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| Mella-flores, D.; Mazard, S.; Humily, F.; Partensky, F.; Mahe, F.; Bariat, L.; Courties, C.; Marie, D.; Ras, J.; Mauriac, R.; Jeanthon, C.; Bendif, El Mahdi; Ostrowski, M.; Scanlan, D. J.; Garczarek, L.. |
| Biological communities populating the Mediterranean Sea, which is situated at the northern boundary of the subtropics, are often claimed to be particularly affected by global warming. This is indicated, for instance, by the introduction of (sub) tropical species of fish or invertebrates that can displace local species. This raises the question of whether microbial communities are similarly affected, especially in the Levantine basin where sea surface temperatures have significantly risen over the last 25 years (0.50 +/- 0.11 degrees C in average per decade, P < 0.01). In this paper, the genetic diversity of the two most abundant members of the phytoplankton community, the picocyanobacteria Prochlorococcus and Synechococcus, was examined during two... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24402/22413.pdf |
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| Lasbleiz, M.; Leblanc, K.; Blain, S.; Ras, J.; Cornet-barthaux, V.; Nunige, S. Helias; Queguiner, B.. |
| The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October-November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m(-2) for chlorophyll a 314 to 744 mmol m(-2) for biogenic silica (BSi), 1106 to 2268 mmol m(-2) for particulate organic carbon, 215 to 436 mmol m(-2) for particulate organic nitrogen, and 29.3 to 39.0 mmol m(-2) for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost... |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40222/39345.pdf |
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| Peloquin, J.; Swan, C.; Gruber, Nicolas; Vogt, M.; Claustre, Hervé; Ras, J.; Uitz, J.; Barlow, R.; Behrenfeld, M.; Bidigare, R.; Dierssen, H.; Ditullio, G.; Fernandez, E.; Gallienne, C.; Gibb, S.; Goericke, R.; Harding, L.; Head, E.; Holligan, P.; Hooker, S.; Karl, D.; Landry, M.; Letelier, R.; Llewellyn, C.a.; Lomas, M.; Lucas, M.; Mannino, A.; Marty, J.-c.; Mitchell, B.g.; Muller-karger, F.; Nelson, N.; O'Brien, C.; Prezelin, B.; Repeta, D.; Smith Jr, W.o.; Smythe-wright, D.; Stumpf, R.; Subramaniam, A.; Suzuki, K.; Trees, C.; Vernet, M.; Wasmund, N.; Wright, S.. |
| A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 17% and 19% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a,... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00128/23975/21932.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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| Lamy, D.; Jeanthon, C.; Cottrell, M. T.; Kirchman, D. L.; Van Wambeke, France; Ras, J.; Dahan, O.; Pujo-pay, M.; Oriol, L.; Bariat, L.; Catala, P.; Cornet-barthaux, V.; Lebaron, P.. |
| Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basin of the Mediterranean Sea and were linked... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24398/22417.pdf |
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| Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.. |
| In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence, although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into... |
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| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00248/35968/34492.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... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24403/22415.pdf |
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