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Romero Oscar E, Van de Vijver Bart, . (2011). Cocconeis crozetensis, a new monoraphid diatom from subantarctic freshwater and moss habitats
. 0269-249X, 26(1), 89–98.
Abstract: Ultrastructural observations of one previously misidentified freshwater species of a Cocconeis (Bacillariophyceae) from the Crozet Archipelago, Indian Sector of the Southern Ocean, are presented. Cocconeis crozetensis sp. nov. possesses small valves (apical axis: 10?13 ?m; transapical axis: 6.7?8.4 ?m). The main frustule features that distinguish the proposed new species are: (1) the sternum valve (SV) areolae with an external vola and the internal vela, (2) the submarginal area of the raphe-sternum valve, and (3) the morphology of valvocopula and fimbriae of the SV. Possible morphological relationships with several other small Cocconeis, such as C. neodiminuta, C. neothumensis, C. placentula var. pseudolineata and C. pseudothumensis, as well as its morphological similarities with placentuloid Cocconeis are discussed. Reliable identification of C. crozetensis sp. nov. under light microscopy can prove difficult for less-experienced diatomologists and ecologists, and the use of electron microscopy proves to be unavoidable for its correct identification.
Programme: 136
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Bachok Zainudin, Meziane Tarik, Mfilinge Prosper L, Tsuchiya Makoto, . (2009). Fatty acid markers as an indicator for temporal changes in food sources of the bivalve Quidnipagus palatum
. Aquatic Ecosystem Health & Management, 12(4), 390–400.
Abstract: Changes in the fatty acid composition in the tissues of the bivalve Quidnipagus palatum from the Tomigusuku intertidal flat, Okinawa, Japan, collected in four different seasons (November 2000, the beginning of cold season; January 2001, the cold season; May 2001, the rainy season; and July 2001, the warm season) were examined and compared to the composition of surface sediments and suspended particulate materials. Assessment of fatty acid markers suggested that the food sources of Q. palatum differed between seasons and depended on the sources of organic material present in the sediment and water column. Vascular plants and bacteria were the main dietary components from July to November because of their abundance in the sediment. From November to January, macroalgae and phytoplankton were the major food sources of Q. palatum, corresponding to their predominance in sediments and algal blooms, respectively. During the May rainy season, organic matter in the sediment was dominated by diatoms, whereas the water column contained diatoms and resuspended macroalgal detritus. The transition to the warm season by July significantly increased the contribution of diatoms to the organic matter present in both the sediment and the water column. Consequently, from May to July, diatoms became the main food source for Q. palatum.
Programme: 1090
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Testut L, Birol F, Delebecque C, . (2012). Regional Tidal Modeling and Evaluation of Jason-2 Tidal Geophysical Correction
. Marine Geodesy, 35(sup1), 299–313.
Abstract: Through a validation exercise in the Kerguelen Island over 13 global, regional, and local tidal atlases, we have demonstrated the superiority of finite element high resolution model at the coast. The evaluation of different tidal geophysical corrections on the de-aliasing performance of the Jason-2 mission exhibited strong differences in the coastal domain (<10?20 km from the coast) with SLA variance reduction that can reach up to 30% from one model to another. The lack of resolution is pointed out as a possible responsible of these difference.
Programme: 688
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Van de Vijver Bart, Cocquyt Christine, de Haan Myriam, Zidarova Ralitsa, . (2012). The genus Surirella (Bacillariophyta) in the sub-Antarctic and maritime Antarctic region
. Diatom Res., 28(1), 93–108.
Abstract: A revision of taxa from the genus Surirella from the Antarctic region resulted in the description of three new taxa: S. subantarctica Van de Vijver & Cocquyt sp. nov., S. heardensis Van de Vijver & Cocquyt sp. nov. and S. australovisurgis Van de Vijver, Cocquyt, Zidarova & Kopalová sp. nov. Detailed light (LM) and scanning electron microscope (SEM) observations are used to characterize these three new taxa. Comparisons with similar taxa and the ecological preferences of each species are added. The morphological characteristics of a fourth Antarctic Surirella taxon, S. kerguelensis Grunow are illustrated as this taxon was only known from a few hand drawings and LM pictures. Finally, a fifth taxon, S. lapponica A. Cleve was found on South Georgia and likewise illustrated. The revision of these species made clear that the genus Surirella showed similar biogeographical trends as other, previously revised genera indicating that a distinct Antarctic diatom flora exists.
Programme: 136
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Hamilton Paul B, de Haan Myriam, Zidarova Ralitsa, Van de Vijver Bart, . (2013). An evaluation of selected Neidium species from the Antarctic region
. Diatom Res., 29(1), 27–40.
Abstract: The presentation of three distinct Neidium taxa from the sub-Antarctic and Maritime Antarctic region after examining more than 1500 samples from a broad variety of aquatic and terrestrial (micro-)habitats suggests that taxa representing the genus Neidium Pfitzer are not only quite rare in these regions, but that the three species also represent well-defined biogeographical distributions. N. nyvltii sp. nov., N. antarcticum sp. nov. and N. aubertii Manguin are characterized by linear to linear?lanceolate valves with rostrate to capitate apices, a single prominent longitudinal canal along the valve margins and lacinia covering the distal raphe endings. Neidium nyvltii is a benthic alkalophile growing in the Maritime Antarctic region under high total phosphorus (TP) and moderately high chloride concentrations, while the closest taxa for comparison (N. kozlowii Mereschkowsky and its varieties) are also alkalophilic, growing under lower TP concentrations in northern temperate?Arctic regions. Neidium aubertii is an acidophile with a sub-Antarctic distribution, whereas the most comparable taxa are N. bisulcatum (Lagestedt) Cleve, and N. bergii (A. Cleve-Euler) Krammer & Lange-Bertalot both are alkalophiles with northern hemisphere distribution and commonly occurring in the Arctic. There is some evidence of parallel similarities in valve forms between the polar northern and southern hemispheres. The significance of this parallelism is yet to be determined.
Programme: 136
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Orange François, Dupont Samuel, Goff Olivier Le, Bienvenu Nadege, Disnar Jean-Robert, Westall Frances, Le Romancer Marc, . (2013). Experimental fossilization of the Thermophilic Gram-positive Bacterium Geobacillus SP7A: A Long Duration Preservation Study
. Geomicrobiol. J., 31(7), 578–589.
Abstract: Recent experiments to fossilize microorganisms using silica have shown that the fossilization process is far more complex than originally thought; microorganisms not only play an active role in silica precipitation but may also remain alive while silica is precipitating on their cell wall. To better understand the mechanisms that lead to the preservation of fossilized microbes in recent and ancient rocks, we experimentally silicified a Gram-positive bacterium, Geobacillus SP7A, over a period of five years. The microbial response to experimental fossilization was monitored with the use of LIVE/DEAD staining to assess the structural integrity of the cells during fossilization. It documented the crucial role of silicification on the preservation of the cells and of their structural integrity after several years. Electron microscopy observations showed that initial fossilization of Gram-positive bacteria was extremely rapid, thus allowing very good preservation of Geobacillus SP7A cells. A thick layer of silica was deposited on the outer surface of cell walls in the earliest phase of silicification before invading the cytoplasmic space. Eventually, the cell wall was the only recognizable feature. Heavily mineralized cells thus showed morphological similarities with natural microfossils found in the rock record.
Programme: 1077
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Willener Astrid S T, Halsey Lewis G, Strike Siobhán, Enstipp Manfred R, Georges Jean-Yves, Handrich Yves, . (2015). Reassessment of the cardio-respiratory stress response, using the king penguin as a model
. Stress, 18(1), 115–120.
Abstract: AbstractResearch in to short-term cardio-respiratory changes in animals in reaction to a psychological stressor typically describes increases in rate of oxygen consumption and heart rate. Consequently, the broad consensus is that they represent a fundamental stressor response generalizable across adult species. However, movement levels can also change in the presence of a stressor, yet studies have not accounted for this possible confound on heart rate. Thus the direct effects of psychological stressors on the cardio-respiratory system are not resolved. We used an innovative experimental design employing accelerometers attached to king penguins (Aptenodytes patagonicus) to measure and thus account for movement levels in a sedentary yet free-to-move animal model during a repeated measures stress experiment. As with previous studies on other species, incubating king penguins (N?=?6) exhibited significant increases in both and heart rate when exposed to the stressor. However, movement levels, while still low, also increased in response to the stressor. Once this was accounted for by comparing periods of time during the control and stress conditions when movement levels were similar as recorded by the accelerometers, only significantly increased; there was no change in heart rate. These findings offer evidence that changing movement levels have an important effect on the measured stress response and that the cardio-respiratory response per se to a psychological stressor (i.e. the response as a result of physiological changes directly attributable to the stressor) is an increase in without an increase in heart rate.
Programme: 394
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Danesi S., M. Dubbini, A. Morelli and L. Vittuari. (2008). Joint geophysical observations of ice stream dynamics (A. Capra and R. Dietrich Eds., Ed.). Bachelor's thesis, Springer-Verlag Berlin Publ., Berlin.
Abstract: Contribution
to ‘Geodetic and Geophysical Observatories in Polar Regions –
Overview in the IPY Perspective’, Springer-Verlag Berlin Publ., A.
Capra and R. Dietrich Eds.,
Programme: 906
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Pondrelli S., L. Margheriti and S. Danesi. (2005). Seismic anisotropy beneath Northern Victoria Land from SKS splitting analysis, Antarctica. Bachelor's thesis, Springer-Verlag Berlin Heidelberg Eds, .
Abstract: Contr.
to Global Earth Sciences, Springer-Verlag Berlin Heidelberg Eds.
Programme: 906
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Pitman RobertL, Durban JohnW, Greenfelder Michael, Guinet Christophe, Jorgensen Morton, Olson PaulaA, Plana Jordi, Tixier Paul, Towers JaredR, . (2011). Observations of a distinctive morphotype of killer whale (Orcinus orca), type D, from subantarctic waters
. 0722-4060, 34(2), 303–306-.
Abstract: Studies have shown that killer whale (Orcinus orca) communities in high latitudes regularly comprise assemblages of sympatric ‘ecotypes’—forms that differ in morphology, behavior, and prey preferences. Although they can appear superficially similar, recent genetic evidence suggests that breeding is assortative among ecotypes within individual communities, and species-level divergences are inferred in some cases. Here, we provide information on a recently recognized ‘type D’ killer whale based on photographs of a 1955 mass stranding in New Zealand and our own six at-sea sightings since 2004. It is the most distinctive-looking form of killer whale that we know of, immediately recognizable by its extremely small white eye patch. Its geographic range appears to be circumglobal in subantarctic waters between latitudes 40°S and 60°S. School sizes are relatively large (mean 17.6; range 9–35; n = 7), and although nothing is known about the type D diet, it is suspected to include fish because groups have been photographed around longline vessels where they reportedly depredate Patagonian toothfish (Dissostichus eleginoides).
Keywords: Killer whale, Orcinus orca, Subantarctic, Type D,
Programme: 109
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