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| Registros recuperados: 14 | |
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| Mauriac, R.; Moutin, T.; Baklouti, M.. |
| The biogeochemistry of carbon and nutrients (N,P) in the surface layer of the ocean strongly depends on the complex interactions between primary producers (phytoplankton) and remineralizers (heterotrophic bacteria). To understand how these interactions impact the overall DOC dynamics in the surface layer of the Mediterranean Sea, we implemented, using Eco3M (Ecological Mechanistic Modular Modelling tool), a multi-element model with a mechanistic description of primary production. We studied the model steady state results under various nutrient conditions and fixed cell abundances. By doing so, we show how the bottom up control of osmotrophs growth can impact the overall DOC dynamics in the system. Based on our set of parameters, the biogeochemical... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24397/22414.pdf |
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| Pagès, R.; Baklouti, M.; Barrier, Nicolas; Richon, C.; Dutay, J.-c.; Moutin, T.. |
| The Mediterranean Sea (MS) is a semi-enclosed sea characterized by a zonal west-east gradient of oligotrophy, where microbial growth is controlled by phosphate availability in most situations. External inputs of nutrients including Gibraltar inputs, river inputs and atmospheric deposition are therefore of major importance for the biogeochemistry of the MS. This has long been considered to be driven mainly by nutrient exchanges at Gibraltar. However, recent studies indicate that river inputs signi cantly a ect nutrients concentrations in the Mediterranean Sea, although their resulting impact on its biogeochemistry remains poorly understood. In this study, our aim was to make good this lack by addressing the large-scale and long-term impact of variations in... |
| Tipo: Text |
Palavras-chave: Mediterranean Sea; River inputs; Coupled physical-biogeochemical model; Flexible stoichiometry model; Biogeochemistry; Nutrient. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71118/69420.pdf |
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| Loisel, H.; Vantrepotte, V.; Norkvist, K.; Meriaux, Xavier; Kheireddine, M.; Ras, J.; Pujo-pay, M.; Combet, Y.; Leblanc, K.; Dall'Olmo, G.; Mauriac, R.; Dessailly, D.; Moutin, T.. |
| The variability of inherent optical properties is investigated in the ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM experiment performed during early summer 2008. Bio-optical relationships found for ultra-oligotrophic waters of the three anticyclonic gyres sampled significantly depart from the mean standard relationships provided for the global ocean, confirming the peculiar character of these Mediterranean waters. These optical anomalies are diversely related to the specific biological and environmental conditions occurring in the studied ecosystem. Specifically, the surface specific phytoplankton absorption coefficient exhibits values lower than those expected from the general relationships mainly in relation with a high... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24403/22415.pdf |
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| Crombet, Y.; Leblanc, K.; Queguiner, B.; Moutin, T.; Rimmelin, P.; Ras, J.; Claustre, H.; Leblond, N.; Oriol, L.; Pujo-pay, M.. |
| The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco), and total chlorophyll-a (TChl-a) were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM) encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM), fucoxanthin (DFM) and TChl-a (DCM) were evidenced during both seasons with maximal... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24393/22421.pdf |
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| Berthelot, H; Moutin, T.; L'Helguen, S.; Leblanc, K.; Helias, S.; Grosso, O.; Leblond, N.; Charriere, B.; Bonnet, S.. |
| In the oligotrophic ocean characterized by nitrate (NO3-) depletion in surface waters, dinitrogen (N-2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. In this study, we deployed large in situ mesocosms in New Caledonia in order to investigate (1) the contribution of N-2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON), i.e., whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (PO43-) in order to prevent phosphorus (P) limitation and promote N-2 fixation. The diazotrophic community was dominated by... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00275/38672/73173.pdf |
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| Popendorf, K. J.; Tanaka, T.; Pujo-pay, M.; Lagaria, A.; Courties, C.; Conan, Pascal; Oriol, L.; Sofen, L. E.; Moutin, T.; Van Mooy, B. A. S.. |
| Intact polar membrane lipids compose a significant fraction of cellular material in plankton and their synthesis imposes a substantial constraint on planktonic nutrient requirements. As a part of the Biogeochemistry from the Oligotrophic to the Ultraoligotrophic Mediterranean (BOUM) cruise we examined the distribution of several classes of intact polar diacylglycerolipids (IP-DAGs) across the Mediterranean, and found that phospholipid concentration as a percent of total lipids correlated with phosphate concentration. In addition, the ratios of non-phosphorus lipids to phospholipids - sulfoquinovosyldiacylglycerol (SQDG) to phosphatidylglycerol (PG), and betaine lipids to phosphatidylcholine (PC) - were also found to increase from west to east across the... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24405/22410.pdf |
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| Dall'Olmo, G.; Boss, E.; Behrenfeld, M. J.; Westberry, T. K.; Courties, C.; Prieur, L.; Pujo-pay, M.; Hardman-mountford, N.; Moutin, T.. |
| The diurnal fluctuations in solar irradiance impose a fundamental frequency on ocean biogeochemistry. Observations of the ocean carbon cycle at these frequencies are rare, but could be considerably expanded by measuring and interpreting the inherent optical properties. A method is presented to analyze diel cycles in particulate beam-attenuation coefficient (c(p)) measured at multiple wavelengths. The method is based on fitting observations with a size-structured population model coupled to an optical model to infer the particle size distribution and physiologically relevant parameters of the cells responsible for the measured diel cycle in c(p). Results show that the information related to size and contained in the spectral data can be exploited to... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24404/22420.pdf |
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| Moutin, T.; Prieur, L.. |
| We studied a longitudinal transect in the Mediterranean Sea (MS) and along this transect, the influence of anticyclonic eddies at three long duration (LD) stations. The deep chlorophyll maximum depth, the euphotic layer depth and the top of the nitracline depth are clearly correlated outside of the eddies, and deepen from the oligotrophic western to the ultraoligotrophic eastern MS. We provide evidence that the locations of the three LD stations studied were near the axis of the eddies. Their diameters were close to 100 km and the studied areas were less than 10 km from the centre of the eddies. The positions of the LD stations are marked by an increase in the flux function and a decrease in apparent oxygen utilization (AOU) and in excess density (sigma),... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00133/24385/22399.pdf |
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| Pujo-pay, M.; Conan, Pascal; Oriol, L.; Cornet-barthaux, V.; Falco, C.; Ghiglione, J. -f.; Goyet, C.; Moutin, T.; Prieur, L.. |
| This paper provides an extensive vertical and longitudinal description of the biogeochemistry along an East-West transect of 3000 km across the Mediterranean Sea during summer 2008 (BOUM cruise). During this period of strong stratification, the distribution of nutrients, particulate and dissolved organic carbon (DOC), nitrogen (DON) and phosphorus (DOP) were examined to produce a detailed spatial and vertically extended description of the elemental stoichiometry of the Mediterranean Sea. Surface waters were depleted in nutrients and the thickness of this depleted layer increased towards the East from about 10 m in the Gulf of Lion to more than 100 m in the Levantine basin, with the phosphacline deepening to a greater extent than that for corresponding... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24396/22409.pdf |
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| Moutin, T.; Van Wambeke, France; Prieur, L.. |
| The overall goal of the BOUM (Biogeochemistry from the Oligotrophic to the Ultraoligotrophic Mediterranean) experiment was to obtain a better representation of the interactions between planktonic organisms and the cycle of biogenic elements in the Mediterranean Sea (MS), in the context of global climate change and, more particularly, on the role of the ocean in carbon sequestration through biological processes. The BOUM experiment was organized around three main objectives: (1) to give a longitudinal description of the biogeochemistry and the biological diversity of the MS during the strongest stratified period, (2) to study processes at the centre of three anticyclonic eddies, and (3) to obtain a representation of the main biogeochemical fluxes and the... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00133/24384/22400.pdf |
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| Christaki, U.; Van Wambeke, France; Lefevre, D.; Lagaria, A.; Prieur, L.; Pujo-pay, M.; Grattepanche, J. -d.; Colombet, J.; Psarra, S.; Dolan, J. R.; Sime-ngando, T.; Conan, Pascal; Weinbauer, M. G.; Moutin, T.. |
| The abundance and activity of the major members of the heterotrophic microbial community - from viruses to ciliates - were studied along a longitudinal transect across the Mediterranean Sea in the summer of 2008. The Mediterranean Sea is characterized by a west to east gradient of deepening of DCM (deep chlorophyll maximum) and increasing oligotrophy reflected in gradients of biomass and production. However, within this well documented longitudinal trend, hydrological mesoscale features exist and likely influence microbial dynamics. Here we present data from a W-E transect of 17 stations during the period of summer stratification. Along the transect the production and fate of organic matter was investigated at three selected sites each one located in the... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24400/22422.pdf |
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| Bonnet, S.; Grosso, O.; Moutin, T.. |
| This study provides extensive data on planktonic N(2) fixation rates across the whole Mediterranean Sea. They show that N(2) fixation occurs in Mediterranean waters during the stratification period, with a clear decreasing trend from the oligotrophic western basin (10-76 mu mol m(-2) d(-1)) to the ultra oligotrophic eastern basin (0-0.4 mu mol m(-2) d(-1)). Highest rates are measured in the less oligotrophic western basin, between the surface and 75 m-depth, where 45 to 75% of N(2) fixation are found within the picoplanktonic fraction (<3 mu m). While the biogeochemical impact of N(2) fixation in the eastern basin seems negligible, N(2) fixation is able to sustain up to 35% of new primary production during the stratified period in the western basin.... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24389/22423.pdf |
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| Messié, M.; Petrenko, A.; Doglioli, A.m.; Aldebert, C.; Martinez, Elodie; Koenig, G.; Bonnet, S.; Moutin, T.. |
| In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in... |
| Tipo: Text |
Palavras-chave: Island mass effect; Lagrangian analysis; Nitrogen fixation; Nutrient supply; Oligotrophic ocean; Phytoplankton bloom. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71162/69489.pdf |
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| Talarmin, A.; Van Wambeke, F.; Lebaron, P.; Moutin, T.. |
| Microbial transformations are key processes in marine phosphorus cycling. In this study, we investigated the contribution of phototrophic and heterotrophic groups to phosphate (Pi) uptake fluxes in the euphotic zone of the low-Pi Mediterranean Sea and estimated Pi uptake kinetic characteristics. Surface soluble reactive phosphorus (SRP) concentrations were in the range of 6–80 nmol L−1 across the transect, and the community Pi turnover times, assessed using radiolabeled orthophosphate incubations, were longer in the western basin, where the highest bulk and cellular rates were measured. Using live cell sorting, four vertical profiles of Pi uptake rates were established for heterotrophic prokaryotes (Hprok), phototrophic picoeukaryotes (Pic) and... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00269/38002/36084.pdf |
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| Registros recuperados: 14 | |
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