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| Registros recuperados: 208 | |
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| Matsumoto, Haru; Bohnenstiehl, Delwayne R.; Tournadre, Jean; Dziak, Robert P.; Haxel, Joseph H.; Lau, T. -k. A.; Fowler, Matt; Salo, Sigrid A.. |
| In late 2007, two massive icebergs, C19a and B15a, drifted into open water and slowly disintegrated in the southernmost Pacific Ocean. Archived acoustic records show that the high-intensity underwater sounds accompanying this breakup increased ocean noise levels at mid-to-equatorial latitudes over a period of ∼1.5 years. More typically, seasonal variations in ocean noise, which are characterized by austral summer-highs and winter-lows, appear to be modulated by the annual cycle of Antarctic iceberg drift and subsequent disintegration. This seasonal pattern is observed in all three Oceans of the Southern Hemisphere. The life cycle of Antarctic icebergs affects not only marine ecosystem but also the sound environment in far-reaching areas and must be... |
| Tipo: Text |
Palavras-chave: Antarctica; Iceberg; Ocean noise; Seasonality; Trend. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00205/31613/30035.pdf |
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| Schmitt, A.; Elliot, M.; Thirumalai, K.; La, C.; Bassinot, F.; Petersen, J.; Movellan, A.; Jorry, Stephan; Borgomano, J.. |
| The ratio of magnesium to calcium (Mg/Ca) in foraminiferal shells is commonly used as a proxy for past ocean temperature. Recent advances in elemental analyses now enable single-specimen measurements of planktic foraminifera and thus, can provide information on past seasonal and interannual variability, owing to the near-monthly lifespan of foraminifera. In this study, we explore the temperature variance recorded by Mg/Ca in tests of foraminifera Globigerinoides ruber, a planktic species that occurs throughout the year in tropical waters. Using LA-ICP-MS, we characterize Mg/Ca variability in single specimens of two morphotypes of G. ruber picked from a sediment core retrieved offshore New Caledonia. We provide an estimate of the range of calcification... |
| Tipo: Text |
Palavras-chave: Globigerinoides ruber; Mg/Ca ratio; Sea surface temperature; LA-ICPMS; Seasonality; Quaternary. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00472/58336/60890.pdf |
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| Barraquand, F.; Picoche, C.; Maurer, Daniele; Carassou, L.; Auby, Isabelle. |
| Phytoplanktonic communities maintain a high diversity in a seemingly homogeneous environment, competing for the same set of resources. Many theories have been proposed to explain this coexistence despite likely competition, such as contrasted responses to temporal environmental variation. However, theory has developed at a faster pace than empirical evaluation using field data, which requires inferring drivers of community dynamics from observational time series. Here, we combine autoregressive models with a data set spanning more than 20 years of phytoplankton counts every two weeks, together with nutrients and physical variables. By comparing models dominated by nutrients or physical variables (hydrodynamics and climate), we first explore which abiotic... |
| Tipo: Text |
Palavras-chave: Competition; Diatoms; Dinoflagellates; Hydrodynamics; Interactions; MAR; Mutualism; Network; Population dynamics; Seasonality; Time series. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57257/59285.pdf |
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| Romero, Estela; Garnier, Josette; Lassaletta, Luis; Billen, Gilles; Le Gendre, Romain; Riou, Philippe; Cugier, Philippe. |
| We provide data on nutrient export for 28 rivers in southwestern Europe and analyze long-term changes in the context of anthropogenic pressures and regulation policies. Special attention is given to seasonal variations, because the integrated annual values that are usually provided do not allow us to establish comparisons with seasonal phytoplankton dynamics. The eutrophication risk associated with river inputs is addressed by means of an indicator (Index of Coastal Eutrophication Potential, ICEP, Billen and Garnier, Mar Chem 106:148–160, 2007). An overview of the temporal evolution and the intra-annual variability of the ICEP is discussed for specific rivers and integrated coastal regions. The annual dynamics of the eutrophication indicator is analyzed to... |
| Tipo: Text |
Palavras-chave: River inputs; Coastal zone; N:P:Si stoichiometry; Eutrophication; Seasonality; Europe. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00090/20152/17928.pdf |
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| Souza, Aj; Simpson, Jh; Harikrishnan, M; Malarkey, J. |
| The intensity, structure and variability of the slope current have been determined from 16 months of observations with Acoustic Doppler Current Profilers (ADCP) and conventional current meters on a cross-slope section at the Hebridean shelf edge during the Shelf Edge Study (SES) programme. After removal of the tidal signals, the mean flow over the upper slope is found to be closely parallel to the topography with speeds of . 20 cmEs.1. The flow extends down to a depth of 500 m and is predominantly barotropic, especially in winter when the flow is practically uniform between 350 m and the surface. In summer, there is a significant baroclinic component with a pronounced maximum in current at a depth of about 200 m but more than 80% of the kinetic energy is... |
| Tipo: Text |
Palavras-chave: Slope current; Seasonality; Velocity structure. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00292/40275/38648.pdf |
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| Garcia-lafuente, J.; Delgado, J.; Sanchez Roman, A.; Soto, J.; Carracedo, Lidia; Diaz Del Rio, G.. |
| Four-year time series of observations in Espartel sill at the western part of the Strait of Gibraltar have been analyzed in order to investigate the variability of the Mediterranean outflow. It is assumed that the observed variability comes from the changing properties of the dense waters that are located at the maximum depth from where they can be uplifted in the upstream basin (Alboran Sea, inside the Mediterranean Sea) and evacuated through the strait. From this perspective, the following three mechanisms are investigated: (1) the replenishment of the deep basin by newly formed Western Mediterranean Deep Water that, depending on its density, can either uplift old resident waters or lay above them leaving in any case a cold signature in the temperature... |
| Tipo: Text |
Palavras-chave: Mediterranean outflow; Alboran Sea gyres; Interannual variability; Strait of Gibraltar; Seasonality; WMDW. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00629/74113/73544.pdf |
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| Pflaumann, U; Sarnthein, M; Chapman, M; D'Abreu, L; Funnell, B; Huels, M; Kiefer, T; Maslin, M; Schulz, H; Swallow, J; Van Kreveld, S; Vautravers, M; Vogelsang, E; Weinelt, M. |
| The response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in paleoclimatology. Our new reconstruction of peak glacial sea surface temperatures (SSTs) in the Atlantic is based on census counts of planktic foraminifera, using the Maximum Similarity Technique Version 28 (SIMMAX-28) modern analog technique with 947 modern analog samples and 119 well-dated sediment cores. Our study compares two slightly different scenarios of the Last Glacial Maximum (LGM), the Environmental Processes of the Ice Age: Land, Oceans, Glaciers (EPILOG), and Glacial Atlantic Ocean Mapping (GLAMAP 2000) time slices. The comparison shows that the maximum LGM cooling in the Southern Hemisphere... |
| Tipo: Text |
Palavras-chave: Last Glacial Maximum; Atlantic sea-surface temperatures; Seasonality; Sea ice cover; Glacial cooling near equator; Glacial upwelling intensity. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00225/33668/32070.pdf |
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| Martinez-lamas, Ruth; Toucanne, Samuel; Debret, Maxime; Riboulot, Vincent; Deloffre, Julien; Boissier, Audrey; Cheron, Sandrine; Pitel, Mathilde; Bayon, Germain; Giosan, Liviu; Soulet, Guillaume. |
| Offshore archives retrieved from marine/lacustrine environments receiving sediment from large river systems are valuable Quaternary continental records. In the present study, we reconstruct the Danube River activity at the end of the last glacial period based on sedimentological, mineralogical and geochemical analyses performed on long-piston cores from the north-west Black Sea margin. Our data suggest that the Danube River produced hyperpycnal floods throughout the ca. 33-17 ka period. Four main periods of enhanced Danube flood frequency, each of 1.5-3 kyr duration, are recorded at ca. 32.5 30.5 ka (equivalent to the first part of Heinrich Stadial HS 3), at ca. 29-27.5 ka (equivalent to Greenland Stadial 4), at ca. 25.3-23.8 ka (equivalent to HS 2) and at... |
| Tipo: Text |
Palavras-chave: Danube river; Floods; Hyperpycnites; Alpine ice sheet; Heinrich stadials; Seasonality; Black sea. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00613/72556/71612.pdf |
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| Mahe, Kelig; Bellamy, Elise; Delpech, Jean-paul; Lazard, Coline; Salaun, Michele; Verin, Yves; Coppin, Franck; Travers-trolet, Morgane. |
| Weight–Body Length relationships (WLR) of 45 fish species (37 Actinopterygii and eight Elasmobranchii) were investigated. A total of 31,167 individuals were caught and their biological parameters measured during the four quarters from 2013 to 2015, on five scientific surveys sampling the North-eastern Atlantic Ocean from the North Sea to the Bay of Biscay (ICES Divisions IVb, IVc, VIId, VIIe, VIIg, VIIh, VIIj, VIIIa and VIIIb). Among 45 tested species, all showed a significant correlation between total length (L) and total weight (W). The influence of sex on WLR was estimated for 39 species and presented a significant sexual dimorphism for 18 species. Condition factor (K) of females was always higher than for males. Moreover, a spatial effect on the WLR... |
| Tipo: Text |
Palavras-chave: Weight-length relationship; Condition factor; Bay of Biscay; Celtic Sea; English Channel; North Sea; Sexual dimorphism; Seasonality. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00363/47418/47513.pdf |
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| Hernandez Farinas, Tania; Ribeiro, Lourenco; Soudant, Dominique; Belin, Catherine; Bacher, Cedric; Lampert, Luis; Barille, Laurent. |
| Suspended marine benthic microalgae in the water column reflect the close relationship between the benthic and pelagic components of coastal ecosystems. In this study, a 12-year phytoplankton time-series was used to investigate the contribution of benthic microalgae to the pelagic system at a site along the French-Atlantic coast. Furthermore, all taxa identified were allocated into different growth forms in order to study their seasonal patterns. The highest contribution of benthic microalgae was observed during the winter period, reaching up to 60% of the carbon biomass in the water column. The haptobenthic growth form showed the highest contribution in terms of biomass, dominant in the fall-winter period when the turbidity and the river flow were high.... |
| Tipo: Text |
Palavras-chave: Co-inertia; Dynamic linear models; Epipelon; Epiphyton; Haptobenthos; Microphytobenthos growth forms; Seasonality; Tychoplankton. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00392/50345/51035.pdf |
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| Le Moullac, Gilles; Tiapari, Jerome; Teissier, Hinano; Martinez, Elodie; Cochard, Jean-claude. |
| The growth and reproductive cycle of cultured black-lipped pearl oysters, Pinctada margaritifera (L.), were studied in the Gambier Islands (134°52' W, 23°07' S) from September 2002 to August 2003. Temperatures were recorded throughout the year, revealing seasonal temperature variations between 22.3 °C and 27.8 °C. The mean annual chlorophyll a value, as computed from satellite data, was 0.188 ± 0.075 µg L-1. To study growth and reproduction, 720 two-year-old individuals were ear hung on longlines suspended at a depth of 7 m. Samples were taken twice a month to obtain the following measurements: shell height; wet weight of flesh and total oyster; dry weight of adductor muscle, mantle and visceral mass; and glycogen content. Gonad development was also... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Pinctada margaritifera; Growth; Reproduction; Temperature; Chlorophyll; Seasonality; Gambier archipelago. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00040/15099/13570.pdf |
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| Delavenne, Juliette; Marchal, Paul; Vaz, Sandrine. |
| Classifying marine habitats is a growing research field and is of increasing interest to spatial planners and managers. Most studies have predominantly focused on the seabed to determine benthic habitat types, and only limited attention has been paid to the water column. Classification projects aim at identifying candidate management units for the application of various regional or national regulations such as the European Water Framework Directive. Here, we propose a seasonal classification of the water column in the eastern English Channel, which we validated with biological data. For the three tested compartments, phytoplankton, zooplankton and pelagic fishes, the validation results were satisfactory, with recall values (i.e. percentage of observations... |
| Tipo: Text |
Palavras-chave: Eastern English Channel; Pelagic typology; Clustering analysis; Seasonality. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00125/23655/22689.pdf |
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| Ali, Elsheikh B.; Skjelvan, Ingunn; Omar, Abdirahman M.; Olsen, Are; De Lange, Tor E.; Johannessen, Truls; Elageed, Salma. |
| The dynamics of sea surface pCO2 () and air-sea CO2 exchange of the Sudanese coastal Red Sea has for the first time been studied over a full annual cycle (October 2014 - October 2015) based on semi-continuous measurements from moored autonomous sensors. showed a seasonal amplitude of approximately 70 atm, overlaid by a high frequency (3-4 days) signal of around 10 atm. The highest values, of about 440 atm occurred during summer and fall, while the lowest values of about 370 atm occurred during winter. The monthly change was primarily driven by temperature, i.e., heating and cooling of the water surface. Additionally, Dissolved Inorganic Carbon (DIC) and Total Alkalinity (AT) contributed significantly to the observed change in as a consequence of... |
| Tipo: Text |
Palavras-chave: Sea surface pCO2; CO2 flux; Time series; Coastal Red Sea; Seasonality. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00690/80252/83332.pdf |
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| Zielhofer, Christoph; Fletcher, William J.; Mischke, Steffen; De Batist, Marc; Campbell, Jennifer F. E.; Joannin, Sebastien; Tjallingii, Rik; El Hamouti, Najib; Junginger, Annett; Stele, Andreas; Bussmann, Jens; Schneider, Birgit; Lauer, Tobias; Spitzer, Katrin; Strupler, Michael; Brachert, Thomas; Mikdad, Abdeslam. |
| The limited availability of high-resolution continuous archives, insufficient chronological control, and complex hydro-climatic forcing mechanisms lead to many uncertainties in palaeo-hydrological reconstructions for the Western Mediterranean. In this study we present a newly recovered 19.63 m long core from Lake Sidi Ali in the North African Middle Atlas, a transition zone of Atlantic, Western Mediterranean and Saharan air mass trajectories. With a multi-proxy approach based on magnetic susceptibility, carbonate and total organic C content: core-scanning and quantitative XRF, stable isotopes of ostracod shells, charcoal counts, Cedrus pollen abundance, and a first set of diatom data, we reconstruct Western Mediterranean hydro-climatic variability,... |
| Tipo: Text |
Palavras-chave: Holocene; Younger Dryas; Winter rain minima; Atlantic forcing; Western Mediterranean; North Atlantic Oscillation (NAO); Seasonality; Solar forcing; Lake sediments; Middle Atlas; Morocco. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53188/55016.pdf |
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| Bourdaud, Pierre; Travers-trolet, Morgane; Vermard, Youen; Cormon, Xochitl; Marchal, Paul. |
| The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles.... |
| Tipo: Text |
Palavras-chave: Commercial data; Eastern English Channel; Seasonality; Spatial distribution; Survey data. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49805/50385.pdf |
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| Lahaye, Noe; Gula, Jonathan; Roullet, Guillaume. |
| The upper ocean is energetic at scales below the Rossby deformation radius owing to the existence of internal waves and submesoscale fronts and vortices. These contribute significantly to energy dissipation, tracer mixing and exchanges between the ocean surface layer, the ocean interior, and the atmospheric boundary layer. Internal waves and submesoscale motions both undergo strong spatial and seasonal variations, driven by different mechanisms. Here, we investigate the sea surface signature of internal waves and its seasonality using linear wave theory and a high‐resolution realistic simulation. In summer, internal waves are greatly amplified near the surface mostly due to a thin mixed layer bounded by a seasonal pycnocline. This surface amplification is... |
| Tipo: Text |
Palavras-chave: Internal tide; Submesosacle dynamics; Seasonality. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59746/62847.pdf |
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| Registros recuperados: 208 | |
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