Bulletin de l'Académie internationale de géographie botanique.

v.11 (1902)

Bulletin de l'Académie internationale de géographie botanique.

v.15 (1905)

Bulletin de l'Académie internationale de géographie botanique.

v.18 (1908)

Le Monde des plantes.

3

Bulletin de l'Académie internationale de géographie botanique.

v.12 (1903)

Bulletin de l'Académie internationale de géographie botanique.

v.8-9 (1898-1899)

Le Monde des plantes.

5-7

Bulletin de l'Académie internationale de géographie botanique.

v.19 (1909)

La québécité comme élément fondateur d'une pensée musicale électroacoustique

Le projet de recherche-création proposé survole la québécité à travers un pan majeur de l’étude des Amériques : le territoire. L’adoption du territoire québécois, de son espace, et de sa densité – effectué à la fois sous un axe méridional (le Saint-Laurent) et septentrional (le Nord) –, s’effectue dans mon corpus acousmatique à travers l’utilisation de concepts théoriques établis par plusieurs figures québécoises et internationales. La description des sources d'inspiration du cycle d’œuvres acousmatique proposé, étant principalement issues de sphères extramusicales — la démarche de divers artistes et chercheurs québécois ayant contribué à l’émergence poétique de mon corpus tels que Pierre Perrault, René Derouin, Daniel Chartier, et Louis-Edmond Hamelin — y tient une place importante. La portion musicale est effectuée de façon analytique à l’aide de deux méthodes propres au genre électroacoustique – analyse typologique de Pierre Schaeffer, et fonctionnelle de Stéphane Roy –, qui, à travers l’œuvre de certains compositeurs de musiques électroniques internationaux permettent de souligner la pluralité des conceptions territoriales et le réseau sémantique universel sous-jacent, laissant place à une lecture plus large de cette thématique. La méthodologie proposée permet donc à la fois de cerner l’universel – modèles naturels, références psychoacoustiques –, le local – utilisation de poèmes québécois, référents animaux ou anecdotiques précis tels que des cris d’oiseaux et des prises sonores du Saint-Laurent –, et la relation dichotomique entre la nature et la culture dans mon corpus, afin qu’émerge un discours musical cohérent basé sur le territoire québécois.

Limitations of microbial hydrocarbon degradation at the Amon Mud Volcano (Nile Deep Sea Fan)

The Amon mud volcano (MV), located at 1250 m water depth on the Nile Deep Sea Fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulphate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition and microbial activities over three years, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulphide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. Furthermore, within three years, cell numbers and hydrocarbon degrading activity increased at the gas-seeping sites. The low microbial activity in the hydrocarbon-vented areas of Amon mud volcano is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer mud volcano area is limited by hydrocarbon transport.

(Table 1) Lithium contents and isotopic composition in sediments from DSDP Holes 64-477 and 64-477A

Lithium isotopic compositions of hydrothermally altered sediments of Deep Sea Drilling Project (DSDP) site 477/477A, as well as high temperature vent fluids of the Guaymas Basin, have been determined to gain an understanding of lithium exchange during fluid-sediment interaction at this sediment-covered spreading center. Unaltered turbidite of the basin has a d6Li value of -10%, 5-7% heavier than fresh oceanic basalts. Contact metamorphism induced by a shallow sill intrusion results in a decrease of the lithium content of the adjacent sediments and a lighter isotopic value (-8%). Below the sill, sediments altered by a deep-seated hydrothermal system show strong depletions in lithium, while lithium isotopic compositions vary greatly, ranging from -11 to +1%. The shift to lighter composition is the result of preferential retention of the lighter isotope in recrystallized phases after destruction of the primary minerals. The complexity of the isotope profile is attributed to inhomogeneity in mineral composition, the tortuous pathway of fluids and the temperature effect on isotopic fractionation. The range of lithium concentration and d6Li values for the vent fluids sampled in 1982 and 1985 overlaps with that of the sediment-free mid-ocean ridge systems. The lack of a distinct expression of sediment input is explained in terms of a flow-through system with continuous water recharge. The observations on the natural system agree well with the results of laboratory hydrothermal experiments. The experimental study demonstrates the importance of temperature, pressure, water/rock ratio, substrate composition and reaction time on the lithium isotopic composition of the reacted fluid. High temperature authigenic phases do not seem to constitute an important sink for lithium and sediments of a hydrothermal system such as Guaymas are a source of lithium to the ocean. The ready mobility of lithium in the sediment under elevated temperature and pressure conditions also has important implications for lithium cycling in subduction zones.

Vertical profiles of environmental parameters measured on discrete water samples collected with Niskin bottles during the Tara Oceans expedition 2009-2013

The present data publication provides permanent links to original and updated versions of validated data files. The data files include properties of seawater, particulate matter and dissolved matter that were measured from discrete water samples collected with Niskin bottles during the 2009-2013 Tara Oceans expedition. Properties include pigment concentrations from HPLC analysis (10 depths per vertical profile, 25 pigments per depth), the carbonate system (Surface and 400m; pH (total scale), CO2, pCO2, fCO2, HCO3, CO3, Total alkalinity, Total carbon, OmegaAragonite, OmegaCalcite, and dosage Flags), nutrients (10 depths per vertical profile; NO2, PO4, N02/NO3, SI, quality Flags), DOC, CDOM, and dissolved oxygen isotopes. The Service National d'Analyse des Paramètres Océaniques du CO2, at the Université Pierre et Marie Curie, determined CT and AT potentiometrically (Edmond 1970; DOE 1994) on samples preserved according to Dickson et al. (2007). More than 250 vertical profiles of these properties were made across the world ocean. DOC, CDOM and dissolved oxygen isotopes are available only for the Arctic Ocean and Arctic Seas (2013).