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| Registros recuperados: 62 | |
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| De Vernal, A; Hillaire-marcel, C; Peltier, Wr; Weaver, Aj. |
| During the Last Glacial Maximum, the northwestern North Atlantic constituted a major conduit for Labrador and Greenland ice sheet meltwaters. Vertical density gradients in its upper water masses have been reconstructed by combining information from transfer functions based on dinocysts and from oxygen isotope measurements (delta(18)O) in planktonic foraminifera. Transfer functions yield temperature and salinity and thus potential density (sigma(theta)) for the warmest (August) and coldest (February) months in the photic zone. The delta(18)O values in different size fractions of epipelagic (Globigerina bulloides) and mesopelagic (Neogloboquadrina pachyderma left-coiled (Np1)) foraminifera allow us to assess sigma(theta) gradients through the pycnocline... |
| Tipo: Text |
Palavras-chave: Last Glacial Maximum; LGM; North Atlantic; Salinity; Density; Pycnocline. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33405/31861.pdf |
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| Joubin, M. L.. |
| L'accroissement considérable du tonnage et de la puissance des navires de pêche employés par les armateurs français leur a permis de manœuvrer les chaluts à des profondeurs de plus en plus grandes qu'ils n'atteignaient jamais, il n’y a pas un bien grand nombre d'années. En opérant dans ces couches profondes ils ont rencontré, à partir de 200 mètres environ, des coraux ramifiés qui sont localisés dans ces eaux plus froides et plus obscures. Ces coraux sont constitués par du calcaire extrêmement dur, à consistance et aspect de porcelaine, à cassure blanche et coupante ; les chaluts déchirent et peuvent même y rester accrochés ; le moindre mal qui leur arrive est de se remplir de branches cassées qui les empêchent de fonctionner. Le chalut de la Tanche en a... |
| Tipo: Text |
Palavras-chave: Chart; North Atlantic; Coral; Fishing net; Obstacle; Fisheries. |
| Ano: 1922 |
URL: http://archimer.ifremer.fr/doc/1922/publication-2394.pdf |
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| Gherardi, Jeanne Marie; Labeyrie, L.; Nave, S.; Francois, R.; Mcmanus, J. F.; Cortijo, E.. |
| Studies from the subtropical western and eastern Atlantic Ocean, using the Pa-231/Th-230 ratio as a kinematic proxy for deep water circulation, provided compelling evidence for a strong link between climate and the rate of meridional overturning circulation (MOC) over the last deglaciation. In this study, we present a compilation of existing and new sedimentary Pa-231/Th-230 records from North Atlantic cores between 1710 and 4550 m water depth. Comparing sedimentary Pa-231/Th-230 from different depths provides new insights into the evolution of the geometry and rate of deep water formation in the North Atlantic during the last 20,000 years. The Pa-231/Th-230 ratio measured in upper Holocene sediments indicates slow water renewal above similar to 2500 m and... |
| Tipo: Text |
Palavras-chave: MOC; North Atlantic; Deglaciation; 231Pa/230Th. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00233/34468/32855.pdf |
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| Treguier, Anne-marie; Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Barnier, Bernard; Madec, Gurvan; Molines, Jean-marc; Penduff, Thierry; Czeschel, Lars; Boning, Claus. |
| Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of... |
| Tipo: Text |
Palavras-chave: Ocean model; Thermohaline circulation; North Atlantic; Climate variability; Oceanography. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2199.pdf |
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| Thomas, Yoann; Cassou, Christophe; Gernez, Pierre; Pouvreau, Stephane. |
| Beyond key ecological services, marine resources are crucial for human food security and socio-economical sustainability. Among them, shellfish aquaculture and fishing are of primary importance but become more vulnerable under anthropogenic pressure, as evidenced by reported mass mortality events linked to global changes such as ocean warming and acidification, chemical contamination, and diseases. Understanding climate-related risks is a vital objective for conservation strategies, ecosystems management and human health. We provide here a comprehensive study of the historical mortality of adult oysters related to observed climate variability along the French Atlantic coast from 1986 to 2015, and we built on this knowledge to develop hindcast and forecast... |
| Tipo: Text |
Palavras-chave: North Atlantic; Weather regime; Oyster; Monitoring network; Mortality risk assessment; Climate models; RCP scenarios. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57255/59281.pdf |
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| Rixen, Michel; Beckers, J; Levitus, S; Antonov, J; Boyer, T; Maillard, Catherine; Fichaut, Michele; Balopoulos, E; Iona, S; Dooley, H; Garcia, M; Manca, B; Giorgetti, A; Manzella, G; Mikhailov, N; Pinardi, N; Zavatarelli, M. |
| Reconstructions of Mediterranean ocean temperature fields back to 1950 show a proxy relationship between heat content changes in the North Atlantic and the Western Mediterranean Deep Water ( WMDW) formed in the Gulf of Lions in winter, because of consistent air-sea heat fluxes over these areas, strongly correlated to the North Atlantic Oscillation ( NAO). |
| Tipo: Text |
Palavras-chave: North Atlantic; West mediterranee; Thermohaline circulation; Temperature variation; Deep water; Water masses; Air sea heat flux. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-760.pdf |
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| Irvali, Nil; Ninnemann, Ulysses S.; Kleiven, Helga (kikki) F.; Galaasen, Eirik V.; Morley, Audrey; Rosenthal, Yair. |
| High-resolution lithic and sea surface climate records are used to portray the progression of North Atlantic climate, hydrography, and Greenland Ice Sheet (GIS) activity through the peak of Marine Isotope Stage (MIS) 5e into the last glacial inception. We use Eirik Drift sediment core MD03-2664 (57°26.34′N, 48°36.35′W), recovered south of Greenland, strategically located to monitor fluctuations in GIS extent and iceberg calving events. Our results show that a significant amount of ice-rafted debris (IRD) was present during the early MIS 5e, until gradually tapering off by 122 kyr BP due to a diminishing GIS. Sea surface temperatures (SSTs) in the northern subpolar gyre reached peak values early in MIS 5e coinciding with peak insolation. Regional cooling... |
| Tipo: Text |
Palavras-chave: Eirik drift; Greenland Ice Sheet; North Atlantic; Last interglacial; Glacial inception; Multi-proxy. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00349/46009/45681.pdf |
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| Macgilchrist, Graeme A.; Marshall, David P.; Johnson, Helen L.; Lique, Camille; Thomas, Matthew. |
| Ventilation of the upper ocean plays an important role in climate variability on interannual to decadal timescales by influencing the exchange of heat and carbon dioxide between the atmosphere and ocean. The turbulent nature of ocean circulation, manifest in a vigorous mesoscale eddy field, means that pathways of ventilation, once thought to be quasi-laminar, are in fact highly chaotic. We characterize the chaotic nature of ventilation pathways according to a nondimensional filamentation number, which estimates the reduction in filament width of a ventilated fluid parcel due to mesoscale strain. In the subtropical North Atlantic of an eddy-permitting ocean model, the filamentation number is large everywhere across three upper ocean density... |
| Tipo: Text |
Palavras-chave: Ventilation; North Atlantic; Thermocline; Chaos; Mesoscale eddies; Lagrangian trajectories. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00410/52104/52807.pdf |
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| Koc, N; Labeyrie, L; Manthe, S; Flower, Bp; Hodell, Da; Aksu, A. |
| Well-preserved diatoms are present in high sedimentation rate Pleistocene cores retrieved on ocean Drilling Program (ODP) Legs 151, 152, 162 and IMAGES cruises of RN Marion Dufresne from the North Atlantic. Investigation of the stratigraphic occurrence of diatom species shows that the youngest diatom event observed in the area is the last occurrence (LO) of Proboscia curvirostris (Jouse) Jordan and Priddle. P. curvirostris is a robust species that can easily be identified in the sediments, and therefore can be a practical biostratigraphic tool. We have mapped its: areal distribution, and found that it stretches from 40 degreesN to 80 degreesN in the North Atlantic. Further, we have correlated the LO P. curvirostris to the oxygen isotope records of six... |
| Tipo: Text |
Palavras-chave: Biostratigraphy; North Atlantic; Diatoms; Pleistocene; Paleoceanography; Isotope stratigraphy; Oxygen. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33210/31708.pdf |
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| Xuan, Chuang; Channel, James E. T.; Hodell, David A.. |
| The sediment sequence from Integrated Ocean Drilling Program (IODP) Site U1304 (53 degrees 03.40'N, 33 degrees 31.78'W; water depth, 3024 m) on the southern Gardar Drift, North Atlantic Ocean, covers the last similar to 1.8 Myr with a mean sedimentation rate of similar to 15 cm/kyr. At Site U1304, paleomagnetic directional and relative paleointensity (RPI) records have been generated for the last similar to 1.5 Myr, and benthic oxygen isotope data for the last similar to 1 Myr. The age model for Site U1304 was established by matching 6180 and RPI data to calibrated reference records. Prominent intervals of diatom mats at Site U1304 are associated with the latter stages of interglacial marine isotope stages (MIS) 9, 11, 13, 15, 21, 27 and 35, and with the... |
| Tipo: Text |
Palavras-chave: Quaternary; North Atlantic; Relative paleointensity; Magnetic excursions; Oxygen isotopes; Diatoms; IODP Site U1304. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53238/83373.pdf |
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| Farmer, Elizabeth J.; Chapman, Mark R.; Andrews, Julian E.. |
| A high-resolution record of Mg/Ca ratios from the planktonic foraminifer Globigerina bulloides has been produced for IMAGES core MD99-2251 from the subpolar North Atlantic. The record extends from the Younger Dryas-Preboreal transition through the Holocene at similar to 70 year resolution, with a more detailed section at similar to 20 year resolution through the interval encompassing the major cooling episode 8200 years ago. Mg/Ca derived temperatures show significant variations through the Holocene, with surface temperatures ranging from similar to 8 to 13 degrees C. The onset of the Holocene is marked by an abrupt warming, with a further increase in early Holocene temperatures occurring prior to 9.5 ka. This is followed by a mid-Holocene period of cooler... |
| Tipo: Text |
Palavras-chave: Planktonic foraminifera; Mg/Ca; G. bulloides; North Atlantic; Holocene. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00236/34760/33396.pdf |
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| Lemaitre, Nolwenn; De Souza, Gregory F.; Archer, Corey; Wang, Ruo-mei; Planquette, Helene; Sarthou, Geraldine; Vance, Derek. |
| In this study, we report seawater dissolved zinc (Zn) concentration and isotope composition (Zn) from the GEOTRACES GA01 (GEOVIDE) section in the North Atlantic. Across the transect, three subsets of samples stand out due to their isotopically light signature: those close to the Reykjanes Ridge, those close to the sediments, and those, pervasively, in the upper ocean. Similar to observations at other locations, the hydrothermal vent of the Reykjanes Ridge is responsible for the isotopically light Zn composition of the surrounding waters, with an estimated source Zn of -0.42 ‰. This isotopically light Zn is then transported over a distance greater than 1000 km from the vent. Sedimentary inputs are also evident all across the trans-Atlantic section,... |
| Tipo: Text |
Palavras-chave: Zinc isotopes; North Atlantic; Zinc sources; GEOTRACES; GEOVIDE. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/73035/72166.pdf |
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| Hughes, Sarah L.; Holliday, N. Penny; Gaillard, Fabienne. |
| The ICES Report on Ocean Climate presents the latest information on the status and trends of sea temperature and salinity in the North Atlantic and Nordic Seas. It is the main product of the ICES Working Group on Oceanic Hydrography, published annually. Bringing together multiple time-series from across the ICES and NAFO regions offers insight into the concurrent spatial and temporal trends in ocean temperature and salinity. This paper presents an overview of the physical variability in the North Atlantic Ocean at decadal and longer time-scales and reviews the current state of understanding of the causes and mechanisms of this variability. Between the 1960s and the 1990s, the North Atlantic Oscillation (NAO) index increased from a persistent negative phase... |
| Tipo: Text |
Palavras-chave: Circulation; Multidecadal variability; North Atlantic; Salinity; Temperature. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19854/17513.pdf |
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| Brunel, Thomas; Boucher, Jean. |
| This study investigates the temporal correspondence between the main patterns of recruitment variations among north-east Atlantic exploited fish populations and large-scale climate and temperature indices. It is of primary importance to know what changes in fish stock productivity can be expected in response to climate change, to design appropriate management strategies. The dominant patterns of recruitment variation were extracted using a standardized principal component analysis (PCA). The first principal component (PC) was a long-term decline, with a stepwise change occurring in 1987. A majority of Baltic Sea, North Sea, west of Scotland and Irish Sea populations, especially the gadoids, have followed this decreasing trend. On the contrary, some herring... |
| Tipo: Text |
Palavras-chave: North Atlantic; Global warming; Fishing impacts; Fish recruitment; Comparative approach; Climate change. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2636.pdf |
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| Wall, Torbjorn. |
| High-resolution magnetic hysteresis measurements were carried out on three sediment cores, one from the North Atlantic and two from the Norwegian Sea. These measurements can be used to reconstruct changes in magnetic grain-size. Physical grain-size has been interpreted as a proxy for bottom current intensity (McCave et al. 1995) and this study shows that the hysteresis measurements can contribute as a proxy for near bottom currents in this region during the Holocene, but only when the magnetic measurements are combined with other proxy records. The magnetic grain-size record of one core from the Norwegian Sea has been compared with sea surface temperature reconstructions produced by Calvo et al. (2002) and Birks & Koç (2002). The dominant magnetic... |
| Tipo: Text |
Palavras-chave: Magnetic grain-size; Magnetic hysteresis loops; Reykjanes Ridge; Vøring plateau; North Atlantic; Norwegian Sea; Deep ocean currents; Holocene. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00499/61042/64449.pdf |
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| Toucanne, Samuel; Zaragosi, S.; Bourillet, Jean-francois; Gibbard, P. L.; Eynaud, F.; Giraudeau, J.; Turon, J. L.; Cremer, M.; Cortijo, E.; Martinez, P.; Rossignol, L.. |
| The correlation of continental sedimentary records with the marine isotope stratigraphy is a challenge of central importance in Quaternary stratigraphy, particularly in Western Europe where long records of glaciation on land areas are particularly rare. Here we demonstrate for the first time the interrelationship of events during the last 1.2 Ma in an ocean-sediment core from the Bay of Biscay (NE Atlantic), SW of the Channel. The identification of discharge variations from tributary river systems to the 'Fleuve Manche' palaeoriver during glacio-eustatic sea-level lowstands demonstrates the correlation of the marine sediment stratigraphy to the expansion and recession of the European ice-sheets. The amplitude and chronology of European ice-sheet... |
| Tipo: Text |
Palavras-chave: Middle pleistocene transition; Ice sheet dynamics; Sea level; Climate change; North Atlantic; English channel; Heinrich events; Fleuve manche; Deep; Origin. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6956.pdf |
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| Registros recuperados: 62 | |
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