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| Registros recuperados: 15 | |
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| Menkes, Christophe; Kennan, Sc; Flament, Pierre; Dandonneau, Y; Masson, S; Biessy, B; Marchal, E; Eldin, G; Grelet, J; Montel, Y; Morliere, A; Lebourges-dhaussy, A; Moulin, C; Champalbert, G; Herbland, Alain. |
| [1] The equatorial Pacific and Atlantic oceans exhibit remarkable meridional undulations in temperature and chlorophyll fronts visible from space over thousands of kilometers and often referred to as tropical instability waves. Here, we present new observations of an ecosystem ranging through three trophic levels: phytoplankton, zooplankton and small pelagic fish whirling within a tropical vortex of the Atlantic ocean and associated with such undulations. Cold, nutrient and biologically rich equatorial waters are advected northward and downward to form sharp fronts visible in all tracers and trophic levels. The equatorward recirculation experiences upwelling at depth, with the pycnocline and ecosystem progressively moving toward the surface to reconnect... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10049/9584.pdf |
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| Van Wynsberge, Simon; Menkes, Christophe; Le Gendre, Romain; Passfield, Teuru; Andrefouet, Serge. |
| In remote coral reef environments, lagoon and reef in situ measurements of temperature are scarce. Sea Surface Temperature (SST) measured by satellite has been frequently used as a proxy of the lagoon temperature experienced by coral reef organisms (TL) especially during coral bleaching events. However, the link between SST and TL is poorly characterized. First, we compared the correlation between various SST series and TL from 2012 to 2016 in three atolls and one island in the Central South Pacific Ocean. Simple linear correlation between SST and TL ranged between 0.44 and 0.97 depending on lagoons, localities of sensors, and type of SST data. High-resolution-satellite-measurements of SST inside the lagoons did not outperform oceanic SST series,... |
| Tipo: Text |
Palavras-chave: Atoll lagoon; Pacific islands; Reef aperture; Climate change; Sea Surface Temperature. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00403/51491/52087.pdf |
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| Receveur, Aurore; Vourey, Elodie; Lebourges-dhaussy, Anne; Menkes, Christophe; Menard, Frederic; Allain, Valerie. |
| Mesopelagic resources are central to the ecosystem but remain poorly studied mainly due to the lack of observations. This paper investigates the assemblages of micronekton organisms and their habitat in the Natural Park of the Coral Sea around New Caledonia (southwest Pacific) using data from 141 pelagic trawls. A total of 67,130 micronekton individuals (fish, crustaceans, and mollusks) were collected with 252 species identified among 152 genus and 76 families. In the analyses, we focused on 22 species; each were present in more than 33 trawls (i.e., in more than 25% of the total number of trawls) and studied their spatial distribution and vertical dynamic behavior. Community structure was investigated through region of common profile (RCP), an innovative... |
| Tipo: Text |
Palavras-chave: Diversity; Southwest Pacific Ocean; Mesopelagic zone; Region of common profile; Diel vertical migration; Pelagic trawl. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00644/75563/76480.pdf |
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| Ravache, Andreas; Bourgeois, Karen; Thibault, Martin; Dromzée, Sylvain; Weimerskirch, Henri; De Grissac, Sophie; Prudor, Aurélien; Lorrain, Anne; Menkes, Christophe; Allain, Valerie; Bustamante, Paco; Letourneur, Yves; Vidal, Eric. |
| Lunar phase and illumination are known to affect nocturnal behavior of many organisms, particularly through predator-prey interactions. Visual predators can benefit from higher light levels to increase their activity, while prey may decrease their activity to avoid predation. The lower number of nocturnal seabirds observed on colonies during full moon nights has been mostly interpreted as a predation avoidance strategy. However, it is also possible that shearwaters take advantage of the moon's illumination to feed also at night, and stay at sea to forage during full moon nights. We used miniaturized GPS-loggers to obtain 179 tracks from 99 wedge-tailed shearwaters breeding in New Caledonia, to investigate moonlight effects on individual behavior. Lunar... |
| Tipo: Text |
Palavras-chave: Ardenna pacifica; Foraging; Lunar phase; Moon; GPS-tracking; Stable isotope analyses. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00607/71880/70608.pdf |
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| Grenier, Melanie; Cravatte, Sophie; Blanke, Bruno; Menkes, Christophe; Koch-larrouy, Ariane; Durand, Fabien; Melet, Angelique; Jeandel, Catherine. |
| The hydrological and geochemical properties of the waters constituting the Pacific Equatorial Undercurrent (EUC) determine the properties of the equatorial cold tongue. Understanding and quantifying the various EUC origins is therefore of prime importance. For this purpose, a high-resolution (1/4 degrees) interannual oceanic simulation was analyzed from the western tropical Pacific boundaries to 140 degrees W, using a Lagrangian framework. Waters from the Low-Latitude Western Boundary Currents (LLWBCs) transiting from Vitiaz Strait (the main contributor), from Solomon Strait, and via the Mindanao Current were identified as the principal sources to the EUC. Waters conveyed by the interior ocean off equator are negligible till 180 E. The LLWBCs' waters... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00060/17105/14621.pdf |
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| Cravatte, Sophie; Serazin, Guillaume; Penduff, Thierry; Menkes, Christophe. |
| The southwestern Pacific Ocean sits at a bifurcation where southern subtropical waters are redistributed equatorward and poleward by different ocean currents. The processes governing the interannual variability of these currents are not completely understood. This issue is investigated using a probabilistic modeling strategy that allows disentangling the atmospherically forced deterministic ocean variability and the chaotic intrinsic ocean variability. A large ensemble of 50 simulations performed with the same ocean general circulation model (OGCM) driven by the same realistic atmospheric forcing and only differing by a small initial perturbation is analyzed over 1980–2015. Our results show that, in the southwestern Pacific, the interannual variability of... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00685/79702/82490.pdf |
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| Guieu, Cecile; Bonnet, Sophie; Petrenko, Anne; Menkes, Christophe; Chavagnac, Valerie; Desboeufs, Karine; Maes, Christophe; Moutin, Thierry. |
| In the Western Tropical South Pacific, patches of high chlorophyll concentrations linked to the occurrence of N2-fixing organisms are found in the vicinity of volcanic islands. The survival of these organisms relies on a high bioavailable iron supply whose origin and fluxes remain unknown. Here, we measured high dissolved iron (DFe) concentrations (up to 66 nM) in the euphotic layer, extending zonally over 10 degrees longitude (174 E−175 W) at ∼20°S latitude. DFe atmospheric fluxes were at the lower end of reported values of the remote ocean and could not explain the high DFe concentrations measured in the water column in the vicinity of Tonga. We argue that the high DFe concentrations may be sustained by a submarine source, also characterized by... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00444/55564/57174.pdf |
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| Dissard, Delphine; Reichart, Gert Jan; Menkes, Christophe; Mangeas, Morgan; Frickenhaus, Stephan; Bijma, Jelle. |
| Over the last decades, sea surface temperature (SST) reconstructions based on the Mg∕Ca of foraminiferal calcite have frequently been used in combination with the δ18O signal from the same material to provide estimates of the δ18O of water (δ18Ow), a proxy for global ice volume and sea surface salinity (SSS). However, because of error propagation from one step to the next, better calibrations are required to increase the accuracy and robustness of existing isotope and element to temperature proxy relationships. Towards that goal, we determined Mg∕Ca, Sr∕Ca and the oxygen isotopic composition of Trilobatus sacculifer (previously referenced as Globigerinoides sacculifer) collected from surface waters (0–10 m) along a north–south transect in the eastern basin... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78884/81200.pdf |
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| Receveur, Aurore; Kestenare, Elodie; Allain, Valerie; Ménard, Frédéric; Cravatte, Sophie; Lebourges-dhaussy, Anne; Lehodey, Patrick; Mangeas, Morgan; Smith, Neville; Radenac, Marie-hélène; Menkes, Christophe. |
| Acoustic data are invaluable information sources for characterizing the distribution and abundance of mid-trophic-level organisms (micronekton). These organisms play a pivotal role in the ecosystem as prey of top predators and as predators of low-trophic-level organisms. Although shipboard-ADCP (acoustic Doppler current profiler) acoustic backscatter signal intensity cannot provide an absolute biomass estimate, it may be a useful proxy to investigate variability in the distribution and relative density of micronekton. This study used acoustic recordings data spread across 19 years (1999–2017) from 54 ADCP cruises in New Caledonia’s subtropical EEZ (exclusive economic zone) to assess seasonal and interannual variabilities and spatial distribution of... |
| Tipo: Text |
Palavras-chave: Micronekton; Southwest Pacific ocean; SEAPODYM; Acoustic; Ecosystem. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72078/70794.pdf |
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| Dutheil, Cyril; Aumont, Olivier; Gorgues, Thomas; Lorrain, Anne; Bonnet, Sophie; Rodier, Martine; Dupouy, Cecile; Shiozaki, Takuhei; Menkes, Christophe. |
| Dinitrogen fixation is now recognized as one of the major sources of bio-available nitrogen in the ocean. Thus, N2 fixation sustains a significant part of the global primary production by supplying the most common limiting nutrient for phytoplankton growth. The Oligotrophy to UlTra-oligotrophy PACific Experiment (OUTPACE) improved the data coverage of the western tropical South Pacific, an area recently recognized as a hotspot of N2 fixation. This new development leads us to develop and test an explicit N2 fixation formulation based on the Trichodesmium physiology (the most studied nitrogen fixer) within a 3-D coupled dynamical–biogeochemical model (ROMS-PISCES). We performed a climatological numerical simulation that is able to reproduce the main physical... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00419/53042/53979.pdf |
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| Garrigue, Claire; Bonneville, Claire; Derville, Solène; Allain, Valérie; Aucan, Jérôme; Bourgogne, Hugo; Bachelier, Celine; Dutheil, Cyril; Grelet, Jacques; Laran, Sophie; Menkes, Christophe; Niksic, Sara; Pallin, Logan; Pérard, Véronique; Portal, Annie; Receveur, Aurore; Renaud, Armelle; Roger, Jean; Varillon, David; Vourey, Elodie. |
| En 2014 le gouvernement de la Nouvelle-Caledonie a cree le parc naturel de la mer de Corail, l'une des plus grandes zones protegees au monde. Afin de renseigner les zones de conservation prioritaires et de faciliter la mise en place de mesures qui puissent efficacement proteger la megafaune marine, il est necessaire d'acquerir des informations sur sa distribution et l'usage des habitats. C'est pourquoi en 2016, l'IRD a lance le programme WHERE1 qui vise a explorer la distribution spatiale et l'habitat des baleines a bosse pour ameliorer leur gestion spatiale dans le parc naturel de la mer de Corail. Les principaux objectifs du programme WHERE consistent a etablir la distribution des baleines a bosse au sein du parc naturel de la mer de Corail, a evaluer la... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00611/72338/71167.pdf |
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| Martinez, Elodie; Gorgues, Thomas; Lengaigne, Matthieu; Fontana, Clement; Sauzède, Raphaëlle; Menkes, Christophe; Uitz, Julia; Di Lorenzo, Emanuele; Fablet, Ronan. |
| Monitoring the spatio-temporal variations of surface chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) greatly benefited from the availability of continuous and global ocean color satellite measurements from 1997 onward. These two decades of satellite observations are however still too short to provide a comprehensive description of Chl variations at decadal to multi-decadal timescales. This paper investigates the ability of a machine learning approach (a non-linear statistical approach based on Support Vector Regression, hereafter SVR) to reconstruct global spatio-temporal Chl variations from selected surface oceanic and atmospheric physical parameters. With a limited training period (13 years), we first demonstrate that Chl variability... |
| Tipo: Text |
Palavras-chave: Machine learning; Phytoplankton variability; Satellite ocean color; Decadel variability; Global scale. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75314/75810.pdf |
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| Raapoto, Hirohiti; Martinez, Elodie; Petrenko, Anne; Doglioli, Andrea; Gorgues, Thomas; Sauzède, Raphaëlle; Maamaatuaiahutapu, Keitapu; Maes, Christophe; Menkes, Christophe; Lefèvre, Jérôme. |
| A remarkable chlorophyll‐a concentration (Chl, a proxy of phytoplankton biomass) plume can be noticed on remotely sensed ocean color observations at the boundary separating the equatorial mesotrophic from the subtropical oligotrophic waters in the central South Pacific Ocean. This prominent biological feature is known as the island mass effect of the Marquesas archipelago. Waters surrounding these islands present high macronutrient concentrations but an iron depletion. In this study, the origin of Chl enhancement is investigated using a modeling approach. Four simulations based on identical physical and biogeochemical forcings but with different iron sources are conducted and analyzed. Only simulations considering an iron input from the island sediments... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00592/70397/68481.pdf |
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| Lorrain, Anne; Houlbreque, Fanny; Benzoni, Francesca; Barjon, Lucie; Tremblay-boyer, Laura; Menkes, Christophe; Gillikin, David P.; Payri, Claude; Jourdan, Herve; Boussarie, Germain; Verheyden, Anouk; Vidal, Eric. |
| Seabirds concentrate nutrients from large marine areas on their nesting islands playing an important ecological role in nutrient transfer between marine and terrestrial ecosystems. Here we investigate the role of guano on corals reefs across scales by analyzing the stable nitrogen isotopic (delta N-15) values of the scleractinian coral Pocillopora damicornis on fringing reefs around two Pacific remote islets with large seabird colonies. Marine stations closest to the seabird colonies had higher nitrate + nitrite concentrations compared to more distant stations. Coral and zooxanthellae delta N-15 values were also higher at these sites, suggesting that guano-derived nitrogen is assimilated into corals and contributes to their nitrogen requirements. The... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00391/50239/50878.pdf |
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| Smeti, Houssem; Pagano, Marc; Menkes, Christophe; Lebourges-dhaussy, Anne; Hunt, Brian P. V.; Allain, Valerie; Rodier, Martine; De Boissieu, Florian; Kestenare, Elodie; Sammari, Cherif. |
| Spatial and temporal distribution of zooplankton off New Caledonia in the eastern Coral Sea was studied during two multidisciplinary cruises in 2011, during the cool and the hot seasons. Acoustic measurements of zooplankton were made using a shipborne acoustic Doppler current profiler (S-ADCP), a scientific echosounder and a Tracor acoustic profiling system (TAPS). Relative backscatter from ADCP was converted to biomass estimates using zooplankton weights from net-samples collected during the cruises. Zooplankton biomass was estimated using four methods: weighing, digital imaging (ZooScan), ADCP and TAPS. Significant correlations were found between the different biomass estimators and between the backscatters of the ADCP and the echosounder. There was a... |
| Tipo: Text |
Palavras-chave: South Pacific; Acoustics; Zooplankton; Vertical migration; Water masses; Mesoscale dynamics. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00297/40809/39836.pdf |
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| Registros recuperados: 15 | |
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