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This dataset contains the complete report, the expedition map as well as a list of stations and sampling types. The 2005 Expedition Report describes the scientific expedition carried out in the Canadian Arctic between August 05 and October 26, 2005. The report is a collection of all the participating research teams’ Cruise Reports provided to the Chief Scientists at the end of each Legs of the 2005 CCGS Amundsen Expedition. The 2005 Expedition Report is divided into two parts: Part I provides an overview of the expedition, the cruise track and the stations visited, and a synopsis of operations conducted during each Leg. Part II contains the reports submitted by participating science teams or researchers, with details on the specific objectives of their project, the field operations conducted and methodology used, and in some cases, preliminary results. When results are presented, they show the data as they were submitted at the end of the Legs in 2005. The data presented in this report are illustrative only and have not been quality checked, thus parties interested in the results should contact the project leader or the researchers who collected the data or the data coordinator at Amundsen Science (amundsen.data@as.ulaval.ca). The 2005 Expedition Report includes four appendices: 1) the list of stations sampled, 2) the scientific log of activities conducted, 3) a copy of the CTD logbook and 4) the list of participants on board during each leg. The core oceanographic data generated by the CTD-Rosette operations, as well as meteorological information (AVOS) and data collected using the Moving Vessel Profiler (MVP), the ship-mounted current meter (SM-ADCP) and the thermosalinograph (TSG) are available in the Polar Data Catalogue (PDC) at www.polardata.ca., Ce jeu de données contient le rapport d'expédition complet, la carte de l'expédition ainsi qu'une liste des stations et les types d'échantillonnage. Le rapport décrit l'expédition scientifique menée dans l'Arctique canadien entre le 05 août et 26 octobre 2005. Le rapport d'expédition 2005 est une collection de tous les rapports de croisière produits par les équipes de recherche participant à l'expédition estivale 2005 du NGCC à Amundsen et rassemblés par les scientifiques en chef au bout de leurs étapes. Le rapport d'expédition 2005 est divisé en deux parties : La première partie donne un aperçu de l'expédition, ainsi que la trajectoire du navire, les stations visitées et un synopsis des opérations menées durant chaque Leg. La deuxième partie contient les rapports soumis par les équipes scientifiques ou les chercheurs participants, avec des détails sur les objectifs spécifiques de leur projet, les opérations de terrain menées et la méthodologie utilisée, et dans certains cas, les résultats préliminaires. Lorsque les résultats sont présentés, ils présentent les données telles qu'elles ont été soumises à la fin des étapes en 2005. Les données présentées dans le rapport sont fournies à titre indicatif uniquement et n'ont pas fait l'objet d'un contrôle de qualité. Par conséquent, les parties intéressées par les résultats doivent contacter le responsable du projet ou les chercheurs qui ont collecté les données ou la personne responsable des données chez Amundsen Science (amundsen.data@as.ulaval.ca). Le rapport d'expédition 2005 comprend également quatre annexes : 1) la liste des stations échantillonnées, 2) le journal scientifique des activités menées, 3) une copie du journal de bord du CTD et 4) la liste des participants à bord pour chaque étape. Les principales données océanographiques générées par les opérations du CTD-Rosette, ainsi que les informations météorologiques (AVOS, Environnement Canada) et les données collectées à l'aide du Moving Vessel Profiler (MVP), du compteur de courant embarqué (SM-ADCP) et du thermosalinographe (TSG) sont disponibles dans le catalogue de données polaires (PDC) à l'adresse www.polardata.ca

This dataset contains the complete report, the expedition map as well as a list of stations and sampling types. The 2021 Expedition Report describes the scientific expedition carried out in the Canadian Arctic between July 04 and November 3, 2021. The report is a collection of all the participating research teams’ Cruise Reports provided to the Chief Scientists at the end of each Leg of the 2021 CCGS Amundsen Expedition. The 2021 Expedition Report is divided into two parts: Part I gives an overview of the expedition, shows the cruise track and the stations visited and provides a synopsis of operations conducted during each of the five legs. Part II contains the reports submitted by participating science teams or researchers, with details on the specific objectives of their project, the field operations conducted and methodology used, and in some cases, preliminary results. When results are presented, they show the data as they were submitted at the end of the legs in 2021. The data presented in the report are illustrative only and have not been quality checked, thus parties interested in the results should contact the project leader, the researchers who collected the data or Amundsen Science’s Data Coordinator (amundsen.data@as.ulaval.ca). The sections in Part II describing each project are organized with atmospheric, surface ocean and sea ice components first, followed by water column properties, which include the mooring and buoy program, CTD-Rosette operations and physicochemical properties, as well as a suite of biological parameters and benthos sampling. Subsequent sections cover sediments sampling and seabed mapping. Five Appendices are included, documenting visited stations and performed sampling as well as a list of science participants onboard during each leg. A description of each ROV dive is also attached. [**Summaries of the 2021 expedition**](https://catalogue.ogsl.ca/dataset/ca-cioos_f77fe17d-c2cb-4edd-b76e-1e4ff45ceaa3) are also available in 3 languages (French, English, inuktitut). The core oceanographic data generated by the CTD-Rosette operations, as well as meteorological information (AVOS) and data collected using the Moving Vessel Profiler (MVP), the ship-mounted current meter (SM-ADCP) and the thermosalinograph (TSG) are available in the [**Polar Data Catalogue (PDC)**](https://www.polardata.ca/pdcsearch/?doi_id=12713) It is possible to consult an [**interactive map**](https://data.amundsen.ulaval.ca/) including all the years of expeditions and the different trajectories (LEG) associated with them., Ce jeu de données contient le rapport d'expédition complet, la carte de l'expédition ainsi qu'une liste des stations et les types d'échantillonnage. Le rapport décrit l'expédition scientifique menée dans l'Arctique canadien entre le 04 juillet et 03 novembre 2021. Le rapport d'expédition 2021 est une collection de tous les rapports de croisière produits par les équipes de recherche participant à l'expédition estivale 2021 à bord NGCC Amundsen et rassemblés par les scientifiques en chef au bout de chaque étape de l'expédition. Le rapport d'expédition 2021 est divisé en deux parties : La première partie donne un aperçu de l'expédition, ainsi que la trajectoire du navire, les stations visitées et un synopsis des opérations menées. La deuxième partie contient les rapports soumis par les équipes scientifiques ou les chercheurs participants, avec des détails sur les objectifs spécifiques de leur projet, les opérations de terrain menées et la méthodologie utilisée, et dans certains cas, les résultats préliminaires. Lorsque les résultats sont présentés, ils présentent les données telles qu'elles ont été soumises à la fin de chacune des étapes de l'expédition en 2021. Les données présentées dans le rapport sont fournies à titre indicatif uniquement et n'ont pas fait l'objet d'un contrôle de qualité. Par conséquent, les parties intéressées par les résultats doivent contacter le responsable du projet ou les chercheurs qui ont collecté les données ou la prsonne responsable des données chez Amundsen Science (amundsen.data@as.ulaval.ca). Les sections de la partie II décrivant chaque projet sont organisées sous forme de rapport multidisciplinaires. Les différents sections couvrent essentiellement les échantillonnages de sédiment, de la colonne d'eau, ainsi que la cartographie des fond marins. Les cinq annexes couvrent les caractéristiques des échantillonnages menées à chacune des stations visitées et la liste des participants à bord du navire NGCC Amundsen pour chaque étape. Une description des plongées effectuées avec le ROV est présenté également. Des [**résumés de l'expédition de 2021**](https://catalogue.ogsl.ca/dataset/ca-cioos_f77fe17d-c2cb-4edd-b76e-1e4ff45ceaa3) sont aussi disponibles en 3 langues (français, anglais, inuktitut). Les principales données océanographiques générées par les opérations du CTD-Rosette, ainsi que les informations météorologiques (AVOS, Environnement Canada) et les données collectées à l'aide du Moving Vessel Profiler (MVP), du compteur de courant embarqué (SM-ADCP) et du thermosalinographe (TSG) sont disponibles dans le [**catalogue de données polaires (PDC)**](https://www.polardata.ca/pdcsearch/?doi_id=12713). Il est possible de consulter une [**carte interactive**](https://data.amundsen.ulaval.ca/) comprenant toutes les années d'expéditions et les différents trajectoires (LEG) qui y sont associées.

This dataset contains the complete expedition report, the expedition map as well as a list of stations and sampling types. The 2018 Expedition Report is a collection of all the participating research teams’ Cruise Reports assembled by the Chief Scientists at the end of Leg 1, Leg 2 and Leg 3 of the Amundsen Expedition carried. The 2018 Expedition Report is divided into two parts: Part I gives an overview of the expedition, shows the cruise track and the stations visited and provides a synopsis of operations conducted during each of the four legs. Part II contains the reports submitted by participating science teams or researchers, with details on the specific objectives of their project, the field operations conducted and methodology used, and in some cases, preliminary results. When results are presented, they show the data as they were submitted at the end of the legs in 2018. The data presented in this report are illustrative only and have not been quality checked, thus parties interested in the results should contact the project leader or the researchers who collected the data. The sections in Part II describing each project are organized with atmospheric, surface ocean and sea ice components first, followed by water column properties, which nclude the mooring programs, CTD-Rosette operations and physical properties, ocean optical properties and freshwater sources as well as a suite of chemical and biological parameters. The contaminants cycling in seawater is also treated. The last sections of the report cover benthos sampling, seabed mapping, sediments sampling and ROV operations. The four Appendices provide information about the location, date, time and type of sampling performed at each station visited by the ship, as well as a list of science participants onboard during each leg. The core oceanographic data generated by the CTD-Rosette operations, as well as meteorological information (AAVOS) and data collected using the Moving Vessel Profiler (MVP), the ship-mounted current meter (SM-ADCP) and the thermosalinograph (TSG) are available in the Polar Data Catalogue (PDC) at www.polardata.ca, Ce jeu de données contient le rapport d'expédition complet, la carte des expéditions ainsi que la liste des stations et les types d'échantillonnage. Le rapport d'expédition 2018 est une collection des rapports de croisière de toutes les équipes de recherche participantes rassemblés par les scientifiques en chef à la fin des étapes 1, 2 et 3 de l'expédition Amundsen. Le rapport d'expédition 2018 est divisé en deux parties : La première partie donne un aperçu de l'expédition, montre le circuit de l'expédition et les stations visitées. Il fournit un synopsis des opérations menées au cours de chacune des quatre étapes. La deuxième partie contient les rapports soumis par les équipes scientifiques ou les chercheurs participants, avec des détails sur les objectifs spécifiques de leur projet, les opérations de terrain menées et la méthodologie utilisée, et dans certains cas, les résultats préliminaires. Lorsque les résultats sont présentés, ils présentent les données telles qu'elles ont été soumises à la fin des étapes en 2018. Les données présentées dans ce rapport sont fournies à titre indicatif uniquement et n'ont pas fait l'objet d'un contrôle de qualité. Par conséquent, les parties intéressées par les résultats doivent contacter le responsable du projet ou les chercheurs qui ont collecté les données. Les sections de la deuxième partie décrivant chaque projet sont organisées en fonction des composantes atmosphériques, océaniques de surface et de glace de mer, suivies des propriétés de la colonne d'eau, qui incluent les programmes d'amarrage, le fonctionnement et les propriétés physiques des rosettes CTD, les propriétés optiques de l'océan et les sources d'eau douce ainsi qu'une série de paramètres chimiques et biologiques. Les contaminants circulant dans l'eau de mer sont également traités. Les dernières sections du rapport portent sur l'échantillonnage du benthos, la cartographie des fonds marins, l'échantillonnage des sédiments et les opérations de ROV. Les quatre annexes fournissent des informations sur le lieu, la date, l'heure et le type d'échantillonnage effectué à chaque station visitée par le navire, ainsi qu'une liste des participants scientifiques à bord pendant chaque étape. Les principales données océanographiques générées par les opérations du CTD-Rosette, ainsi que les informations météorologiques (AAVOS) et les données collectées à l'aide du Moving Vessel Profiler (MVP), du compteur de courant embarqué (SM-ADCP) et du thermosalinographe (TSG) sont disponibles dans le catalogue de données polaires (PDC) à l'adresse www.polardata.ca

En 2011, un poisson-globe a été observé pour la première fois près de l’archipel de Ryukyu au large du Japon. Ce poisson construit un nid circulaire en sable afin de réaliser sa parade nuptiale et pour protéger ses œufs. Celui-ci est d’environ 2m de diamètre et il possède deux parties, centrale et périphérique. La partie périphérie possède un motif constitué d’une dune et deux vallées, répété entre 24 et 32 fois autour de la structure. Dans le cadre de la reproduction, les œufs sont déposés par la femelle dans la partie centrale du nid afin de les protéger jusqu’à l’éclosion. L’objectif de ce Mémoire d’Initiation à la Recherche en partenariat avec Dassault Systèmes est de mettre en évidence un ralentissement du courant marin par la structure du nid, de manière qualitative et quantitative. Pour cela, des simulations fluides sont utilisées afin de modéliser un écoulement sur un modèle 3D de la structure du nid. Des premiers résultats visuels ont montré ce ralentissement du courant au sein de la structure du nid. En effet, les vitesses au centre du nid et à la sortie du nid sont quasiment nulles. Une étude statistique des valeurs de vitesses selon des zones prédéfinies au sein du nid a montré que la géométrie des dunes ralentit la vitesse de 78% entre l’entrée et le centre du nid. De plus, l’ensemble de la structure ralentit le courant au cours du temps., Les données XFlow exploitées ici sont disponibles sur Figshare : https://figshare.com/s/ff4fd0aa641cfba97d72 Le code source Python est accessible sur GitHub : https://github.com/Cadmiom/Biomimicry.git Les fichiers en sortie du code Python sont accessibles ici : https://figshare.com/s/e82ec635f02bc050ea33 L'étude préliminaire (Vient et al., 2018) est accessible ici : https://figshare.com/s/aba3f2bde813fa630ff7 Le modèle 3D du nid est accessible ici : https://figshare.com/s/257ae135af0cb025f999

International audience; We evidence and study the differences in turbulence statistics in ocean dynamics carried by wind forcing at the air-sea interface. Surface currents at the air-sea interaction are of crucial importance because they transport heat from low to high latitudes. At first order, oceanic currents are generated by the balance of the Coriolis and pressure gradient forces (geostrophic current) and the balance of the Coriolis and the frictional forces dominated by wind stress (Ekman current) in the surface ocean layers. The study was conducted by computing statistical moments on the shapes of spectra computed within the framework of microcanonical multi-fractal formalism. Remotely sensed daily datasets derived from one year of altimetry and wind data were used in this study, allowing for the computation of two kinds of vector fields: geostrophy with and geostrophy without wind stress forcing. We explore the statistical properties of singularity spectra computed from velocity norms and vorticity data, notably in relation with kurtosis information to underline the differences in the turbulent regimes associated with both kinds of velocity fields.

International audience

Early life stages of dominant West African pelagic fishes, most of which are commercially important, are rarely studied especially in Senegalese and Mauritanian coastal waters. The aim of the present study was to examine the horizontal distribution of pelagic fish eggs of European sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), round sardinella (Sardinella aurita) and horse mackerel (Trachurus trachurus) in winter-spring and summer. The two seasons revealed two contrasting environmental conditions. While in late winter strong upwelling shaped the environmental conditions, in summer a warm tropical influx of surface water from Senegal towards Mauritania was observed. Fish eggs occurred in both seasons along the shelf coasts of Mauritania and Senegal. The distribution of fish eggs was related to temperature, salinity and chlorophyll data obtained at each sampling position. Eggs of most species were concentrated in coastal waters off the Banc d'Arguin, in Saint-Louis and along the Senegalese sub-region. Spawning occurs mainly during winter and would be linked to environmental changes in particular temperature that significantly vary eggs distribution as notified with Sardina pilchardus and Sardinella aurita during late winter. Moreover, results have shown a significant role of other habitat factors such as chlorophyll, depth and also the continental shelf-break, as a mechanism of retention of fish eggs.

Thanks to technical staff of the European Grid Infrastructure and the supporting National Grid Initiatives for providing technical support and infrastructure.; International audience; Understanding the factors that contribute to population genetic divergence across a species' range is a long-standing goal in evolutionary biology and ecological genetics. We examined the relative importance of historical and ecological features in shaping the present-day spatial patterns of genetic structure in two related plant species, Beta vulgaris subsp. maritima and Beta macrocarpa. Using nuclear and mitochondrial markers, we surveyed 93 populations from Brittany (France) to Morocco - the southern limit of their species' range distribution. Whereas B. macrocarpa showed a genotypic structure and a high level of genetic differentiation indicative of selfing, the population genetic structure of B. vulgaris subsp. maritima was consistent with an outcrossing mating system. We further showed (1) a strong geographic clustering in coastal B. vulgaris subsp. maritima populations that highlighted the influence of marine currents in shaping different lineages and (2) a peculiar genetic structure of inland B. vulgaris subsp. maritima populations that could indicate the admixture of distinct evolutionary lineages and recent expansions associated with anthropogenic disturbances. Spatial patterns of nuclear diversity and differentiation also supported a stepwise recolonization of Europe from Atlantic-Mediterranean refugia after the last glacial period, with leading-edge expansions. However, cytoplasmic diversity was not impacted by postglacial recolonization: stochastic long-distance seed dispersal mediated by major oceanic currents may mitigate the common patterns of reduced cytoplasmic diversity observed for edge populations. Overall, the patterns we documented here challenge the general view of reduced genetic diversity at the edge of a species' range distribution and provide clues for understanding how life-history and major geographic features interact to shape the distribution of genetic diversity.

The Pilot (later termed Prediction) and Research Moored Array in the Tropical Atlantic (PIRATA) programme, developed as a multinational network by Brazil, France and the USA, has deployed and maintained an array of 17 Autonomous Temperature Line Acquisition Systems (ATLAS) buoys in the tropical Atlantic Ocean since 1997. The Benguela Current Large Marine Ecosystem (BCLME) PIRATA buoy, called Kizomba is the south-eastern extension of the original PIRATA array of moorings. It was deployed 4 100 m deep at about 6° S, 8° E on 27 June 2006 and recovered on 9 June 2007. The mooring is fitted with a current meter/temperature sensor deployed 10–13 m deep, five temperature/conductivity sensors deployed at depths of 1, 10, 20, 40 and 120 m, five temperature sensors positioned at depths of 60, 80, 100, 140 and 180 m, and two temperature/pressure sensors at 300 m and 500 m, as well as an anemometer, air temperature, humidity and short-wave solar radiation probes, and a rain gauge. The initial results from the first year of data collected by the buoy are presented with a view to providing scientific and societal motivation for the continuation of the extension of PIRATA in the tropical South-East Atlantic. Keywords: Angola–Benguela Front; ocean observing system; PIRATA; tropical Atlantic; upwellingAfrican Journal of Marine Science 2009, 31(1): 63–71

The individual-based trophic model Osmose is applied to the upwelling marine ecosystem off the coast of Peru. The dynamics and life cycle of eight major species of the Peruvian marine ecosystem are explicitly considered in the model. Reference simulations provide an overview of the trophic structure of the Peruvian ecosystem during the period 2000–2006. Results of model calibration and simulations are discussed in the light of current empirical knowledge on the trophic functioning of the Peruvian ecosystem and are compared to outputs obtained recently using the trophic model Ecopath. The impacts on the ecosystem of restoration plans for the depleted hake ( Merluccius gayi peruanus ) population are explored through two management scenarios: a) a long term reduction of fishing effort targeting hake and b) a moratorium on the hake fishery. The simulations help better understand the recent failure of a 20 month hake moratorium and provide long-term strategic support to ecosystem-based management. Limits of our approach are discussed and recommendations are detailed for future developments of the Osmose model and ecosystem approach to fishery management in the Peruvian context.

International audience; Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2–3 months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation.

Pacific Ocean western boundary currents and the interlinked equatorial Pacific circulation system were among the first currents of these types to be explored by pioneering oceanographers. The widely accepted but poorly quantified importance of these currents - in processes such as the El Niño/Southern Oscillation, the Pacific Decadal Oscillation and the Indonesian Throughflow - has triggered renewed interest. Ongoing efforts are seeking to understand the heat and mass balances of the equatorial Pacific, and possible changes associated with greenhouse-gas-induced climate change. Only a concerted international effort will close the observational, theoretical and technical gaps currently limiting a robust answer to these elusive questions.

International audience; Nine years of Topex/Poseidon and ERS satellite altimetry and XBT data from the SURVOSTRAL program were used to analyze the seasonal and interannual variations of the eddy energetics in terms of its spatial distribution and relation with the upper ocean heat content. Eddy kinetic energy is calculated in two frequency bands one associated with transient and the other with low-frequency variability. The two eddy components have distinct geographical distribution. At the SURVOSTRAL line, the transient eddy energy is twice the low-frequency energy, with maximum transient energy occurring during the austral summer period and maximum low-frequency energy in winter. The site is one of growing eddy energy. Eddy momentum flux is northward over the SURVOSTRAL line, and the summertime eddy heat flux is poleward across the Subantarctic and Subtropical Fronts, and equatorward either side of the fronts. Eddy fluxes are strongly influenced by their position relative to the bathymetry and the mean current.

A water mass analysis of the Coral Sea thermocline waters provides a description of their distribution, pathways and mixture based on recent oceanographic cruises in this region of strong western boundary currents. The Optimum Multiparameter method is used to determine the relative contribution of core water masses based on their measured temperature, salinity and dissolved oxygen. The thermocline waters, carried by the broad South Equatorial Current (SEC), are essentially composed of four core water masses of different origins. Coming from the south, the South Pacific Tropical Water South (SPTWS, delta = 25.3 kg m−3) and the Western South Pacific Central Water (WSPCW, σ = 26.3 kg m−3) enter the Coral Sea by the channel between the island of New Caledonia and the Vanuatu archipelago. Coming from the north, the South Pacific Tropical Water North (SPTWN, σ = 24.5 kg m−3) and the Pacific Equatorial Water (PEW, σ = 26.3 kg m−3) flow north of Vanuatu. The upper thermocline water that exits the Coral Sea equatorward, is mainly composed of SPTWN carried by the New Guinea Coastal Undercurrent. In contrast, upper thermocline waters exiting the Coral Sea poleward, in the East Australian Current, is dominated by SPTWS. The relative contributions are different in the lower thermocline where WSPCW dominates both western boundary currents. This refined description is consistent with the dynamics of the main currents, with a very strong depth dependence in the partitioning of incoming SEC waters.

Heat fluxes are estimated across transatlantic sections made at 4°30′S and 7°30′N in January–March 1993, following Hall and Bryden (1982. Deep-Sea Research 29, 339–359). Particular care is given to the computation of Ekman volume and heat fluxes, which are assessed both (a) from the windstress data for the period of the cruise and (b) from the comparison between geostrophic and Vessel Mounted Acoustic Doppler Current Profiler (VM-ADCP) velocities. In contrast with previous studies, the two estimates for Ekman fluxes do not converge for either section: (a) (11.5±0.5 Sv; 1.01±0.05 PW) across 7°30′N and (−9.3±1.2 Sv; −0.85±0.12 PW) across 4°30′S when windstress data at the date of the hydrographic stations are used; (b) (6.3±1.1 Sv; 0.56±0.09 PW) across 7°30′N and (−3.4±3.0 Sv; −0.35±0.24 PW) across 4°30′N when the ageostrophic transport above the thermocline is used. The divergence would have been even greater at 4°30′S if the strong ageostrophic signal beneath the thermocline, which brings a transport of (8.4 Sv; 0.82 PW), had been considered. The corresponding total meridional heat fluxes are: (a) 1.40±0.16 PW and (b) 0.95±0.20 PW across 7°30′N, (a) 1.05±0.12 PW and (b) 1.67±0.14 PW (2.39±0.14 PW when the subthermocline ageostrophic transport is taken into account) across 4°30′S. The estimates based on windstress data are compared with the results from an inverse model (Lux and Mercier, 1999) to show the importance of the heat flux due to the deviation of the local depth-averaged potential temperature from its average over the section, which is neglected in the Hall and Bryden (1982. Deep-Sea Research 29, 339–359) method but is not negligible in our computation in which we do not isolate the transport of the western boundary current east of the 200 m isobath; this corrective flux amounts here to −0.19 PW across 7°30′N and 0.33 PW across 4°30′S. The seasonal variability of the meridional heat flux across 7°30′N is studied through the hydrographic data collected during the ETAMBOT 1–2 cruises, which repeated the 7°30′N section west of 35°W in September 1995 and April 1996. When the section is completed east of 35°W with CITHER 1 data and when windstress data are used for the computation of the Ekman transport, the estimates for the meridional heat fluxes are 0.20±0.14 PW in September 1995 and 1.69±0.27 PW in April 1996. The estimates fit well with results from numerical models.

The salinity, temperature and current distributions have been measured during the TROPAC cruise (Oct./Nov. 1996) at two sections, i.e. 143°E and 150°E, during the final phase of the 1995/1996 La Niña. The results present evidence that the fresh pool and the salinity front at its eastern boundary had moved far to the west, and that a barrier layer existed in that phase. The observed currents support the idea that advective processes play an essential role in creating the thermohaline structure during this ENSO phase. In relation with this process, it is found that the westward subduction mechanism of relatively dense eastern equatorial waters may apply during that phase.

From the K-L model proposed by Lewellen [LEW 77], an analytical expression of turbulence macroscale L was established. This expression, obtained with the hypothesis of a zero horizontal pressure gradient can be used for inertial or Couette flow. This formulation is better than the classical linear expression and in good agreement with numerical computations. We obtain a new solution for the velocity profile which can be compared with the logarithmic profile.

Expendable bathythermograph (XBT) data and the climatological temperature/salinity relationship were used to calculate the mean annual cycle of dynamic height and geostrophic transport of major currents relative to 400 db along five shipping tracks covering a large part of the tropical Pacific Ocean. The data were selected in bands centered on the most frequently repeated XBT tracklines for the period 1967-1988. Long-term bimonthly mean temperature was calculated in 1° latitude bins along the tracks. The transport function (vertically integrated dynamic height) was then calculated using the mean temperature/salinity relationship. The mean annual cycle of transport of the North Equatorial Current (NEC), the North Equatorial Countercurrent (NECC) and the South Equatorial Current (SEC) (south of 2.5°S) were determined between the ridges and troughs of the transport function. The stochastic errors in bimonthly mean transports were 1-2 Sverdrups on the most sampled tracks. Mean transports of the NEC and NECC increase regularly with longitude from east to west. The NECC has a large annual cycle with a transport-maximum during northern fall and winter. Seasonal variations of the NEC are small. Seasonal variations of the SEC are slightly larger, and they have considerably different phase from track to track. The variation of thermal structure associated with the currents is described. The results of this study are compared in detail to the results of earlier studies of the transports. The differences between the studies are larger than the expected stochastic errors in the mean transports due to differences in the definition of boundaries of the currents and to differences in the procedure for calculating the mean annual variation. The results of all the studies are summarised to facilitate future comparisons to ocean general circulation models and other applications. (Résumé d'auteur)

The Java Australia Dynamic Experiment high-resolution February–March 1992 conductivity-temperature-depth and chlorofluoromethane section obtained between Australia and Bali and on the sills between Flores, Sumba, Sawu, Roti, and the Australian continental shelf allows detailed examination of the water masses distribution and their inferred circulation. A sharp hydrological front between the Indonesian waters and the southern Indian Ocean waters is found between 13°S and 14°S in both seasons (February–March 1992 and August 1989). It separates the high-salinity surface waters to the south from the lower-salinity surface waters derived from the Indonesian Seas to the north. It reaches the surface in February 1992, whereas it was capped by a particularly low salinity surface layer in August 1989. Near Bali, the NW monsoon of February–March produces large intrusions of low-salinity water from the Java Sea, through Lombok Strait in the upper 100 m. At depth, the North Indian Intermediate Water, flowing along the Indonesian coast, brings salty, low-oxygen and low-chlorofluorocarbon water. It enters the Sawu Sea through Sumba Strait toward the east, while it undergoes strong mixing with the Indonesian Seas water. The primary pathway of the Indonesian waters is found north of the front and south of the North Indian Intermediate Water, between 13°S and 9°30′S, and the associated salinity minimum can be followed all across the Indian Ocean.

Hydrodynamic functioning and water circulation of the semi-closed deep lagoon of Ahe atoll (Tuamotu Archipelago, French Polynesia) were investigated using 1 year of field data and a 3D hydrodynamical model. Tidal amplitude averaged less than 30 cm, but tide generated very strong currents (2 m s-1) in the pass, creating a jet-like circulation that partitioned the lagoon into three residual circulation cells. The pass entirely flushed excess water brought by waves-induced radiation stress. Circulation patterns were computed for climatological meteorological conditions and summarized with stream function and flushing time. Lagoon hydrodynamics and general overturning circulation was driven by wind. Renewal time was 250 days, whereas the e-flushing time yielded a lagoon-wide 80-days average. Tide-driven flush through the pass and wind-driven overturning circulation designate Ahe as a wind-driven, tidally and weakly wave-flushed deep lagoon. The 3D model allows studying pearl oyster larvae dispersal in both realistic and climatological conditions for aquaculture applications.

Se analizó información sobre parámetros biogeoquímicos como pH, CO2 parcialmente disuelto, clorofila-a, oxígeno, salinidad y temperatura, obtenidos en el Sistema de Humboldt frente a Peru en los años 2007-2009, a fin de comprender la importancia del pH como una variable clave para trazar la variabilidad biogeoquímica del Sistema de Afloramiento de Humboldt. Las Aguas Costeras Frías (ACF) ricas en nutrientes evidencian una relación inversa con el pH, en ese sentido valores de 7,6 a 8,0 se encontraron asociados a la ocurrencia de eventos de afloramiento; en condiciones frías como La Niña 2007 el pH predominante se encuentra por debajo de 8,0, y en el caso de las Aguas Subtropicales Superficiales presentan un pH entorno a 8,3. La productividad en los veranos se incrementa debido a factores como la intensidad de luz generándose nucleos de clorofila-a superiores a 10,0 μg.L-1; como constituyentes de la reacción bioquímica de fotosíntesis se tiene en cuenta la forma inmediata del compuesto CO2 y el consumo de iones hidronio; en situaciones extremas de fertilización, se tiene elevado pH entre 8,2 e inclusive 9,0, en donde los contenidos de oxígeno disuelto superan los 6,0 mL.L-1.

International audience; The upwelling events that follow strong trade wind episodes have been described in terms of their remarkable signature in the sea surface temperature southwest off New Caledonia. Upwelling brings deeper, and colder waters to the surface, causing 2-4 °C drops in temperature in a few hours, followed by a slower relaxation over several days. Upwelling may sporadically bring nutrients to the surface under certain conditions, and increase the biological productivity. Two multidisciplinary hydrographic cruises allow the impact of upwelling on the chemical and biological properties of the water to be documented. Both cruises took place in austral summer (December 2004 and December 2005), but the first cruise occurred during a strong upwelling event, while the second cruise occurred in calm conditions. The water properties and planktonic composition show important contrasts, with a strong southeastward current (the "ALIS current of New Caledonia") competing with the upwelling system. Our analysis suggests that, while observed productivities are far less than those of typical upwelling systems, some wind events in New Caledonia may contribute to biological activity. A currentmeter mooring, deployed during the second cruise, documents the ocean response to a changing wind field and the local impact of upwelling on currents and temperatures on the water column. The results are discussed, with the help of climatology, Argo float profiler data, satellite data and of a high-resolution numerical simulation.

Profiling current meter (PCM) measurements under adrifting buoy are compared with concurrent shipboard acoustic Doppler current profiler (ADCP) measurements camed out in the western equatorial Pacific in March 1991, from 10"s to 7ON along the 165"E meridian. The mean (ADCP minus PCM) zk rms differences between zonal and meridional velocity components are 5.7 t 11.2 cm s-' and 0.0 t 8.8 cm s-'. respectively, when PCM measurements are relative to 600 m. The mean f rms differences decrease to 2.3 t 7.8 cm s-' and 0.0 k 6.3 cm s-' when the PCM and ADCP data are both referenced to the same layer (on a mean, 16-240 m). As compared with ADCP, it is found that PCM underestimates velocities of less than 20 cm s-' by about 25%.

This thesis participates to a study that has been lead for several years by IRD which aims increased knowledge of hydrodynamics and transport of dissolved substances and particles on the South-West Lagoon of New Caledonia (SLNC). This work stands on field measurements and numerical modelling.The first step of this thesis is an attempt to synthesise the great amount of data produced by a numerical hydrodynamic model (MARS3D). Indexes having the dimension of time and related to the renewal of water masses were computed from numerical tools applied to the hydrodynamic model. The computation methods, the significance and the application of these indexes to the Southwest Lagoon of New-Caledonia (SLNC) are exposed. Examples ofapplication of these indexes aiming to quantify the influence of hydrodynamics on biological processes are shown.Out of flooding periods, the re-suspension of freshly deposited sediments is the main source of suspended particles on the SLNC. The combined actions of waves and currents induce a bottom shear stress that is responsible for particle re-suspension. In order to access the wave field characteristics, a wave model (WavewatchIII) was implemented over the SLNC. It was validated by in situ directional measurements of the wave field.The last part of this thesis focuses on the determination of physical properties of suspended particles such as particle size distributions, density, and fall velocity, are compulsory to model particle transport. This work stands on in situ measurements and laboratory experiences performed with laser particle size analyser. Results emphasise the importance of bioaggregation in a coral reef ecosystem., Cette thèse s’inscrit dans le cadre d’une étude conduite depuis plusieurs années par l’IRD qui vise à mieux connaître les processus de l’hydrodynamique et du transport d’éléments dissous et de particules dans le Lagon Sud-Ouest de Nouvelle Calédonie (SLNC). Les travaux présentés s’appuient sur des mesures de terrain et la modélisation numérique.Le premier volet de la thèse vise à synthétiser l’abondante information produite par un modèle numérique hydrodynamique (MARS3D). Des indices relatifs au renouvellement des masses d’eau et ayant la dimension d’un temps, communément appelés temps de résidence, sont élaborés à partir d’outils numériques. La signification de ces indices, leur mode de calcul et leur application au SLNC sont exposés. Plusieurs applications mettent en évidence les effets de l’hydrodynamique sur des processus biologiques et biochimiques.Hors période de crue, les sédiments fraîchement déposés constituent la principale source de particules en suspension. Les tensions de cisaillement provoquées par les effets combinés de la houle et du courant provoquent leur remise en suspension. Pour les calculer en tout point, il est nécessaire de simuler précisément le champ de vagues. La seconde partie de la thèse y est consacrée. Pour cela, le modèle de houle WaveWatchIII est adapté au SLNC et validé par des mesures directionnelles de vagues.Le troisième et dernier volet de la thèse est focalisé sur la détermination des propriétés physiques des particules en suspension. Ces paramètres (concentration par classe granulométrique, densité, vitesse de chute) sont nécessaires pour modéliser le transport desparticules. Ce travail s’appuie sur des mesures in situ et des expériences en laboratoire réalisées à l’aide d’un granulomètre laser.

An ocean GCM, interpreted in light of linear models and sparse observations, is used to diagnose the dynamics of the annual cycle of circulation in the western boundary current system of the southwest Pacific Ocean. The simple structure of annual wind stress curl over the South Pacific produces a large region of uniformly phased, stationary thermocline depth anomalies such that the western subtropical gyre spins up and down during the year, directing flow anomalies alternately toward and away from the boundary at its northern end, near 10°S. The response of the western boundary currents is to redistribute these anomalies northward toward the equator and southward to the subtropical gyre, a redistribution that is determined principally by linear Rossby processes, not boundary dynamics. When the subtropical gyre and South Equatorial Current (SEC) are strong (in the second half of the year), the result is both increased equatorward transport of the New Guinea Coastal Current and poleward transport anomalies along the entire Australian coast. Because of this opposite phasing of boundary current anomalies across 10°S, annual migration of the bifurcation point of the total SEC, near 18°S in the mean, has no significance regarding variability of transport from subtropics to equator.

International audience; This paper focuses on the invasion by Turbinaria ornata (a brown algae) in the Tuamotu archipelago, French Polynesia [(5-35 degrees S)/(200-230 degrees E)]. Prior to 1980, this alga existed only in the Society and Austral archipelagoes. Between 1985 and 1990, it began to appear in the southern and northern parts of the Tuamotu archipelago. Genetic analyses have been shown not to be appropriate in determining the origin of this algae population. This study investigated the possible ocean drift of floating aggregates of algae. Ocean currents were calculated from satellite data from 1993 to 2001. Their spatial variations as well as their seasonal and interannual variations are described along with calculated drift trajectories. While it was found that mean currents cannot directly transport algae from the Society and Austral archipelagoes to the Tuamotu, the large interannual changes during the El Nino-Southern Oscillation phenomenon produce current reversals that are strong enough to create a transport pathway in a short enough time to allow their survival.

Les observations et les modèles globaux ont montré que l'écoulement vers l'ouest du Courant Equatorial Sud est perturbé par la topographie complexe du Pacifique Sud-Ouest. Il se concentre alors en jets zonaux associés aux îles de Fidji, Vanuatu et Nouvelle-Calédonie. Une simulation régionale à haute résolution a été réalisée. Le Pacifique Sud-Ouest étant considéré comme une région clef dans la modulation décennale du climat, ce travail tend à affirmer la nécessité de prendre en compte plus finement les effets topographiques de cette région dans les modèles d'océan globaux et de climat. (D'après résumé d'auteur)

This thesis participates to a study that has been lead for several years by IRD which aims increased knowledge of hydrodynamics and transport of dissolved substances and particles on the South-West Lagoon of New Caledonia (SLNC). This work stands on field measurements and numerical modelling.The first step of this thesis is an attempt to synthesise the great amount of data produced by a numerical hydrodynamic model (MARS3D). Indexes having the dimension of time and related to the renewal of water masses were computed from numerical tools applied to the hydrodynamic model. The computation methods, the significance and the application of these indexes to the Southwest Lagoon of New-Caledonia (SLNC) are exposed. Examples ofapplication of these indexes aiming to quantify the influence of hydrodynamics on biological processes are shown.Out of flooding periods, the re-suspension of freshly deposited sediments is the main source of suspended particles on the SLNC. The combined actions of waves and currents induce a bottom shear stress that is responsible for particle re-suspension. In order to access the wave field characteristics, a wave model (WavewatchIII) was implemented over the SLNC. It was validated by in situ directional measurements of the wave field.The last part of this thesis focuses on the determination of physical properties of suspended particles such as particle size distributions, density, and fall velocity, are compulsory to model particle transport. This work stands on in situ measurements and laboratory experiences performed with laser particle size analyser. Results emphasise the importance of bioaggregation in a coral reef ecosystem., Cette thèse s’inscrit dans le cadre d’une étude conduite depuis plusieurs années par l’IRD qui vise à mieux connaître les processus de l’hydrodynamique et du transport d’éléments dissous et de particules dans le Lagon Sud-Ouest de Nouvelle Calédonie (SLNC). Les travaux présentés s’appuient sur des mesures de terrain et la modélisation numérique.Le premier volet de la thèse vise à synthétiser l’abondante information produite par un modèle numérique hydrodynamique (MARS3D). Des indices relatifs au renouvellement des masses d’eau et ayant la dimension d’un temps, communément appelés temps de résidence, sont élaborés à partir d’outils numériques. La signification de ces indices, leur mode de calcul et leur application au SLNC sont exposés. Plusieurs applications mettent en évidence les effets de l’hydrodynamique sur des processus biologiques et biochimiques.Hors période de crue, les sédiments fraîchement déposés constituent la principale source de particules en suspension. Les tensions de cisaillement provoquées par les effets combinés de la houle et du courant provoquent leur remise en suspension. Pour les calculer en tout point, il est nécessaire de simuler précisément le champ de vagues. La seconde partie de la thèse y est consacrée. Pour cela, le modèle de houle WaveWatchIII est adapté au SLNC et validé par des mesures directionnelles de vagues.Le troisième et dernier volet de la thèse est focalisé sur la détermination des propriétés physiques des particules en suspension. Ces paramètres (concentration par classe granulométrique, densité, vitesse de chute) sont nécessaires pour modéliser le transport desparticules. Ce travail s’appuie sur des mesures in situ et des expériences en laboratoire réalisées à l’aide d’un granulomètre laser.

New satellite and in situ observations show large intraseasonal (10–60 day) variability of surface winds and upper-ocean current in the equatorial Indian Ocean, particularly in the east. An ocean model forced by the Quick Scatterometer (QuikSCAT) wind stress is used to study the dynamics of the intraseasonal zonal current. The model has realistic upper-ocean currents and thermocline depth variabilities on intraseasonal to interannual scales. The quality of the simulation is directly attributed to the accuracy of the wind forcing. At the equator, moderate westerly winds are punctuated by strong 10–40-day westerly wind bursts. The wind bursts force swift, intraseasonal (20–50 day) eastward equatorial jets in spring, summer, and fall. The zonal momentum balance is between local acceleration, stress, and pressure, while nonlinearity deepens and strengthens the eastward current. The westward pressure force associated with the thermocline deepening toward the east rapidly arrests eastward jets and, subsequently, generates (weak) westward flow. Thus, in accord with direct observations in the east, the spring jet is a single intraseasonal event, there are intraseasonal jets in summer, and the fall jet is long lived but strongly modulated on an intraseasonal scale. The zonal pressure force is almost always westward in the upper 120 m, and changes sign twice a year in the 120–200-m layer. Transient eastward equatorial undercurrents in early spring and late summer are associated with semiannual Rossby waves generated at the eastern boundary following thermocline deepening by the spring and fall jets. An easterly wind stress is not necessary to generate the undercurrents. Experiments with a single westerly wind burst forcing show that apart from the intraseasonal response, the zonal pressure force and current in the east have an intrinsic 90-day time scale that arises purely from equatorial adjustment.