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| Registros recuperados: 62 | |
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| 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 |
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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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| 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 > 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 |
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| 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 |
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| 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 |
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| 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 |
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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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| 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 |
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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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| 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 |
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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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| 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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| 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 |
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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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| 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 |
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| Registros recuperados: 62 | |
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