Consulta: subjectFacets:"North Atlantic"
Registros recuperados: 62
Data/hora: 01/06/2024 12:17:34

Structure of the upper water column in the northwest North Atlantic: Modern versus last glacial maximum conditions
Provedor de dados: 5
Autores: 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

Les coraux de mer profonde nuisibles aux chalutiers
Provedor de dados: 5
Autores: 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

North Atlantic Western Boundary Currents Are Intense Dissolved Organic Carbon Streams
Provedor de dados: 5
Autores: Fontela, Marcos; Pérez, Fiz F; Mercier, Herle; Lherminier, Pascale.
In the North Atlantic, there are two main western boundary currents related to the Atlantic Meridional Overturning Circulation (AMOC): the Gulf Stream flowing northward and the Deep Western Boundary Current (DWBC) flowing southward. Here we analyze data from the OVIDE section (GO-SHIP A25 Portugal-Greenland 40–60°N) that crosses the DWBC and the northward extension of the Gulf Stream, the North Atlantic Current. We show that North Atlantic western boundary currents play a key role in the transport of dissolved organic matter, specifically dissolved organic carbon (DOC). Revisited transports and budgets of DOC with new available data identify the eastern Subpolar North Atlantic (eSPNA) as an important source of locally produced organic matter for the North...
Tipo: Text
Palavras-chave: Dissolved organic carbon; North Atlantic; Carbon budget; Carbon dioxide; Biogeochemistry; Atlantic Meridional Overturning Circulation.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00661/77268/78702.pdf

Glacial-interglacial circulation changes inferred from Pa-231/Th-230 sedimentary record in the North Atlantic region
Provedor de dados: 5
Autores: 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

Internal and forced variability along a section between Greenland and Portugal in the CLIPPER Atlantic model
Provedor de dados: 5
Autores: 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

Does trace element composition of bivalve shells record utra-high frequency environmental variations?
Provedor de dados: 5
Autores: Poitevin, Pierre; Chauvaud, Laurent; Pecheyran, Christophe; Lazure, Pascal; Jolivet, Aurélie; Thebault, Julien.
Saint-Pierre and Miquelon (SPM) is a small archipelago where instrumental measures based on water column velocity and temperature profiles compiled comprehensive evidence for strong near-diurnal (25.8h) current and bottom temperature oscillations (up to 11.5 °C) which is possibly the largest ever observed — at any frequency — on a stratified mid-latitude continental shelf. The main objective of our study was to identify if Placopecten magellanicus can record on its shell these high frequency environmental variations. To this end, we have tried to identify proxies for water temperature and food availability through development of a new ultra-high resolution LA-ICPMS analyses method capable of resolving shell surface elemental composition with a 10 μm...
Tipo: Text
Palavras-chave: Ultra-high resolution LA-ICPMS; Placopecten magellanicus; Shell chemistry; Trace elements; Environmental change; Bivalve; Environmental proxies; North Atlantic; Saint-Pierre and Miquelon; Coastal trapped wave.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00612/72400/71345.pdf

Oysters as sentinels of climate variability and climate change in coastal ecosystems
Provedor de dados: 5
Autores: 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

The Western Mediterranean Deep Water: A proxy for climate change - art. no. L12608
Provedor de dados: 5
Autores: 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

Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial
Provedor de dados: 5
Autores: 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

Characterizing the chaotic nature of ocean ventilation
Provedor de dados: 5
Autores: 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

The last occurrence of Proboscia curvirostris in the North Atlantic marine isotope stages 9-8
Provedor de dados: 5
Autores: 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

Quaternary magnetic and oxygen isotope stratigraphy in diatom-rich sediments of the southern Gardar Drift (IODP Site U1304, North Atlantic)
Provedor de dados: 5
Autores: 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

Nd and Pb isotope signatures of the clay-size fraction of Labrador Sea sediments during the Holocene: Implications for the inception of the modern deep circulation pattern
Provedor de dados: 5
Autores: Fagel, N; Hillaire-marcel, C; Humblet, M; Brasseur, R; Weis, D; Stevenson, R.
Nd and Pb isotopes were measured on the fine fraction of one sediment core drilled off southern Greenland. This work aims to reconstruct the evolution of deep circulation patterns in the North Atlantic during the Holocene on the basis of sediment supply variations. For the last 12 kyr, three sources have contributed to the sediment mixture: the North American Shield, the Pan-African and Variscan crusts, and the Mid-Atlantic Ridge. Clay isotope signatures indicate two mixtures of sediment sources. The first mixture (12.2-6.5 ka) is composed of material derived from the North American shield and from a "young'' crustal source. From 6.5 ka onward the mixture is characterized by a young crustal component and by a volcanic component characteristic of the...
Tipo: Text
Palavras-chave: Clay-size fraction; Sedimentary mixings; Deep circulation; Nd and Pb isotopes; North Atlantic; Labrador Sea.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00226/33731/32199.pdf

Deep-dwelling foraminifera as thermocline temperature recorders
Provedor de dados: 5
Autores: Cleroux, Caroline; Cortijo, Elsa; Duplessy, Jean-claude; Zahn, Rainer.
We measured the oxygen isotopic composition of the deep-dwelling foraminiferal species G. inflata, G. truncatulinoides dextral and sinistral, and P. obliquiloculata in 29 modern core tops raised from the North Atlantic Ocean. We compared calculated isotopic temperatures with atlas temperatures and defined ecological models for each species. G. inflata and G. truncatulinoides live preferentially at the base of the seasonal thermocline. Under temperature stress, i.e., when the base of the seasonal thermocline is warmer than 16 degrees C, G. inflata and G. truncatulinoides live deeper in the main thermocline. P. obliquiloculata inhabits the seasonal thermocline in warm regions. We tested our model using 10 cores along the Mauritanian upwelling and show that...
Tipo: Text
Palavras-chave: Deep-dwelling foraminifera; Depth habitat; Isotopic temperature; Thermocline; North Atlantic; Mauritanian upwelling; Ecological prediction; Stable isotopes; Micropaleontology.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00236/34727/33178.pdf

Centennial-scale Holocene North Atlantic surface temperatures from Mg/Ca ratios in Globigerina bulloides
Provedor de dados: 5
Autores: 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

Pervasive sources of isotopically light zinc in the North Atlantic Ocean
Provedor de dados: 5
Autores: 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

Variability in the ICES/NAFO region between 1950 and 2009: observations from the ICES Report on Ocean Climate
Provedor de dados: 5
Autores: 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

Long-term trends in fish recruitment in the north-east Atlantic related to climate change
Provedor de dados: 5
Autores: 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

Magnetic grain-size analyses of Holocene sediments in the North Atlantic and Norwegian Sea : palaeoceanographic applications
Provedor de dados: 5
Autores: 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 &amp; 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

A 1.2 Ma record of glaciation and fluvial discharge from the West European Atlantic margin
Provedor de dados: 5
Autores: 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

Overview of (Sub)mesoscale Ocean Dynamics for the NAAMES Field Program
Provedor de dados: 5
Autores: Della Penna, Alice; Gaube, Peter.
Tipo: Text
Palavras-chave: Mesoscale; Eddies; North Atlantic aerosols and marine ecosystems study; North Atlantic; NAAMES; Altimeter; Satellite oceanography; Lagrangian reanalysis.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62022/66142.pdf

Linking ocean biogeochemical cycles and ecosystem structure and function: results of the complex SWAMCO-4 model
Provedor de dados: 5
Autores: Pasquer, B; Laruelle, G; Becquevort, S; Schoemann, V; Goosse, H; Lancelot, C.
We present results obtained with SWAMCO-4, a complex model of the marine planktonic system calculating C, N, P, Si, Fe cycling within the upper ocean, the export production and the exchange of CO2 between the ocean and atmosphere. The model, constrained by physical, chemical and biological (grazing, lysis) controls, explicitly details the dynamics of four relevant phytoplankton functional groups with respect to C, N, P, Si, Fe cycling and climate change. Those are diatoms, pico/nano phytoplankton, coccolithophorids, and Phaeocystis spp. whose growth regulation by light, temperature and nutrients has been obtained based on a comprehensive analysis of literature reviews on these taxonomic groups. The performance of SWAMCO-4 is first evaluated in a 1D...
Tipo: Text
Palavras-chave: Ecological modelling; Diatoms; Pico/nanophytoplankton; Coccolithophorids; Phaeocystis spp.; Iron; Air-sea CO2 fluxes; Global ocean; Antarctic ocean; North Atlantic.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00232/34302/32677.pdf

A continuous tephrostratigraphic record from the Labrador Sea spanning the last 65 ka
Provedor de dados: 5
Autores: Rutledal, Sunniva; Haflidason, Hafkidi; Berben, Sarah Mp; Griem, Lisa; Jansen, Eystein.
Volcanic ash preserved in marine sediment sequences is key for independent synchronization of palaeoclimate records within and across different climate archives. Here we present a continuous tephrostratigraphic record from the Labrador Sea, spanning the last 65.5 ka, an area and time period that has not been investigated in detail within the established North Atlantic tephra framework. We investigated marine sediment core GS16]204] 22CC for increased tephra occurrences and geochemically analysed the major element composition of tephra shards to identify their source volcano(es). In total we observed eight tephra zones, of which five concentration peaks show isochronous features that can be used as independent tie]points in future studies. The main...
Tipo: Text
Palavras-chave: Marine tephra; North Atlantic; Quaternary; Tephra isochrons; Tephrochronology.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00648/76044/76980.pdf

The ICES Working Group on Oceanic Hydrography: A Bridge From In-situ Sampling to the Remote Autonomous Observation Era
Provedor de dados: 5
Autores: Gonzalez-pola, Cesar; Fratantoni, Paula; Larsen, Karin M. H.; Holliday, N. Penny; Dye, Stephen; Mork, Kjell Arne; Beszczynska-moller, Agnieszka; Valdimarsson, Hedinn; Trofimov, Alexander; Parner, Hjalte; Klein, Holger; Cisewski, Boris; Fontan, Almudena; Lyons, Kieran; Kolodziejczyk, Nicolas; Grana, Rocio; Linders, Johanna; Wodzinowski, Tycjan; Goszczko, Ilona; Cusack, Caroline.
The ICES (International Council for the Exploration of the Sea) Working Group on Oceanic Hydrography (WGOH) was established in the late 1970's with the aim of gathering experts in physical oceanography to provide regular science-based assessments of the North Atlantic hydrographical condition (basically termohaline fields). From the beginning, the WGOH has relied on repeated long-term in-situ sampling at key sites around the North Atlantic, the Nordic Seas and adjacent shelf seas. An annual Report on Ocean Climate (IROC), produced by the WGOH since the late 1990's, summarizes trends in regional hydrography and identifies patterns linking these changes across the North Atlantic. Regional analyses are prepared by local experts who are directly involved in...
Tipo: Text
Palavras-chave: Ocean climate; Hydrography; Timeseries; In-situ sampling; Periodical report; Science to policy; North Atlantic.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00488/59977/63224.pdf

Composition en cires, triglycérides, protéines et sucres du mésozooplancton
Provedor de dados: 5
Autores: Alayse-danet, Anne-marie; Daniel, Jean-yves; Le Coz, Jean-rene.
Analyses effectuées sur le zooplancton total des pêches verticales au WP2 et sur des animaux triés à partir des pêches horizontales (Campagne RCA sur les côtes Atlantiques du Portugal). On ne signale pas de différence significative entre la composition biochimique des populations du large et de la côte
Tipo: Text
Palavras-chave: Zooplancton; Milieu marin; Composition chimique; Glucide; Cire animale; Triglycéride; Protéine; Océan Atlantique Nord; Upwelling; Méiofaune; Portugal; France; Zone côtière; Zooplankton; Marine environment; Chemical composition; Carbohydrate; Animal wax; Triglyceride; Proteins; North Atlantic; Upwelling; Meiofauna; Portugal; France; Coastal zone.
Ano: 1983
URL: http://archimer.ifremer.fr/doc/00189/29976/28429.pdf

La cinématique de l'Atlantique Nord : la question de la déformation intraplaque
Provedor de dados: 5
Autores: Fidalgo González, Luis.
The main features of geodynamic evolution in the North Atlantic and the lithospheric plates surrounding it have been known for a quarter of a century now.  However, a number of questions raised by the first models published have still not been clearly answered in detail. Among them, the difficulty in adjusting the domain to the north and the south of the Faeroe-Iceland-Greenland ridge should be highlighted. This study addresses the issue by using fracture zones as the main data for our reconstructions. We show that they accurately bound the kinematical reconstructions. They also enable kinematical reorganisation periods to be studied on the scale of oceans, as well as their duration.  Reconstructions carried out on these bases confirm the existence of...
Tipo: Text
Palavras-chave: Europa; Africa; North Atlantic; Modelling; Fracture zone; Magnetic anomaly; Ocean crust; Deformation; Plate tectonic; Europe; Afrique; Atlantique Nord; Modélisation; Zone Fracture; Ouverture; Anomalie Magnétique; Croute Oceanique; Déformation; Tectonique Plaque.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/these-1205.pdf

Long-term time series in Calanus finmarchicus abundance - A question of space?
Provedor de dados: 5
Autores: Planque, Benjamin; Ibanez, F.
Year-to-year changes in abundance of the copepod Calanus finmarchicus in the North Atlantic are studied by means of the Continuous Plankton Recorder (CPR). Using data collected during the years 1962 to 1974, the spatial heterogeneity of long-term trends is studied by numerical analysis: Mantel test, Mantel correlogram, and spatio-temporal clustering. Results reveal that (1) interannual changes of C. finmarchicus abundance are spatially autocorrelated; (2) the spatial structures have a radius varying between 400 and 1100 km; and (3) there is a high variability in the annual changes observed between the different zones detected by clustering. These results show that observations made in the Northeast Atlantic cannot be extrapolated to the whole North...
Tipo: Text
Palavras-chave: North Atlantic; Calanus finmarchicus; Long-term changes; Space-time interactions; Continuous Plankton Recorder.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00093/20388/18055.pdf

Rapid switches in subpolar North Atlantic hydrography and climate during the Last Interglacial (MIS 5e)
Provedor de dados: 5
Autores: Irvali, Nil; Ninnemann, Ulysses S.; Galaasen, Eirik V.; Rosenthal, Yair; Kroon, Dick; Oppo, Delia W.; Kleiven, Helga F.; Darling, Kate F.; Kissel, Catherine.
At the peak of the previous interglacial period, North Atlantic and subpolar climate shared many features in common with projections of our future climate, including warmer-than-present conditions and a diminished Greenland Ice Sheet (GIS). Here we portray changes in North Atlantic hydrography linked with Greenland climate during Marine Isotope Stage (MIS) 5e using (sub)centennially sampled records of planktonic foraminiferal isotopes and assemblage counts and ice-rafted debris counts, as well as modern analog technique and Mg/Ca-based paleothermometry. We use the core MD03-2664 recovered from a high accumulation rate site (similar to 34 cm/kyr) on the Eirik sediment drift (57 degrees 26.34'N, 48 degrees 36.35'W). The results indicate that surface waters...
Tipo: Text
Palavras-chave: Eirik Drift; MIS 5e; North Atlantic; Last interglacial; Multiproxy.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00139/25046/23154.pdf

Les Eaux Modales du gyre subpolaire de l'Atlantique Nord : origine, formation, variabilité
Provedor de dados: 5
Autores: De Boisseson, Eric.
The subpolar Mode Waters of the North Atlantic ocean play a key role in the general oceanic surface circulation. Their life cycle has only been described from an average of observations over several decades. This description avoids the real time scale of this life cycle and smooths its variaribility. It also does not adress the setting the Mode Water properties. This thesis work deals with these aspects by analysing both the ORCA025-G70 model fields and the observations.The lagrangian analysis of the ORCA025-G70 fields highlights the key role of the North Atlantic current in the life cycle of the Mode Waters. The Mode Waters are fed and carried by this current. They form during the winter mixed layer deepening due to the surface atmospheric fluxes. The...
Tipo: Text
Palavras-chave: ORCA025 G70; Lagrangian analysis; Argo; Advection; Atmospheric fluxes; North Atlantic current; Subpolar gyre; North Atlantic; Mode water; ORCA025 G70; Analyse lagrangienne; Argo; Advection; Flux atmosphériques; Courant Nord Atlantique; Gyre subpolaire; Atlantique Nord; Eau modale.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/2010/these-7469.pdf

Independent tephrochronological evidence for rapid and synchronous oceanic and atmospheric temperature rises over the Greenland stadial-interstadial transitions between ca. 32 and 40 ka b2k
Provedor de dados: 5
Autores: Berben, Sarah M.p.; Dokken, Trond M.; Abbott, Peter M.; Cook, Eliza; Sadatzki, Henrik; Simon, Margit H; Jansen, Eystein.
Understanding the dynamics that drove past abrupt climate changes, such as the Dansgaard-Oeschger (DO) events, depends on combined proxy evidence from disparate archives. To identify leads, lags and synchronicity between different climate system components, independent and robust chronologies are required. Cryptotephrochronology is a key geochronological tool as cryptotephra horizons can act as isochrons linking disparate and/or distant records. Here, we investigated marine sediment core MD99-2284 from the Norwegian Sea to look for previously identified Greenland ice core cryptotephra horizons and define time-parallel markers between the archives. We explored potential secondary transport and depositional mechanisms that could hamper the isochronous...
Tipo: Text
Palavras-chave: Quaternary; Paleoclimatology; Paleoceanography; North Atlantic; Sedimentology; Marine cores; Ice cores; Cryptotephrochronology; DO-Events; Synchronization.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00622/73391/72606.pdf

The Atlantic Meridional Overturning Circulation and the subpolar gyre observed at the A25-OVIDE section in June 2002 and 2004
Provedor de dados: 5
Autores: Lherminier, Pascale; Mercier, Herle; Huck, Thierry; Gourcuff, Claire; Perez, Fiz F.; Morin, Pascal; Sarafanov, Artem; Falina, Anastasia.
The horizontal circulation of the subpolar gyre and the Meridional Overturning Circulation (MOC) are investigated here by comparing two snapshots of the North Atlantic as delivered by two hydrographic sections between Greenland and Portugal. The corresponding cruises were carried out in June–July 2002 and June–July 2004 on R/V Thalassa within the framework of the Ovide project. The absolute transports in June 2004 are described in detail, and then compared with transports in June 2002. The MOC (in density coordinates), driven by the volume balance between the northward North Atlantic Current (NAC) and the net southward export of dense water from the subpolar gyre, did not change: View the MathML source (1 Sv=106 m3 s−1). Its upper limb, above σ1=32.1, is...
Tipo: Text
Palavras-chave: North Atlantic; Subpolar gyre; Meridional Overturning Circulation; OVIDE; Hydrology; ADCP.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12272/9057.pdf

Decadal stability in top predator habitat preferences in the Bay of Biscay
Provedor de dados: 5
Autores: Lambert, C.; Authier, M.; Doray, Mathieu; Doremus, G.; Spitz, J.; Ridoux, V.
Most oceanographic systems, especially shelf ecosystems, are characterised by interannual variability in the timing, extent and intensity of their seasonal patterns. Such interannual variations have important consequences on top predator habitat preferences. Capitalising on oceanographic surveys performed every spring since 2004 in the Bay of Biscay (BoB), this study explored interannual variations in habitat preferences exhibited by five mobile top predator species: bottlenose and common dolphins, auks, fulmars and northern gannets. We expected to find species with similar habitat preferences every year or species exhibiting important variability in their habitat preferences. First, we identified with a Principal Component Analysis (PCA) three different...
Tipo: Text
Palavras-chave: Habitat preference; Temporal variability; Cetaceans; Seabirds; North Atlantic; Bay of Biscay.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00431/54226/55549.pdf

Les dinophycées pélagiques et benthiques du Golfe de Gascogne sud de la Bretagne à Arcachon
Provedor de dados: 5
Autores: Paulmier, Gerard.
Les microphytes planctoniques et benthiques du Golfe de Gascogne sont relativement diversifiés. Cette diversification est probablement en rapport avec la situation hydrologique particulière de cette région enrichie par des mélanges de masses d'eau de diverses origines et par des apports continentaux importants. Dans ce contexte, les dinophycées sont nombreuses et variées et occupent toutes les niches écologiques. 230 taxons ont été répertoriés. Quelques espèces sont connues pour provoquer périodiquement des colorations de la mer "eaux rouges" et quelques-unes sont maintenant redoutées pour leur toxicité.
Tipo: Text
Palavras-chave: Zone pélagique; Zone benthique; Phytoplancton; Diversité espèces; Niche écologique; Inventaire floristique; Cycle développement; Répartition géographique; Morphologie; Pyrrophycophyta; Golfe de Gascogne; Bretagne; Landes; Algae; Thallophyta; Océan Atlantique Nord; Océan Atlantique; France; Europe; Aquitaine; Pelagic zone; Benthic zone; Phytoplankton; Species diversity; Niche; Floral survey; Life cycle; Geographic distribution; Morphology; Pyrrophycophyta; Bay of Biscay; Bretagne; Landes; Algae; Thallophyta; North Atlantic; Atlantic Ocean; France; Europe; Aquitaine.
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00260/37097/35613.pdf

Neodymium isotopic composition and rare earth element concentrations in the deep and intermediate Nordic Seas: Constraints on the Iceland Scotland Overflow Water signature
Provedor de dados: 5
Autores: Lacan, F; Jeandel, C.
Neodymium isotopic composition and rare earth element concentrations were measured in seawater samples from eleven stations in the Nordic Seas. These data allow us to study how the Iceland Scotland Overflow Water ( ISOW) acquires its neodymium signature in the modern ocean. The waters overflowing the Faroe Shetland channel are characterized by epsilon(Nd) = -8.2 +/- 0.6, in good agreement with the only other data point, published 19 years ago. In the Greenland and Iceland Seas the water masses leading to the formation of the ISOW display lower neodymium isotopic composition, with epsilon(Nd) around -11 and -9, respectively. Since no water masses in the Nordic Seas are characterized by epsilon(Nd) &gt; -8, the radiogenic signature of the ISOW likely...
Tipo: Text
Palavras-chave: Iceland Scotland Overflow Water; Neodymium isotopic composition; Nordic Seas; North Atlantic; Rare earth; Sediment water mass interactions; Paleoceanography; Water masses; Geochemistry.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00228/33924/32308.pdf

Présence d'un Protogonyaulax sp. sur le littoral atlantique français pendant l'hiver 1987
Provedor de dados: 5
Autores: Lassus, Patrick; Bardouil, Michele.
A dinoflagellate belonging to Protogonyaulax genera and forming more than 20 cells chains was observed from November 1987 to February 1988 in Vilaine Bay and in the west ofIle d'Yeu (France). This species was not detected in coastal phytoplankton during preceding surveys. Close to Protogonyaulax affinis it seems to be a winter developing species for this coastal area. Vertical distribution shows in december a migration of the patch towards deeper layers. Increasing occurrences of species belonging to Protogonyaulax (Alexandrium Balech) genera inshore or coastal waters need to pay more attention to the taxonomy of such organisms. Some species are effectively well known as poisons producers.
Tipo: Text
Palavras-chave: Pyrrophycophyta; Milieu marin; Morbihan; Vendée; Océan Atlantique Nord; Plancton; Morphologie; Algae; Thallophyta; Bretagne; France; Europe; Pays de Loire; Océan Atlantique; Pyrrophycophyta; Marine environment; Morbihan; Vendée; North Atlantic; Plankton; Morphology; Algae; Thallophyta; Bretagne; France; Europe; Pays de Loire; Atlantic Ocean.
Ano: 1988
URL: http://archimer.ifremer.fr/doc/00133/24474/22485.pdf

The main pycnocline in the North Atlantic subtropical gyre from Argo Data
Provedor de dados: 5
Autores: Feucher, Charlene; Maze, Guillaume; Mercier, Herle.
In the north Atlantic subtropical gyre, the oceanic vertical structure of density is characterized by a region of rapid increase with depth. This layer is called the permanent pycnocline because this density feature is observed throughout the year. The pycnocline is the transition layer between light, low-latitude, surface water masses which are ventilated every winter when penetrated locally by the mixed layer and dense, deeper water masses whose properties are set in the high latitudes and circulate equatorward. In-situ data from the Argo array provide temperature/salinity profiles allowing the characterization in space and time of the permanent pycnocline. We thus developed a new method to characterize its depth, thickness and thermohaline...
Tipo: Text
Palavras-chave: Argo; Quality Control; Pattern; Clustering; North Atlantic; Subtropical gyre; Stratification.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00242/35315/33838.pdf

The influence of high-latitude flux lobes on the Holocene paleomagnetic record of IODP Site U1305 and the northern North Atlantic
Provedor de dados: 5
Autores: Stoner, Joseph S.; Channell, James E. T.; Mazaud, Alain; Strano, Sarah E.; Xuan, Chuang.
Paleomagnetic analysis and radiocarbon dating of an expanded Holocene deep-sea sediment sequence recovered by Integrated Ocean Drilling Program (IODP) Expedition 303 from Labrador Sea Site U1305 (Lat.: 57 degrees 28.5 N, Long.: 48 degrees 31.8 W, water depth 3459 m) provides insights into mechanisms that drive both paleomagnetic secular variation (PSV) and magnetization acquisition in deep-sea sediments. Seventeen radiocarbon dates on planktonic foraminifera define postglacial (ca. 8 ka) sedimentation rates as ranging from 35 to &gt; 90 cm/kyr. Alternating field (AF) demagnetization of u-channel samples show that these homogeneous sediments preserve a strong, stable, and consistently well-defined component magnetization. Normalized remanence records pass...
Tipo: Text
Palavras-chave: Paleomagnetism; North Atlantic; Paleointensity.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00264/37480/36500.pdf

Holocene sea surface conditions in the western North Atlantic: Spatial and temporal heterogeneities
Provedor de dados: 5
Autores: Solignac, S; Giraudeau, J; De Vernal, A.
Holocene records of sea surface conditions in the western Nordic seas were obtained from quantitative reconstructions based on dinoflagellate cyst assemblages. Two sediment cores from the east Greenland and the north Iceland shelves provide a detailed account of the long- and short-term dynamics of the opposing flows of Arctic versus Atlantic waters. Both marker species and quantitative reconstructions depict an overall trend toward warmer winter temperatures, saltier surface waters, and decreased sea ice extent. The latter is supported by a close relationship between relative abundances of an Atlantic dinocyst species, Nematosphaeropsis labyrinthus, and ice-rafted debris (IRD) records. We propose that the late Holocene increased IRD delivery in the...
Tipo: Text
Palavras-chave: Holocene; North Atlantic; Sea-surface conditions.
Ano: 2006
URL: https://archimer.ifremer.fr/doc/00234/34573/33124.pdf

Sources, cycling and transfer of mercury in the Labrador Sea (Geotraces -Geovide cruise)
Provedor de dados: 5
Autores: Cossa, Daniel; Heimburger, L. E.; Sonke, J. E.; Planquette, H.; Lherminier, Pascale; Garcia-ibanez, Maria Isabel; Perez, Ff; Sarthou, G.
The Labrador Sea links the Arctic and North Atlantic oceans and constitutes one of the main entrances of atmospheric inputs into the Ocean's interior. We report here the first high-resolution Hg distribution pattern along a transect from Greenland to Labrador coasts sampled after the 2014 winter convection. Total Hg concentrations in unfiltered (HgTUNF) samples ranged from 0.25 pmol L− 1 to 0.67 pmol L− 1 averaging 0.44 ± 0.10 pmol L− 1 (n = 113, 1σ). Concentrations in filtered samples (HgTF, &lt; 0.45 μm) represented from 62 to 92% of the HgTUNF and exhibited a similar distribution. High HgTUNF concentrations were found (i) in the waters of the Labrador Current, which receive desalted waters from the Canadian Arctic Archipelago, and (ii) in the waters...
Tipo: Text
Palavras-chave: Labrador Sea; Mercury; North Atlantic.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00411/52207/52929.pdf

Regulation of the Phytoplankton Heme b Iron Pool During the North Atlantic Spring Bloom
Provedor de dados: 5
Autores: Louropoulou, Evangelia; Gledhill, Martha; Browningi, Thomas J.; Desai, Dhwani K.; Barraqueta, Jan-lukas Menzel; Tonnard, Manon; Sarthou, Geraldine; Planquette, Helene; Bowie, Andrew R.; Schmitz, Ruth A.; Laroche, Julie; Achterberg, Eric P.
Heme b is an iron-containing co-factor in hemoproteins. Heme b concentrations are low (&lt; 1 pmol L-1) in iron limited phytoplankton in cultures and in the field. Here, we determined heme b in marine particulate material (&gt; 0.7 mu m) from the North Atlantic Ocean (GEOVIDE cruise - GEOTRACES section GA01), which spanned several biogeochemical regimes. We examined the relationship between heme b abundance and the microbial community composition, and its utility for mapping iron limited phytoplankton. Heme b concentrations ranged from 0.16 to 5.1 pmol L-1 (median = 2.0 pmol L-1, n = 62) in the surface mixed layer (SML) along the cruise track, driven mainly by variability in biomass. However, in the Irminger Basin, the lowest heme b levels (SML: median =...
Tipo: Text
Palavras-chave: Heme b; North Atlantic; Phytoplankton; Diatoms; Iron; Limitation; GEOTRACES; GEOVIDE.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00508/61940/66029.pdf

Contrasting intrainterstadial climatic evolution between high and middle North Atlantic latitudes: A close-up of Greenland Interstadials 8 and 12
Provedor de dados: 5
Autores: Sanchez Goni, Maria Fernanda; Landais, Amaelle; Cacho, Isabel; Duprat, Josette; Rossignol, Linda.
Three highly resolved pollen and sea surface temperature records from the Iberian margin (36-42 degrees N) reveal the local evolution of vegetation and climate associated with the rapid climatic variability of marine isotope stage 3. The comparison of the climate at these midlatitudes with delta D and d excess from Greenland ice cores shows that the north-south climatic gradient underwent strong variations during the long Greenland Interstadials (GIs) 8 and 12. After the Northern Hemispheric rapid warming at the Greenland Stadial (GS)-GI transition, the trend during the first part of the GI is a Greenland cooling and an Iberian warming. This increase of the North Atlantic climatic gradient led to moisture transportation to Greenland from midlatitudes...
Tipo: Text
Palavras-chave: Greenland interstadial; Iberia; Dansgaard-Oeschger variability; North Atlantic; Precipitation source; Pollen.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00218/32912/31412.pdf

Oversampling of sedimentary series collected by giant piston corer: Evidence and corrections based on 3.5-kHz chirp profiles
Provedor de dados: 5
Autores: Szeremeta, N; Bassinot, F; Balut, Y; Labeyrie, L; Pagel, M.
The depth-scale accuracy of marine sedimentary series collected by coring is of key importance for the precise calculation of sedimentation rates and fluxes. For three giant piston cores collected during the InterPole MD99-114/International Marine Past Global Changes Study (IMAGES) V cruise (MD99-2227, MD99-2246, and MD99-2251), the 3.5-kHz chirp profiles recorded on board are compared to synthetic seismograms computed from physical property logs measured on cores. In each case, the perfect match of main deep reflectors requires a significant upward shift of the water-sediment (W/S) interface in the synthetic seismograms with respect to the 3.5-kHz profiles. Since no drastic perturbation of the physical property logs is observed, this upward shift is...
Tipo: Text
Palavras-chave: Correction of coring-induced sediment oversampling; Giant piston coring; IMAGES cores; North Atlantic.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00229/33978/32344.pdf

Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic
Provedor de dados: 5
Autores: Puerta, Patricia; Johnson, Clare; Carreiro-silva, Marina; Henry, Lea-anne; Kenchington, Ellen; Morato, Telmo; Kazanidis, Georgios; Luis Rueda, Jose; Urra, Javier; Ross, Steve; Wei, Chih-lin; Manuel Gonzalez-irusta, Jose; Arnaud-haond, Sophie; Orejas, Covadonga.
Circulation patterns in the North Atlantic Ocean have changed and re-organized multiple times over millions of years, influencing the biodiversity, distribution, and connectivity patterns of deep-sea species and ecosystems. In this study, we review the effects of the water mass properties (temperature, salinity, food supply, carbonate chemistry, and oxygen) on deep-sea benthic megafauna (from species to community level) and discussed in future scenarios of climate change. We focus on the key oceanic controls on deep-sea megafauna biodiversity and biogeography patterns. We place particular attention on cold-water corals and sponges, as these are ecosystem-engineering organisms that constitute vulnerable marine ecosystems (VME) with high associated...
Tipo: Text
Palavras-chave: North Atlantic; Deep-sea; Biodiversity; Biogeography; Water masses; Vulnerable marine ecosystems.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00628/74006/73330.pdf

Full-depth temperature trends in the northeastern Atlantic through the early 21st century
Provedor de dados: 5
Autores: Desbruyeres, D.g.; Mcdonagh, E. L.; King, B. A.; Garry, F. K.; Blaker, A. T.; Moat, B. I.; Mercier, Herle.
The vertical structure of temperature trends in the northeastern Atlantic (NEA) is investigated using a blend of Argo and hydrography data. The representativeness of sparse hydrography sampling in the basin mean is assessed using a numerical model. Between 2003 and 2013, the NEA underwent a strong surface cooling (0–450 m) and a significant warming at intermediate and deep levels (1000 m to 3000 m) that followed a strong cooling trend observed between 1988 and 2003. During 2003–2013, gyre-specific changes are found in the upper 1000 m (warming and cooling of the subtropical and subpolar gyres, respectively), while the intermediate and deep warming primarily occurred in the subpolar gyre, with important contributions from isopycnal heave and water mass...
Tipo: Text
Palavras-chave: North Atlantic; Temperature; Observations; Hiatus.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00236/34677/33026.pdf

Freshwater influx, hydrographic reorganization and the dispersal of ice-rafted detritus in the sub-polar North Atlantic Ocean during the last deglaciation
Provedor de dados: 5
Autores: Small, David; Austin, William; Rinterknecht, Vincent.
A sediment core from the north-east North Atlantic contains high-resolution co-registered foraminiferal O-18 and ice-rafted detritus (IRD) records for the last deglaciation. These reveal a distinct ice-rafting event that occurred at the time of Greenland Interstade 1d (GI-1d), a feature also seen in other high-resolution cores from the North Atlantic. The occurrence of a geographically widespread peak in IRD at ice distal sites at a time when increased freshwater flux to the surface ocean is inferred to have caused rapid cooling suggests a mechanistic link between the processes, analogous to the Younger Dryas (GS-1) cooling episode. The general absence of IRD at southern locations at other times during GI-1 when the flux of icebergs from surviving ice...
Tipo: Text
Palavras-chave: Deglaciation; Hydrography; Ice-rafted detritus; North Atlantic; Sea surface temperature.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00291/40180/39238.pdf

Growth Response of Arctica Islandica to North Atlantic Oceanographic Conditions Since 1850
Provedor de dados: 5
Autores: Poitevin, Pierre; Thébault, Julien; Siebert, Valentin; Donnet, Sébastien; Archambault, Philippe; Doré, Justine; Chauvaud, Laurent; Lazure, Pascal.
The Northwest Atlantic is a key region with an essential role in global climate regulation, redistributing heat and influencing the carbon cycle. However, little is known about its evolution before 1950, mainly because of the lack of long-term instrumental measurements. The hard parts of long-lived marine biota hold the potential to extend instrumentally derived observation by several decades or centuries and enhance our understanding of global climate processes. Here, we investigate the effects of local, regional, and large-scale climate variability on the marine bivalve, Arctica islandica (Linnaeus, 1767) from Saint-Pierre and Miquelon (SPM). This archipelago lies at the boundary zone between the cold Labrador Current in the north and the warm Gulf...
Tipo: Text
Palavras-chave: Arctica islandica; Paleoecology; North Atlantic; Sub polar gyre; Labrador current; Bivalve; Sclerochronology; Climate change.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00509/62050/66198.pdf

Tracing marine cryptotephras in the North Atlantic during the last glacial period: Protocols for identification, characterisation and evaluating depositional controls
Provedor de dados: 5
Autores: Abbott, Peter M.; Griggs, Adam J.; Bourne, Anna J.; Davies, Siwan M.
Tephrochronology is increasingly being utilised as a key tool for improving chronological models and correlating disparate palaeoclimatic sequences. For many sedimentary environments, however, there is an increased recognition that a range of processes may impart a delay in deposition and/or rework tephra. These processes can affect the integrity of tephra deposits as time-synchronous markers, therefore, it is crucial to assess their isochronous nature, especially when cryptotephras are investigated in a dynamic marine environment. A methodology for the identification and characterisation of marine cryptotephras alongside a protocol for assessing their integrity is outlined. This methodology was applied to a wide network of North Atlantic marine sequences...
Tipo: Text
Palavras-chave: Quaternary; Palaeoceanography; Tephrochronology; North Atlantic; Transport and deposition; Marine cores; Glass shard concentrations.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00495/60700/83609.pdf

Tracing marine cryptotephras in the North Atlantic during the last glacial period: Improving the North Atlantic marine tephrostratigraphic framework
Provedor de dados: 5
Autores: Abbott, Peter M.; Griggs, Adam J.; Bourne, Anna J.; Chapman, Mark R.; Davies, Siwan M.
Tephrochronology is increasingly being recognised as a key tool for the correlation of disparate palae-oclimatic archives, underpinning chronological models and facilitating climatically independent comparisons of climate proxies. Tephra frameworks integrating both distal and proximal tephra occurrences are essential to these investigations providing key details on their spatial distributions, geochemical signatures, eruptive sources as well as any available chronological and/or stratigraphic information. Frameworks also help to avoid mis-correlation of horizons and provide important information on volcanic history. Here we present a comprehensive chronostratigraphic framework of 14 tephra horizons from North Atlantic marine sequences spanning 60-25 cal ka...
Tipo: Text
Palavras-chave: Quaternary; Palaeoceanography; Tephrochronology; North Atlantic; Tephra framework; Marine cores.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00495/60702/83611.pdf

Assessment of contaminant concentrations in sediments, fish and mussels sampled from the North Atlantic and European regional seas within the ICON project
Provedor de dados: 5
Autores: Robinson, Craig D.; Webster, Lynda; Martinez-gomez, Concepcion; 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 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...
Tipo: Text
Palavras-chave: Integrated assessment; ICES; North Atlantic; North Sea; Baltic Sea; Mediterranean Sea; Polycyclic aromatic hydrocarbons (PAHs); Polychlorinated biphenyls (PCBs); Trace metals; Environmental monitoring.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00324/43520/43051.pdf

The duration of migration of Atlantic Anguilla larvae
Provedor de dados: 5
Autores: Bonhommeau, Sylvain; Castonguay, Martin; Rivot, Etienne; Sabatie, Richard; Le Pape, Olivier.
Oceanic larvae of the European (Anguilla anguilla) and American (A. rostrata) eels have to cross the Atlantic Ocean from the Sargasso Sea to European or North American coasts before entering continental habitats. In some European rivers, eel recruitment is now &lt; 1% of levels in the 1980s. A better understanding of the effects of anthropogenic pressures and environmental fluctuations on eel larvae and subsequent recruitment is a prerequisite to build efficient management plans. The present paper provides insight into the critical oceanic phase of the eel life cycle with a focus on the duration of the larval migration whose estimates varies between 7 months and more than 2 years in both species. Does this range correspond to a natural variability in...
Tipo: Text
Palavras-chave: Lagrangian modelling; Leptocephali; North Atlantic; Otoliths; Sargasso Sea.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12208/9033.pdf

Deep-water mass source and dynamic associated with rapid climatic variations during the last glacial stage in the North Atlantic: A multiproxy investigation of the detrital fraction of deep-sea sediments
Provedor de dados: 5
Autores: Ballini, M; Kissel, C; Colin, C; Richter, T.
[1] In order to investigate North Atlantic Deep Water (NADW) dynamics and variability during the last glacial stage, a very high resolution multiproxy analysis of the detrital fraction of sediments deposited during Heinrich event 4 and Dansgaard-Oeschger cycles 8 and 7 has been conducted on three deep-sea cores. These cores are distributed along the path of the North Atlantic Deep Water from the Faeroe Shetland Channel to the Reykjanes ridge and the Irminger basin. The concentration in fine-grained magnetites, the Ti-content, and the smectite percentage within the clay minerals show similar and coeval fluctuations at each site and are comparable from one site to the other. This is the imprint of the detrital fraction originating from the northern basaltic...
Tipo: Text
Palavras-chave: Glacial period; Dansgaard-Oeschger cycles; North Atlantic; Bottom water circulation; Magnetic properties; Clay minerals.
Ano: 2006
URL: https://archimer.ifremer.fr/doc/00235/34585/33077.pdf

Do changes in environmental and fishing pressures impact marine communities? An empirical assessment
Provedor de dados: 5
Autores: Rochet, Marie-joelle; Trenkel, Verena; Carpentier, Andre; Coppin, Franck; Gil De Sola, Luis; Leaute, Jean-pierre; Mahe, Jean-claude; Maiorano, Porzia; Mannini, Alessandro; Murenu, Matteo; Piet, Gerjan; Politou, Chrissi-yianna; Reale, Bruno; Spedicato, Maria-teresa; Tserpes, George; Bertrand, Jacques.
P&gt;1. The development of ecosystem approaches to environmental management implies the need to account for multiple pressures on ecosystems. Trends in multiple metrics that respond differently to changes in major environmental pressures need to be combined to evaluate the impacts of fishing and environmental changes on fish communities. 2. An exploited fish community is viewed as a three-level food chain in which the two upper levels, or functional groups, are targeted by fishing fleets, while the lowest level is subject to environmental variation. Qualitative modelling is used to predict changes at the two upper levels, that is, top-down vs. bottom-up perturbations. Abundance and length metrics are calculated from survey data for 14 Mediterranean and...
Tipo: Text
Palavras-chave: Bottom-up control; Community metrics; Compensation; Ecosystem approach to fisheries; Ecosystem assessment; Functional groups; Groundfish community; Mediterranean; North Atlantic; Top-down control.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00008/11925/8637.pdf

Optimising the use of marine tephrochronology in the North Atlantic: a detailed investigation of the Faroe Marine Ash Zones II, III and IV
Provedor de dados: 5
Autores: Griggs, Adam J.; Davies, Siwan M.; Abbott, Peter M.; Rasmussen, Tine L.; Palmer, Adrian P.
Tephrochronology is central to the INTIMATE(1) goals for testing the degree of climatic synchroneity during abrupt climatic events that punctuated the last glacial period. Since their identification in North Atlantic marine sequences, the Faroe Marine Ash Zone II (FMAZ II), FMAZ III and FMAZ IV have received considerable attention due to their potential for high-precision synchronisation with the Greenland ice-cores. In order to optimise the use of these horizons as isochronous markers, a detailed re-investigation of their geochemical composition, sedimentology and the processes that deposited each ash zone is presented. Shard concentration profiles, geochemical homogeneity and micro-sedimentological structures are investigated for each ash zone preserved...
Tipo: Text
Palavras-chave: North Atlantic; Tephra; Taphonomy; Synchronisation; Micromorphology.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00496/60734/65220.pdf

Etude de la variabilité de la circulation du gyre subpolaire de l'Atlantique Nord à partir des données Ovide et de mesures satellitaires
Provedor de dados: 5
Autores: Gourcuff, Claire.
The cyclonic circulation of the North Atlantic subpolar gyre, between 50°N and 63°N, plays a key role in the climate variability. The Ovide program contributes to the observation of the circulation in this region. A section is repeated every two years in summer since 2002 between Greenland and Portugal following a path close the Fourex 1997 section. To get transport estimates across the sections, a geostrophic box inverse model is used, constrained with direct current measurements.  Our new estimates of Fourex transports show the need to use constraints temporally associated with the section to get transports estimates representative of the circulation at the section realisation dates. It is also shown that altimetry velocities can be used instead of ADCP...
Tipo: Text
Palavras-chave: Inverse Model; Courantology; Geostrophy; Altimetry; East Greenland Coastal Current; Freshwater fluxes; Heat transport; Meridionnal Overturning Circulation (MOC); Variability; North Atlantic; Subpolar gyre; Ovide; Modèle inverse; Géostrophie; Courantométrie; Altimétrie; Courant Côtier Est Groenlandais; Flux d'eau douce; Transport de chaleur; Circulation Méridienne de Retournement (MOC); Variabilité; Atlantique Nord; Gyre subpolaire; Ovide.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-6226.pdf

Marine shallow-water Haplosclerida (Porifera) from the South-Eastern Part of the North Atlantic Ocean
Provedor de dados: 16
Autores: Weerdt, W.H. de; Soest, R.W.M van.
Sixteen species of marine Haplosclerida were collected by the CANCAP-expeditions, among which two are new to science, viz. Petrosia canariensis and Oceanapia cancap. The Haplosclerida fauna of the south-eastern part of the North Atlantic, comprising 46 species, is reviewed, discussed and compared with those of neighbouring areas of the North Atlantic (NE Atlantic, W Atlantic, West Indies, Mediterranean). Three distribution patterns are recognized: Mediterranean-Atlantic, endemic and amphi-Atlantic.
Tipo: Article / Letter to the editor
Palavras-chave: Porifera: Haplosclerida; North Atlantic; Biogeography; New species.; 42.72.
Ano: 1986
URL: http://www.repository.naturalis.nl/record/317675

Pectinoidea (Mollusca: Bivalvia) from Iceland
Provedor de dados: 16
Autores: Dijkstra, H.H.; Waren, A.; Gudmundsson, G.
The Icelandic pectinoid fauna is reviewed, based on material from the benthic survey programme BIOICE and 17 species are recorded. Similipecten oskarssoni is proposed as a replacement name for Pecten groenlandicus var. minor Locard, 1898 (Propeamussiidae), which is considered a valid species. Lectotypes are designated for Pecten groenlandicus var. minor and Pecten frigidus Jensen, 1904 (Pectinidae). Cyclopecten ambiannulatus Schein, 1989, Parvamussium propinquum (Smith, 1885), Catillopecten eucymatus (Dall, 1898), and Aequipecten opercularis (Linnaeus, 1758) were previously not known from the Icelandic fauna. All species are figured and described and distinguishing characters are discussed. The distribution in Scandinavian and North Atlantic waters is...
Tipo: Article / Letter to the editor
Palavras-chave: Pectinoidea; Taxonomy; New species; North Atlantic; Iceland; BIOICE; 42.73.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/410534

Revision of the Genera Bellonella, Eleutherobia, Nidalia and Nidaliopsis (Octocorallia: Alcyoniidae and Nidalliidae), with descriptions of two new Genera
Provedor de dados: 16
Autores: Verseveldt, J.; Bayer, F.M.
Nineteen species of Alcyoniidae formerly assigned to various genera are here placed in the genera Bellonella and Eleutherobia; three new species are described in Bellonella. Sixteen species characterized by an abundance of capstans among their sclerites, formerly assigned to Alcyonium, Bellonella and Nidalia are now transferred as valid species or synonyms to the genus Eleutherobia, in which two new species are described making a total of 14 valid species. A new genus Inflatocalyx is established for a digitiform subantarctic species having only very few sclerites, in the form of nearly smooth spindles, and polyps retractile within large, inflated calyces. Six species comprising the genus Cactogorgia are transferred to Nidalia, and three new species are...
Tipo: Article / Letter to the editor
Palavras-chave: Octocorallia; Alcyoniidae; Nidaliidae; Inflatocalyx genus nov.; Pieterfaurea genus nov.; New species; Keys; North Atlantic; Pacific; Philippines; Japan; Hawaii.; 42.72.
Ano: 1988
URL: http://www.repository.naturalis.nl/record/317855

The find of a whale barnacle, Cetopirus complanatus (Mörch, 1853), in 10th century deposits in the Netherlands
Provedor de dados: 16
Autores: Holthuis, L.B.; Smeenk, C.; Laarman, F.J.
A specimen of Cetopirus complanatus dating from the 10th century A.D. is described from archaeological excavations at Tiel, the Netherlands. Two vertebral parts of northern right whales Eubalaena glacialis: a vertebral arch and an epiphysis, were also found, possibly dating from the same period. The disc-like epiphysis had been used as a cutting board. The specimens probably had reached Tiel through early trade in whale products. Cetopirus complanatus is only known from right whales of the genus Eubalaena. It has not been found in the Northern Hemisphere since the late 19th century. Its host species in the North Atlantic and North Pacific, E. glacialis, is now very rare as a result of whaling.
Tipo: Article / Letter to the editor
Palavras-chave: Cetopirus complanatus; Cirripedia; Whale barnacles; The Netherlands; Archaeological find; History; Distribution; Host species; Eubalaena; Right whales; Eubalaena glacialis; Northern right whale; North Atlantic; North Sea; Whaling.; 42.74.
Ano: 1998
URL: http://www.repository.naturalis.nl/record/317559

Sponge diversity and community composition in Irish bathyal coral reefs
Provedor de dados: 16
Autores: Soest, R.W.M van; Cleary, D.F.R.; Kluijver, M.J. de; Lavaleye, M.S.S.; Maier, C.; Duy, F.C. van.
Sponge diversity and community composition in bathyal cold water coral reefs (CWRs) were examined at 500-900 m depth on the southeastern slopes of Rockall Bank and the northwestern slope of Porcupine Bank, to the west of Ireland in 2004 and 2005 with boxcores. A total of 104 boxcore samples, supplemented with 10 trawl/dredge attempts, were analyzed for the presence and abundance of sponges, using microscopical examination of (sub)samples of collected coral branches, and semi-quantitative macroscopic examination. Approximate minimum size of identified and counted sponge individuals was 1 mm. Literature data were added to the Porcupine Bank results to compensate for a less intensive sampling program in that location. Species richness and abundance were...
Tipo: Article / Letter to the editor
Palavras-chave: Coldwater; Multivariate analysis; North Atlantic; Ordination; PCA; Porifera; RDA; 42.72.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/226534

Pasiphaeid shrimps from the eastern North Atlantic and the Caribbean Sea, with the description of a new species of Pasiphae (Crustacea: Decapoda: Pasiphaeidae)
Provedor de dados: 16
Autores: Iwasaki, N.
Seven species of Pasiphaeid shrimps including a new species from the eastern North Atlantic and the Caribbean Sea are described.
Tipo: Article / Letter to the editor
Palavras-chave: Crustacea Decapoda; Pasiphaeidae; Pasiphaea; Parapasiphae; New species; North Atlantic; Caribbean Sea; 42.74.
Ano: 1990
URL: http://www.repository.naturalis.nl/record/318173

Distribution of Myctophidae (Pisces, Myctophiformes) during the four seasons in the mid North Atlantic
Provedor de dados: 16
Autores: Spoel, S. van der; Bleeker, J.
The distribution, temperature, and size ranges of 60 species of myctophids in the North Atlantic between 55°N and 24°N along approximately 30°W are recorded for the four seasons. The general zoogeography and migration is discussed. Faunal groups of species, faunal borders, and transition zones near 50°N, 41 °N, and 29°N for myctophids are distinguished and discussed.
Tipo: Article / Letter to the editor
Palavras-chave: Myctophidae; Biogeography; North Atlantic; Faunal borders.
Ano: 1991
URL: http://www.repository.naturalis.nl/record/504270

New morphological data on Solariella obscura (Trochoidea: Solariellidae) from New Jersey, USA
Provedor de dados: 103
Autores: Dornellas,Ana Paula S.; Simone,Luiz R.L.
Anatomical data on Solariellaobscura (Couthouy, 1838) are presented and analyzed. The main features of this species, when compared with other known trochoids, are: ctenidium with thick lamellae; enlarged ureter (that may indicate sexual dimorphism) instead of a modified urogenital papilla; odontophore very different from other trochoids such as Calliostoma, Agathistoma, Monodonta, and Gaza, with short m6, large mj and m4 pairs and absent m8 pair and posterior cartilages; esophageal valve surrounding the odontophore ventrally; anterior and mid-esophagus composed of several thin folds and a very wide cerebral ganglion. Solariellaobscura differs from Solariellavaricosa (Mighels &amp; Adams, 1842) by having lower spire, spiral cords weaker on the base and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Anatomy; Comparative data; North Atlantic; Redescription.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702015000200162