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| Martini, Severine; Al Ali, Badr; Garel, Marc; Nerini, David; Grossi, Vincent; Pacton, Muriel; Casalot, Laurence; Cuny, Philippe; Tamburini, Christian. |
| Bacterial bioluminescence is commonly found in the deep sea and depends on environmental conditions. Photobacterium phosphoreum ANT-2200 has been isolated from the NW Mediterranean Sea at 2200-m depth (in situ temperature of 13 degrees C) close to the ANTARES neutrino telescope. The effects of hydrostatic pressure on its growth and luminescence have been investigated under controlled laboratory conditions, using a specifically developed high-pressure bioluminescence system. The growth rate and the maximum population density of the strain were determined at different temperatures (from 4 to 37 degrees C) and pressures (from 0.1 to 40 MPa), using the logistic model to define these two growth parameters. Indeed, using the growth rate only, no optimal... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00296/40679/39664.pdf |
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| Jacquet, Stéphanie Hm; Tamburini, Christian; Garel, Marc; Dufour, Aurélie; Van Vambeke, France; Le Moigne, Frédéric Ac; Bhairy, Nagib; Guasco, Sophie. |
| We report on the sub-basins variability of particulate organic carbon (POC) remineralization in the central and western Mediterranean Sea during a late spring period (PEACETIME cruise). POC remineralization rates (MR) were estimated using the excess non-lithogenic particulate barium (Baxs) inventories in mesopelagic waters (100–1000 m) and compared with prokaryotic heterotrophic production (PHP). MR range from 25 ± 2 to 306 ± 70 mg C m−2 d−1. Results reveal larger MR processes in the Algerian (ALG) basin compared to the Tyrrhenian (TYR) and Ionian (ION) basins. Baxs inventories and PHP also indicates that significant remineralization occurs over the whole mesopelagic layers in the ALG basin in contrast to the ION and TYR basins where remineralization is... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76399/77438.pdf |
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| Jacquet, Stéphanie Hm; Lefèvre, Dominique; Tamburini, Christian; Garel, Marc; Le Moigne, Frédéric Ac; Bhairy, Nagib; Guasco, Sophie. |
| n the ocean, remineralization rate associated with sinking particles is a crucial variable. Since the 1990s, particulate biogenic barium (Baxs) has been used as an indicator of carbon remineralization by applying a transfer function relating Baxs to O2 consumption (Dehairs's transfer function, Southern Ocean-based). Here, we tested its validity in the Mediterranean Sea (ANTARES/EMSO-LO) for the first time by investigating connections between Baxs, prokaryotic heterotrophic production (PHP) and oxygen consumption (JO2-Opt; optodes measurement). We show that (1) higher Baxs (409 pM; 100–500 m) occurs in situations where integrated PHP (PHP100/500=0.90) is located deeper, (2) higher Baxs occurs with increasing JO2-Opt, and (3) there is similar magnitude... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00648/76038/76959.pdf |
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| Garel, Marc; Bonin, Patricia; Martini, Severine; Guasco, Sophie; Roumagnac, Marie; Bhairy, Nagib; Armougom, Fabrice; Tamburini, Christian. |
| The pelagic realm of the dark ocean is characterized by high hydrostatic pressure, low temperature, high-inorganic nutrients, and low organic carbon concentrations. Measurements of metabolic activities of bathypelagic bacteria are often underestimated due to the technological limitations in recovering samples and maintaining them under in situ environmental conditions. Moreover, most of the pressure-retaining samplers, developed by a number of different labs, able to maintain seawater samples at in situ pressure during recovery have remained at the prototype stage, and therefore not available to the scientific community. In this paper, we will describe a ready-to-use pressure-retaining sampler, which can be adapted to use on a CTD-carousel sampler. As well... |
| Tipo: Text |
Palavras-chave: Pressure-retaining sampler; Deep sea; In situ sampling; Prokaryotic activities; Prokaryotic diversity. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00688/79992/82967.pdf |
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| Van Wambeke, France; Pulido, Elvira; Catala, Philippe; Dinasquet, Julie; Djaoudi, Kahina; Engel, Anja; Garel, Marc; Guasco, Sophie; Barbara, Marie; Nunige, Sandra; Taillandier, Vincent; Zancker, Birthe; Tamburini, Christian. |
| Ectoenzymatic activity, prokaryotic heterotrophic abundances and production were determined in the Mediterranean Sea. Sampling was carried out in the sub-surface, the deep chlorophyll maximum layer (DCM), the core of the Levantine intermediate waters and in the deeper part of the mesopelagic layers. Michaelis–Menten kinetics were assessed using a large range of concentrations of fluorogenic substrates (0.025 to 50 µM). As a consequence, Km (Michaelis–Menten half-saturation constant) and Vm (maximum hydrolysis velocity) parameters were determined for both low- and high-affinity enzymes for alkaline phosphatase, aminopeptidase (LAP) and β-glucosidase (βGLU). Based on the constant derived from the high-LAP-affinity enzyme (0.025–1 µM substrate concentration... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00642/75452/76268.pdf |
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