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. (2016). Where to Forage in the Absence of Sea Ice? Bathymetry As a Key Factor for an Arctic Seabird (Vol. 11).
Abstract: The earth is warming at an alarming rate, especially in the Arctic, where a marked decline in sea ice cover may have far-ranging consequences for endemic species. Little auks, endemic Arctic seabirds, are key bioindicators as they forage in the marginal ice zone and feed preferentially on lipid-rich Arctic copepods and ice-associated amphipods sensitive to the consequences of global warming. We tested how little auks cope with an ice-free foraging environment during the breeding season. To this end, we took advantage of natural variation in sea ice concentration along the east coast of Greenland. We compared foraging and diving behaviour, chick diet and growth and adult body condition between two years, in the presence versus nearby absence of sea ice in the vicinity of their breeding site. Moreover, we sampled zooplankton at sea when sea ice was absent to evaluate prey location and little auk dietary preferences. Little auks foraged in the same areas both years, irrespective of sea ice presence/concentration, and targeted the shelf break and the continental shelf. We confirmed that breeding little auks showed a clear preference for larger copepod species to feed their chick, but caught smaller copepods and nearly no ice-associated amphipod when sea ice was absent. Nevertheless, these dietary changes had no impact on chick growth and adult body condition. Our findings demonstrate the importance of bathymetry for profitable little auk foraging, whatever the sea-ice conditions. Our investigations, along with recent studies, also confirm more flexibility than previously predicted for this key species in a warming Arctic.
Keywords: Birds Copepods Foraging Oceans Predation Sea ice Seabirds Zooplankton
Programme: 388
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Neala Creasy, Maureen D. Long, Heather A. Ford. (2017). Deformation in the lowermost mantle beneath Australia from observations and models of seismic anisotropy (Vol. 122).
Abstract: Observations of seismic anisotropy near the core-mantle boundary may yield constraints on patterns of lowermost mantle flow. We examine seismic anisotropy in the lowermost mantle beneath Australia, bounded by the African and Pacific Large Low Shear Velocity Provinces. We combined measurements of differential splitting of SKS-SKKS and S-ScS phases sampling our study region over a range of azimuths, using data from 10 long-running seismic stations. Observations reveal complex and laterally heterogeneous anisotropy in the lowermost mantle. We identified two subregions for which we have robust measurements of D?-associated splitting for a range of ray propagation directions and applied a forward modeling strategy to understand which anisotropic scenarios are consistent with the observations. We tested a variety of elastic tensors and orientations, including single-crystal elasticity of lowermost mantle minerals (bridgmanite, postperovskite, and ferropericlase), tensors based on texture modeling in postperovskite aggregates, elasticity predicted from deformation experiments on polycrystalline MgO aggregates, and tensors that approximate the shape preferred orientation of partial melt. We find that postperovskite scenarios are more consistently able to reproduce the observations. Beneath New Zealand, the observations suggest a nearly horizontal [100] axis orientation with an azimuth that agrees well with the horizontal flow direction predicted by previous mantle flow models. Our modeling results further suggest that dominant slip on the (010) plane in postperovskite aggregates provides a good fit to the data but the solution is nonunique. Our results have implications for the mechanisms of deformation and anisotropy in the lowermost mantle and for the patterns of mantle flow.
Keywords: anisotropy lowermost mantle mantle dynamics postperovskite shear wave splitting
Programme: 133
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Ingrid T. van der Laan-Luijkx, Ivar R. van der Velde, Emma van der Veen, Aki Tsuruta, Karolina Stanislawska, Arne Babenhauserheide, Hui Fang Zhang, Yu Liu, Wei He, Huilin Chen, Kenneth A. Masarie, Maarten C. Krol, Wouter Peters. (2017). (Vol. 10).
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. (2018). Abundance and observations of thermophilic microbial and viral communities in submarine and terrestrial hot fluid systems of the French Southern and Antarctic Lands (Vol. 41).
Keywords: Abundance Epifluorescence microscopy Flow cytometry Hot spring Thermophilic Virus-like particle
Programme: 1077
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. (2018). Global and Interregion Characterization of Subduction Interface Earthquakes Derived From Source Time Functions Properties (Vol. 123).
Keywords: global earthquake seismology radiated energy seismic coupling source time functions stress drop subduction earthquakes
Programme: 133
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Ghislain Picard, Laurent Arnaud, Romain Caneill, Eric Lefebvre, Maxim Lamare. (2019). Observation of the process of snow accumulation on the Antarctic Plateau by time lapse laser scanning (Vol. 13).
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. (2018). Seabird Tissues As Efficient Biomonitoring Tools for Hg Isotopic Investigations: Implications of Using Blood and Feathers from Chicks and Adults (Vol. 52).
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. (2021). Meeting Paris agreement objectives will temper seabird winter distribution shifts in the North Atlantic Ocean (Vol. 27). Bachelor's thesis, , .
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Bastien S. Lemaire, Vincent A. Viblanc, Christelle Jozet?Alves. (2019). Sex-specific lateralization during aggressive interactions in breeding king penguins (Vol. 125).
Keywords: aggressiveness courtship frontal visual hemifield king penguins lateral visual hemifield sex-dependent lateralization visual lateralization
Programme: 119
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Christophe Barbraud. (2019). Senescence in nature: New insights from a long-term seabird study (Vol. 88).
Keywords: early-life diet mate dynamics Nazca booby senescence sex
Programme: 109
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