacial and within the Holocene interglacial stage. At the deeper sites (4500- and 3400-m water depth), BWT decreased during the last glacial maximum (LGM), the late Holocene, and possibly during the Younger Dryas. Maximum deep-sea warming occurred during the latest deglacial and early Holocene, when BWT exceeded modern values by as much as 2.5°C. This warming was apparently most intense around 3000 m, the depth of the modern-day core of North Atlantic deep water (NADW). The BWT variations at the deeper water sites are consistent with changes in thermohaline circulation: warmer BWT signifies enhanced NADW influence relative to Antarctic bottom water (AABW). Thus maximum NADW production and associated heat flux likely occurred during the early Holocene and decreased abruptly around 6500 years B.P., a finding that is largely consistent with paleonutrient studies in the deep North Atlantic. BWT changes in intermediate waters (1000-m water depth) of the subtropical gyre roughly parallel the deep BWT variations including dramatic mid-Holocene cooling of around 4°C. Joint consideration of the Mg/Ca-based BWT estimates and benthic oxygen isotopes suggests that the cooling was accompanied by a decrease in salinity at this site. Subsequently, intermediate waters warmed to modern

  2. Formation of early-middle Miocene red beds in the South China Sea: element geochemistry and mineralogy analysis

    Science.gov (United States)

    Lyu, X.; Liu, Z.

    2017-12-01

    The formation of oceanic red beds that usually present oxic and oligotrophic conditions with low sedimentation rate has been used to trace depositional paleoenvironment and paleoclimate change. Red beds overlying oceanic basalts were drilled at two adjacent Sites U1433 and U1434 of IODP Expedition 349 in the Southwest Subbasin of the South China Sea. The occurrence of early-middle Miocene red beds may indicate that at that time there was oxic and quiet marine environment in the deep South China Sea. To understand their formation of red-color, local depositional condition, and potential paleoceanographic significance, major elements (XRF), trace and rare earth elements (ICP-MS), Fe chemical speciation (modified sequential iron extraction procedure), and Fe oxic minerals (CBD and DRS) were analyzed. Geochemical and mineralogical data reveal that hematite and goethite are responsible for the reddish color and red beds were deposited under highly oxic, oligotrophic conditions with a little later hydrothermal influence in the South China Sea. Our results indicate that: (1) after treatment using the CBD procedure, the red samples presented a change in color to greenish, showing the iron oxides being responsible for the sediment color; (2) enriched Mn, depleted U, S enrichment factors, and negative Ce anomaly show that the water mass was pre-oxidized before transported to the study location; (3) low primary productivity was inferred from the lower P, Ba enrichment factors in red beds compared to non-red beds; (4) the excess Mo influx at the bottom may come from the later hydrothermal input; (5) the diverse Ca enrichment factors and correlations between Fe and Al suggest different allogenic sources for red beds at our two sites. We conclude that the red beds at Sites U1433 and U1434 despite their diverse sources both developed in externally oxidized water mass and low primary productivity conditions, and partially altered by hydrothermal fluids after their pelagic

  3. EVALUATION OF FISHING LOBSTERS PALINURUS ELEPHAS (FABRICIUS, 1787 BY LOBSTER TRAPS IN THE MIDDLE ADRIATIC SEA

    Directory of Open Access Journals (Sweden)

    Perica Cetinić

    1997-04-01

    Full Text Available The work contains the results of fishing lobsters Palinurus elephas by lobsters traps from Komiža, island Vis with one eye side size of 60 mm as well as the evaluation of its effect to their population. The correct size of her eye was evaluated by the analysis of representation of immature lobsters in the catchs of the lobsters traps. 171 examples of lobsters were analyzed (116 males and 55 females with their lengths ranging from 22 to 45 cm. Total of 53 units (31% were less than 28 mm and at that length lobsters are barred from catch and transport. Such a length has been regulated by the valid Regulation on protection of fish and other sea organisms. Therefore, the lobster trap from Komiža, island Vis was evaluated as having the negative impact on the lobsters population.

  4. Management measures and fishers’ commitment towards sustainable exploitation: a case study of Atlantic salmon fisheries in the Baltic Sea

    DEFF Research Database (Denmark)

    Haapasaari, Päivi Elisabet; Michielsens, Catherina C.G.J.; Karjalainen, Timo P.

    2007-01-01

    management measures on the stocks. Based on interviews and a questionnaire, we use a Bayesian belief network to examine which factors determine fishers’ commitment to sustainable fisheries goals, what impact commitment has on exploitation rate, and what measures can be taken to improve commitment. In addition...... of Atlantic salmon (Salmo salar) stocks. The results indicate that the more fishers rely on fishing as their source of income, the less is their commitment and the smaller is the impact of changes in commitment on subsequent catches. The results suggest that commitment can be improved by selecting management...

  5. CURRENT STATE OF FISHERIES AND ASSESSMENT OF FISH STOCKS IN THE WESTERN MIDDLE OF THE CASPIAN SEA. PROSPECTS FOR THE USE OF THE FISH RESOURCES

    Directory of Open Access Journals (Sweden)

    A. S. Abdusamadov

    2016-01-01

    Full Text Available Aim. To aim is to assess stocks and the fisheries of aquatic biological resources in the western part of the middle Caspian Sea and perspectives for the use of their resource potential.Methods. On the basis of the literature sources and our own data on the fish inventory in the western part of the Middle Caspian, we discuss possible reasons for emerging environmental, economic and other problems in the use of biological resources.Results. The main negative factors are the large-scale poaching, resulting in a catastrophic reduction in stocks of sturgeon and other valuable fish species of the Caspian Sea, a natural penetration of alien organisms (Mnemiopsis and overfishing of some species. The potential danger is large-scale development of oil and gas fields in the Caspian Sea, which can lead to even worse situation for the biological resources of the sea.Conclusions. In order to preserve the biological resources of the sea it is necessary to create conditions for steadily developing fishing and fish processing enterprises, thus ensuring the satisfaction of the constant demand for fish products and an increase in the revenue base of the budget and the well-being of the Russian population.

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from CEFAS ENDEAVOUR in the North Sea and South Atlantic Ocean from 2013-07-28 to 2013-07-31 (NCEI Accession 0157362)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157362 includes Surface underway, chemical, meteorological and physical data collected from CEFAS ENDEAVOUR in the North Sea and South Atlantic Ocean...

  7. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the G.O. SARS in the Barents Sea, North Atlantic Ocean and others from 2009-05-28 to 2009-08-11 (NODC Accession 0114433)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0114433 includes biological, chemical, discrete sample, physical and profile data collected from G.O. SARS in the Barents Sea, North Atlantic Ocean,...

  8. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HUDSON in the Labrador Sea and North Atlantic Ocean from 1992-05-27 to 1992-06-15 (NODC Accession 0113550)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113550 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Labrador Sea and North Atlantic Ocean from...

  9. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from MARTHA L. BLACK in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2012-06-01 to 2012-06-17 (NCEI Accession 0144337)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144337 includes discrete sample and profile data collected from MARTHA L. BLACK in the Davis Strait, Labrador Sea and North Atlantic Ocean from...

  10. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2015-05-04 to 2015-05-24 (NCEI Accession 0160487)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0160487 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  11. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2009-05-17 to 2009-06-01 (NODC Accession 0108073)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108073 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  12. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2003-07-13 to 2003-08-04 (NODC Accession 0108219)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108219 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  13. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2014-05-02 to 2014-05-24 (NCEI Accession 0157623)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157623 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  14. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1997-07-07 to 1997-08-09 (NODC Accession 0113913)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113913 includes chemical, discrete sample, physical and profile data collected from METEOR in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  15. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Caribbean Sea and North Atlantic Ocean from 2005-08-13 to 2005-09-19 (NODC Accession 0116566)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116566 includes chemical, discrete sample, physical and profile data collected from METEOR in the Caribbean Sea and North Atlantic Ocean from...

  16. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the KNORR in the Caribbean Sea and North Atlantic Ocean from 1996-11-02 to 1997-09-03 (NODC Accession 0115005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115005 includes chemical, discrete sample, physical and profile data collected from KNORR in the Caribbean Sea and North Atlantic Ocean from...

  17. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2008-05-20 to 2008-06-04 (NODC Accession 0108224)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108224 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  18. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1997-05-09 to 1997-06-11 (NODC Accession 0113557)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113557 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  19. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1994-05-24 to 1994-06-12 (NODC Accession 0113554)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113554 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  20. Dissolved inorganic carbon, pH, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from METEOR in the Labrador Sea and North Atlantic Ocean from 1999-07-11 to 1999-08-10 (NODC Accession 0113585)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113585 includes chemical, discrete sample, physical and profile data collected from METEOR in the Labrador Sea and North Atlantic Ocean from...

  1. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1994-11-15 to 1994-12-19 (NODC Accession 0113581)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113581 includes chemical, discrete sample, physical and profile data collected from METEOR in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  2. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Labrador Sea and North Atlantic Ocean from 2003-08-31 to 2003-10-05 (NODC Accession 0115587)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115587 includes chemical, discrete sample, physical and profile data collected from METEOR in the Labrador Sea and North Atlantic Ocean from...

  3. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the METEOR in the Labrador Sea and North Atlantic Ocean from 2003-07-23 to 2003-08-29 (NODC Accession 0113891)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113891 includes chemical, discrete sample, physical and profile data collected from METEOR in the Labrador Sea and North Atlantic Ocean from...

  4. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from METEOR in the Caribbean Sea and North Atlantic Ocean from 2004-07-10 to 2004-08-07 (NODC Accession 0116644)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116644 includes chemical, discrete sample, physical and profile data collected from METEOR in the Caribbean Sea and North Atlantic Ocean from...

  5. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2011-05-06 to 2011-05-28 (NODC Accession 0108124)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108124 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from G.O. SARS in the Barents Sea, North Atlantic Ocean and others from 2009-01-18 to 2009-07-17 (NCEI Accession 0157383)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157383 includes Surface underway, chemical, meteorological and physical data collected from G.O. SARS in the Barents Sea, North Atlantic Ocean, North...

  7. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from KNORR in the Caribbean Sea and North Atlantic Ocean from 2003-09-22 to 2003-11-13 (NODC Accession 0108060)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108060 includes chemical, discrete sample, physical and profile data collected from KNORR in the Caribbean Sea and North Atlantic Ocean from...

  8. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2005-05-26 to 2005-06-17 (NODC Accession 0108221)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108221 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  9. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2010-05-13 to 2010-05-30 (NODC Accession 0108225)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108225 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  10. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2002-06-23 to 2002-07-19 (NODC Accession 0108218)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108218 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  11. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2007-05-10 to 2007-05-27 (NODC Accession 0108223)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108223 includes chemical, discrete sample, physical and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean...

  12. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the ARANDA in the North Atlantic Ocean and North Greenland Sea from 1997-08-05 to 1997-09-25 (NODC Accession 0115602)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115602 includes chemical, discrete sample, physical and profile data collected from ARANDA in the North Atlantic Ocean and North Greenland Sea from...

  13. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from ATLANTIS in the Caribbean Sea and North Atlantic Ocean from 2012-03-24 to 2012-04-17 (NODC Accession 0109915)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109915 includes discrete sample and profile data collected from ATLANTIS in the Caribbean Sea and North Atlantic Ocean from 2012-03-24 to 2012-04-17...

  14. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the L'ATALANTE in the Caribbean Sea and North Atlantic Ocean from 2003-04-12 to 2003-04-25 (NODC Accession 0117494)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0117494 includes chemical, discrete sample, physical and profile data collected from L'ATALANTE in the Caribbean Sea and North Atlantic Ocean from...

  15. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the KNORR in the Barents Sea, North Atlantic Ocean and others from 2002-05-30 to 2002-07-01 (NODC Accession 0113569)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113569 includes chemical, discrete sample, physical and profile data collected from KNORR in the Barents Sea, North Atlantic Ocean, North Greenland...

  16. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from METEOR in the Labrador Sea and North Atlantic Ocean from 2001-05-07 to 2001-05-31 (NODC Accession 0113586)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113586 includes chemical, discrete sample, physical and profile data collected from METEOR in the Labrador Sea and North Atlantic Ocean from...

  17. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from DISCOVERY in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2008-08-20 to 2008-09-25 (NODC Accession 0108367)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108367 includes discrete sample and profile data collected from DISCOVERY in the Davis Strait, Labrador Sea and North Atlantic Ocean from 2008-08-20...

  18. Partial pressure (or fugacity) of carbon dioxide, temperature, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from METEOR in the North Atlantic Ocean and North Sea from 1996-06-22 to 1996-07-17 (NCEI Accession 0157292)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157292 includes Surface underway, chemical, meteorological and physical data collected from METEOR in the North Atlantic Ocean and North Sea from...

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from ATLANTIS in the Caribbean Sea and North Atlantic Ocean from 2012-03-24 to 2012-04-17 (NCEI Accession 0144247)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144247 includes Surface underway data collected from ATLANTIS in the Caribbean Sea and North Atlantic Ocean from 2012-03-24 to 2012-04-17. These data...

  20. PH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from Sarmiento de Gamboa in the Labrador Sea and North Atlantic Ocean from 2012-06-22 to 2012-07-20 (NCEI Accession 0156920)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0156920 includes chemical, discrete sample, physical and profile data collected from Sarmiento de Gamboa in the Labrador Sea and North Atlantic Ocean...

  1. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Atlantic Cartier in the English Channel, Inner Sea - West Coast Scotland and others from 2016-03-07 to 2016-11-09 (NCEI Accession 0157322)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157322 includes Surface underway, chemical, meteorological and physical data collected from Atlantic Cartier in the English Channel, Inner Sea - West...

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the DARVIN in the Inner Sea - West Coast Scotland and North Atlantic Ocean from 1991-06-14 to 1991-07-02 (NODC Accession 0113525)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113525 includes chemical, discrete sample, physical and profile data collected from DARVIN in the Inner Sea - West Coast Scotland and North Atlantic...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1996-05-12 to 1996-06-01 (NODC Accession 0115010)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115010 includes discrete sample and profile data collected from HUDSON in the Davis Strait, Labrador Sea and North Atlantic Ocean from 1996-05-12 to...

  4. Beach- ridge internal architecture and use for Holocene sea-level reconstruction: A case study from the Miquelon-Langlade Isthmus (NW Atlantic)

    Science.gov (United States)

    Hein, C. J.; Billy, J.; Robin, N.; FitzGerald, D.; Certain, R.

    2017-12-01

    The internal architecture of beach-ridge systems can provide insight into processes ongoing during its period of formation, such as changing relative sea-level (RSL). The paraglacial beach-ridge plain at Miquelon-Langlade (south of Newfoundland - NW Atlantic) is an example of a well-preserved regressive barrier. Initiation of this plain correlates with a decrease in the rate of RSL rise (from +4.4 mm/yr to 1.3 mm/yr) at around 3000 years ago. The combination of stratigraphic (ground-penetrating radar and sediment cores), topographic (RTK-GPS) and chronologic (optically stimulated luminescence, OSL) data provide a detailed understanding of the constructional history of the plain. The internal architecture of individual beach ridges are characterized by sigmoidal configurations with seaward-dipping (2.3-4.7°) beds. Field mapping data reveal the processes associated with development of individual ridges in relation to sea level elevation. First, wave-built facies (sand-and-gravel) are deposited as beach berms, likely by fair-weather waves, with their elevations controlled by sea level and the swash height of constructive waves. This is followed by the accretion of aeolian sand deposits (foredunes) on the previous relict ridge, and then colonization by pioneer grasses. The well-defined contact between coarse-grained, wave-built facies and overlying aeolian deposits is used to demonstrate the dominant influence of RSL change in the development of the barrier system and, with chronology provided by OSL dating, produce a RSL curve for the 2500-year period of its formation. A net increase of 2.4 m in the surface elevation of wave-built facies is observed across the plain, corresponding to an overall increase in mean sea level through time. Three distinct periods can be distinguished: (1) an increase from 2.4 to 1 m below modern MSL between 2400 and 1500 years (rate: +1.3 mm/yr); (2) relatively stable or slowly rising RSL (<+0.2 mm/yr) from 1400 to 700 years; and (3) a

  5. Validation of Mean Absolute Sea Level of the North Atlantic obtained from Drifter, Altimetry and Wind Data

    Science.gov (United States)

    Maximenko, Nikolai A.

    2003-01-01

    Mean absolute sea level reflects the deviation of the Ocean surface from geoid due to the ocean currents and is an important characteristic of the dynamical state of the ocean. Values of its spatial variations (order of 1 m) are generally much smaller than deviations of the geoid shape from ellipsoid (order of 100 m) that makes the derivation of the absolute mean sea level a difficult task for gravity and satellite altimetry observations. Technique used by Niiler et al. for computation of the absolute mean sea level in the Kuroshio Extension was then developed into more general method and applied by Niiler et al. (2003b) to the global Ocean. The method is based on the consideration of balance of horizontal momentum.

  6. Rare earth element geochemistry of South Atlantic deep sea sediments: Ce anomaly change at approx. 54 My

    International Nuclear Information System (INIS)

    Wang, Y.L.; Liu, Y.-G.; Schmitt, R.A.; Oregon State Univ., Corvallis; Oregon State Univ., Corvallis; Oregon State Univ., Corvallis

    1986-01-01

    The geochemistry of the REE (rare earth elements) in oceanic sediments is discussed, based mainly on samples from DSDP Holes 530A and 530B, Leg 75, and Hole 525A, Leg 74. The proposed mechanisms for incorporation of the REE into the marine carbonate phases are adsorption, chiefly onto the carbonate minerals and on Sc, Hf, and Ta-rich FE-Mn hydroxide flocs as carbonate coatings. The Ce anomaly of marine carbonate was used as an indicator of paleo-ocean water redox conditions: the bottom water of the Angola Basin was in a reducing condition in the Cretaceous. At ca. 54 My, the South Atlantic water condition became oxidizing, similar to the present seawater redox condition. This change was related to the improvement of circulation due to the widening of South Atlantic and the subsidence of water circulation barriers such as the Walvis Ridge and perhaps the Romanche Fracture Zone. The REE abundances and patterns of younger sediments in the Angola Basin (YSAB) are very similar to those observed in NASC, PAAS, and ES sediments. The YSAB REE abundances and patterns may represent the average REE distribution of the exposed African continental crust. The strong resemblance of REE distributions of YSAB, NASC, PAAS and ES suggests thorough REE mixing from different sources and the uniformity of the average crustal compositions of different continents: Africa, North America, Australia, and Europe. (author)

  7. Coupling between marine boundary layer clouds and summer-to-summer sea surface temperature variability over the North Atlantic and Pacific

    Science.gov (United States)

    Myers, Timothy A.; Mechoso, Carlos R.; DeFlorio, Michael J.

    2018-02-01

    Climate modes of variability over the Atlantic and Pacific may be amplified by a positive feedback between sea-surface temperature (SST) and marine boundary layer clouds. However, it is well known that climate models poorly simulate this feedback. Does this deficiency contribute to model-to-model differences in the representation of climate modes of variability? Over both the North Atlantic and Pacific, typical summertime interannual to interdecadal SST variability exhibits horseshoe-like patterns of co-located anomalies of shortwave cloud radiative effect (CRE), low-level cloud fraction, SST, and estimated inversion strength over the subtropics and midlatitudes that are consistent with a positive cloud feedback. During winter over the midlatitudes, this feedback appears to be diminished. Models participating in the Coupled Model Intercomparison Project phase 5 that simulate a weak feedback between subtropical SST and shortwave CRE produce smaller and less realistic amplitudes of summertime SST and CRE variability over the northern oceans compared to models with a stronger feedback. The change in SST amplitude per unit change in CRE amplitude among the models and observations may be understood as the temperature response of the ocean mixed layer to a unit change in radiative flux over the course of a season. These results highlight the importance of boundary layer clouds in interannual to interdecadal atmosphere-ocean variability over the northern oceans during summer. The results also suggest that deficiencies in the simulation of these clouds in coupled climate models contribute to underestimation in their simulation of summer-to-summer SST variability.

  8. Plasma levels of pollutants are much higher in loggerhead turtle populations from the Adriatic Sea than in those from open waters (Eastern Atlantic Ocean).

    Science.gov (United States)

    Bucchia, Matteo; Camacho, María; Santos, Marcelo R D; Boada, Luis D; Roncada, Paola; Mateo, Rafael; Ortiz-Santaliestra, Manuel E; Rodríguez-Estival, Jaime; Zumbado, Manuel; Orós, Jorge; Henríquez-Hernández, Luis A; García-Álvarez, Natalia; Luzardo, Octavio P

    2015-08-01

    In this paper we determined the levels of 63 environmental contaminants, including organic (PCBs, organochlorine pesticides, and PAHs) and inorganic (As, Cd, Cu, Pb, Hg and Zn) compounds in the blood of loggerhead turtles (Caretta caretta) from two comparable populations that inhabit distinct geographic areas: the Adriatic Sea (Mediterranean basin) and the Canary Islands (Eastern Atlantic Ocean). All animals were sampled at the end of a period of rehabilitation in centers of wildlife recovery, before being released back into the wild, so they can be considered to be in good health condition. The dual purpose of this paper is to provide reliable data on the current levels of contamination of this species in these geographic areas, and secondly to compare the results of both populations, as it has been reported that marine biota inhabiting the Mediterranean basin is exposed to much higher pollution levels than that which inhabit in other areas of the planet. According to our results it is found that current levels of contamination by organic compounds are considerably higher in Adriatic turtles than in the Atlantic ones (∑PCBs, 28.45 vs. 1.12ng/ml; ∑OCPs, 1.63 vs. 0.19ng/ml; ∑PAHs, 13.39 vs. 4.91ng/ml; pmercury (5.74 vs. 7.59μg/ml, p<0.01). The results of this study confirm that the concentrations are larger in turtles from the Mediterranean, probably related to the high degree of anthropogenic pressure in this basin, and thus they are more likely to suffer adverse effects related to contaminants. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Evaluating bath treatment effectiveness in the control of sea lice burdens on Atlantic salmon in New Brunswick, Canada.

    Science.gov (United States)

    Gautam, R; Vanderstichel, R; Boerlage, A S; Revie, C W; Hammell, K L

    2017-07-01

    The use of medicinal bath treatment for sea lice is becoming more common, due to increasing resistance to in-feed treatments with emamectin benzoate. Common treatment modalities in New Brunswick, Canada, include Salmosan administered by tarpaulin or wellboat, and Paramove administered by wellboat. In this study, we assessed the effectiveness of these treatment modalities in the field between 2010 and 2015 using a web-based sea lice data management system (Fish-iTrends © ). Effectiveness was evaluated for adult female (AF) and for pre-adult and adult male (PAAM) life stages separately. We also investigated the impact of variability in pretreatment lead and post-treatment lag time on effectiveness measures. There were 1185 treatment events at 57 farms that uniquely matched our pre- and post-treatment count criteria. The effectiveness of treatment modality was significantly influenced by season, pretreatment level of sea lice and by lead and lag times. In summer, Salmosan administered by tarpaulin had the greatest effectiveness on both AF and PAAM, when pretreatment levels were above 10 sea lice; whereas in autumn, the performance of treatment modalities varied significantly, depending on the pretreatment levels for the life stages. Ignoring the lead or lag time effect generally resulted in an underestimation of treatment effectiveness. © 2016 John Wiley & Sons Ltd.

  10. 78 FR 33969 - Special Local Regulations; Daytona Beach Grand Prix of the Sea, Atlantic Ocean; Daytona Beach, FL

    Science.gov (United States)

    2013-06-06

    ... through Sunday, June 14-16, 2013, Powerboat P1-USA will host the Daytona Beach Grand Prix of the Sea, a... private sector of $100,000,000 (adjusted for inflation) or more in any one year. Though this rule will not...

  11. Effects of sea lamprey substrate modification and carcass nutrients on macroinvertebrate assemblages in a small Atlantic coastal stream

    Science.gov (United States)

    Weaver, Daniel M.; Coghlan, Stephen M.; Zydlewski, Joseph D.

    2018-01-01

    Aquatic macroinvertebrates respond to patch dynamics arising from interactions of physical and chemical disturbances across space and time. Anadromous fish, such as sea lamprey, Petromyzon marinus, migrate from the ocean and alter physical and chemical properties of recipient spawning streams. Sea lamprey disturb stream benthos physically through nest construction and spawning, and enrich food webs through nutrient deposition from decomposing carcasses. Sea lamprey spawning nests support greater macroinvertebrate abundance than adjacent reference areas, but concurrent effects of stream bed modification and nutrient supplementation have not been examined sequentially. We added carcasses and cleared substrate experimentally to mimic the physical disturbance and nutrient enrichment associated with lamprey spawning, and characterized effects on macroinvertebrate assemblage structure. We found that areas receiving cleared substrate and carcass nutrients were colonized largely by Simuliidae compared to upstream and downstream control areas that were colonized largely by Hydropsychidae, Philopotamidae, and Chironomidae. Environmental factors such as stream flow likely shape assemblages by physically constraining macroinvertebrate establishment and feeding. Our results indicate potential changes in macroinvertebrate assemblages from the physical and chemical changes to streams brought by spawning populations of sea lamprey.

  12. Sea surface temperatures from the southern Benguela region from the Pliocene and Pleistocene: tracking Agulhas Current input into the SE Atlantic

    Science.gov (United States)

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

    2011-12-01

    The Pliocene and-Pleistocene epochs provide a way to understand the effect of past climate changes on key ocean currents. Here, we show results from ODP Site1087 (31.28'S, 15.19'E, 1374m water depth) to investigate changes in ocean circulation over the period of the mid-Pliocene warm period 3.0-3.5 Ma and compare these to the time of the 100 kyr Pleistocene glacial cycles. ODP 1087 is located in the South-eastern Atlantic Ocean, outside of the Benguela upwelling region; reconstructing the temperature history of the site will therefore provide an important data set from a part of the ocean that has few orbital-scale and continuous Pliocene temperature reconstructions. ODP 1087 can be used to investigate the history of the heat and salt transfer to the Atlantic Ocean from the Indian Ocean via the Agulhas Retroflection, which plays an important part in the global thermohaline circulation (Lutjeharms, 2007). Climate models and reconstructions for the most recent glacial-interglacial cycles have shown that changes to the strength of the heat transfer may cause major climatic changes and may play a role in transitions from glacial to interglacial events (Knorr & Lohmann, 2003). It is unknown how this transfer reacted to generally warmer global temperatures during the mid-Pliocene. Because the mid-Pliocene is seen as a model for future climate change it might provide a model for ocean circulations in a warmer world. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the history of ODP 1087. The UK37' index records differences in the unsaturated bonds in the C37 alkenones to reconstruct sea surface temperatures (Brassell et al., 1986). We present SSTs generated for the mid-Pliocene Warm period with a resolution of 4000 years. We compare this data to the time of the 100 kyr glacial cycles during the late Pleistocene. Even though ODP 1087 is located outside the Benguela upwelling system, it has lower Pliocene temperatures

  13. Biomarker candidate discovery in Atlantic cod (Gadus morhua) continuously exposed to North Sea produced water from egg to fry

    DEFF Research Database (Denmark)

    Bohne-Kjersem, Anneli; Bache, Nicolai; Meier, Sonnich

    2010-01-01

    were able to compare the induced changes by PW to the mode of action of oestrogens. Changes in the proteome in response to exposure in whole cod fry (approximately 80 days post-hatching, dph) were detected by two-dimensional gel electrophoresis and image analysis and identified by MALDI-ToF-ToF mass...... spectrometry, using a newly developed cod EST database and the NCBI database. Many of the protein changes occurred at low levels (0.01% and 0.1% PW) of exposure, indicating putative biological responses at lower levels than previously detected. Using discriminant analysis, we identified a set of protein...... changes that may be useful as biomarker candidates of produced water (PW) and oestradiol exposure in Atlantic cod fry. The biomarker candidates discovered in this study may, following validation, prove effective as diagnostic tools in monitoring exposure and effects of discharges from the petroleum...

  14. Matrilinear phylogeography of Atlantic salmon ( Salmo salar L.) in Europe and postglacial colonization of the Baltic Sea area

    DEFF Research Database (Denmark)

    Nilsson, J.; Gross, R.; Asplund, T.

    2001-01-01

    was analysed by RFLP of ND3/4/5/6. Representative RFLP haplotypes from different parts of the distribution area were sequenced and the phylogeny of European haplotypes and their relations to the North American lineage was described. The four common European haplotypes derive from the ancestral ND1-BBBA...... (rooting the European clade to the North American) by one-step substitutions: AAAA BBBB. The Swedish west- coast populations differ from the geographically close southern Baltic, indicating absence of inward and limited outward gene flow through the Danish straits during the last 8000 years....... Within the Baltic Sea, only three ND1 haplotypes were detected and there was no variation for ND3/4/5/6. In the whole southern Baltic and in lakes Vanern, Ladoga and Onega the haplotype AABA dominated. Proposed postglacial colonization routes to the Baltic Sea are discussed in relation to the haplotype...

  15. Five year prediction of Sea Surface Temperature in the Tropical Atlantic: a comparison of simple statistical methods

    OpenAIRE

    Laepple, Thomas; Jewson, Stephen; Meagher, Jonathan; O'Shay, Adam; Penzer, Jeremy

    2007-01-01

    We are developing schemes that predict future hurricane numbers by first predicting future sea surface temperatures (SSTs), and then apply the observed statistical relationship between SST and hurricane numbers. As part of this overall goal, in this study we compare the historical performance of three simple statistical methods for making five-year SST forecasts. We also present SST forecasts for 2006-2010 using these methods and compare them to forecasts made from two structural time series ...

  16. The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation

    Science.gov (United States)

    Lim, Young-Kwon

    2014-01-01

    Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

  17. Late Eocene to middle Miocene (33 to 13 million years ago) vegetation and climate development on the North American Atlantic Coastal Plain (IODP Expedition 313, Site M0027)

    Science.gov (United States)

    Kotthoff, U.; Greenwood, D. R.; McCarthy, F. M. G.; Müller-Navarra, K.; Prader, S.; Hesselbo, S. P.

    2014-08-01

    We investigated the palynology of sediment cores from Site M0027 of IODP (Integrated Ocean Drilling Program) Expedition 313 on the New Jersey shallow shelf to examine vegetation and climate dynamics on the east coast of North America between 33 and 13 million years ago and to assess the impact of over-regional climate events on the region. Palynological results are complemented with pollen-based quantitative climate reconstructions. Our results indicate that the hinterland vegetation of the New Jersey shelf was characterized by oak-hickory forests in the lowlands and conifer-dominated vegetation in the highlands from the early Oligocene to the middle Miocene. The Oligocene witnessed several expansions of conifer forest, probably related to cooling events. The pollen-based climate data imply an increase in annual temperatures from ∼11.5 °C to more than 16 °C during the Oligocene. The Mi-1 cooling event at the onset of the Miocene is reflected by an expansion of conifers and mean annual temperature decrease of ∼4 °C, from ∼16 °C to ∼12 °C around 23 million years before present. Relatively low annual temperatures are also recorded for several samples during an interval around ∼20 million years before present, which may reflect the Mi-1a and the Mi-1aa cooling events. Generally, the Miocene ecosystem and climate conditions were very similar to those of the Oligocene. Miocene grasslands, as known from other areas in the USA during that time period, are not evident for the hinterland of the New Jersey shelf, possibly reflecting moisture from the proto-Gulf Stream. The palaeovegetation data reveal stable conditions during the mid-Miocene climatic optimum at ∼15 million years before present, with only a minor increase in deciduous-evergreen mixed forest taxa and a decrease in swamp forest taxa. Pollen-based annual temperature reconstructions show average annual temperatures of ∼14 °C during the mid-Miocene climatic optimum, ∼2 °C higher than today

  18. Field trials in Norway with SLICE (0.2% emamectin benzoate) for the oral treatment of sea lice infestation in farmed Atlantic salmon Salmo salar.

    Science.gov (United States)

    Ramstad, A; Colquhoun, D J; Nordmo, R; Sutherland, I H; Simmons, R

    2002-06-21

    Four commercial salmon farms on the West coast of Norway were recruited to a programme of field trials in which the efficacy of SLICE (0.2% emamectin benzoate; Schering-Plough Animal Health) was compared with a commercially available product, EKTOBANN (teflubenzuron 2 g kg(-1); Skretting A/S) in treating natural sea lice Lepeophtheirus salmonis infections in Atlantic salmon Salmo salmar L. At each test site, 3 fish pens were treated with each product. In total, nearly 1.2 million first-year-class fish were included in the trial, of which approximately 561,000 received emamectin benzoate at a dosage of 50 microg kg(-1) body wt d(-1), while approximately 610,000 received teflubenzuron at a dosage of 10 mg kg(-1) body wt d(-1). Medicated feed was provided at 0.5% body wt d(-1) over 7 consecutive days. Feed containing emamectin benzoate was generally well accepted by the fish and no problems were encountered in feeding the medicated diet at the desired dose. Lice numbers were counted 2 d before and 1, 7, 14 and 21 d after commencement of treatment. While treatment with both substances rapidly reduced lice numbers, pens treated with emamectin benzoate were found to harbour significantly fewer lice 14 and 21 d post-treatment. Twenty-one days following treatment with emamectin benzoate the lice abundance was reduced on average by 94%. Limited sampling outside the main study period indicated that emamectin benzoate protects against sea-lice infestation over longer periods.

  19. Divergent trends in life-history traits between Atlantic salmon Salmo salar of wild and hatchery origin in the Baltic Sea.

    Science.gov (United States)

    Vainikka, A; Kallio-Nyberg, I; Heino, M; Koljonen, M-L

    2010-02-01

    Four Atlantic salmon Salmo salar stocks in the Baltic Sea, varying in their breeding history, were studied for changes in life-history traits over the years 1972-1995. Total length (L(T)) at age of captured (L(TC)) fish had increased throughout the study period, partly due to increased temperature and increased L(T) at release, (L(TR)) but also due to remaining cohort effects that could represent unaccounted environmental or genetic change. Simultaneously, maturation probabilities controlled for water temperature, L(TC) and L(TR) had increased in all stocks. The least change was observed in the River Tornionjoki S. salar that was subject only to supportive stockings originating from wild parents. These results suggest a long-term divergence between semi-natural and broodstock-based S. salar stocks. Increased L(T) at age explained advanced maturation only marginally, and it remains an open question to what extent the generally increased probabilities to mature at early age reflected underlying genetic changes.

  20. Hamacantha (Hamacantha) boomerang sp. nov. from deep-sea coral mounds at Campos Basin, SW Atlantic, and redescription of H. (H.) schmidtii (Carter, 1882) (Hamacanthidae, Poecilosclerida, Demospongiae).

    Science.gov (United States)

    Hajdu, Eduardo; Castello-Branco, Cristiana

    2014-01-08

    There are 22 species of Hamacantha registered from all over the world, and frequently from deep-waters, only two of which had previously been reported from the SW Atlantic. Here we describe a third species for this area, Hamacantha (H.) boomerang sp. nov., collected from deep-sea coral mounds at Campos Basin (off Rio de Janeiro state). We found oxeas 271-630 µm long, diancistras in three size classes, 125-155, 45-69 and 20-29 µm, and toxas, 58-82 µm. This is the only Hamacantha combining oxeas and toxas, but the latter are very rare. The species approaches the Caribbean H. (H.) schmidtii (Carter, 1882), where we observed oxeas 390-495 µm long, and diancistras in three size classes, 109-124,  44-54 and 26-41 μm, however toxas appear to be absent. Both species are clearly distinct by micrometric values, as well as the overall morphology of the smaller diancistras, distinct from the intermediate category in the new species, but quite similar in H. (H.) schmidtii. Hamacantha (Vomerula) falcula approaches the new species very closely in microsclere dimensions and morphology, but is set apart by its styloid and smaller megascleres.

  1. Meat Composition and Quality Assessment of King Scallops (Pecten maximus and Frozen Atlantic Sea Scallops (Placopecten magellanicus on a Retail Level

    Directory of Open Access Journals (Sweden)

    Monika Manthey-Karl

    2015-09-01

    Full Text Available An enlarged range of scallop products on the market allows the consumer to buy lower priced alternatives, which often raises the question of quality and control. Frozen meat of king scallops (Pecten maximus and Atlantic sea scallops (Placopecten magellanicus were purchased on the German market and compared with fresh shell-on king scallops of various origin. The approximate composition, inclusive citric acid and phosphates, minerals, free amino acids (FAA and fatty acid profiles were examined in the muscle to identify changes as a result of processing. The FAA glycine and taurine as well the fatty acids 20:5n-3 (EPA and 22:6n-3 (DHA were the most abundant, but were reduced in processed samples. Di- and triphosphate contents were not detectable (<0.01 g·kg−1 in untreated meats. Most frozen scallop products contained added citrates and polyphosphates and had distinctly higher water contents (up to 89% and an increased moisture to protein ratio (M/P (up to 9 compared with the fresh king scallops (78%, M/P < 5. Labelling of species, verified by PCR-based DNA analysis, and ingredients were not correct in each case. Overall results indicated no relevant differences in mineral content, except high sodium contents, resulting from additives. Labelling does not readily allow the consumer to recognize the extent of processing effects.

  2. Exploring neutral and adaptive processes in expanding populations of gilthead sea bream, Sparus aurata L., in the North-East Atlantic.

    Science.gov (United States)

    Coscia, I; Vogiatzi, E; Kotoulas, G; Tsigenopoulos, C S; Mariani, S

    2012-05-01

    Recent studies in empirical population genetics have highlighted the importance of taking into account both neutral and adaptive genetic variation in characterizing microevolutionary dynamics. Here, we explore the genetic population structure and the footprints of selection in four populations of the warm-temperate coastal fish, the gilthead sea bream (Sparus aurata), whose recent northward expansion has been linked to climate change. Samples were collected at four Atlantic locations, including Spain, Portugal, France and the South of Ireland, and genetically assayed using a suite of species-specific markers, including 15 putatively neutral microsatellites and 23 expressed sequence tag-linked markers, as well as a portion of the mitochondrial DNA (mtDNA) control region. Two of the putatively neutral markers, Bld-10 and Ad-10, bore signatures of strong directional selection, particularly in the newly established Irish population, although the potential 'surfing effect' of rare alleles at the edge of the expansion front was also considered. Analyses after the removal of these loci suggest low but significant population structure likely affected by some degree of gene flow counteracting random genetic drift. No signal of historic divergence was detected at mtDNA. BLAST searches conducted with all 38 markers used failed to identify specific genomic regions associated to adaptive functions. However, the availability of genomic resources for this commercially valuable species is rapidly increasing, bringing us closer to the understanding of the interplay between selective and neutral evolutionary forces, shaping population divergence of an expanding species in a heterogeneous milieu.

  3. Linking spatial distribution and feeding behavior of Atlantic horse mackerel (Trachurus trachurus) in the Strait of Sicily (Central Mediterranean Sea)

    Science.gov (United States)

    Rumolo, Paola; Basilone, Gualtiero; Fanelli, Emanuela; Barra, Marco; Calabrò, Monica; Genovese, Simona; Gherardi, Serena; Ferreri, Rosalia; Mazzola, Salvatore; Bonanno, Angelo

    2017-03-01

    The Atlantic horse mackerel (Trachurus trachurus) is a semi-pelagic fish species with a wide geographical distribution and commonly found on the continental shelf. In recent years, the species has received some attention due to its ecological role in pelagic food webs. Stable isotope of nitrogen and carbon (δ15N and δ13C) and Stomach Content Analysis (SCA) of T. trachurus were adopted as tools to provide necessary knowledge on its feeding habits in the Strait of Sicily. The strong correlation found between δ15N and δ13C values with body length, together with significant ontogenetic shift evidenced by SCA, could be associated to changes in food availability, which in turn is triggered by environmental conditions. Spatial distribution of T. trachurus in the study area, mainly for small and medium size specimens, is linked to lower temperature, salinity and Photosynthetically Active Radiation (PARsat) values with higher aggregations on the Adventure Bank (i.e., an area characterized by periodic upwelling events). Larger size specimens mostly inhabited shallower waters characterized by higher temperature, salinity and PAR values, typical of the central-eastern part of the study area. Our results support the hypothesis that feeding behavior of T. trachurus is strictly linked to environmental factors (i.e. chiefly oceanographic conditions of the water column and day duration) that in turn influences the distribution of its prey. Findings can supply knowledge needed for improving fish stock management and promoting plans able to take into account also local ecosystem analysis.

  4. Evaluation of emamectin benzoate and substance EX against salmon lice in sea-ranched Atlantic salmon smolts.

    Science.gov (United States)

    Skilbrei, Ove Tommy; Espedal, Per Gunnar; Nilsen, Frank; Garcia, Enrique Perez; Glover, Kevin A

    2015-04-08

    Experimental releases of Atlantic salmon smolts treated with emamectin benzoate (EB) against salmon lice have previously been used to estimate the significance of salmon lice on the survival of migrating smolts. In recent years, the salmon louse has developed reduced sensitivity to EB, which may influence the results of such release experiments. We therefore tested the use of 2 anti-lice drugs: EB was administered to salmon smolts in high doses by intra-peritoneal injection and the prophylactic substance EX (SubEX) was administered by bathing. A third, untreated control group was also established. Salmon were challenged with copepodids of 2 strains of salmon lice (1 EB-sensitive strain and 1 with reduced EB-sensitivity) in mixed-group experimental tanks. At 31 d post-challenge, the numbers of pre-adult lice on treated fish were around 20% compared with the control fish, with minor or no differences between the 2 treatments and lice strains. Both treatments therefore appeared to give the smolts a high degree of protection against infestation of copepodids of salmon lice. However, significantly lower growth of the EB-treatment group indicates that bathing the fish in SubEX is less stressful for smolts than intra-peritoneal injection of EB.

  5. Notes on a mating event of the deep-sea crab Chaecon affinis in the Gorringe Bank (NE Atlantic)

    Science.gov (United States)

    Hilário, A.; Cunha, M. R.

    2013-08-01

    The deep-water red crab Chaceon affinis is the largest species of the family Geryonidae. Unlike other species of the same genus, C. affinis is not yet subject to intense commercial exploitation but it has been appointed as a new target resource in European waters, in spite of the lack of information on its biology, life cycle and distribution, which is essential to provide advice for a sustainable exploitation. Here we report for the first time the presence of C. affinis in the Gorringe Bank and give the first account of the mating behavior of this species. All mating pairs were found at the interface of the Mediterranean Outflow Water with North Atlantic Deep Water, suggesting that environmental parameters associated with the interface of these water masses may be relevant for mating in this species. The majority of C. affinis was mating which is an indication of synchrony and reproductive seasonality. A biennial female reproductive cycle is hypothesized, involving molting and mating in the first year with subsequent oviposition during the autumn, and spawning during spring of the second year. We suggest that synchrony and seasonality in the reproduction of C. affinis is linked to the formation of phytoplankton blooms in surface waters, with females carrying embryos from autumn to spring, possibly timing the release of planktotrophic larvae to exploit a seasonal peak in surface productivity and its export.

  6. Why Do Organisms in the Atlantic Ocean Produce So Much CaCO3?

    Science.gov (United States)

    Toggweiler, J. R.

    2010-12-01

    Sediments in the Atlantic are richer in CaCO3 than sediments in the other oceans. Sediment trap observations show that sinking particles in the Atlantic also tend to have more CaCO3 in relation to organic carbon than sinking particles elsewhere. The reason for the extra production of CaCO3 has never been very clear. The Atlantic is unusual because it receives much more than its share of the global input of river water. River water adds alkalinity to the surface ocean while the production of CaCO3 takes it away. In this presentation a new tracer, called Alk*, is derived from the surface alkalinity distribution to highlight the impact of river inputs and the production of CaCO3. If the production of CaCO3 were evenly distributed across the ocean one would expect the Atlantic to have a higher level of Alk* becaused of its river inputs. We find instead that Alk* is lower in the middle of the Atlantic than almost any place else. This, of course, is consistent with the fact that organisms in the Atlantic produce a lot of CaCO3. Comparison with other areas with especially low values of Alk* (Red Sea and northern Arabian Sea) shows that the production of CaCO3 is highly correlated across the ocean with the surface salinity. Hence, we argue that organisms in the Atlantic produce a lot of CaCO3 simply because the Atlantic is so salty. Salty waters, by definition, have more CO3= ions, which increase the supersaturation with respect to calcite and aragonite. This finding, while extremely simple, has major implifications for the impact of ocean acidification on calcifying organisms.

  7. New Cheilostomata (Bryozoa from NE Atlantic seamounts, islands, and the continental slope: evidence for deep-sea endemism

    Directory of Open Access Journals (Sweden)

    Björn Berning

    2017-08-01

    Full Text Available Ten new species belonging to three new genera (Atlantisina gen. nov., Bathycyclopora gen. nov., Calvetopora gen. nov. of umbonulomorph bryozoans from northeastern Atlantic seamounts, islands, and the continental slope are introduced. We furthermore erect the new family Atlantisinidae fam. nov. for these genera. Eight new species belong to the new genus Atlantisina: Atlantisina atlantis gen. et sp. nov. (type species, A. acantha gen. et sp. nov., A. gorringensis gen. et sp. nov., A. inarmata gen. et sp. nov., A. lionensis gen. et sp. nov., A. meteor gen. et sp. nov., A. seinensis gen. et sp. nov., and A. tricornis gen. et sp. nov. The genus Bathycyclopora gen. nov. is introduced for ?Phylactella vibraculata Calvet from the Azores, and also includes Bathycyclopora suroiti gen. et sp. nov. The type species of Calvetopora gen. nov. is Lepralia inflata Calvet from the Gulf of Cadiz; this genus also includes Calvetopora otapostasis gen. et sp. nov. and another species left in open nomenclature. Of the 13 species described herein, 11 occur on seamounts and islands, and nine species are endemic to a single seamount, island or station. The present results show that bryozoans provide striking examples of the function of seamounts as areas of endemism, most likely intrinsically linked to the low dispersal abilities of bryozoan larvae.

  8. Habitat use, vertical and horizontal behaviour of Atlantic bluefin tuna (Thunnus thynnus) in the Northwestern Mediterranean Sea in relation to oceanographic conditions

    Science.gov (United States)

    Bauer, Robert Klaus; Fromentin, Jean-Marc; Demarcq, Hervé; Bonhommeau, Sylvain

    2017-07-01

    We investigated the habitat utilization, vertical and horizontal behaviour of Atlantic bluefin tuna Thunnus thynnus (ABFT) in relation to oceanographic conditions in the northwestern Mediterranean Sea, based on 36 pop-up archival tags and different environmental data sets. Tags were deployed on early mature ABFT (127-255 cm) between July and November in 2007-2014, on the shelf area off Marseille, France. The data obtained from these tags provided 1643 daily summaries of ABFT vertical behaviour over 8 years of tag deployment. Based on a hierarchical clustering of this data, we could identify four principle daily vertical behaviour types, representing surface (≦ 10 m) and subsurface (10-100 m) orientation, moderate (50-200 m) and deep (≧ 200 m) diving behaviour. These vertical behaviour types showed seasonal variations with partly opposing trends in their frequencies. Accordingly, ABFT were more surface orientated during summer, while moderate diving behaviour was more common during winter. Depth time series data further revealed inverted day-night patterns for both of these periods. Tagged ABFT frequented the surface waters more regularly during daytime and deeper waters during the night in summer, while the opposite pattern was found in winter. Seasonal changes in the vertical behaviour of ABFT were accompanied by simultaneous changes in environmental conditions (SST, chla, thermal stratification). Accordingly, surface orientation and moderate diving behaviour appeared to be triggered by the thermal stratification of the water column, though less pronounced than previously reported for ABFT in the North Atlantic, probably indicating adaptive vertical behaviour related to the availability of epipelagic food resources (anchovies and sardines). Deep diving behaviour was particularly frequent during months of high biological productivity (February-May), although one recovered tag showed periodic and unusual long spike dives during summer-autumn, in relation to

  9. The Eocene-Oligocene sedimentary record in the Chesapeake Bay impact structure: Implications for climate and sea-level changes on the western Atlantic margin

    Science.gov (United States)

    Schulte, P.; Wade, B.S.; Kontny, A.; ,

    2009-01-01

    other northwest Atlantic margin sections. It could result from a shift to more distal depositional environments and condensed sedimentation during maximum fl ooding, rather than refl ecting a climatic change in the hinterland. The distinct 1% increase of the oxygen isotopes may correspond to the short-term latest Eocene "precursor isotope event." (4) The abrupt increase of sediment grainsize, carbonate content, and abundance of authigenic minerals (glauconite) across the major unconformity that separates Eocene from Oligocene sediments in the Eyreville core refl ects deposition in shallower settings associated with erosion, winnowing, and reworking. Sediments within the central crater were affected by the rapid eustatic sea-level changes associated with the greenhouse-icehouse transition, as well as by an abrupt major uplift event and possibly enhanced current activity on the northwestern Atlantic margin. ?? 2009 The Geological Society of America.

  10. What is left? Macrophyte meadows and Atlantic herring (Clupea harengus) spawning sites in the Greifswalder Bodden, Baltic Sea

    Science.gov (United States)

    Kanstinger, Philipp; Beher, Jutta; Grenzdörffer, Görres; Hammer, Cornelius; Huebert, Klaus B.; Stepputis, Daniel; Peck, Myron A.

    2018-02-01

    Coastal zones are productive areas of marine ecosystems which are also hotspots of anthropogenic activities causing habitat degradation. In the southwest Baltic Sea, eutrophication is thought to have caused the massive reduction in submerged macrophytes observed in recent decades. Here, we surveyed the submarine vegetation and examined locations of spawning of herring (Clupea harengus) in the Greifswalder Bodden, one of the most important reproductive habitats of the Western Baltic Spring Spawner herring stock (WBSS). This stock deposits eggs onto submerged vegetation and changes in macrophyte coverage are expected to influence the availability of reproductive habitat. Aerial, underwater video tows and SCUBA surveys conducted in spring 2009 revealed that only ∼7% of the lagoon was vegetated. Herring eggs were observed on 12 of 32 SCUBA transects, at depths between 0.2 and 5 m and were attached to a variety of spermatophyte and algae species but not to stones or mussels. A classification tree model indicated that spawning sites were strongly associated with the vegetation cover within a 100- and 500-m radius, implying that herring schools preferentially spawn on dense and large underwater meadows. Only ∼5% of the lagoon now falls into this vegetation category. Despite 20 years of efforts to reduce eutrophication, no increase in macroalgae and spermatophyte vegetation towards the historical level of 90% coverage in the area is apparent.

  11. Mercury and selenium ingestion rates of Atlantic leatherback sea turtles (Dermochelys coriacea): a cause for concern in this species?

    Science.gov (United States)

    Perrault, Justin R

    2014-08-01

    Bodily accumulation of certain toxic elements can cause physiologic harm to marine organisms and be detrimental to their health and survival. The leatherback sea turtle (Dermochelys coriacea) is a broadly distributed marine reptile capable of consuming hundreds of kilograms of gelatinous zooplankton each day. Little is known about toxicants present in these prey items. Specifically, mercury is a known neurotoxin with no known essential function, while selenium detoxifies bodily mercury, but can be toxic at elevated concentrations. I collected 121 leatherback prey items (i.e., gelatinous zooplankton) from known leatherback foraging grounds and sampled the esophagus and stomach contents of stranded turtles. All samples were analyzed for total mercury and selenium. Additionally, two prey items and three liver samples were analyzed for methylmercury, the most toxic form of the element. Total mercury concentrations in prey items ranged from 0.2 to 17 ppb, while selenium concentrations ranged from concerning, especially since bodily mercury and selenium concentrations increase as organisms age. Because leatherbacks are long-lived and have large daily prey consumption rates, mercury and selenium loads may increase to physiologically harmful levels in this imperiled species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. A modelling study of the influence of anomalous wind forcing over the Barents Sea on the Atlantic water flow to the Arctic Ocean in the period 1979-2004

    Science.gov (United States)

    Marciniak, Jakub; Schlichtholz, Pawel; Maslowski, Wieslaw

    2016-04-01

    Arctic climate system is influenced by oceanic heat transport with the Atlantic water (AW) streaming towards the Arctic Ocean in two branches, through the deep Fram Strait and the shallow Barents Sea. In Fram Strait, the AW submerges below the Polar surface water and then flows cyclonically along the margin of the Arctic Ocean as a subsurface water mass in the Arctic Slope Current. In contrast to the Fram Strait branch, which is the major source of heat for the Arctic Ocean, most of the heat influx to the Barents Sea through the Barents Sea opening (BSO) is passed to the atmosphere. Only cold remnants of AW outflow to the Arctic Ocean through the northeastern gate of the Barents Sea. Some AW entering the Barents Sea recirculates westward, contributing to an outflow from the Barents Sea through the BSO along the shelf slope south of Bear Island, in the Bear Island Slope Current. Even though the two-branched AW flow toward the Arctic Ocean has been known for more than a century, little is known about co-variability of heat fluxes in the two branches, its mechanisms and climatic implications. Recent studies indicate that the Bear Island Slope Current may play a role in this co-variability. Here, co-variability of the flow through the BSO and Fram Strait is investigated using a pan-Arctic coupled ice-ocean hindcast model run for the period 1979-2004 and forced with daily atmospheric data from the ECMWF. Significant wintertime co-variability between the volume transport in the Bear Island and Arctic slope currents and its link to wind forcing over the Barents Sea is confirmed. It is found that the volume transports in these currents are, however, not correlated in the annual mean and that the wintertime co-variability of these currents has no immediate effect on either the net heat flux through the BSO or the net heat flux divergence in the Barents Sea. It is shown that the main climatic effect of wind forcing over the northern Barents Sea shelf is to induce temperature

  13. Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from DISCOVERY and CHARLES DARWIN in the NE Atlantic, North Atlantic Ocean and Norwegian Sea from 1988-05-21 to 1990-07-20 (NODC Accession 9600083)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in NE Atlantic (limit-40 W) as part of Global Ocean Data Archeaology and Rescue (GODAR)...

  14. Air-sea heat fluxes associated to mesoscale eddies in the Southwestern Atlantic Ocean and their dependence on different regional conditions

    Science.gov (United States)

    Leyba, Inés M.; Saraceno, Martín; Solman, Silvina A.

    2017-10-01

    Heat fluxes between the ocean and the atmosphere largely represent the link between the two media. A possible mechanism of interaction is generated by mesoscale ocean eddies. In this work we evaluate if eddies in Southwestern Atlantic (SWA) Ocean may significantly affect flows between the ocean and the atmosphere. Atmospherics conditions associated with eddies were examined using data of sea surface temperature (SST), sensible (SHF) and latent heat flux (LHF) from NCEP-CFSR reanalysis. On average, we found that NCEP-CFSR reanalysis adequately reflects the variability expected from eddies in the SWA, considering the classical eddy-pumping theory: anticyclonic (cyclonic) eddies cause maximum positive (negative) anomalies with maximum mean anomalies of 0.5 °C (-0.5 °C) in SST, 6 W/m2 (-4 W/m2) in SHF and 12 W/m2 (-9 W/m2) in LHF. However, a regional dependence of heat fluxes associated to mesoscale cyclonic eddies was found: in the turbulent Brazil-Malvinas Confluence (BMC) region they are related with positive heat flux anomaly (ocean heat loss), while in the rest of the SWA they behave as expected (ocean heat gain). We argue that eddy-pumping do not cool enough the center of the cyclonic eddies in the BMC region simply because most of them trapped very warm waters when they originate in the subtropics. The article therefore concludes that in the SWA: (1) a robust link exists between the SST anomalies generated by eddies and the local anomalous heat flow between the ocean and the atmosphere; (2) in the BMC region cyclonic eddies are related with positive heat anomalies, contrary to what is expected.

  15. Early-to-middle Holocene sea-level fluctuations, coastal progradation and the Neolithic occupations in Yaojiang valley of southern Hangzhou bay, eastern China

    Science.gov (United States)

    Liu, Y.; Sun, Q.; Fan, D.; Chen, Z.

    2017-12-01

    The formation of Holocene coast in eastern China provided material base for the development of Neolithic civilizations. The coastal Yaojiang valley of south Hangzhou bay was one of the examples where the well-known Neolithic Hemudu Culture (HC) of Eastern China initiated. Here, we studied the early-to-middle Holocene environment changes in relation to sea-level fluctuations on the basis of a serial of sediment cores based on a set of new Accelerator Mass Spectrometry radiocarbon (AMS 14C) chronology. The result indicated that relative sea-level rose rapidly in the Yaojiang valley at the early Holocene, reaching its maximum at ca. 8000-7800 cal yr BP and then decelerated at ca. 7800-7500 cal yr BP. The alluvial plain in Yaojiang valley began to form at the foothills first and then grew towards the valley center accompanying with the sea-level stabilization after ca. 7500 cal yr BP. This progressive progradation of alluvial plain would attract the early arrivals of foragers to dwell at the foothills to engaging in rice farming after ca.7000 cal yr BP and starting the epic Hemudu Culture. The HC people then move down to the valley center as more land became available thanks to sediment aggregation and progradation. The rise and development of HC were closely associated with the sea-level induced landscape changes in Yaojiang valley at the early-middle Holocene, and the unstable hydraulic condition in the valley after 5000 cal yr BP could be accountable for the cultural termination.

  16. South Atlantic pale oceanography and evolution during the Albian; Paleoceanografia e a evolucao do Atlantico Sul no Albiano

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Ricardo Latge Milward de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Diretoria de Exploracao e Producao]. E-mail: ricardolatge@petrobras.com.

    2004-11-01

    A vast array of geochemical, geophysical, sedimentological and paleontological data, together with modern environmental analogues in the Red Sea, support the view that the South Atlantic maintained its bi partitioned condition from latest Aptian to the middle Albian. The lineament comprising the Florianopolis High and Sao Paulo Dorsal formed an effective barrier to sea-water circulation between the Southern South Atlantic (SSA) and Central South Atlantic (CSA) until late Albian times. During that time, the latter communicated mainly with the North Atlantic, which in turn was connected to the Tethys Sea. The CSA was then entirely located within an arid climatic belt, and subject to a negative hydric balance, whereas an estuarine circulation pattern prevailed in the SSA. The comparison of carbon and oxygen stable isotope results from limestones in various parts of the world demonstrates that the CSA waters were warmer than those of the Malvinas in the South, and the Tethyan Sea to the North. The CSA sedimentary evolution was coeval with profound paleoceanographic changes. These were mainly induced by global tectonic phenomena related to the dynamics of oceanic crustal accretion, culminating with the definitive interconnection of the Tethyan and Indian oceanic waters by the end-Albian. Halokynetic movements and orbital variations brought about oscillations in accommodation space, which permitted the stacking of tens of shallowing-upward cycles with varied magnitudes. (author)

  17. Immunohistochemical localization of CYP1A, vitellogenin and Zona radiata proteins in the liver of swordfish (Xiphias gladius L.) taken from the Mediterranean Sea, South Atlantic, South Western Indian and Central North Pacific Oceans

    International Nuclear Information System (INIS)

    Desantis, S.; Corriero, A.; Cirillo, F.; Deflorio, M.; Brill, R.; Griffiths, M.; Lopata, A.L.; Serna, J.M. de la; Bridges, C.R.; Kime, D.E.; De Metrio, G.

    2005-01-01

    Cytochrome P4501A (CYP1A) monoxygenase, vitellogenin (Vtg) and Zona radiata proteins (Zrp) are frequently used as biomarkers of fish exposure to organic contaminants. In this work, swordfish liver sections obtained from the Mediterranean Sea, the South African coasts (South Atlantic and South Western Indian Oceans) and the Central North Pacific Ocean were immunostained with antisera against CYP1A, Zrp, and Vtg. CYP1A induction was found in hepatocytes, epithelium of the biliary ductus and the endothelium of large blood vessels of fish from the Mediterranean Sea and South African waters, but not from the Pacific Ocean. Zrp and Vtg were immunolocalized in hepatocytes of male swordfish from the Mediterranean Sea and from South African waters. Plasma Dot-Blot analysis, performed in Mediterranean and Pacific specimens, revealed the presence of Zrp and Vtg in males from Mediterranean but not from Pacific. These results confirm previous findings about the potential exposure of Mediterranean swordfish to endocrine, disrupting chemicals and raise questions concerning the possible presence of xenobiotic contaminants off the Southern coasts of South Africa in both the South Atlantic and South Western Indian Oceans

  18. Deep-Sea Mega-Epibenthic Assemblages from the SW Portuguese Margin (NE Atlantic Subjected to Bottom-Trawling Fisheries

    Directory of Open Access Journals (Sweden)

    Sofia P. Ramalho

    2017-11-01

    Full Text Available Bottom-trawling fisheries are a common threat to the health of continental margins worldwide. Together with numerous environmental and biological processes, physical disturbance induced by trawlers can largely shape the benthic habitats and their associated assemblages. At the SW Portuguese Margin, crustacean bottom trawlers have exploited deep-sea habitats for a few decades, but its effects on the benthic biodiversity are practically unknown. During the spring-summer of 2013 and 2014, several Remotely Operated Vehicle (ROV video transects were used to investigate mega-epibenthic abundance, composition, and diversity in soft-sediment areas subjected to varying trawling pressures off Sines and Setúbal (200–800 m. Differences in mega-epibenthic assemblages were linked with environmental changes (depth, grain size, primary productivity and trawling disturbance. The effect of trawling was assessed between segments with similar habitat characteristics, i.e., muddy-sand bottoms between 300 and 500 m. Areas subjected to intensive trawling pressure showed a generally flattened seabed, with abundant recent trawl marks (up to 3 scars.100 m−1, indicating that the seabed physical integrity was compromised. Significant negative correlations were detected between various mega-epibenthic diversity indices [S, H′, and ET(20] and trawling pressure (h.cell−1.y−1. Furthermore, the distinct mega-epibenthic assemblages and absence of several sessile erect morphospecies at both low and highly disturbed locations by trawling off Sines, namely all seapen morphospecies found in non-trawled areas, demonstrates the negative influence of trawling fisheries on the benthic component of the study area. Also, low dissimilarity between assemblages from the main fishing grounds and the adjacent low-disturbance locations, suggests that the potentially negative influence of trawling can extend beyond the targeted areas (e.g., by the plumes of re-suspended sediments. The

  19. Nuclear fuel cycle and marine environment. Behavior of the Rhone river effluents in the mediterranean sea and of wastes dumped in the northeast atlantic

    International Nuclear Information System (INIS)

    Charmasson, S.

    1998-01-01

    Man-made radionuclides released into the marine environment by the installations from the nuclear fuel cycle are used as tracers of various bio-geochemical processes. Several installations belonging to the whole nuclear fuel cycle, except the uranium mining, are set up on the Rhone River Banks. The sea disposal of low and intermediate level radioactive waste has never been authorized in the Mediterranean sea but several sites have been used in the North-East especially in abyssal waters. Radionuclides released by the Rhone river installations are used in order to study the dynamics of the Rhone inputs into the Mediterranean Sea. In the river, freshwater samples reflect quite accurately the discharge composition with a predominance of 106 Ru, a radionuclide mostly released by the spent nuclear fuel reprocessing plant in Marcoule. Conversely, at the Rhone mouth, in the sediment compartment 106 Ru yields to caesium isotopes ( 134 Cs and 137 Cs) in importance. As these two isotopes demonstrate very different half-lives (30,2 and 2,1 years respectively), the temporal evolution of their ratio acts as a chronometer enabled to date sediment accumulation near the river mouth. Mean accumulation rates greater than 35 cm y -1 have been determined in the pro-deltaic zone near the Roustan buoys over the period 1983-1991. Accumulation rates decrease rapidly with distance from the mouth and therefore most of the 137 Cs inventory in this part of the Gulf of Lions is limited to the pro-deltaic area. A first study about the part the different 137 Cs sources in the Mediterranean Sea play in this inventory has been carried out. Direct (atmospheric) and indirect (fluviatile) inputs due to fallout from both past nuclear tests and the Chernobyl accident could contribute to this inventory at the highest to 40 % while the industrial releases could contribute at the lowest to 60 %. The last site used for the dumping of low and intermediate level radioactive waste in the North-East Atlantic

  20. SEA LEVEL AND PALAEOCLIMATIC CHANGES IN THE SOUTH AND MIDDLE CASPIAN SEA REGION SINCE THE LATEGLACIAL FROM PALYNOLOGICAL ANALYSES OF MARINE SEDIMENT CORES

    Directory of Open Access Journals (Sweden)

    Suzanne Leroy

    2010-01-01

    Full Text Available A review of pollen, spores, non-pollen palynomorphs and dinocyst analyses made in the last two decades is proposed here. Building on spare palynological analyses before 1990, a series of new projects have allowed taking cores in the deeper parts of the Caspian Sea, hence providing access to low-stand sediment. However, still nowadays no complete record exists for the Holocene. The first steps towards quantification of the palynological spectra have been taken. Some of the most urgent problems to solve are the uncertainties related to radiocarbon dating, which are especially acute in the Caspian Sea.

  1. Modeling the influence of a reduced equator-to-pole sea surface temperature gradient on the distribution of water isotopes in the Early/Middle Eocene

    Science.gov (United States)

    Speelman, Eveline N.; Sewall, Jacob O.; Noone, David; Huber, Matthew; von der Heydt, Anna; Damsté, Jaap Sinninghe; Reichart, Gert-Jan

    2010-09-01

    Proxy-based climate reconstructions suggest the existence of a strongly reduced equator-to-pole temperature gradient during the Azolla interval in the Early/Middle Eocene, compared to modern. Changes in the hydrological cycle, as a consequence of a reduced temperature gradient, are expected to be reflected in the isotopic composition of precipitation (δD, δ 18O). The interpretation of water isotopic records to quantitatively reconstruct past precipitation patterns is, however, hampered by a lack of detailed information on changes in their spatial and temporal distribution. Using the isotope-enabled version of the National Center for Atmospheric Research (NCAR) atmospheric general circulation model, Community Atmosphere Model v.3 (isoCAM3), relationships between water isotopes and past climates can be simulated. Here we examine the influence of an imposed reduced meridional sea surface temperature gradient on the spatial distribution of precipitation and its isotopic composition in an Early/Middle Eocene setting. As a result of the applied forcings, the Eocene simulation predicts the occurrence of less depleted high latitude precipitation, with δD values ranging only between 0 and -140‰ (compared to Present-day 0 to -300‰). Comparison with Early/Middle Eocene-age isotopic proxy data shows that the simulation accurately captures the main features of the spatial distribution of the isotopic composition of Early/Middle Eocene precipitation over land in conjunction with the aspects of the modeled Early/Middle Eocene climate. Hence, the included stable isotope module quantitatively supports the existence of a reduced meridional temperature gradient during this interval.

  2. Unlocking the hydrocarbon potential of the eastern Black Sea basin. Prospectivity of middle Miocene submarine fan reservoirs by seismic sequence stratigraphy

    International Nuclear Information System (INIS)

    Gundogan, Coskun; Galip, Ozbek; Ali, Demirer

    2002-01-01

    Full text : The objective of this paper is to present present depositional characteristics and hydrocarbon prospectivity of the middle Miocene submarine basin floor fan deposits from the exploration stand point of view by using seismic data available in the offshore eastern Black Sea basin. This basin is a Tertiary trough formed as a continuation of the Mesozoic oceanic basin. The hydrocarbon potential of the basin is believed to be high in the Tertiary section because of the existence of the elements necessary for generation, migration and entrapment of hydrocarbon. A sequence stratigraphic study has been carried out by using 2-d seismic data in the Turkish portion of the eastern Black Sea basin. The objective of the study was to determine periods of major clastic sediment influxes which might lead to identify good reservoir intervals and their spatial distribution in this basin. All basic seismic sequence stratigraphic interpretation techniques and seismic facies analysis were used to identify times of these sand rich deposition periods. Sequence stratigraphy and seismic facies analysis indicate that the basinal areas of the middle Miocene sequences were dominated mainly by submarine fan complexes introduced in the lowstand stages and pelagic sediments deposited during the transgressive and highstand stages. It was proposed that Turkish portion of this basin which is one of the best frontier exploration area with its high potential left in the world, is glimpsing to those looking for good future exploration opportunities.

  3. Severnaya Zemlya, arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    DEFF Research Database (Denmark)

    Möller, Per; Lubinski, David J.; Ingólfsson, Ólafur

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from...... of a large Kara Sea ice sheet, with exception of the Last Glacial Maximum (MIS 2), when Kara Sea ice did not impact Severnaya Zemlya and barely graced northernmost Taymyr Peninsula.......Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from......-5e and MIS 5d-3. The MIS 6-5e event, associated with the high marine limit, implies ice-sheet thickness of >2000 m only 200 km from the deep Arctic Ocean, consistent with published evidence of ice grounding at ~1000 m water depth in the central Arctic Ocean. Till fabrics and glacial tectonics record...

  4. Temperature and salinity profile data collected by bottle on multiple cruises in the Baltic Sea, Baffin Bay, Davis Strait, the North Atlantic Ocean, and the North Sea from 02 January 1985 to 13 November 1989 (NODC Accession 0000056)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and nutrients data were collected using bottle casts from DANA and other platforms in Baffin Sea, Baltic Sea, Davis Strait, North Sea, and North...

  5. PALEOBATHYMETRIC INTERPRETATION OF THE FISH OTOLITHS FROM THE LOWER - MIDDLE QUATERNARY DEPOSITS OF KEPHALLONIA AND ZAKYNTHOS ISLANDS (IONIAN SEA, WESTERN GREECE

    Directory of Open Access Journals (Sweden)

    KONSTANTINA AGIADI

    2010-03-01

    Full Text Available Fish otoliths are herein used to estimate the depositional depth of the Early - Middle Pleistocene deposits at SE Zakynthos and SW Kephallonia Islands (Ionian Sea, Western Greece, through comparison with the modern bathymetric distributions of the identified fish taxa. These estimates provide a more detailed picture of the depth variations for the Gelasian - Ionian stage interval in the study areas. The Lower Pleistocene marine deposits of the Gerakas Formation (SE Zakynthos Island, Ionian Sea were deposited at average depths of 400-450 meters, with eustacy playing an important role in the depth variability, between 1.95-1.73 Ma. An uplifting episode, followed by subsidence takes place between 1.73-1.66 Ma, taking the area to 200-300 meters of depth, and then back to 400-500 meters. However, the area seems uplifted again to 200-400 meters later on in the Calabrian stage (1.25-0.97 Ma. Sedimentation of the Akrotiri deposits (NW Kephallonia Island, Ionian Sea, during the same chronostratigraphic interval, took place in a similar setting. At the Early Pleistocene (1.95-1.73 Ma this basin reached depths of 400-450 meters, with uplift and following subsidence taking place between 1.73-1.66 Ma. Overall, the application of fish otolith paleobathymetry in the study areas provide a detailed picture of the depth variations for the Early Quaternary interval and refine the currently hypothesized pattern of tectonic movements. 

  6. A “Rosetta Stone” for metazoan zooplankton: DNA barcode analysis of species diversity of the Sargasso Sea (Northwest Atlantic Ocean)

    Science.gov (United States)

    Bucklin, Ann; Ortman, Brian D.; Jennings, Robert M.; Nigro, Lisa M.; Sweetman, Christopher J.; Copley, Nancy J.; Sutton, Tracey; Wiebe, Peter H.

    2010-12-01

    Species diversity of the metazoan holozooplankton assemblage of the Sargasso Sea, Northwest Atlantic Ocean, was examined through coordinated morphological taxonomic identification of species and DNA sequencing of a ˜650 base-pair region of mitochondrial cytochrome oxidase I (mtCOI) as a DNA barcode (i.e., short sequence for species recognition and discrimination). Zooplankton collections were made from the surface to 5,000 meters during April, 2006 on the R/V R.H. Brown. Samples were examined by a ship-board team of morphological taxonomists; DNA barcoding was carried out in both ship-board and land-based DNA sequencing laboratories. DNA barcodes were determined for a total of 297 individuals of 175 holozooplankton species in four phyla, including: Cnidaria (Hydromedusae, 4 species; Siphonophora, 47); Arthropoda (Amphipoda, 10; Copepoda, 34; Decapoda, 9; Euphausiacea, 10; Mysidacea, 1; Ostracoda, 27); and Mollusca (Cephalopoda, 8; Heteropoda, 6; Pteropoda, 15); and Chaetognatha (4). Thirty species of fish (Teleostei) were also barcoded. For all seven zooplankton groups for which sufficient data were available, Kimura-2-Parameter genetic distances were significantly lower between individuals of the same species (mean=0.0114; S.D. 0.0117) than between individuals of different species within the same group (mean=0.3166; S.D. 0.0378). This difference, known as the barcode gap, ensures that mtCOI sequences are reliable characters for species identification for the oceanic holozooplankton assemblage. In addition, DNA barcodes allow recognition of new or undescribed species, reveal cryptic species within known taxa, and inform phylogeographic and population genetic studies of geographic variation. The growing database of "gold standard" DNA barcodes serves as a Rosetta Stone for marine zooplankton, providing the key for decoding species diversity by linking species names, morphology, and DNA sequence variation. In light of the pivotal position of zooplankton in ocean

  7. Copepod colonization of organic and inorganic substrata at a deep-sea hydrothermal vent site on the Mid-Atlantic Ridge

    Science.gov (United States)

    Plum, Christoph; Pradillon, Florence; Fujiwara, Yoshihiro; Sarrazin, Jozée

    2017-03-01

    The few existing studies on deep-sea hydrothermal vent copepods indicate low connectivity with surrounding environments and reveal high endemism among vents. However, the finding of non-endemic copepod species in association with engineer species at different reduced ecosystems poses questions about the dispersal of copepods and the colonization of hydrothermal vents as well as their ecological connectivity. The objective of this study is to understand copepod colonization patterns at a hydrothermal vent site in response to environmental factors such as temperature and fluid flow as well as the presence of different types of substrata. To address this objective, an in situ experiment was deployed using both organic (woods, pig bones) and inorganic (slates) substrata along a gradient of hydrothermal activity at the Lucky Strike vent field (Eiffel Tower, Mid-Atlantic Ridge). The substrata were deployed in 2011 during the MoMARSAT cruise and were recovered after two years in 2013. Overall, copepod density showed significant differences between substrata types, but was similar among different hydrothermal activity regimes. Highest densities were observed on woods at sites with moderate or low fluid input, whereas bones were the most densely colonized substrata at the 2 sites with higher hydrothermal influence. Although differences in copepod diversity were not significant, the observed trends revealed overall increasing diversity with decreasing temperature and fluid input. Slates showed highest diversity compared to the organic substrata. Temperature and fluid input had a significant influence on copepod community composition, resulting in higher similarity among stations with relatively high and low fluid inputs, respectively. While vent-specialists such as dirivultids and the tegastid Smacigastes micheli dominated substrata at high vent activity, the experiment demonstrated increasing abundance and dominance of non-vent taxa with decreasing temperature and fluid

  8. Severnaya Zemlya, arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

    DEFF Research Database (Denmark)

    Möller, Per; Lubinski, David J.; Ingólfsson, Ólafur

    2006-01-01

    Quaternary glacial stratigraphy and relative sea-level changes reveal at least four expansions of the Kara Sea ice sheet over the Severnaya Zemlya Archipelago at 79°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from......-5e and MIS 5d-3. The MIS 6-5e event, associated with the high marine limit, implies ice-sheet thickness of >2000 m only 200 km from the deep Arctic Ocean, consistent with published evidence of ice grounding at ~1000 m water depth in the central Arctic Ocean. Till fabrics and glacial tectonics record...... repeated expansions of local ice caps exclusively, suggesting wet-based ice cap advance followed by cold-based regional ice-sheet expansion. Local ice caps over highland sites along the perimeter of the shallow Kara Sea, including the Byrranga Mountains, appear to have repeatedly fostered initiation...

  9. Model output for deep-sea coral habitat suitability in the U.S. North and Mid-Atlantic from 2013 (NCEI Accession 0145923)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset was created for potential use as an environmental predictor in spatial predictive models of deep-sea coral habitat suitability. Deep-sea corals are of...

  10. Sea Turtle Satellite Telemetry Data in North Atlantic Ocean from 2007-10-16 to 2010-11-26 (NCEI Accession 0159216)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains satellite telemetry data for sea turtles. Movements, migratory pathways, and foraging behavior of sea turtles were tracked and surfacing...

  11. Sea-level related resedimentation processes on the northern slope of Little Bahama Bank (Middle Pleistocene to Holocene)

    DEFF Research Database (Denmark)

    Lantzsch, H.; Roth, S.; Reijmer, J.J.G.

    2007-01-01

    -slope depositional environment. The sediment composition indicates sea-level related deposition processes for the past 375000 years (marine isotope stages 1 to 11). The sediments consist of: (i) periplatform ooze (fine-grained particles of shallow-water and pelagic origin) with moderate variations in carbonate...

  12. Sea ice and wind variability during the Holocene in East Antarctica: Insight on middle high latitude coupling

    NARCIS (Netherlands)

    Denis, D.; Crosta, X.; Barbera, L.; Masse, G.; Renssen, H.; Ther, O.; Giraudeau, J.

    2010-01-01

    Micropaleontological and biomarker data from two high-accumulation marine sites from the Coastal and Continental Shelf Zone (CCSZ) off East Antarctica (Adélie Land at ∼140°E and eastern Prydz Bay at ∼77°E) are used to reconstruct Holocene changes in sea ice and wind stress at the basin-wide scale.

  13. Nematocarcinus Milne Edwards, 1881 (Crustacea, Decapoda) from Southwestern Atlantic, including the Southern Mid-Atlantic Ridge area.

    Science.gov (United States)

    Cardoso, Irene A; Burukovsky, Rudolf N

    2014-11-26

    The deep sea shrimp genus Nematocarcinus Milne Edwards, 1881 includes 47 species, ten of them have been recorded from the Atlantic Ocean. Herein, material sampled during three scientific projects (REVIZEE Central Fishery project; Campos Basin Deep Sea Environmental Project; Evaluation of Environmental Heterogeneity in the Campos Basin) made in the Southwestern Atlantic, off Brazil, is examined. In addition, material sampled from the South Mid Atlantic Ridge (MAR-ECO Project) was also examined. Four species are recorded for the first time to the southwestern Atlantic Ocean including Mid Atlantic Ridge area: Nematocarcinus faxoni Burukovsky, 2001; N. gracilipes Filhol, 1884; N. rotundus Crosnier & Forest, 1973 and N. tenuipes Spence-Bate, 1888.

  14. Life in the fluvial hinterland of the late Sarmatian Sea (middle Miocene): a rare terrestrial fossil site in the Styrian Basin (Austria)

    Science.gov (United States)

    Doubrawa, Monika; Gross, Martin; Harzhauser, Mathias

    2018-02-01

    This paper describes the section and fossil content of a former gravel pit in the Eastern Styrian Basin (SE Austria), which exposes sediments of a fluvial system, ranging from within channel to overbank environments. A predominately terrestrial gastropod fauna of 15 species so far, was recovered from a palaeosol formed in a moist and vegetated, floodplain or abandoned channel. Up-section, a shallow freshwater pond/lake developed within the floodplain, settled by fishes, molluscs and ostracods. By integrating regional geological and biostratigraphical data derived from the terrestrial gastropod fauna as well as from the other recovered biota, these strata are of late middle Miocene (late Sarmatian s.str.) age. Hence, this fossil site provides a rare insight into the terrestrial habitats in the hinterland of the Sarmatian Sea and their biota, which are otherwise barely known in Central Europe.

  15. Variability of PAHs and trace metals in the sediments in relation to environmental characteristics of the bottom layer in the middle Adriatic Sea

    Science.gov (United States)

    Grilli, Federica; Frapiccini, Emanuela; Campanelli, Alessandra; Guicciardi, Stefano; Marini, Mauro; Marasovic, Ivona; Grbec, Branka; Skejić, Sanda; Ujević, Ivana; Lušić, Jelena

    2015-04-01

    In the framework of the project PERSEUS (Policy-oriented marine Environmental Research in the Southern EUropean Seas), two interdisciplinary surveys were carried out in April 2013 and April 2014 in the middle Adriatic Sea along the Pescara-Sibenik transect (Jabuka Pits area) and Vieste-Split transect (Palagruza Sill area) with Croatian research vessel "Bios II" and the Italian research vessel "G. Dallaporta", respectively. The main objective of these research cruises was the implementation of the Marine Strategy Framework Directive (MSFD) in the Adriatic region for collecting physical, chemical and biological data in order to get a better understanding of whole Adriatic ecosystem. The two transects are already recognised as a key areas for the interception and the study of dense water modification (Zore-Armanda, 1963; Marini et al., 2006; Grilli et al., 2013). Due to seasonal circulation patterns, they are characterized by high temporal variability of the thermohaline structure (Grbec and Morović, 1997; Vilibić, et al., 2004) and other oceanographic parameters. Long term oceanographic records from the Middle Adriatic enable better understanding of the ecosystem response to changes of atmospheric and sea conditions through physical, chemical and biological processes (Marasović et al., 1995). Several oceanographic parameters relevant and useful for the ecosystem assessment of the two areas (temperature, salinity, density, fluorescence, oxygen, nutrients, chlorophyll, phyto- and zoo-plankton as well as selected pollutants , trace metals and Polycyclic Aromatic Hydrocarbons-PAHs in sediments) were collected. In the present work, the variations of PAHs and trace metals concentration in the marine sediments are presented in relation to the physical and chemical characteristics of the bottom layer. A constant influx of metal induces more intense accumulation of anthropogenic metals, especially Cd, in sediment from Jabuka Pit, and the metal content slightly increases

  16. Building a bio-based industry in the Middle East through harnessing the potential of the Red Sea biodiversity

    KAUST Repository

    Nielsen, Jens; Archer, John A.C.; Essack, Magbubah; Bajic, Vladimir B.; Gojobori, Takashi; Mijakovic, Ivan

    2017-01-01

    The incentive for developing microbial cell factories for production of fuels and chemicals comes from the ability of microbes to deliver these valuable compounds at a reduced cost and with a smaller environmental impact compared to the analogous chemical synthesis. Another crucial advantage of microbes is their great biological diversity, which offers a much larger “catalog” of molecules than the one obtainable by chemical synthesis. Adaptation to different environments is one of the important drives behind microbial diversity. We argue that the Red Sea, which is a rather unique marine niche, represents a remarkable source of biodiversity that can be geared towards economical and sustainable bioproduction processes in the local area and can be competitive in the international bio-based economy. Recent bioprospecting studies, conducted by the King Abdullah University of Science and Technology, have established important leads on the Red Sea biological potential, with newly isolated strains of Bacilli and Cyanobacteria. We argue that these two groups of local organisms are currently most promising in terms of developing cell factories, due to their ability to operate in saline conditions, thus reducing the cost of desalination and sterilization. The ability of Cyanobacteria to perform photosynthesis can be fully exploited in this particular environment with one of the highest levels of irradiation on the planet. We highlight the importance of new experimental and in silico methodologies needed to overcome the hurdles of developing efficient cell factories from the Red Sea isolates.

  17. Building a bio-based industry in the Middle East through harnessing the potential of the Red Sea biodiversity.

    Science.gov (United States)

    Nielsen, Jens; Archer, John; Essack, Magbubah; Bajic, Vladimir B; Gojobori, Takashi; Mijakovic, Ivan

    2017-06-01

    The incentive for developing microbial cell factories for production of fuels and chemicals comes from the ability of microbes to deliver these valuable compounds at a reduced cost and with a smaller environmental impact compared to the analogous chemical synthesis. Another crucial advantage of microbes is their great biological diversity, which offers a much larger "catalog" of molecules than the one obtainable by chemical synthesis. Adaptation to different environments is one of the important drives behind microbial diversity. We argue that the Red Sea, which is a rather unique marine niche, represents a remarkable source of biodiversity that can be geared towards economical and sustainable bioproduction processes in the local area and can be competitive in the international bio-based economy. Recent bioprospecting studies, conducted by the King Abdullah University of Science and Technology, have established important leads on the Red Sea biological potential, with newly isolated strains of Bacilli and Cyanobacteria. We argue that these two groups of local organisms are currently most promising in terms of developing cell factories, due to their ability to operate in saline conditions, thus reducing the cost of desalination and sterilization. The ability of Cyanobacteria to perform photosynthesis can be fully exploited in this particular environment with one of the highest levels of irradiation on the planet. We highlight the importance of new experimental and in silico methodologies needed to overcome the hurdles of developing efficient cell factories from the Red Sea isolates.

  18. Building a bio-based industry in the Middle East through harnessing the potential of the Red Sea biodiversity

    KAUST Repository

    Nielsen, Jens

    2017-05-20

    The incentive for developing microbial cell factories for production of fuels and chemicals comes from the ability of microbes to deliver these valuable compounds at a reduced cost and with a smaller environmental impact compared to the analogous chemical synthesis. Another crucial advantage of microbes is their great biological diversity, which offers a much larger “catalog” of molecules than the one obtainable by chemical synthesis. Adaptation to different environments is one of the important drives behind microbial diversity. We argue that the Red Sea, which is a rather unique marine niche, represents a remarkable source of biodiversity that can be geared towards economical and sustainable bioproduction processes in the local area and can be competitive in the international bio-based economy. Recent bioprospecting studies, conducted by the King Abdullah University of Science and Technology, have established important leads on the Red Sea biological potential, with newly isolated strains of Bacilli and Cyanobacteria. We argue that these two groups of local organisms are currently most promising in terms of developing cell factories, due to their ability to operate in saline conditions, thus reducing the cost of desalination and sterilization. The ability of Cyanobacteria to perform photosynthesis can be fully exploited in this particular environment with one of the highest levels of irradiation on the planet. We highlight the importance of new experimental and in silico methodologies needed to overcome the hurdles of developing efficient cell factories from the Red Sea isolates.

  19. Atlantic continental margin of the United States

    Science.gov (United States)

    Grow, John A.; Sheridan, Robert E.; Palmer, A.R.

    1982-01-01

    The objective of this Decade of North American Geology (D-NAG) volume will be to focus on the Mesozoic and Cenozoic evolution of the U.S. Atlantic continental margin, including the onshore coastal plain, related onshore Triassic-Jurassic rift grabens, and the offshore basins and platforms. Following multiple compressional tectonic episodes between Africa and North America during the Paleozoic Era that formed the Appalachian Mountains, the Mesozoic and Cenozoic Eras were dominated by tensional tectonic processes that separated Africa and North America. Extensional rifting during Triassic and Early Jurassic times resulted in numerous tensional grabens both onshore and offshore, which filled with nonmarine continental red beds, lacustrine deposits, and volcanic flows and debris. The final stage of this breakup between Africa and North America occurred beneath the present outer continental shelf and continental slope during Early or Middle Jurassic time when sea-floor spreading began to form new oceanic crust and lithosophere between the two continents as they drifted apart. Postrift subsidence of the marginal basins continued in response to cooling of the lithosphere and sedimentary loading.Geophysical surveys and oil-exploration drilling along the U.S. Atlantic continental margin during the past 5 years are beginning to answer many questions concerning its deep structure and stratigraphy and how it evolved during the rifting and early sea-floor-spreading stages of the separation of this region from Africa. Earlier geophysical studies of the U.S. continental margin used marine refraction and submarine gravity measurements. Single-channel seismic-reflection, marine magnetic, aeromagnetic, and continuous gravity measurements became available during the 1960s.

  20. Early to Middle Holocene sea level fluctuation, coastal progradation and the Neolithic occupation in the Yaojiang Valley of southern Hangzhou Bay, Eastern China

    Science.gov (United States)

    Liu, Yan; Sun, Qianli; Fan, Daidu; Dai, Bin; Ma, Fuwei; Xu, Lichen; Chen, Jing; Chen, Zhongyuan

    2018-06-01

    The Yaojiang Valley (YJV) of southern Hangzhou Bay was the birthplace of the well-known Hemudu Culture (HC), one of the representatives of Neolithic civilization in eastern China. To explore the magnitude of natural environmental effects on the HC trajectory, the palaeo-embayment setting of the YJV was studied in detail for the first time in terms of 3D Holocene strata supported by a series of new radiocarbon-dated cores. The results indicated that the local relative sea level rose rapidly during the Early Holocene in the YJV, reached its maximum flooding surface ca. 7900 cal yr BP, and then remained stable ca. 7900-7600 cal yr BP. Thereupon, an estuary stretching inland was first formed by marine transgression, and then, it was transformed to an alluvial-coastal plain by regressive progradation. The alluvial plain was initiated in the foothills and then spread towards the valley centre after sea level stabilization ca. 7600 cal yr BP. Accompanying these natural environmental changes, the earliest arrivals of foragers in the valley occurred no later than ca. 7000 cal yr BP. They engaged in rice farming and fostered the HC for approximately two millennia from ca. 7000-5000 cal yr BP as more lands developed from coastal progradation. The rise and development of the HC are closely associated with the sea level-induced landscape changes in the YJV in the Early-Middle Holocene, but the enigmatic exodus of the HC people after ca. 5000 cal yr BP is still contentious and possibly linked with the rapid waterlogging and deterioration of this setting in such a low-lying coastal plain as well as with associated social reasons.

  1. Patagonian and southern South Atlantic view of Holocene climate

    Science.gov (United States)

    Kaplan, M. R.; Schaefer, J. M.; Strelin, J. A.; Denton, G. H.; Anderson, R. F.; Vandergoes, M. J.; Finkel, R. C.; Schwartz, R.; Travis, S. G.; Garcia, J. L.; Martini, M. A.; Nielsen, S. H. H.

    2016-06-01

    We present a comprehensive 10Be chronology for Holocene moraines in the Lago Argentino basin, on the east side of the South Patagonian Icefield. We focus on three different areas, where prior studies show ample glacier moraine records exist because they were formed by outlet glaciers sensitive to climate change. The 10Be dated records are from the Lago Pearson, Herminita Península-Brazo Upsala, and Lago Frías areas, which span a distance of almost 100 km adjacent to the modern Icefield. New 10Be ages show that expanded glaciers and moraine building events occurred at least at 6120 ± 390 (n = 13), 4450 ± 220 (n = 7), 1450 or 1410 ± 110 (n = 18), 360 ± 30 (n = 5), and 240 ± 20 (n = 8) years ago. Furthermore, other less well-dated glacier expansions of the Upsala Glacier occurred between 1400 and ∼1000 and ∼2300 and ∼2000 years ago. The most extensive glaciers occurred over the interval from ∼6100 to ∼4500 years ago, and their margins over the last ∼600 years were well within and lower than those in the middle Holocene. The 10Be ages agree with 14C-limiting data for the glacier histories in this area. We then link southern South American, adjacent South Atlantic, and other Southern Hemisphere records to elucidate broader regional patterns of climate and their possible causes. In the early Holocene, a far southward position of the westerly winds fostered warmth, small Patagonian glaciers, and reduced sea ice coverage over the South Atlantic. Although we infer a pronounced southward displacement of the westerlies during the early Holocene, these conditions did not occur throughout the southern mid-high latitudes, an important exception being over the southwest Pacific sector. Subsequently, a northward locus and/or expansion of the winds over the Patagonia-South Atlantic sector promoted the largest glaciers between ∼6100 and ∼4500 years ago and greatest sea ice coverage. Over the last few millennia, the South Patagonian Icefield has experienced

  2. Re-Os Geochronology Pins Age and Os Isotope Composition of Middle Triassic Black Shales and Seawater, Barents Sea and Spitsbergen (Svalbard)

    Science.gov (United States)

    Xu, G.; Hannah, J. L.; Bingen, B.; Stein, H. J.; Yang, G.; Zimmerman, A.; Weitschat, W.; Weiss, H. M.

    2008-12-01

    Absolute age control throughout the Triassic is extraordinarily sparse. Two "golden spikes" have been added recently (http://www.stratigraphy.org/cheu.pdf) within the otherwise unconstrained Triassic, but ages of stage boundaries remain controversial. Here we report two Re-Os isochrons for Anisian (Middle Triassic) black shales from outcrop in western Svalbard and drill core from the Svalis Dome about 600 km to the SE in the Barents Sea. Black shales of the Blanknuten Member, Botneheia Formation, from the type section at Botneheia, western Spitsbergen (Svalbard), have total organic carbon (TOC) contents of 2.6 to 6.0 wt%. Rock-Eval data suggest moderately mature (Tmax = 440-450° C) Type II-III kerogens (Hydrogen Index (HI) = 232-311 mg HC/g TOC). Re-Os data yield a well-constrained Model 3 age of 241 Ma and initial 187Os/188Os (Osi) of 0.83 (MSWD = 16, n = 6). Samples of the possibly correlative Steinkobbe Formation from IKU core hole 7323/07-U-04 into the Svalis Dome in the Barents Sea (at about 73°30'N, 23°15'E) have TOC contents of 1.4 to 2.4%. Rock-Eval data suggest immature (Tmax = 410-430°) Type II-III kerogens (HI = 246-294 mg HC/g TOC). Re-Os data yield a precise Model 1 age of 239 Ma and Osi of 0.776 (MSWD = 0.2, n = 5). The sampled section of Blanknuten shale underlies a distinctive Frechitas (formerly Ptychites) layer, and is therefore assumed to be middle Anisian. The Steinkobbe core was sampled at 99-100 m, just above the Olenekian-Anisian transition. It is therefore assumed to be lower Anisian. The two isochron ages overlap within uncertainty, and fall within constraints provided by biozones and the current ICS-approved stage boundary ages. The Re-Os ages support the correlation of the Botneheia and Steinkobbe formations. The nearly identical Osi ratios suggest regional homogeneity of seawater and provide new information for the Os seawater curve, marking a relatively high 187Os/188Os ratio during profound ocean anoxia in the Middle Triassic.

  3. 76 FR 13583 - Atlantic Highly Migratory Species; Atlantic Bluefin Tuna Quotas and Atlantic Tuna Fisheries...

    Science.gov (United States)

    2011-03-14

    ... address concerns raised in a recent decision by a NOAA Administrative Law Judge (see Atlantic Tunas Transfer at Sea section for case reference). NMFS has prepared a draft Environmental Assessment (EA... subtraction of these allocations directly from the TAC, the recommendation allocates the remainder to the UK...

  4. 76 FR 56120 - Atlantic Highly Migratory Species; North and South Atlantic Swordfish Quotas

    Science.gov (United States)

    2011-09-12

    ... recreational fishing for swordfish in the Atlantic Ocean, including the Caribbean Sea and Gulf of Mexico, by... http://www.iccat.int/en/ . One swordfish measure adopted at the 2010 meeting, and one swordfish measure...

  5. The role of Atlantic-Arctic exchange in North Atlantic multidecadal climate variability

    NARCIS (Netherlands)

    Frankcombe, L.M.; Dijkstra, H.A.

    2011-01-01

    It has recently been suggested that multidecadal variability in North Atlantic sea surface temperature occurs with two dominant periods. In this paper we investigate the origin of these two time scales in a 500 year control run of the GFDL CM2.1 model. We focus on the exchange between the Atlantic

  6. Middle-Holocene sea-level fluctuations interrupted the developing Hemudu culture in the lower Yangtze River, China

    Science.gov (United States)

    He, Keyang; Lu, Houyuan; Zheng, Yunfei; Zhang, Jianping; Xu, Deke; Huan, Xiujia; Wang, Jiehua; Lei, Shao

    2018-05-01

    The eastern coastal zone of China is densely populated and widely recognized as a center of rice domestication, which has undergone dramatic sea-level fluctuation during the Holocene epoch. Hemudu culture is distributed mainly in the eastern coastal area and was once presumed as a mature agricultural economy based on rice, making it an ideal case for examining the remarkable human-environment interaction in the Lower Yangtze River. Though numerous studies have been conducted on the cultural evolution, ecological environment, and rice domestication of Hemudu culture, the impact of sea-level fluctuation on human settlement and food production remains controversial. In this study, we report high-resolution pollen, phytolith, and diatom records, and accurately measured elevation from the Yushan site, which is the closest site of Hemudu culture to the modern coastline. Based on the data gathered, we suggest that the Hemudu culture and subsequent Liangzhu culture developed in the context of regression and were interrupted by two transgressions that occurred during 6300-5600 BP and 5000-4500 BP. The regional ecological environment of the Yushan site alternated between intertidal mudflat and freshwater wetlands induced by sea-level fluctuations in the mid-late Holocene. Though rice was cultivated in the wetland as early as 6700 BP, this cultivation was subsequently discontinued due to the transgression; thus, full domestication of rice did not occur until 5600 BP in this region. Comprehensive analysis of multiple proxies in this study promote the understanding of the relationship between environmental evolution, cultural interruption, and rice domestication.

  7. Sedimentology of middle ordovician carbonates in the Argentine precordillera: evidence of regional relative sea-level changes

    Science.gov (United States)

    Keller, M.; Eberlein, S.; Lehnert, O.

    1993-07-01

    The Las Aguaditas Formation in the Argentine Precordillera of San Juan is the only Ordovician carbonate sequence deposited on a slope. Spiculites, mudstones and calcisiltites represent the autochthonous sediments, characterized by a fine lamination, rare fossils and their dark colour. The pelagic fauna consists of rare radiolarians/calcispheres, trinucleid trilobites, graptolites and conodonts. The latter are typical of an open marine environment and proved a Llanvirn—Llandeilo age for the Las Aguaditas Formation. In the upper part of the succession there are several intercalations of megabreccias. Their thickness decreases from about 20 to 4 m towards the top of the formation, accompanied by an increasing amount of carbonate turbidites. The clasts of the breccias are derived from the slope as well as the platform. Each of the megabreccia horizons represents a system of channels, lobes and interchannel deposits, which together form a slope apron. On top of the lower breccia a small biostrome developed, where bryozoans and crinoids are preserved in an autochthonous position. Sedimentation of the Las Aguaditas Formation started with the drowning of the underlying carbonate platform (San Juan limestones). Near the Arenig-Llanvirn boundary, a rapid ecstatic sea-level rise led to the deposition of graptolitic black shales and mudstones. Upwards, allochthonous carbonates become increasingly abundant. The onset of megabreccia deposition coincides with a major relative sea-level fall, caused by block movements in connection with rifting. The subsequent transition from breccia formation towards turbiditic sedimentation corresponds to an environmental shift from the slope towards the toe of slope and basin and marks a renewed moderate sea-level rise.

  8. Engaging Middle School Students with Google Earth Technology to Analyze Ocean Cores as Evidence for Sea Floor Spreading

    Science.gov (United States)

    Prouhet, T.; Cook, J.

    2006-12-01

    Google Earth's ability to captivate students' attention, its ease of use, and its high quality images give it the potential to be an extremely effective tool for earth science educators. The unique properties of Google Earth satisfy a growing demand to incorporate technology in science instruction. Google Earth is free and relatively easy to use unlike some other visualization software. Students often have difficulty conceptualizing and visualizing earth systems, such as deep-ocean basins, because of the complexity and dynamic nature of the processes associated with them (e.g. plate tectonics). Google Earth's combination of aerial photography, satellite images and remote sensing data brings a sense of realism to science concepts. The unobstructed view of the ocean floor provided by this technology illustrates three-dimensional subsurface features such as rift valleys, subduction zones, and sea-mounts enabling students to better understand the seafloor's dynamic nature. Students will use Google Earth to navigate the sea floor, and examine Deep Sea Drilling Project (DSDP) core locations the from the Glomar Challenger Leg 3 expedition. The lesson to be implemented was expanded upon and derived from the Joint Oceanographic Insitute (JOI) Learning exercise, Nannofossils Reveal Seafloor Spreading. In addition, students take on the role of scientists as they graph and analyze paleontological data against the distance from the Mid Ocean Ridge. The integration of ocean core data in this three-dimensional view aids students' ability to draw and communicate valid conclusions about their scientific observations. A pre and post survey will be given to examine attitudes, self-efficacy, achievement and content mastery to a sample of approximately 300 eighth grade science students. The hypothesis is that the integration of Google Earth will significantly improve all areas of focus as mentioned above.

  9. The genus Hippolyte Leach, 1814 (Crustacea: Decapoda: Caridea: Hippolytidae) in the East Atlantic Ocean and the Mediterranean Sea, with a checklist of all species in the genus

    NARCIS (Netherlands)

    d'Udekem d'Acoz, C.

    1996-01-01

    The genus Hippolyte Leach in the East Atlantic and the Mediterranean is revised and a list of the world species is given. Eleven species occur in the area studied: H. coerulescens (Fabricius), H. garciarasoi spec. nov., H. inermis Leach, H. lagarderei d'Udekem d'Acoz, H. leptocerus (Heller), H.

  10. Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

    DEFF Research Database (Denmark)

    Mackenzie, Brian R; Mariani, Patrizio

    2012-01-01

    The lucrative and highly migratory Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758; Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity...

  11. Fish Species in a Changing World: The Route and Timing of Species Migration between Tropical and Temperate Ecosystems in Eastern Atlantic.

    Directory of Open Access Journals (Sweden)

    Awaluddin Halirin Kaimuddin

    2016-09-01

    Full Text Available The presence of tropical species has been reported in Atlantic-European waters with increasing frequency in recent years. Unfortunately, the history of their migrations is not well understood. In this study, we examined the routes and timing of fish migrations in several ecosystems of the East Atlantic Ocean, combining several publicly available and unpublicized datasets on species occurrences. The species studied were those noted as exotic or rare outside their previous known area of distribution. We used sea surface temperature (SST data obtained from 30 years of satellite observation to define three distinct time periods. Within these periods, temperature trends were studied in six ecosystems: the North Sea, the Celtic Sea, the South European Atlantic Waters, the Mediterranean Sea, the Canary Current and the Guinea Current. We also incorporated bathymetry data to describe the distribution of species. Measurement across a relatively large spatial extent was made possible by incorporating the capabilities of GIS.While SST increased consistently over time in all of the ecosystems observed, the change in number of species differed among ecosystems. The number of species in the middle regions, such as the South European Atlantic Shelf and the Western Mediterranean Sea, tended to increase over time. These regions received numbers of species from the lower or the upper latitudes according to season. Of all of the species observed in the recent period, 7 species from the Canary Current tended to be found in the Western Mediterranean Sea, and 6 species from these two regions extended their distributions to the South European Atlantic Shelf. Twelve species from the Canary Current moved seasonally to the Guinea Current. In the northern regions, 13 species moved seasonally in the North Sea and the Celtic Seas, and 12 of these species reached the South European Atlantic Shelf.This study presents a picture of routes and timing of species migration at the

  12. Decadal and multi-decadal variability of Labrador Sea Water in the north-western North Atlantic Ocean derived from tracer distributions: Heat budget, ventilation, and advection

    NARCIS (Netherlands)

    van Aken, H.M.; de Jong, M.F.; Yashayaev, I.

    2011-01-01

    Time series of profiles of potential temperature, salinity, dissolved oxygen, and planetary potential vorticity at intermediate depths in the Labrador Sea, the Irminger Sea, and the Iceland Basin have been constructed by combining the hydrographic sections crossing the sub-arctic gyre of the North

  13. Predictability of Ice Concentration in the High-Latitude North Atlantic from Statistical Analysis of SST (Sea Surface Temperature) and Ice Concentration Data.

    Science.gov (United States)

    1987-09-01

    Nautical- Metorological Annuals (Yearbooks), Charlottenlund, Copenhagen. Jokill, 1953-67: Reports of sea ice off the Icelandic coasts (Annual reports...Proceeding of 7th annual climate diagnostic workshop (NOAA) pub. Washington, D.C., 189-195. * Weeks, W. F., 1978: Sea ice conditions in the Arctic. In

  14. Tissue and size-related changes in the fatty acid and stable isotope signatures of the deep sea grenadier fish Coryphaenoides armatus from the Charlie-Gibbs Fracture Zone region of the Mid-Atlantic Ridge

    Science.gov (United States)

    Mayor, Daniel J.; Sharples, Caroline J.; Webster, Lynda; Walsham, Pamela; Lacaze, Jean-Pierre; Cousins, Nicola J.

    2013-12-01

    Coryphaenoides armatus is a cosmopolitan deep-sea fish that plays a major role in the ecology of abyssal ecosystems. We investigated the trophic ecology and physiology of this species by determining the δ13C, δ15N and fatty acid signatures of muscle, liver and ovary tissues of individuals collected from ∼2700 m to the north and south of the Charlie-Gibbs Fracture Zone (CGFZ) of the Mid-Atlantic Ridge, NE Atlantic. Fatty acid and δ13C data both suggested that C. armatus shows an ontogenetic dietary shift, with the relative contributions of benthic and pelagic prey decreasing and increasing respectively as the animals grow. They also indicated that dietary overlap between animals living to the north and south of the CGFZ increases as they grow, suggesting that larger animals forage over greater distances and are not hindered by the presence of the CGFZ. Comparison of tissue-specific fatty acid signatures with previously published data suggests compositional homeostasis of the fatty acids 20:5(n-3) and 22:6(n-3) in the muscle, and 18:1(n-9) in the liver tissues. We ascribe this primarily to strict physiological requirements for these compounds, rather than simply to their abundance in the diet. We pose several speculative mechanisms to explain the observed trends in tissue-specific δ13C and δ15N values, illustrating some of the numerous processes that can influence the isotopic signatures of bulk tissues.

  15. Sea Turtle Research Program Summary Report

    National Research Council Canada - National Science Library

    1997-01-01

    The USACE Sea Turtle Research Program (STRP) was conducted to minimize the risk to sea turtle populations in channels along the southeast Atlantic region of the United States from hopper-dredging activities...

  16. Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    尹明端; 曾宪章; 曾文义; 吴世炎; 施纯坦

    2002-01-01

    In this paper, the 18O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ18O value of surface water from the Bering Sea is averagely -0.5‰; the δ18O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ18O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ18O vertical distribution in some deep water stations from the Chukchi Sea and the Bering Sea is also studied. In the southern margin of Canadian Basin, the δ18O value is -2‰ -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ18O is about -0.5‰ for surface layer and increases to 0 at the depth of 300 m. The NO tracer can reflect obviously three water masses vertically distributed in the central Bering Sea: the upper Bering water mass, the middle Bering water mass and the deep Pacific water mass. The distributive ranges of NO and temperature for the various water masses are T780 μmol/dm3 and T≥7℃, NO>650 μmol/dm3 for upper Bering water mass, T<4℃, 550middle Bering water mass, and T<4℃, 330sea bottom. Its isotopic characteristics are the same as the Atlantic water, showing that the sea water comes from the north Atlantic. The freshwater end-member of the Chukchi Sea in the survey period is also explored.

  17. Mid-Holocene Strengthening of the Bering Strait Inflow to the Arctic and its Linkage With the North Atlantic Subpolar Gyre Circulation

    Science.gov (United States)

    Yamamoto, M.; Nam, S. I.; Polyak, L.; Kobayashi, D.; Suzuki, K.; Irino, T.; Shimada, K.

    2017-12-01

    The Bering Strait inflow (BSI) is an important element of the Arctic Ocean circulation system. We report records of the chlorite/illite ratios in three sediment cores from the northern Chukchi Sea providing insights into the long-term dynamics of the BSI during the Holocene. The BSI approximation by the chlorite/illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified. This middle Holocene strengthening of the BSI was coeval with intense subpolar gyre circulation in the North Atlantic. We propose that the BSI is linked with the North Atlantic circulation via an atmospheric teleconnection between the Aleutian and Icelandic Lows.

  18. Summer monsoon rainfall variability over North East regions of India and its association with Eurasian snow, Atlantic Sea Surface temperature and Arctic Oscillation

    Science.gov (United States)

    Prabhu, Amita; Oh, Jaiho; Kim, In-won; Kripalani, R. H.; Mitra, A. K.; Pandithurai, G.

    2017-10-01

    This observational study during the 29-year period from 1979 to 2007 evaluates the potential role of Eurasian snow in modulating the North East-Indian Summer Monsoon Rainfall with a lead time of almost 6 months. This link is manifested by the changes in high-latitude atmospheric winter snow variability over Eurasia associated with Arctic Oscillation (AO). Excessive wintertime Eurasian snow leads to an anomalous cooling of the overlying atmosphere and is associated with the negative mode of AO, inducing a meridional wave-train descending over the tropical north Atlantic and is associated with cooling of this region. Once the cold anomalies are established over the tropical Atlantic, it persists up to the following summer leading to an anomalous zonal wave-train further inducing a descending branch over NE-India resulting in weak summer monsoon rainfall.

  19. Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea

    Directory of Open Access Journals (Sweden)

    J.-B. P. Koehl

    2018-03-01

    Full Text Available The SW Barents Sea margin experienced a pulse of extensional deformation in the Middle–Late Devonian through the Carboniferous, after the Caledonian Orogeny terminated. These events marked the initial stages of formation of major offshore basins such as the Hammerfest and Nordkapp basins. We mapped and analyzed three major fault complexes, (i the Måsøy Fault Complex, (ii the Rolvsøya fault, and (iii the Troms–Finnmark Fault Complex. We discuss the formation of the Måsøy Fault Complex as a possible extensional splay of an overall NE–SW-trending, NW-dipping, basement-seated Caledonian shear zone, the Sørøya–Ingøya shear zone, which was partly inverted during the collapse of the Caledonides and accommodated top–NW normal displacement in Middle to Late Devonian–Carboniferous times. The Troms–Finnmark Fault Complex displays a zigzag-shaped pattern of NNE–SSW- and ENE–WSW-trending extensional faults before it terminates to the north as a WNW–ESE-trending, NE-dipping normal fault that separates the southwesternmost Nordkapp basin in the northeast from the western Finnmark Platform and the Gjesvær Low in the southwest. The WNW–ESE-trending, margin-oblique segment of the Troms–Finnmark Fault Complex is considered to represent the offshore prolongation of a major Neoproterozoic fault complex, the Trollfjorden–Komagelva Fault Zone, which is made of WNW–ESE-trending, subvertical faults that crop out on the island of Magerøya in NW Finnmark. Our results suggest that the Trollfjorden–Komagelva Fault Zone dies out to the northwest before reaching the western Finnmark Platform. We propose an alternative model for the origin of the WNW–ESE-trending segment of the Troms–Finnmark Fault Complex as a possible hard-linked, accommodation cross fault that developed along the Sørøy–Ingøya shear zone. This brittle fault decoupled the western Finnmark Platform from the southwesternmost Nordkapp basin and merged with the

  20. Update on geographic spread of invasive lionfishes (Pterois volitans [Linnaeus, 1758] and P. miles [Bennett, 1828]) in the Western North Atlantic Ocean, Caribbean Sea and Gulf of Mexico

    Science.gov (United States)

    Schofield, Pamela J.

    2010-01-01

    The Indo-Pacific lionfishes (Pterois volitans [Linnaeus, 1758] and P. miles [Bennett, 1828]: Family Scorpaenidae) are the first nonnative marine fishes to establish in the Western North Atlantic/Caribbean region. The chronology of the invasion was reported last year (Schofield 2009) using records from the US Geological Survey's Nonindigenous Aquatic Species database. This article provides an update of lionfish geographic spread (as of October 2010) and predictions of future range.

  1. Pollutant tracking for 3 Western North Atlantic sea grasses by remote sensing: Preliminary diminishing white light responses of Thalassia testudinum, Halodule wrightii, and Zostera marina

    International Nuclear Information System (INIS)

    Thorhaug, Anitra; Berlyn, Graeme P.; Poulos, Helen M.; Goodale, Uromi M.

    2015-01-01

    Highlights: • Sea grass accessory pigments are more important than Chl at medium to low light intensity. • Partial absorption changes in Thalassia and also in Halodule at low intensity visible light ranges. • NDVI and chlNDI do not detect these changes or low light responses of sea grasses. • Intertidal sea grasses are less stressed than the subtidal species at low and high light. • Chl b is an important photosynthetic pigment in tropical/subtropical species. - Abstract: Sea grasses are foundation species for estuarine ecosystems. The available light for sea grasses diminishes rapidly during pollutant spills, effluent releases, disturbances such as intense riverine input, and tidal changes. We studied how sea grasses’ remote-sensing signatures and light-capturing ability respond to short term light alterations. In vivo responses were measured over the entire visible-light spectra to diminishing white-light on whole-living-plants’ spectral reflectance, including 6 h of full oceanic-light fluences from 10% to 100%. We analyzed differences by various reflectance indices. We compared the sea grasses species responses of tropical vs. temperate and intertidals (Halodule wrightii, and Zostera marina) vs. subtidal (Thalassia testudinum). Reflectance diminished with decreasing light intensity that coincided with greater accessory pigment stimulation (anthocyanin, carotenoids, xanthins). Chlorophyll a and Chlorophyll b differed significantly among species (Thalassia vs. Halodule). Photosynthetic efficiency diminished at high light intensities. The NDVI index was inadequate to perceive these differences. Our results demonstrate the leaf-level utility of data to remote sensing for mapping sea grass and sea grass stress

  2. Biomonitoring of heavy metals and arsenic on the east coast of the Middle Adriatic Sea using Mytilus galloprovincialis

    International Nuclear Information System (INIS)

    Orescanin, Visnja; Lovrencic, Ivanka; Mikelic, Luka; Barisic, Delko; Matasin, Zeljka; Lulic, Stipe; Pezelj, Durdica

    2006-01-01

    Results of two years monitoring of heavy metals and arsenic concentrations in soft tissue of Mediterranean blue mussel Mytilus galloprovincialis are presented. Samples were taken at six localities (five exposed to various pollution sources and one control site) on the east coast of the Middle Adriatic in October 2003 and 2004 and in April 2004 and 2005. All measurements were carried out with source excited Energy Dispersive X-ray Fluorescence Method (EDXRF). Measured concentrations were in the following ranges: Pb (2-7 mg/kg); As (4-30 mg/kg); Cr (1-2.9 mg/kg); Mn (2-13 mg/kg); Fe (53.4-719 mg/kg); Ni (0.8-5 mg/kg); Cu (3.7-11.1 mg/kg) and Zn (59.1-273 mg/kg). Maximum values of the most elements were measured in samples from the most polluted Vranjic region. Statistically significant difference among six localities (p = 0.05) was found for As, Fe and Zn while Mn, Fe and Cu showed significantly higher concentrations in spring period. None of the selected elements showed significant difference between the control and exposed regions

  3. Mountains in the Sea - Exploring the New England Seamount Chain on RV Atlantis in North Atlantic Ocean between 20030711 and 20030719

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This summer, an interdisciplinary scientific team spent 9 days aboard the Woods Hole Oceanographic Institution's research vessel Atlantis II and used the deep-sea...

  4. SEA SURFACE TEMPERATURE and Other Data from AIRCRAFT From NW Atlantic (limit-40 W) from 19761209 to 19761211 (NCEI Accession 7700021)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is Sea Surface Temperature data collected by United States coast guard (USCG), Groton, CT, US. Data was collected between December 9-11, 1976 over the NW...

  5. The length-weight and length-length relationships of bluefish, Pomatomus saltatrix (Linnaeus, 1766 from Samsun, middle Black Sea region

    Directory of Open Access Journals (Sweden)

    Melek Özpiçak

    2017-10-01

    Full Text Available In this study, length-weight relationship (LWR and length-length relationship (LLR of bluefish, Pomatomus saltatrix were determined. A total of 125 specimens were sampled from Samsun, the middle Black Sea in 2014 fishing season. Bluefish specimens were monthly collected from commercial fishing boats from October to December 2014. All captured individuals (N=125 were measured to the nearest 0.1 cm for total, fork and standard lengths. The weight of each fish (W was recorded to the nearest 0.01 g. According to results of analyses, there were no statistically significant differences between sexes in term of length and weight (P˃0.05. The minimum and maximum total, fork and standard lengths of bluefish ranged between 13.5-23.6 cm, 12.50-21.80 cm and 10.60-20.10 cm, respectively. The equation of length-weight relationship were calculated as W=0.008TL3.12 (r2>0.962. Positive allometric growth was observed for bluefish (b>3. Length-length relationship was also highly significant (P<0.001 with coefficient of determination (r2 ranging from 0.916 to 0.988.

  6. Natural variability of parasite communities of Macrouridae of the middle and lower slope of the Mediterranean Sea and their relation with fish diet and health indicators

    Science.gov (United States)

    Pérez-i-García, D.; Constenla, M.; Soler-Membrives, A.; Cartes, J. E.; Solé, M.; Carrassón, M.

    2017-06-01

    This study examines the parasite communities of Coelorinchus caelorhincus, Coelorinchus mediterraneus, Coryphaenoides guentheri and Coryphaenoides mediterraneus of the middle and lower slopes of the Mediterranean Sea. Histopathological, enzymatic activity (acetylcholinesterase and lactate dehydrogenase), dietary and environmental (oxygen, salinity, temperature and turbidity) information were also obtained. A total of 11 parasite taxa were found in the four fish species, the copepod Hamaticolax resupinus being the only parasite shared by all of them. Coelorinchus mediterraneus, Coryphaenoides guentheri and Cor. mediterraneus exhibited rather homogeneous parasite communities, especially in the case of the latter two. Coelorinchus mediterraneus showed the highest richness of parasite taxa (eight species), whereas C. guentheri and Cor. mediterraneus harboured up to five and six, respectively, and C. caelorhincus up to three. Several of the parasites encountered occurred at very low prevalences (level, probably due to the low parasite burden in their hosts. It is possible that the major role of small macrourids, especially C. guentheri, is to act as an intermediate hosts in deep-Mediterranean trophic webs.

  7. Isotope paleoclimatology and Atlantic deep water history since 15 million years

    International Nuclear Information System (INIS)

    Blanc, P.L.

    1981-12-01

    18 O/ 16 O and 13 C/ 12 C ratios measurements in foraminiferal calcite are applied to the paleoclimatology of the North Atlantic and to the reconstruction of deep water exchanges between the Atlantic and Pacific Oceans, from middle miocene time (15 m.y. ago) to the present, on samples from 2 DSDP wells. Chapters 1 to 4 describe the structural frame and hydrological setting of these sites, and the stratigraphy of the deposits. A .4 m.y. lag between the initiation of the first boreal ice-caps and their extension to northern Europe is explained by the persistency of the North-Atlantic Drift. In chapters 5 to 8, the 13 C/ 12 C ratio of dissolved mineral carbon is used as a tracer of the residence time of the deep waters, the indications of which are preserved in benthonic foraminiferal calcite. It is shown that present-day type thermo-haline circulation was initiated 13.2 m.y. ago in the northern Atlantic, when the volcanic Scotland-Iceland-Greenland ridge subsided; that the closure of the Mediterranean sea during the Messinian (6.2 to 5 m.y. ago) caused this circulation to stop, and that the present circulation started again when the Mediterranean re-opened, at the beginning of the Pliocene [fr

  8. Disease resistance in Atlantic salmon (Salmo salar: coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Directory of Open Access Journals (Sweden)

    Jean Paul Lhorente

    Full Text Available BACKGROUND: Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1 coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2 coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. METHODOLOGY: In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI of P. salmonis (primary pathogen or coinfection with C. rogercresseyi (secondary pathogen. Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish. Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. MAIN FINDINGS: C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545. Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07. A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01 but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34. CONCLUSIONS/SIGNIFICANCE: C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future

  9. Disease resistance in Atlantic salmon (Salmo salar): coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Science.gov (United States)

    Lhorente, Jean Paul; Gallardo, José A; Villanueva, Beatriz; Carabaño, María J; Neira, Roberto

    2014-01-01

    Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01) but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34). C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on salmon farming, selective breeding and conservation.

  10. Assessment of contaminant concentrations in sediments, fish and mussels sampled from the North Atlantic and European regional seas within the ICON project.

    Science.gov (United States)

    Robinson, Craig D; Webster, Lynda; Martínez-Gómez, Concepción; Burgeot, Thierry; Gubbins, Matthew J; Thain, John E; Vethaak, A Dick; McIntosh, Alistair D; Hylland, Ketil

    2017-03-01

    Understanding the status of contaminants in the marine environment is a requirement of European Union Directives and the Regional Seas Conventions, so that measures to reduce pollution can be identified and their efficacy assessed. The international ICON workshop (Hylland et al., in this issue) was developed in order to test an integrated approach to assessing both contaminant concentrations and their effects. This paper describes and assesses the concentrations of trace metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in sediments, mussels, and fish collected from estuarine, coastal and offshore waters from Iceland to the Mediterranean Sea. For organic contaminants, concentrations progressively increased from Iceland, to the offshore North Sea, to the coastal seas, and were highest in estuaries. Metals had a more complex distribution, reflecting local anthropogenic inputs, natural sources and hydrological conditions. Use of internationally recognised assessment criteria indicated that at no site were concentrations of all contaminants at background and that concentrations of some contaminants were of significant concern in all areas, except the central North Sea. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  11. An Atlantic streamer in stratospheric ozone observations and SD-WACCM simulation data

    Science.gov (United States)

    Hocke, Klemens; Schranz, Franziska; Maillard Barras, Eliane; Moreira, Lorena; Kämpfer, Niklaus

    2017-03-01

    Observation and simulation of individual ozone streamers are important for the description and understanding of non-linear transport processes in the middle atmosphere. A sudden increase in mid-stratospheric ozone occurred above central Europe on 4 December 2015. The GROund-based Millimeter-wave Ozone Spectrometer (GROMOS) and the Stratospheric Ozone MOnitoring RAdiometer (SOMORA) in Switzerland measured an ozone enhancement of about 30 % at 34 km altitude (8.3 hPa) from 1 to 4 December. A similar ozone increase is simulated by the Specified Dynamics Whole Atmosphere Community Climate (SD-WACCM) model. Further, the global ozone fields at 34 km altitude (8.3 hPa) from SD-WACCM and the satellite experiment Aura/MLS show a remarkable agreement for the location and timing of an ozone streamer (large-scale tongue-like structure) extending from the subtropics in northern America over the Atlantic to central Europe. This agreement indicates that SD-WACCM can inform us about the wind inside the Atlantic ozone streamer. SD-WACCM shows an eastward wind of about 100 m s-1 inside the Atlantic streamer in the mid-stratosphere. SD-WACCM shows that the Atlantic streamer flows along the edge of the polar vortex. The Atlantic streamer turns southward at an erosion region of the polar vortex located above the Caspian Sea. The spatial distribution of stratospheric water vapour indicates a filament outgoing from this erosion region. The Atlantic streamer, the polar vortex erosion region and the water vapour filament belong to the process of planetary wave breaking in the so-called surf zone of the northern midlatitude winter stratosphere.

  12. Atlantic CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    R. Steinfeldt

    2010-01-01

    Full Text Available Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic. In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC. The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl4. The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor'' quality flag.

  13. Gigantic oocytes in the deep sea black coral Dendrobathypathes grandis (Antipatharia) from the Mar del Plata submarine canyon area (southwestern Atlantic)

    Science.gov (United States)

    Lauretta, Daniel; Penchaszadeh, Pablo E.

    2017-10-01

    The black coral Dendrobathypathes grandis (Cnidaria: Antipatharia) is studied for the first time in the southwestern Atlantic off Argentina. This is the only antipatharian reported from the Atlantic between 35°S and 54°S. Eleven specimens were collected at depths of 819-2204 m during three expeditions to the Mar del Plata submarine canyon (2012-2013); seven were females. The species is gonochoric, and the polyps in female colonies contain up to nine oocytes per polyp, which can reach 1500 μm in diameter. In contrast, the largest oocyte currently reported for antipatharians is 500 μm, and usual diameters do not exceed 200 μm. These large oocytes have over 20 times more volume than the biggest oocyte reported, but over 800 times more volume when compared with the common oocyte size of the group. Sperm size and morphology is similar to previous data from other species. As in previous studies, neither embryos nor larvae were found in any specimens. This species was previously only reported from waters off South Georgia Island, and so these specimens expand the known distribution north by 1800 km.

  14. Population structure of Atlantic Mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    Atlantic mackerel (Scomber scombrus) occurs on both sides of the north Atlantic and has traditionally been grouped into 5 spawning components, some of which were thought to be isolated natal homing stocks. Previous studies have provided no evidence for cross Atlantic migration and no or weak...... between the North Sea and Celtic Sea, which indicates that the two spawning components may be connected by straying individuals. This finding is based on unique larvae samples collected before the collapse of North Sea component, thus showing that the exchange is not a recent phenomenon due...... to the collapse. The analyses of old as well as more recent age distributions show that strong year classes spread into other areas where they spawn as adults (“twinning”). Our findings are in accordance with the lack of solid evidence for stock separation from previous analyses of tagging data, genetics...

  15. Sub-basin-scale sea level budgets from satellite altimetry, Argo floats and satellite gravimetry: a case study in the North Atlantic Ocean

    NARCIS (Netherlands)

    Kleinherenbrink, M.; Riva, R.E.M.; Sun, Y.

    2016-01-01

    . In this study, for the first time, an attempt is made to close the sea level budget on a sub-basin scale in terms of trend and amplitude of the annual cycle. We also compare the residual time series after removing the trend, the semiannual and the annual signals. To obtain errors for altimetry and

  16. Assessment of contaminant concentrations in sediments, fish and mussels sampled from the North Atlantic and European regional seas within the ICON project

    NARCIS (Netherlands)

    Robinson, Craig D.; Webster, Lynda; Martínez-Gómez, Concepción; Burgeot, Thierry; Gubbins, Matthew J.; Thain, John E.; Vethaak, A. Dick; McIntosh, Alistair D.; Hylland, Ketil

    Understanding the status of contaminants in the marine environment is a requirement of European Union Directives and the Regional Seas Conventions, so that measures to reduce pollution can be identified and their efficacy assessed. The international ICON workshop (Hylland et al., in this issue) was

  17. Long-term hydrothermal temperature and pressure monitoring equipped with a Kuroko cultivation apparatus on the deep-sea artificial hydrothermal vent at the middle Okinawa Trough

    Science.gov (United States)

    Masaki, Y.; Nozaki, T.; Saruhashi, T.; Kyo, M.; Sakurai, N.; Yokoyama, T.; Akiyama, K.; Watanabe, M.; Kumagai, H.; Maeda, L.; Kinoshita, M.

    2017-12-01

    The middle Okinawa Trough, located along the Ryukyu- arc on the margin of the East China Sea, has several active hydrothermal fields. From February to March 2016, Cruise CK16-01 by D/V Chikyu targeted the Iheya-North Knoll and southern flank of the Iheya Minor Ridge to comprehend sub-seafloor geological structure and polymetallic sulfide mineralization. In this cruise, we installed two Kuroko cultivation apparatuses equipped with P/T sensors, flowmeter and load cell to monitor pressure, temperature and flow rate of hydrothermal fluid discharged from the artificial hydrothermal vent together with weight of hydrothermal precipitate. During Cruise KR16-17 in January 2017, two cultivation cells with sensor loggers were successfully recovered by ROV Kaiko MK-IV and R/V Kairei. We report these physical sensor data obtained by more than 10 months monitoring at two deep-sea artificial hydrothermal vents through many first and challenging operations.Hole C9017B at southern flank of the Iheya Minor Ridge (water depth of 1,500 mbsl), fluid temperature was constant ca. 75 ºC for 5 months from the beginning of monitoring. Then temperature gradually decrease to be 40 ºC. In November 2016, temperature and pressure suddenly dropped and quickly recovered due to the disturbance of subseafloor hydrology, induced by another drilling operation at Hole C9017A which is 10.8 meters northeastward from Hole C9017B during Cruise CK16-05. Temperature data exhibit conspicuous periodic 12.4hour cycles and this is attributable to oceanic tidal response. The amplitude of temperature variations increased along with decline of the temperature variations increased along with decline of the temperature. The average flow rate was 67 L/min for 9 hours from the onset of monitoring.Hole C9024A at the Iheya-North Knoll (water depth of 1,050 msl), the maximum temperature reached 308 ºC, which is similar to the maximum value of 311 ºC obtained from the ROV thermometer. The average flow rate was 289 L

  18. Metal contamination as a possible etiology of fibropapillomatosis in juvenile female green sea turtles Chelonia mydas from the southern Atlantic Ocean.

    Science.gov (United States)

    da Silva, Cinthia Carneiro; Klein, Roberta Daniele; Barcarolli, Indianara Fernanda; Bianchini, Adalto

    2016-01-01

    Environmental contaminants have been suggested as a possible cause of fibropapillomatosis (FP) in green sea turtles. In turn, a reduced concentration of serum cholesterol has been indicated as a reliable biomarker of malignancy in vertebrates, including marine turtles. In the present study, metal (Ag, Cd, Cu, Fe, Ni, Pb and Zn) concentrations, oxidative stress parameters [antioxidant capacity against peroxyl radicals (ACAP), protein carbonyls (PC), lipid peroxidation (LPO), frequency of micronucleated cells (FMC)], water content, cholesterol concentration and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) activity were analyzed in the blood/serum of juvenile (29.3-59.5cm) female green sea turtles (Chelonia mydas) with FP (n=14) and without FP (n=13) sampled at Ubatuba coast (São Paulo State, southeastern Brazil). Green sea turtles were grouped and analyzed according to the severity of tumors. Individuals heavily afflicted with FP showed significantly higher blood Cu, Pb and Fe concentrations, blood LPO levels, as well as significantly lower serum cholesterol concentrations and HMGR activity than turtles without FP. Significant and positive correlations were observed between HMGR activity and cholesterol concentrations, as well as LPO levels and Fe and Pb concentrations. In turn, Cu and Pb concentrations were significantly and negatively correlated with HMGR activity and cholesterol concentration. Furthermore, Cu, Fe and Pb were positively correlated with each other. Therefore, the reduced concentration of serum cholesterol observed in green sea turtles heavily afflicted with FP is related to a Cu- and Pb-induced inhibition of HMGR activity paralleled by a higher LPO rate induced by increased Fe and Pb concentrations. As oxidative stress is implicated in the pathogenesis of viral infections, our findings support the idea that metal contamination, especially by Cu, Fe and Pb, may be implicated in the etiology of FP in green sea turtles through oxidative stress

  19. Influence of Atlantic SST anomalies on the atmospheric circulation in the Atlantic-European sector

    Directory of Open Access Journals (Sweden)

    E. Kestenare

    2003-06-01

    Full Text Available Recent studies of observational data suggest that Sea Surface Temperature (SST anomalies in the Atlantic Ocean have a significant influence on the atmospheric circulation in the Atlantic-European sector in early winter and in spring. After reviewing this work and showing that the spring signal is part of a global air-sea interaction, we analyze for comparison an ensemble of simulations with the ECHAM4 atmospheric general circulation model in T42 resolution forced by the observed distribution of SST and sea ice, and a simulation with the ECHAM4/OPA8 coupled model in T30 resolution. In the two cases, a significant influence of the Atlantic on the atmosphere is detected in the Atlantic-European sector. In the forced mode, ECHAM4 responds to SST anomalies from early spring to late summer, and also in early winter. The forcing involves SST anomalies not only in the tropical Atlantic, but also in the whole tropical band, suggesting a strong ENSO influence. The modeled signal resembles that seen in the observations in spring, but not in early winter. In the coupled mode, the Atlantic SST only has a significant influence on the atmosphere in summer. Although the SST anomaly is confined to the Atlantic, the summer signal shows some similarity with that seen in the forced simulations. However, there is no counterpart in the observations.

  20. Quantifying changes in abundance, biomass and spatial distribution of Northeast Atlantic (NEA) mackerel (Scomber scombrus) in the Nordic Seas from 2007 to 2014

    DEFF Research Database (Denmark)

    Nøttestad, Leif; Utne, Kjell Rong; Óskarsson, Gudmundur .J.

    2016-01-01

    The Northeast Atlantic (NEA) mackerel (Scomber scombrus) is a widely distributed pelagic fish species that plays a key role in the marine ecosystem. In recent years, there has been a large fishery targeting mackerel in the NEA. At the same time as the geographic range of the mackerel fishery has...... on coordinated and standardized swept-area surface trawling in July–August from IESSNS increased from 1.96 million t [relative standard error (RSE) ¼ 30.35%] in 2007 to 8.77 million t (RSE ¼ 7.95%) in 2014. Simultaneously, the mackerel stock expanded its geographic range during the feeding season from 1......%). Furthermore, evaluation of the performance of the estimated abundance indices by age for this time-series, based on internal consistency and catch curves, suggest that the abundance indices of ages 3–12 track the temporal variation in abundance reasonably, and thus is applicable for stock assessments...

  1. Effects of cold-water corals on fish diversity and density (European continental margin: Arctic, NE Atlantic and Mediterranean Sea): Data from three baited lander systems

    Science.gov (United States)

    Linley, T. D.; Lavaleye, M.; Maiorano, P.; Bergman, M.; Capezzuto, F.; Cousins, N. J.; D'Onghia, G.; Duineveld, G.; Shields, M. A.; Sion, L.; Tursi, A.; Priede, I. G.

    2017-11-01

    Autonomous photographic landers are a low-impact survey method for the assessment of mobile fauna in situations where methods such as trawling are not feasible or ethical. Three institutions collaborated through the CoralFISH project, each using differing lander systems, to assess the effects of cold-water corals on fish diversity and density. The Biogenic Reef Ichthyofauna Lander (BRIL, Oceanlab), Autonomous Lander for Biological Experiments (ALBEX, NIOZ) and the Marine Environment MOnitoring system (MEMO, CoNISMa) were deployed in four CoralFISH European study regions covering the Arctic, NE Atlantic and Mediterranean, namely Northern Norway (275-310 m depth), Belgica Mound Province (686-1025 m depth), the Bay of Biscay (623-936 m depth), and Santa Maria di Leuca (547-670 m depth). A total of 33 deployments were carried out in the different regions. Both the time of first arrival (Tarr) and the maximum observed number of fish (MaxN) were standardised between the different lander systems and compared between coral and reference stations as indicators of local fish density. Fish reached significantly higher MaxN at the coral stations than at the reference stations. Fish were also found to have significantly lower Tarr in the coral areas in data obtained from the BRIL and MEMO landers. All data indicated that fish abundance is higher within the coral areas. Fish species diversity was higher within the coral areas of Atlantic Ocean while in Northern Norway and Santa Maria di Leuca coral areas, diversity was similar at coral and reference stations but a single dominant species (Brosme brosme and Conger conger respectively) showed much higher density within the coral areas. Indicating that, while cold-water coral reefs have a positive effect on fish diversity and/or abundance, this effect varies across Europe's reefs.

  2. Evaluation of the Atlantic Multidecadal Oscillation Impact on Large-Scale Atmospheric Circulation in the Atlantic Region in Summer

    Science.gov (United States)

    Semenov, V. A.; Cherenkova, E. A.

    2018-02-01

    The influence of the Atlantic Multidecadal Oscillation (AMO) on large-scale atmospheric circulation in the Atlantic region in summer for the period of 1950-2015 is investigated. It is shown that the intensification of the summer North Atlantic Oscillation (NAO) with significant changes in sea level pressure anomalies in the main centers of action (over Greenland and the British Isles) occurred while the North Atlantic was cooler. Sea surface temperature anomalies, which are linked to the AMO in the summer season, affect both the NAO index and fluctuations of the Eastern Atlantic/Western Russia (EAWR) centers of action. The positive (negative) phase of the AMO is characterized by a combination of negative (positive) values of the NAO and EAWR indices. The dominance of the opposite phases of the teleconnection indices in summer during the warm North Atlantic and in its colder period resulted in differences in the regional climate in Europe.

  3. 77 FR 33443 - Mid-Atlantic Fishery Management Council (MAFMC); Meeting

    Science.gov (United States)

    2012-06-06

    ...-Atlantic Fishery Management Council's (Council) Summer Flounder, Scup, Black Sea Bass, and Bluefish... Summer Flounder, Scup, Black Sea Bass, and Bluefish. Although non-emergency issues not contained in this...

  4. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-10-26

    ...) of scup, 184,280 lb (83,588 kg) of black sea bass, and 200,000 lb (90,718 kg) of bluefish. Project... summer flounder, scup, black sea bass, longfin squid, butterfish, and Atlantic bluefish, and assessment...

  5. Holocene sedimentary processes in the Gemlik Gulf: a transtensional basin on the middle Strand of the North Anatolian Fault, Sea of Marmara

    Science.gov (United States)

    Özmaral, A.; Çagatay, M. N.; Imren, C.; Gasperini, L.; Henry, P.

    2012-04-01

    Gemlik Gulf is an oval-shaped transtensional basin with a maximum depth of 113 m, located on the middle strand of the North Anatolian Fault (NAF) in the eastern part of the Sea of Marmara (SOM). During the last glacial period until the Holocene marine transgression about 12 ka BP, the sea level was below the Çanakkale (Dardanelles) Strait's bedrock sill depth of -85 m, and the Gemlik Basin became a lake isolated lake from the rest of the Sea of Marmara "Lake" and the global ocean. The high resolution seismic profiles and the multi- beam bathymetric map of the basin show that the basin is characterized by NW-SE trending transtensional oblique faults, delta lobes of the Büyükdere (Kocadere) to the east and an erosional surface below an up to 15 m-thick Holocene mud drape. The Holocene mud drape was studied in up to 9.5 m-long gravity-piston and 0.84 m-long sediment/water interface cores located at -105 to -113 m in the basin's depocentre. The Holocene mud consists mainly of plastic gray green marine clayey mud that includes thick-red brown clay layers and a laminated organic-rich, dark olive green sapropel in the lower part, which was previously dated at 11.6-6.4 14Ckyr (uncalib) BP. Multi-proxy analyses of the Holocene mud drape in the sediment cores were carried out using Multisensor Core Logger, XRF Core Scanner equipped with digital X-Ray radiography, and laser particle size analyzer. Seismic-core correlation was made using seismic data of the chirp profiles at the core locations and the synthetic seismograms generated using the MSCL P-wave velocity and gamma density measurements. The long piston-gravity cores include five 20 to 100 mm-thick "red brown mud layers" in the top 2.5 m of the core. These layers have a sharp basal boundary and gradational upper boundary. The red brown layers consist of 55-75% clay-size material with an average grain size of 3-4 µm, and have relatively a high magnetic susceptibility. They are enriched in K, Fe, Ti and Zr that are

  6. Hydrogen sulphide eruptions in the Atlantic Ocean off southern Africa: implications of a new view based on SeaWiFS satellite imagery

    Science.gov (United States)

    Weeks, Scarla J.; Currie, Bronwen; Bakun, Andrew; Peard, Kathleen R.

    2004-02-01

    Conventional wisdom has held that eruptions of toxic hydrogen sulphide that occur from time to time in the ocean off southwestern Africa were rather isolated near-coastal features, limited both in extent and in ecosystem-scale consequences. Now, however, it has become possible to identify sulphide outbreaks by satellite remote sensing. This new capability appears to lead to a complete revision of the conventional view, with some eruption episodes being observed to affect areas of ocean surface exceeding 20,000 km 2. The occurrences are also seen to be more frequent and longer lasting than previously supposed. Example sequences of Sea-viewing Wide Field of View (SeaWiFS) images are presented to indicate general classes of eruption types that are observed and to support discussion of potential eruption mechanisms. Certain methodological problems in interpreting effects on local productivity are outlined. Spatial configurations of eruptions indicate that simple upward advection in the upwelling process may not be a sufficient explanation for the range of eruption characteristics experienced. Eruptions seem often to be coincident with one of two contrasting types of atmospheric weather situation: either (1) increased intensity of wind driven coastal upwelling, or (2) indications of passage of a low pressure weather cell (e.g. interruption of coastal upwelling, sudden warming of the sea surface, rainfall in the hinterland). Such a pattern may imply that related lowering of hydrostatic pressure at depth may tend to trigger incipient eruptions. It also suggests an episodic mechanism driven by the buoyancy introduced by the effervescence of gases trapped by hydrostatic pressure within the sea-floor sediments. Connotations of these phenomena to the local ecology and to that of the entire Benguela Current regional ecosystem would appear to be major. Their relevance to the valuable but extremely variable fishery resource populations of the region, which have undergone drastic

  7. Structure and Evolution of Thermohaline Staircases in Tropical North Atlantic

    National Research Council Canada - National Science Library

    Wall, Steven

    2007-01-01

    .... Salt finger convection is generally observed in mid-latitude regions, particularly in the Atlantic Ocean and Mediterranean Sea, between the hase of the mixed layer and the top of the intermediate water...

  8. Are North Atlantic Multidecadal SST Anomalies Westward Propagating?

    NARCIS (Netherlands)

    Feng, Qingyi; Dijkstra, Hendrik

    2014-01-01

    The westward propagation of sea surface temperature (SST) anomalies is one of the main characteristics of one of the theories of the Atlantic Multidecadal Oscillation. Here we use techniques from complex network modeling to investigate the existence of the westward propagation in the North Atlantic

  9. Comparison of the ocean surface vector winds from atmospheric reanalysis and scatterometer-based wind products over the Nordic Seas and the northern North Atlantic and their application for ocean modeling

    Science.gov (United States)

    Dukhovskoy, Dmitry S.; Bourassa, Mark A.; Petersen, Gudrún Nína; Steffen, John

    2017-03-01

    Ocean surface vector wind fields from reanalysis data sets and scatterometer-derived gridded products are analyzed over the Nordic Seas and the northern North Atlantic for the time period from 2000 to 2009. The data sets include the National Center for Environmental Prediction Reanalysis 2 (NCEPR2), Climate Forecast System Reanalysis (CFSR), Arctic System Reanalysis (ASR), Cross-Calibrated Multiplatform (CCMP) wind product version 1.1 and recently released version 2.0, and QuikSCAT. The goal of the study is to assess discrepancies across the wind vector fields in the data sets and demonstrate possible implications of these differences for ocean modeling. Large-scale and mesoscale characteristics of winds are compared at interannual, seasonal, and synoptic timescales. A cyclone tracking methodology is developed and applied to the wind fields to compare cyclone characteristics in the data sets. Additionally, the winds are evaluated against observations collected from meteorological buoys deployed in the Iceland and Irminger Seas. The agreement among the wind fields is better for longer time and larger spatial scales. The discrepancies are clearly apparent for synoptic timescales and mesoscales. CCMP, ASR, and CFSR show the closest overall agreement with each other. Substantial biases are found in the NCEPR2 winds. Numerical sensitivity experiments are conducted with a coupled ice-ocean model forced by different wind fields. The experiments demonstrate differences in the net surface heat fluxes during storms. In the experiment forced by NCEPR2 winds, there are discrepancies in the large-scale wind-driven ocean dynamics compared to the other experiments.

  10. The Opening of the Arctic-Atlantic Gateway: Tectonic, Oceanographic and Climatic Dynamics - an IODP Initiative

    Science.gov (United States)

    Geissler, Wolfram; Knies, Jochen

    2016-04-01

    The modern polar cryosphere reflects an extreme climate state with profound temperature gradients towards high-latitudes. It developed in association with stepwise Cenozoic cooling, beginning with ephemeral glaciations and the appearance of sea ice in the late middle Eocene. The polar ocean gateways played a pivotal role in changing the polar and global climate, along with declining greenhouse gas levels. The opening of the Drake Passage finalized the oceanographic isolation of Antarctica, some 40 Ma ago. The Arctic Ocean was an isolated basin until the early Miocene when rifting and subsequent sea-floor spreading started between Greenland and Svalbard, initiating the opening of the Fram Strait / Arctic-Atlantic Gateway (AAG). Although this gateway is known to be important in Earth's past and modern climate, little is known about its Cenozoic development. However, the opening history and AAG's consecutive widening and deepening must have had a strong impact on circulation and water mass exchange between the Arctic Ocean and the North Atlantic. To study the AAG's complete history, ocean drilling at two primary sites and one alternate site located between 73°N and 78°N in the Boreas Basin and along the East Greenland continental margin are proposed. These sites will provide unprecedented sedimentary records that will unveil (1) the history of shallow-water exchange between the Arctic Ocean and the North Atlantic, and (2) the development of the AAG to a deep-water connection and its influence on the global climate system. The specific overarching goals of our proposal are to study: (1) the influence of distinct tectonic events in the development of the AAG and the formation of deep water passage on the North Atlantic and Arctic paleoceanography, and (2) the role of the AAG in the climate transition from the Paleogene greenhouse to the Neogene icehouse for the long-term (~50 Ma) climate history of the northern North Atlantic. Getting a continuous record of the

  11. Fishing effects in northeast Atlantic shelf seas : patterns in fishing effort, diversity and community structure. III. International trawling effort in the North Sea : an analysis of spatial and temporal trends

    DEFF Research Database (Denmark)

    Jennings, S.; Alsväg, J.; Cotter, A.J.R.

    1999-01-01

    of beam trawling effort increases from north to south. Plots of annual fishing effort by ICES statistical rectangle (211 boxes of 0.5 degrees latitude x 1 degrees longitude) indicate that the majority of fishing effort in the North Sea are concentrated in a very few rectangles. Thus mean annual total...

  12. Twentieth century North Atlantic climate change. Part II: Understanding the effect of Indian Ocean warming

    Energy Technology Data Exchange (ETDEWEB)

    Hoerling, M.P.; Xu, T.; Bates, G.T. [Climate Diagnostics Center NOAA, Boulder, CO 80305-3328 (United States); Hurrell, J.W.; Phillips, A.S. [National Center for Atmospheric Research, Boulder, CO (United States)

    2004-09-01

    Ensembles of atmospheric general circulation model (AGCM) experiments are used in an effort to understand the boreal winter Northern Hemisphere (NH) extratropical climate response to the observed warming of tropical sea surface temperatures (SSTs) over the last half of the twentieth Century. Specifically, we inquire about the origins of unusual, if not unprecedented, changes in the wintertime North Atlantic and European climate that are well described by a linear trend in most indices of the North Atlantic Oscillation (NAO). The simulated NH atmospheric response to the linear trend component of tropic-wide SST change since 1950 projects strongly onto the positive polarity of the NAO and is a hemispheric pattern distinguished by decreased (increased) Arctic (middle latitude) sea level pressure. Progressive warming of the Indian Ocean is the principal contributor to this wintertime extratropical response, as shown through additional AGCM ensembles forced with only the SST trend in that sector. The Indian Ocean influence is further established through the reproducibility of results across three different models forced with identical, idealized patterns of the observed warming. Examination of the transient atmospheric adjustment to a sudden ''switch-on'' of an Indian Ocean SST anomaly reveals that the North Atlantic response is not consistent with linear theory and most likely involves synoptic eddy feedbacks associated with changes in the North Atlantic storm track. The tropical SST control exerted over twentieth century regional climate underlies the importance of determining the future course of tropical SST for regional climate change and its uncertainty. Better understanding of the extratropical responses to different, plausible trajectories of the tropical oceans is key to such efforts. (orig.)

  13. Two new species of Syndesmis (Platyhelminthes, Rhabdocoela, Umagillidae from the sea urchin Pseudechinus magellanicus (Echinodermata, Echinoidea in the Southwestern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Francisco Brusa

    2017-08-01

    Full Text Available In this paper, we describe two new species of Syndesmis living in Pseudechinus magellanicus in the Southwest Atlantic Ocean. The new species have a long stylet in the male reproductive system, which is different from that of the known species of the genus. Specimens of Syndesmis selknami n. sp. have a ∼220-μm-long stylet (∼1/3 of the body length, 0.69 mm. This ratio is unique because only four species (Syndesmis echinorum, Syndesmis rubida, Syndesmis inconspicua and Syndesmis echiniacuti have similar stylet lengths but are larger in body sizes (3–5 mm. Specimens of Syndesmis aonikenki n. sp. have a ∼148-μm-long stylet (∼1/10 of the body length, 1.11 mm. Syndesmis pallida has a similar ratio but the uterus is located posteriorly, and the filament glands are very small and located in the posterior region of the body. These are the first flatworms reported parasitizing Pseudechinus magellanicus.

  14. Deep-sea parasitic nematodes of the genus Trophomera Rubtsov et Platonova, 1974 (Benthimermithidae) from the Equatorial Atlantic, with the descriptions of two new species

    Science.gov (United States)

    Miljutin, Dmitry M.

    2011-06-01

    Nematode females of the genus Trophomera (Benthimermithidae) from the collection of the Smithsonian's National Museum of Natural History (Washington, DC, USA) were examined. Nematodes were collected in different parts of the Western Atlantic (Hatteras Abyssal Plain, Brazil Basin, and Argentina Basin) from depths of 467-5,223 m. Two new species are described. Body length of T. americana sp. n. is 3,250-4,470 μm; posterior end conical with rounded tip; cephalic setae about 3-4 μm long; trophosome consisting of several longitudinal rows of large cells; ovaries reflected; mature eggs 35 μm in diameter. Body length of T. longiovaris sp. n. is 7,870-15,400 μm; posterior end conical with rounded tip; cephalic sensilla 7 μm long; mouth opening vestigial, present as very narrow apical pore; pharynx devoid of internal lumen and muscular envelope; midgut represents a trophosome without internal lumen; trophosomal cells arranged in 3-4 longitudinal rows; rectum and anus vestigial; female reproductive system didelphic, amphidelphic, very long, occupying about 0.8 total body length; ovaries telogonic, outstretched; oviducts very long, repeatedly folded across body axis; proximal parts of oviducts being than distal ones, uterus distinctly formed. New finds of two known species, T. arnauidi and T. marionensis, are also recorded and described.

  15. El Niño, Sea Surface Temperature Anomaly and Coral Bleaching in the South Atlantic: A Chain of Events Modeled With a Bayesian Approach

    Science.gov (United States)

    Lisboa, D. S.; Kikuchi, R. K. P.; Leão, Zelinda M. A. N.

    2018-04-01

    Coral bleaching represents one of the main climate-change related threats to reef ecosystems. This research represents a methodological alternative for modeling this phenomenon, focused on assessing uncertainties and complexities with a low number of observations. To develop this model, intermittent reef monitoring data from the largest reef complex in the South Atlantic collected over nine summers between 2000 and 2014 were used with remote sensing data to construct and train a bleaching seasonal prediction model. The Bayesian approach was used to construct the network as it is suitable for hierarchically organizing local thermal variables and combining them with El Niño indicators from the preceding winter to generate accurate bleaching predictions for the coming season. Network count information from six environmental indicators was used to calculate the probability of bleaching, which is mainly influenced by the combined information of two thermal indices; one thermal index is designed to track short period anomalies in the early summer that are capable of triggering bleaching (SST of five consecutive days), and the other index is responsible for tracking the accumulation of thermal stress over time, an index called degree heating trimester (DHT). In addition to developing the network, this study conducted the three tests of applicability proposed for model: 1- Perform the forecast of coral bleaching for the summer of 2016; 2- Investigate the role of turbidity during the bleaching episodes; and 3- Use the model information to identify areas with a lower predisposition to bleaching events.

  16. Turtle cleaners: reef fishes foraging on epibionts of sea turtles in the tropical Southwestern Atlantic, with a summary of this association type

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    Full Text Available In the present study we record several instances of reef fish species foraging on epibionts of sea turtles (cleaning symbiosis at the oceanic islands of Fernando de Noronha Archipelago and near a shipwreck, both off the coast of Pernambuco State, northeast Brazil. Nine reef fish species and three turtle species involved in cleaning are herein recorded. Besides our records, a summary of the literature on this association type is presented. Postures adopted by turtles during the interaction are related to the habits of associated fishes. Feeding associations between fishes and turtles seem a localized, albeit common, phenomenon.

  17. Seasonal influence of ENSO on the Atlantic ITCZ and equatorial South America

    Science.gov (United States)

    Münnich, M.; Neelin, J. D.

    2005-11-01

    In late boreal spring, especially May, a strong relationship exists in observations among precipitation anomalies over equatorial South America and the Atlantic intertropical convergence zone (ITCZ), and eastern equatorial Pacific and central equatorial Atlantic sea surface temperature anomalies (SSTA). A chain of correlations of equatorial Pacific SSTA, western equatorial Atlantic wind stress (WEA), equatorial Atlantic SSTA, sea surface height, and precipitation supports a causal chain in which El Niño/Southern Oscillation (ENSO) induces WEA stress anomalies, which in turn affect Atlantic equatorial ocean dynamics. These correlations show strong seasonality, apparently arising within the atmospheric links of the chain. This pathway and the influence of equatorial Atlantic SSTA on South American rainfall in May appear independent of that of the northern tropical Atlantic. Brazil's Nordeste is affected by the northern tropical Atlantic. The equatorial influence lies further to the north over the eastern Amazon and the Guiana Highlands.

  18. North atlantic multidecadal climate variability: An investigation of dominant time scales and processes

    NARCIS (Netherlands)

    Frankcombe, L.M.|info:eu-repo/dai/nl/304829838; von der Heydt, A.S.|info:eu-repo/dai/nl/245567526; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467

    2010-01-01

    The issue of multidecadal variability in the North Atlantic has been an important topic of late. It is clear that there are multidecadal variations in several climate variables in the North Atlantic, such as sea surface temperature and sea level height. The details of this variability, in particular

  19. Catch and post-release mortalities of deep-water sharks caught by bottom longlines in the Cantabrian Sea (NE Atlantic)

    Science.gov (United States)

    Rodríguez-Cabello, Cristina; Sánchez, Francisco

    2017-12-01

    The majority of deep-water fish have very low capacity to survive discarding as fishery bycatch due to their biological characteristics and adaptation to depth. This study explores the catch and post-release mortalities of several deep-water shark species caught by bottom longline in the El Cachucho (Le Danois Bank) MPA in northern Spanish waters (NE Atlantic). Survivorship was qualitatively evaluated according to health condition and responses of individuals after capture and subsequent release. A total of 15 species were caught, of which the most abundant were leafscale gulper shark Centrophorus squamosus (39%), birdbeak dogfish Deania calcea (39%) and Portuguese dogfish Centroscymnus coelolepis (10%). Catch or at-vessel mortality (AVM) for these species was lower than expected, 1.2%, 8.8% and 4.5%, respectively but 18.9%, 37.4% and 38.6% including both those specimens dead on retrieval and those scored in poor condition). The species with the highest vitality rate was C. squamosus (37.3% in good condition; 43.8% in moderate condition), followed by D. calcea (22.8% in good condition; 39.8% in moderate condition) and C. coelolepis (6.8% and 54.5%). Post-release mortality (PRM) was examined using electronic tags (PSATs, n = 14). Of the nine C. squamosus tagged successfully, three died within 5-10 weeks after release, whereas the other six survived for periods of at least 45-120 days, when tags were programmed to release). In the case of C. coelolepis, two of the four tagged specimens died almost immediately after release, whereas the other two tags indicated that the fish survived immediate release, but data were too limited to gauge survival due to tag failure.

  20. Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves.

    Directory of Open Access Journals (Sweden)

    Magdalene N Ngeve

    Full Text Available Mangroves are seafaring taxa through their hydrochorous propagules that have the potential to disperse over long distances. Therefore, investigating their patterns of gene flow provides insights on the processes involved in the spatial genetic structuring of populations. The coastline of Cameroon has a particular geomorphological history and coastal hydrology with complex contemporary patterns of ocean currents, which we hypothesize to have effects on the spatial configuration and composition of present-day mangroves within its spans. A total of 982 trees were sampled from 33 transects (11 sites in 4 estuaries. Using 11 polymorphic SSR markers, we investigated genetic diversity and structure of Rhizophora racemosa, a widespread species in the region. Genetic diversity was low to moderate and genetic differentiation between nearly all population pairs was significant. Bayesian clustering analysis, PCoA, estimates of contemporary migration rates and identification of barriers to gene flow were used and complemented with estimated dispersal trajectories of hourly released virtual propagules, using high-resolution surface current from a mesoscale and tide-resolving ocean simulation. These indicate that the Cameroon Volcanic Line (CVL is not a present-day barrier to gene flow. Rather, the Inter-Bioko-Cameroon (IBC corridor, formed due to sea level rise, allows for connectivity between two mangrove areas that were isolated during glacial times by the CVL. Genetic data and numerical ocean simulations indicated that an oceanic convergence zone near the Cameroon Estuary complex (CEC presents a strong barrier to gene flow, resulting in genetic discontinuities between the mangrove areas on either side. This convergence did not result in higher genetic diversity at the CEC as we had hypothesized. In conclusion, the genetic structure of Rhizophora racemosa is maintained by the contrasting effects of the contemporary oceanic convergence and historical climate

  1. Relative sea-level changes and glacio-isostatic adjustment on the Magdalen Islands archipelago (Atlantic Canada) from MIS 5 to the late Holocene

    Science.gov (United States)

    Rémillard, Audrey M.; St-Onge, Guillaume; Bernatchez, Pascal; Hétu, Bernard; Buylaert, Jan-Pieter; Murray, Andrew S.; Lajeunesse, Patrick

    2017-09-01

    The Magdalen Islands (Québec, Canada) in the centre of the Gulf of St. Lawrence are located in a strategic position for providing an overview of the relative sea-level (RSL) history of the Maritime Provinces of eastern Canada. Although data are available for the coastal terrestrial areas of the Maritimes, data from the Gulf are very scarce and both the RSL and glacio-isostatic adjustment (GIA) models extrapolate for this central region. This study provides new stratigraphic and chronological data from four outcrops and two coring sites on the Magdalen Islands. In addition to the five samples used mainly for age control purposes, nine new luminescence ages are presented. With these new data added to the available literature, a new RSL curve is reconstructed for the LGM to the late Holocene period and a partial curve is proposed for the interval between the late MIS 4 to the MIS 3. Data also indicate a few insights for the MIS 5 period. Results reveal that for the LGM to the late Holocene, the curve corresponds to the J-shaped curve scenario recognized in the literature. The RSL changes during this period are the result of glacio-isostatic rebound, migration and collapse of the peripheral forebulge, and eustatic sea-level changes. For the LGM to the early Holocene, glacio-isostatic depression curves displaying a few local differences are also proposed. For the late Holocene, the data constrain the curve between two types of indicators, i.e. marine and terrestrial, and indicate that the RSL has risen at least 3 m during the last two millennia. Sediments dated to the MIS 5 and the interval between the late MIS 4 and the MIS 3 illustrate that the GIA following the LGM also occurred for the MIS 5 interglacial and the MIS 3 interstadial. Finally, recent GIA models are discussed in light of the results of this paper.

  2. Food-web and ecosystem structure of the open-ocean and deep-sea environments of the Azores, NE Atlantic

    Directory of Open Access Journals (Sweden)

    Telmo Morato

    2016-12-01

    Full Text Available The Marine Strategy Framework Directive intends to adopt ecosystem-based management for resources, biodiversity and habitats that puts emphasis on maintaining the health of the ecosystem alongside appropriate human use of the marine environment, for the benefit of current and future generations. Within the overall framework of ecosystem-based management, ecosystem models are tools to evaluate and gain insights in ecosystem properties. The low data availability and complexity of modelling deep-water ecosystems has limited the application of ecosystem models to few deep-water ecosystems. Here, we aim to develop an ecosystem model for the deep-sea and open ocean in the Azores exclusive economic zone with the overarching objective of characterising the food-web and ecosystem structure of the ecosystem. An ecosystem model with 45 functional groups, including a detritus group, two primary producer groups, eight invertebrate groups, 29 fish groups, three marine mammal groups, a turtle and a seabird group was built. Overall data quality measured by the pedigree index was estimated to be higher than the mean value of all published models. Therefore, the model was built with source data of an overall reasonable quality, especially considering the normally low data availability for deep-sea ecosystems. The total biomass (excluding detritus of the modelled ecosystem for the whole area was calculated as 24.7 t km-². The mean trophic level for the total marine catch of the Azores was estimated to be 3.95, similar to the trophic level of the bathypelagic and medium-size pelagic fish. Trophic levels for the different functional groups were estimated to be similar to those obtained with stable isotopes and stomach contents analyses, with some exceptions on both ends of the trophic spectra. Omnivory indices were in general low, indicating prey speciation for the majority of the groups. Cephalopods, pelagic sharks and toothed whales were identified as groups with

  3. Turtle cleaners: reef fishes foraging on epibionts of sea turtles in the tropical Southwestern Atlantic, with a summary of this association type

    Directory of Open Access Journals (Sweden)

    Cristina Sazima

    2010-03-01

    Full Text Available In the present study we record several instances of reef fish species foraging on epibionts of sea turtles (cleaning symbiosis at the oceanic islands of Fernando de Noronha Archipelago and near a shipwreck, both off the coast of Pernambuco State, northeast Brazil. Nine reef fish species and three turtle species involved in cleaning are herein recorded. Besides our records, a summary of the literature on this association type is presented. Postures adopted by turtles during the interaction are related to the habits of associated fishes. Feeding associations between fishes and turtles seem a localized, albeit common, phenomenon.No presente estudo registramos diversos episódios de peixes recifais alimentando-se de epibiontes sobre o corpo de tartarugas marinhas (simbiose de limpeza nas ilhas oceânicas do arquipélago de Fernando de Noronha e próximo a um naufrágio na costa de Pernambuco, nordeste do Brasil. Nove espécies de peixes recifais e três espécies de tartarugas envolvidas nas associações são aqui registradas. Além de nossos registros, apresentamos também um resumo da literatura sobre o tema. As posturas adotadas pelas tartarugas durante as interações estão relacionadas com os hábitos dos peixes associados. Associações alimentares entre peixes e tartarugas podem ser consideradas como um fenômeno local, embora comum.

  4. Understanding the life of a sandy beach polychaete of functional importance - Scolelepis squamata (Polychaeta: Spionidae) on Belgian sandy beaches (northeastern Atlantic, North Sea)

    Science.gov (United States)

    Speybroeck, Jeroen; Alsteens, Lotte; Vincx, Magda; Degraer, Steven

    2007-08-01

    The cosmopolitan sandy beach polychaete Scolelepis squamata constitutes an important food resource for juvenile flatfish and wading birds in the northeastern Atlantic, thus playing an important role in sandy beach ecosystem functioning. However, its population dynamics and life history in this part of the world have gone widely uninvestigated. Eight beach transects on Belgian sandy beaches were sampled monthly from October 2003 until October 2004, in order to investigate seasonal trends in the species' abundance, biomass, secondary production, and patterns in reproduction and zonation. Average density, modal density and modal biomass (ash-free dry weight) (mean average density = 169 ± 9 SE ind/m 2; mean modal density = 505 ± 38 SE ind/m 2; mean modal biomass = 0.25 ± 0.02 SE g/m 2) did not exhibit major seasonal changes, whereas average biomass (0.081 ± 0.005 SE g/m 2) and individuals and biomass per strip transect (IST = 16286 ± 1330 SE ind/m; BMST = 7.8 + 0.7 SE g/m) did, peaking in May 2004. Production was calculated at 1.9 g/(m 2*year) (size-frequency method, SFM) and 0.88 g/(m 2*year) (mass specific growth rate method, MSGR) and mean annual biomass was 0.797 g/m 2; resulting in a P/B ratio of 2.40/year (SFM) and 1.11/year (MSGR), which is intermediate to moderately low compared to other polychaete species. Gravid individuals were found from February until August and a single recruitment period was observed from July until September. An average sex ratio of 1.41 ± 0.08 SE was calculated, with a female predominance. Highest densities (>200 ind/m 2) were mostly found above 3 m above MLLWS and at a median grain size from 190 to 320 μm. Average modal or peak density along each transect was situated from 3.95 m up to 4.40 m above MLLWS, in contrast to some other studies where the species was restricted to mid-tidal levels. Significant differences in elevation of peak density were found between non-gravid (411 ± 4 SE cm) and gravid (402 ± 5 SE cm) animals

  5. An Atlantic influence on Amazon rainfall

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jin-Ho [University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States); Zeng, Ning [University of Maryland, Earth System Science Interdisciplinary Center, College Park, MD (United States); University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States)

    2010-02-15

    Rainfall variability over the Amazon basin has often been linked to variations in Pacific sea surface temperature (SST), and in particular, to the El Nino/Southern Oscillation (ENSO). However, only a fraction of Amazon rainfall variability can be explained by ENSO. Building upon the recent work of Zeng (Environ Res Lett 3:014002, 2008), here we provide further evidence for an influence on Amazon rainfall from the tropical Atlantic Ocean. The strength of the North Atlantic influence is found to be comparable to the better-known Pacific ENSO connection. The tropical South Atlantic Ocean also shows some influence during the wet-to-dry season transition period. The Atlantic influence is through changes in the north-south divergent circulation and the movement of the ITCZ following warm SST. Therefore, it is strongest in the southern part of the Amazon basin during the Amazon's dry season (July-October). In contrast, the ENSO related teleconnection is through anomalous east-west Walker circulation with largely concentrated in the eastern (lower) Amazon. This ENSO connection is seasonally locked to boreal winter. A complication due to the influence of ENSO on Atlantic SST causes an apparent North Atlantic SST lag of Amazon rainfall. Removing ENSO from North Atlantic SST via linear regression resolves this causality problem in that the residual Atlantic variability correlates well and is in phase with the Amazon rainfall. A strong Atlantic influence during boreal summer and autumn is particularly significant in terms of the impact on the hydro-ecosystem which is most vulnerable during the dry season, as highlighted by the severe 2005 Amazon drought. Such findings have implications for both seasonal-interannual climate prediction and understanding the longer-term changes of the Amazon rainforest. (orig.)

  6. 76 FR 61285 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; South Atlantic Snapper-Grouper...

    Science.gov (United States)

    2011-10-04

    ... recreational ACL overage. This action is necessary to reduce overfishing of the South Atlantic black sea bass... (AMs) be implemented to end overfishing and prevent overfishing from occurring. AMs are management... overfishing, including black sea bass, and AMs if these ACLs are reached or exceeded. The recreational ACL for...

  7. Leatherback sea turtle age and growth

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study involves analysis of skeletal growth marks in scleral ossicle bones of 33 leatherback sea turtles stranded dead along the Atlantic and Gulf of Mexico US...

  8. Oceanographic Telecommuting: Going to Sea Virtually

    Science.gov (United States)

    Smith, Deborah K.; Lemmond, Peter

    2005-09-01

    Oceanography in the 21st century is on the verge of changing the way it does business. Telecommuting from office to sea is about to make the same impact as telecommuting between home and the office did 20 years ago. A recent geophysical survey highlighted the role that telecommuting will soon play in ocean research. In June 2005, R/V Knorr was in the middle of the Atlantic Ocean conducting a geophysical survey of a region centered at 13°N along the Mid-Atlantic Ridge in the general area of the diffuse triple junction between the North America (NA),Africa (AF), and South America (SA) plates. This region is particularly notable because of a unique zone of seismicity that occurs ~70 km west of the ridge axis between 14°20'N and 12°50'N.The survey conducted on this cruise (KN182-3) was a first step toward understanding how slow spreading lithosphere is deforming in the NA-SA-AF triple junction region.

  9. Investigating sediment size distributions and size-specific Sm-Nd isotopes as paleoceanographic proxy in the North Atlantic Ocean: reconstructing past deep-sea current speeds since Last Glacial Maximum

    OpenAIRE

    Li, Yuting

    2017-01-01

    To explore whether the dispersion of sediments in the North Atlantic can be related to modern and past Atlantic Meridional Overturning Circulation (AMOC) flow speed, particle size distributions (weight%, Sortable Silt mean grain size) and grain-size separated (0–4, 4–10, 10–20, 20–30, 30–40 and 40–63 µm) Sm-Nd isotopes and trace element concentrations are measured on 12 cores along the flow-path of Western Boundary Undercurrent and in the central North Atlantic since the Last glacial Maximum ...

  10. 2005 Atlantic Hurricanes Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2005 Atlantic Hurricanes poster features high quality satellite images of 15 hurricanes which formed in the Atlantic Basin (includes Gulf of Mexico and Caribbean...

  11. Northeast Atlantic blue whiting

    OpenAIRE

    Heino, Mikko

    2010-01-01

    Heino, M. 2010. Northeast Atlantic blue whiting. In Life cycle spatial patterns of small pelagic fish in the Northeast Atlantic, pp. 59-64. Ed by P. Petitgas. ICES Cooperative Research Report 306. ICES, Copenhagen.

  12. Sedimentary architecture and optical dating of Middle and Late Pleistocene Rhine-Meuse deposits – fluvial response to climate change, sea-level fluctuation and glaciation

    NARCIS (Netherlands)

    Busschers, F.S.; Weerts, H.J.T.; Wallinga, J.; Cleveringa, P.; Kasse, C.; Wolf, H. de; Cohen, K.M.

    2005-01-01

    Eight continuous corings in the west-central Netherlands show a 15 to 25 m thick stacked sequence of sandy to gravelly channel-belt deposits of the Rhine-Meuse system. This succession of fluvial sediments was deposited under net subsiding conditions in the southern part of the North Sea Basin and

  13. Sedimentary architecture and optical dating of Middle and Late Pleistocene Rhine-Meuse deposits - Fluvial response to climate change, sea-level fluctuation and glaciation

    NARCIS (Netherlands)

    Busschers, F.S.; Weerts, H.J.T.; Wallinga, J.; Cleveringa, P.; Kasse, C.; Wolf, H.de; Cohen, K.M.

    2005-01-01

    Eight continuous corings in the west-central Netherlands show a 15 to 25 m thick stacked sequence of sandy to gravelly channel-belt deposits of the Rhine-Meuse system. This succession of fluvial sediments was deposited under net subsiding conditions in the southern part of the North Sea Basin and

  14. Sedimentary architecture and optical dating of Middle and Late Pleistocene Rhine-Meuse deposits fluvial response to climate change, sea-level fluctuation and glaciation

    NARCIS (Netherlands)

    Busschers, F.S.; Weerts, H.J.T.; Wallinga, J.; Kasse, C.; Cleveringa, P.; de Wolf, H.; Cohen, K.M.

    2005-01-01

    Eight continuous corings in the west-central Netherlands show a 15 to 25 m thick stacked sequence of sandy to gravelly channel-belt deposits of the Rhine-Meuse system. This succession of fluvial sediments was deposited under net subsiding conditions in the southern part of the North Sea Basin and

  15. Temperature and other data collected using visual observations and other instruments in the Mid-Atlantic Bight and other Seas from GYRE from 01 August 1985 to 26 May 1990 (NODC Accession 9300074)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and other data were collected using visual observations, bottle casts, and other instruments from GYRE and other platforms in the Mid-Atlantic Bight and...

  16. Profile chemical, physical and optical data collected aboard the SEWARD JOHNSON in the Caribbean Sea and North Atlantic Ocean from June 22, 2006 to July 24, 2006 (NODC Accession 0059071)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains hydrographic data collected during cruise SJ0609 in the tropical North Atlantic. Leg 1 of the cruise began in Ft. Pierce FL with a rapid...

  17. Temperature, salinity, and oxygen profiles from bottle casts in the North Atlantic Ocean by the Ukrainian Scientific Centre of the Ecology of Sea from 25 November 1983 to 15 February 1990 (NODC Accession 0000434)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bottle and other data were collected from the North Atlantic Ocean from 25 November 1983 to 15 February 199. Data were collected by the Ukrainian Scientific Centre...

  18. Temperature profile data from CTD casts in the North Atlantic Ocean near Newfoundland by the Ukrainian Scientific Centre of the Ecology of Sea from 1972-10-13 to 1991-05-10 (NODC Accession 9900116)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected using CTD casts in the North Atlantic Ocean from October 13, 1972 to May 10, 1991. Data were collected and submitted by Dr....

  19. Physical trajectory profile data from glider SG610 deployed by Atlantic Oceanographic and Meteorological Laboratory in the Caribbean Sea from 2015-02-06 to 2015-04-27 (NCEI Accession 0137961)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seaglider data gathered as part of the Sustained Ocean Observations for Improving Atlantic Tropical Cyclone Intensity and Hurricane Seasonal Forecast project funded...

  20. Temperature profile and water depth data collected from USS ROBERT G. BRADLEY using BT and XBT casts in the NE/NW Atlantic Ocean and other seas from 03 May 1988 to 31 May 1988 (NODC Accession 8800213)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS ROBERT G. BRADLEY in the Northwest / Northeast Atlantic Ocean, Arabian...

  1. Physical trajectory profile data from glider SG609 deployed by Atlantic Oceanographic and Meteorological Laboratory in the Caribbean Sea from 2016-03-10 to 2016-06-02 (NCEI Accession 0154495)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seaglider data gathered as part of the Sustained Ocean Observations for Improving Atlantic Tropical Cyclone Intensity and Hurricane Seasonal Forecast project funded...

  2. Physical trajectory profile data from glider SG630 deployed by US DOC; NOAA; OAR; Atlantic Oceanographic and Meteorological Laboratory in the Caribbean Sea from 2016-07-21 to 2016-11-10 (NCEI Accession 0157713)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seaglider data gathered as part of the Sustained Ocean Observations for Improving Atlantic Tropical Cyclone Intensity and Hurricane Seasonal Forecast project funded...

  3. Physical trajectory profile data from glider SG609 deployed by US DOC; NOAA; OAR; Atlantic Oceanographic and Meteorological Laboratory in the Caribbean Sea from 2016-07-21 to 2016-11-10 (NCEI Accession 0157655)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seaglider data gathered as part of the Sustained Ocean Observations for Improving Atlantic Tropical Cyclone Intensity and Hurricane Seasonal Forecast project funded...

  4. Physical trajectory profile data from glider SG609 deployed by Atlantic Oceanographic and Meteorological Laboratory in the Caribbean Sea from 2015-07-15 to 2015-11-16 (NCEI Accession 0145655)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seaglider data gathered as part of the Sustained Ocean Observations for Improving Atlantic Tropical Cyclone Intensity and Hurricane Seasonal Forecast project funded...

  5. Temperature profile data from CTD casts in the North Atlantic Ocean near Newfoundland by the Ukrainian Scientific Centre of the Ecology of Sea from 1982-07-21 to 1982-07-28 (NODC Accession 9900122)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected using CTD casts in the North Atlantic Ocean from July 21, 1982 to July 28, 1982. Data were collected and submitted by Dr....

  6. Temperature profile data from CTD casts in the North Atlantic Ocean near Newfoundland by the Ukrainian Scientific Centre of the Ecology of Sea from 1983-04-21 to 1991-05-01 (NODC Accession 9900123)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected using CTD casts in the North Atlantic Ocean from April 21, 1983 to May 1, 1991. Data were collected and submitted by Dr. Yuri...

  7. Dissolved inorganic carbon, alkalinity, salinity and SEA SURFACE TEMPERATURE collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the ANTEA in the Gulf of Guinea, North Atlantic Ocean and South Atlantic Ocean from 2005-09-04 to 2005-09-26 (NODC Accession 0108087)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108087 includes chemical, discrete sample, physical and profile data collected from ANTEA in the Gulf of Guinea, North Atlantic Ocean and South...

  8. Dissolved inorganic carbon, alkalinity, salinity and SEA SURFACE TEMPERATURE collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the ANTEA in the Gulf of Guinea, North Atlantic Ocean and South Atlantic Ocean from 2007-06-06 to 2007-07-03 (NODC Accession 0108090)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108090 includes chemical, discrete sample, physical and profile data collected from ANTEA in the Gulf of Guinea, North Atlantic Ocean and South...

  9. Dissolved inorganic carbon, alkalinity, salinity and SEA SURFACE TEMPERATURE collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the ANTEA in the Gulf of Guinea, North Atlantic Ocean and South Atlantic Ocean from 2006-11-01 to 2006-11-30 (NODC Accession 0108089)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108089 includes chemical, discrete sample, physical and profile data collected from ANTEA in the Gulf of Guinea, North Atlantic Ocean and South...

  10. Dissolved inorganic carbon, alkalinity, salinity and SEA SURFACE TEMPERATURE collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the ANTEA in the Gulf of Guinea, North Atlantic Ocean and South Atlantic Ocean from 2007-09-03 to 2007-09-24 (NODC Accession 0108091)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108091 includes chemical, discrete sample, physical and profile data collected from ANTEA in the Gulf of Guinea, North Atlantic Ocean and South...

  11. Physical and chemical oceanographic profile data, and meteorological data collected in the Atlantic and Arctic Oceans, and adjoining seas by multiple platforms from 14 August 1951 to 27 October 1994 (NODC Accession 0073741)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, oxygen, silicate, phosphate, nitrite, nitrate, alkalinity, and pH data collected in Arctic Ocean, Barents Sea, East Siberian Sea, Greenland...

  12. The UK-SEA-ME Psychosocial-Cultural Cancer Research Network: setting the stage for applied qualitative research on cancer health behaviour in southeast Asia and the Middle East.

    Science.gov (United States)

    Lim, Jennifer N W

    2011-01-01

    Psychosocial and cultural factors influencing cancer health behaviour have not been systematically investigated outside the western culture, and qualitative research is the best approach for this type of social research. The research methods employed to study health problems in Asia predominantly are quantitative techniques. The set up of the first psychosocial cancer research network in Asia marks the beginning of a collaboration to promote and spearhead applied qualitative healthcare research in cancer in the UK, Southeast Asia and the Middle East. This paper sets out the rationale, objectives and mission for the UK-SEA-ME Psychosocial-Cultural Cancer Research Network. The UK-SEA-ME network is made up of collaborators from the University of Leeds (UK), the University of Malaya (Malaysia), the National University of Singapore (Singapore) and the University of United Arab Emirates (UAE). The network promotes applied qualitative research to investigate the psychosocial and cultural factors influencing delayed and late presentation and diagnosis for cancer (breast cancer) in partner countries, as well as advocating the use of the mixed-methods research approach. The network also offers knowledge transfer for capacity building within network universities. The mission of the network is to improve public awareness about the importance of early management and prevention of cancer through research in Asia.

  13. Disposal of radioactive waste in the Atlantic

    International Nuclear Information System (INIS)

    1982-06-01

    An operation to dispose of low-level radioactive waste in the North Atlantic deeps is undertaken each year. This leaflet seeks to answer questions which are sometimes asked about the operation. It deals with origin, composition, quantity, reason for sea- rather than land-disposal, packaging, transport (rail, road), route of transport, safety precautions, radiation protection, personnel, contamination, site of dump, international regulations, neutral observers, safety standards of containers and control of level of radioactivity of wastes. (U.K.)

  14. Differential response of continental stock complexes of Atlantic salmon (Salmo salar) to the Atlantic Multidecadal Oscillation

    Science.gov (United States)

    Friedland, Kevin D.; Shank, Burton V.; Todd, Christopher D.; McGinnity, Philip; Nye, Janet A.

    2014-05-01

    Atlantic salmon, Salmo salar, in the North Atlantic are managed as a set of population complexes distributed in North America and Europe. In recent years, these complexes have experienced reduced marine survival and many populations within the complexes are at risk, especially those at the southern ends of the species amphi-Atlantic range. Atlantic salmon is an anadromous fish dividing its life history between residence in freshwater and the marine environment. The freshwater portion of the life history includes spawning and the rearing of juveniles where in-river production has tended to be relatively stable, whereas the first year at sea, termed the post-smolt year, is characterized by more variable rates of mortality. Although their habitats are widely separated geographically along the North Atlantic seaboards, strong recruitment coherence exists between North American and European stock complexes. This recruitment coherence is correlated with ocean temperature variation associated with the Atlantic Multidecadal Oscillation (AMO). The North Atlantic Oscillation (NAO) appears to be relatively unimportant as a driver of salmon abundance. The mechanism determining the link between AMO-related thermal variation and abundance appears to differ fundamentally for the two continental stock groupings. Whereas ocean climate variability during the first springtime months of juvenile salmon migration to sea appears to be important to the survival of North American stocks, summer climate variation appears to be central to adult recruitment variation for European stocks. This contrast in seasonal effects appears to be related to the varying roles of predation pressure and size-related mortality on the continental stock complexes. The anticipated warming due to global climate change will impose thermal conditions on salmon populations outside historical context and challenge the ability of many populations to persist.

  15. An Anatomy of the 1960s Atlantic Cooling.

    Science.gov (United States)

    Hodson, Dan; Robson, Jon; Sutton, Rowan

    2014-05-01

    North Atlantic Sea Surface Temperatures (SSTs) exhibited pronounced multidecadal variability during the 20th Century. In particular, the North Atlantic SSTs exhibited a rapid warming between 1920 and 1940 followed by a rapid cooling between 1960 and 1980. SSTs outside the North Atlantic display a much smaller level of decadal variability over the 20th Century. This pattern of North Atlantic warming and cooling has been linked to subsequent changes in rainfall over the Sahel and Nordeste Brazil, Summertime North American Climate and Atlantic Hurricane Genesis. Several hypotheses for the rapid 1960s Atlantic cooling have been proposed, including a reduction in northward ocean heat transport due to a reduced Atlantic Meridional Overturning Circulation (AMOC) and the significant rise in anthropogenic sulphur dioxide emissions during the latter half of the 20th century. Here we examine the observed 1960s Atlantic cooling in more detail. We describe the evolution of the rapid cooling by constructing a detailed multivariate anatomy of the cooling period in order to illuminate the possible explanations and mechanisms involved. We show that the observed 1960s cooling began around 1964-68 in the Greenland-Iceland-Norway (GIN) seas, later spreading to the Atlantic Sub Polar Gyre and much of the subtropical Atlantic. This initial cooling of the Sub Polar Gyre is associated with a marked reduction in salinity (the Great Salinity Anomaly). The cooling peaked between 1972-76, extending into the Tropical North Atlantic. This period also saw the development of a significant Winter North-South Dipole Mean Sea Level Pressure dipole pattern reminiscent of a positive NAO (High over the Azores, Low over Iceland). The cooling then retreated back to higher latitudes during 1976:80. Our analysis demonstrates that the cooling of the North Atlantic during the 1960s cannot be understood as a simple thermodynamic response to aerosol induced reductions in shortwave radiation. Dynamical changes

  16. Comparative visual ecophysiology of mid-Atlantic temperate reef fishes

    Directory of Open Access Journals (Sweden)

    Andrij Z. Horodysky

    2013-11-01

    The absolute light sensitivities, temporal properties, and spectral sensitivities of the visual systems of three mid-Atlantic temperate reef fishes (Atlantic spadefish [Ephippidae: Chaetodipterus faber], tautog [Labridae: Tautoga onitis], and black sea bass [Serranidae: Centropristis striata] were studied via electroretinography (ERG. Pelagic Atlantic spadefish exhibited higher temporal resolution but a narrower dynamic range than the two more demersal foragers. The higher luminous sensitivities of tautog and black sea bass were similar to other benthic and demersal coastal mid-Atlantic fishes. Flicker fusion frequency experiments revealed significant interspecific differences at maximum intensities that correlated with lifestyle and habitat. Spectral responses of the three species spanned 400–610 nm, with high likelihood of cone dichromacy providing the basis for color and contrast discrimination. Significant day-night differences in spectral responses were evident in spadefish and black sea bass but not tautog, a labrid with characteristic structure-associated nocturnal torpor. Atlantic spadefish responded to a wider range of wavelengths than did deeper-dwelling tautog or black sea bass. Collectively, these results suggest that temperate reef-associated fishes are well-adapted to their gradient of brighter to dimmer photoclimates, representative of their unique ecologies and life histories. Continuing anthropogenic degradation of water quality in coastal environments, at a pace faster than the evolution of visual systems, may however impede visual foraging and reproductive signaling in temperate reef fishes.

  17. Factores de riesgo modificables o no, relacionados con la densidad mineral ósea en mujeres de edad mediana Modifiable or not factors related to mineral bone density in middle aged women

    Directory of Open Access Journals (Sweden)

    Cossette Díaz Socorro

    2012-04-01

    ,025, antecedente familiar de fractura (Odds Ratio= 2,836, p= 0,044, y la posmenopausia (Odds Ratio= 10,185, p= 0,008. Conclusiones: las mujeres de edad mediana que presentaron mayor probabilidad de tener una masa ósea disminuida fueron aquellas de color de la piel blanca, con antecedentes familiares de fractura, y en las que la posmenopausia comparece.Introduction: in Cuba there are not national data on the osteoporosis's prevalence. The world demographic changes make necessary the research and the diffusion of information relative to osteoporosis. Objective: to identify the possible differences in the bon mineral density, according to the presence of modifiable or not risk factors in middle aged women. Methods: a cross-sectional and descriptive study was conducted in 259 patients came to ClimOs consultation in the National Institute of Endocrinology ruled out the women presenting with secondary osteoporosis. The bone mineral density is determined by means of dual beam absorptiometry in distal forearm and lumbar spine. Patients were divided into two categories: those with a normal mineral bone density located in I group and those with a low bone mineral density (osteopenia and/or osteoporosis corresponded to II group. To establish differences among groups the t student and chi2 tests with a 5 % significance level. The multiple logistic regression was used for analysis of bone mineral density integrating both study regions. Results: combining the results of the densitometry carried out in th forearm and lumbar spine of the 259 middle aged women, the 72.2 % had a low bone mass including 99 patients (38.2 % with osteopenia and 88 (34.0 % diagnosed with osteoporosis, only 72 (27.8 % women had a normal bone mass. Applying the multiple logistic regression to statistically significant variables: age, skin color, family pathological background of fracture, ovarian function, body mass rate, follicle-stimulating hormone, luteinizing hormone and estradiol, those associated with a great

  18. Temperature profile and water depth data collected from TOWERS in the NE Atlantic (limit-180 W) from 06 June 1986 to 29 August 1986 (NODC Accession 8600378)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the TOWERS in the Northeast Atlantic Ocean, South China Sea, Philippine Sea, and...

  19. Links between the recruitment success of northern European hake (Merluccius merluccius L.) and a regime shift on the NE Atlantic continental shelf

    KAUST Repository

    Goikoetxea, Nerea; Irigoien, Xabier

    2013-01-01

    variables in the North Sea also affected the Northeast Atlantic shelf oceanography. Hake recruitment success as well as parameters such as the sea surface temperature, wind patterns and copepod abundance changed significantly at the end of the 1980s

  20. Response of the Adriatic Sea to the atmospheric anomaly in 2003

    Directory of Open Access Journals (Sweden)

    B. Grbec

    2007-05-01

    Full Text Available Unusual weather conditions over the southern Europe and the Mediterranean area in 2003 significantly impacted the oceanographic properties of the Adriatic Sea. To document these changes, both in the atmosphere and the sea, anomalies from the normal climate were calculated. The winter 2003 was extremely cold, whereas the spring/summer period was extremely warm. The air temperature in June was more than 3 standard deviations above the average. On the other hand, precipitation and river runoff were extremely low between February and August. The response of the sea was remarkable, especially in surface salinity during spring and summer, with values at least one standard deviation above the average. Analysis of thermohaline properties in the middle Adriatic showed the importance of two phenomena responsible for the occurrence of exceptionally high salinity: (1 enhanced inflow of saline Levantine Intermediate Water (LIW in the Adriatic, and (2 extremely low precipitation and river runoff, accompanied with strong evaporation. Two large-scale atmospheric indices: NAOI (North Atlantic Oscillation Index and MOI (Mediterranean Oscillation Index, although generally correlated to the Adriatic climate, failed to describe anomalies in 2003. The air pressure gradients used for the definition of both indices significantly decreased in 2003 due to the presence of the high pressure areas over most of Europe and the northern Atlantic, and were actually responsible for the observed anomalies above and in the Adriatic.