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. (2021). Viability and stress state of bacteria associated with primary production or zooplankton-derived suspended particulate matter in summer along a transect in Baffin Bay (Arctic Ocean) (Vol. 770).
Abstract: In the framework of the GreenEdge Project (whose the general objective is to understand the dynamic of the phytoplankton spring bloom in Arctic Ocean), lipid composition and viability and stress state of bacteria were monitored in sea ice and suspended particulate matter (SPM) samples collected in 2016 along a transect from sea ice to open water in Baffin Bay (Arctic Ocean). Lipid analyses confirmed the dominance of diatoms in the bottommost layer of ice and suggested (i) the presence of a strong proportion of micro-zooplankton in SPM samples collected at the western ice covered St 403 and St 409 and (ii) a high proportion of macro-zooplankton (copepods) in SPM samples collected at the eastern ice covered St 413 and open water St 418. The use of the propidium monoazide (PMA) method allowed to show a high bacterial mortality in sea ice and in SPM material collected in shallower waters at St 409 and St 418. This mortality was attributed to the release of bactericidal free fatty acids by sympagic diatoms under the effect of light stress. A strong cis-trans isomerization of bacterial MUFAs was observed in the deeper SPM samples collected at the St 403 and St 409. It was attributed to the ingestion of bacteria stressed by salinity in brine channels of ice by sympagic bacterivorous microzooplankton (ciliates) incorporating trans fatty acids of their preys before to be released in the water column during melting. The high trans/cis ratios also observed in SPM samples collected in the shallower waters at St 413 and St 418 suggest the presence of positively or neutrally buoyant extracellular polymeric substances (EPS)-rich particles retained in sea ice and discharged (with bacteria stressed by salinity) in seawater after the initial release of algal biomass. Such EPS particles, which are generally considered as ideal vectors for bacterial horizontal distribution in the Arctic, appeared to contain a high proportion of dead and non-growing bacteria.
Keywords: Bacterial viability EPS isomerase Micro- and macro-zooplankton Salinity stress Sea ice algae
Programme: 1164
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F. R. Fontaine, G. Roult, B. Hejrani, L. Michon, V. Ferrazzini, G. Barruol, H. Tkal?i?, A. Di Muro, A. Peltier, D. Reymond, T. Staudacher, F. Massin. (2019). (Vol. 9).
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Gallet J-C, Domine F, Arnaud L, Picard G, Savarino J,. (2011). Vertical profile of the specific surface area and density of the snow at Dome C and on a transect to Dumont D'Urville, Antarctica – albedo calculations and comparison to remote sensing products (Vol. 5). Bachelor's thesis, Copernicus Publications, .
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Moore, C., Helmig, D., Fain, X., Obrist, D., Barbero, A., Barret, M., Van Dam, B., Dommergue, A., Hueber, J., Magand, O., Mass, A., Pirrone, N., Savarino, J., Seok, B., Sprovieri, F., Stephens, C., Williams, M., 2013. (2013). Vertical gaseous elemental mercury concentration gradients, mercury redox processes, and surface exchanges in alpine and polar snowpacks..
Abstract: The 11th International Conference on Mercury as a Global Pollutant (ICMGP), Edinburgh, Scotland, 28 July-2 August.
Programme: 1028
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Amalvict M. and de Linage C. (2004). Vertical displacement and variation of gravity predicted and observed in Antarctica.
Abstract: SCAR Open Science, Bremen, Germany
Programme: 337
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Lambotte S, Rivera L, Hinderer J. (2006). Vertical and horizontal seismometric observations of tides. Journal of geodynamics, 41, 39–58.
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Tranchant Y.-T. (2022).
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Carole Ferret. (2012). L'Homme, (202), p. 113–140.
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CHANTELOUP L., JOLIET F. (2015).
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. (2022). Vegetation type is an important predictor of the arctic summer land surface energy budget (Vol. 13).
Keywords: Atmospheric dynamics Climate and Earth system modelling Cryospheric science Ecosystem ecology Phenology
Programme: 1042
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