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Author Catalina Morales-Yáñez, Zacharie Duputel, Luis Rivera doi  openurl
  Title Impact of 3-D Earth structure on W-phase CMT parameters Type Journal
  Year 2020 Publication Geophysical Journal International Abbreviated Journal  
  Volume 223 Issue 2 Pages 1432-1445  
  Keywords  
  Abstract We investigate the impact of unmodelled 3-D structural heterogeneity on inverted W-phase source parameters. We generate a large data set of synthetic seismograms accounting for the Earths 3-D structure for 250 earthquakes globally distributed. The W-phase algorithm is then used to invert for earthquake CMT parameters, assuming a spherical Earth model. The impact of lateral heterogeneity is assessed by comparing inverted source parameters with those used to compute the 3-D synthetics. Results show that the 3-D structure mainly affects centroid location while the effect on the other source parameters remains small. Centroid mislocations present clear geographical patterns. In particular, W-phase solutions for earthquakes in South America are on average biased 17 km to the east of the actual centroid locations. This effect is significantly reduced using an azimuthally well balanced distribution of seismological stations. Source parameters are generally more impacted by mantle heterogeneity while the scalar moment of shallow earthquakes seems to be mainly impacted by the crustal structure. Shallow earthquakes present a variability of Mrθ and Mrϕ moment tensor elements, resulting both from the small amplitude and a larger uncertainty of the associated Green’s functions.  
  Programme 133  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0956-540X ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7890  
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Author Wenjie Lei, Youyi Ruan, Ebru Bozdağ, Daniel Peter, Matthieu Lefebvre, Dimitri Komatitsch, Jeroen Tromp, Judith Hill, Norbert Podhorszki, David Pugmire doi  openurl
  Title Global adjoint tomography—model GLAD-M25 Type Journal
  Year 2020 Publication Geophysical Journal International Abbreviated Journal  
  Volume 223 Issue 1 Pages 1-21  
  Keywords  
  Abstract Building on global adjoint tomography model GLAD-M15, we present transversely isotropic global model GLAD-M25, which is the result of 10 quasi-Newton tomographic iterations with an earthquake database consisting of 1480 events in the magnitude range 5.5 ≤ Mw ≤ 7.2, an almost sixfold increase over the first-generation model. We calculated fully 3-D synthetic seismograms with a shortest period of 17 s based on a GPU-accelerated spectral-element wave propagation solver which accommodates effects due to 3-D anelastic crust and mantle structure, topography and bathymetry, the ocean load, ellipticity, rotation and self-gravitation. We used an adjoint-state method to calculate Fréchet derivatives in 3-D anelastic Earth models facilitated by a parsimonious storage algorithm. The simulations were performed on the Cray XK7 ‘Titan’ and the IBM Power 9 ‘Summit’ at the Oak Ridge Leadership Computing Facility. We quantitatively evaluated GLAD-M25 by assessing misfit reductions and traveltime anomaly histograms in 12 measurement categories. We performed similar assessments for a held-out data set consisting of 360 earthquakes, with results comparable to the actual inversion. We highlight the new model for a variety of plumes and subduction zones.  
  Programme 133  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0956-540X ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7990  
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Author Barbara Delmonte, Holly Winton, Mélanie Baroni, Giovanni Baccolo, Margareta Hansson, Per Andersson, Carlo Baroni, Maria Cristina Salvatore, Luca Lanci, Valter Maggi doi  openurl
  Title Holocene dust in East Antarctica: Provenance and variability in time and space Type Journal
  Year 2020 Publication The Holocene Abbreviated Journal  
  Volume 30 Issue 4 Pages 546-558  
  Keywords East Antarctica ice cores dust dust stratigraphy Holocene provenance  
  Abstract In this paper, we provide a comprehensive overview of the state-of-knowledge of dust flux and variability in time and space in different sectors of East Antarctica during the Holocene. By integrating the literature data with new evidences, we discuss the dust flux and grain-size variability during the current interglacial and its provenance in the innermost part of the East Antarctic plateau as well as in peripheral regions located close to the Transantarctic Mountains. The local importance of aeolian mineral dust aerosol deflated from low-elevation areas of peripheral East Antarctica is also discussed in the light of new data from several coastal, low-elevation sites.  
  Programme 1145  
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  Series Volume Series Issue Edition  
  ISSN (up) 0959-6836 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7610  
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Author Yves Cherel, Evgeny V. Romanov, Pavanee Annasawmy, Delphine Thibault, Frédéric Ménard doi  isbn
openurl 
  Title Micronektonic fish species over three seamounts in the southwestern Indian Ocean Type Journal
  Year 2020 Publication Deep Sea Research Part II: Topical Studies in Oceanography Abbreviated Journal  
  Volume 176 Issue Pages 104777  
  Keywords Lanternfish Tropical waters  
  Abstract Taxonomic composition, abundance and biological features of micronektonic fish were investigated using pelagic trawls conducted near and over the summits of three seamounts located in the western Indian Ocean (La Pérouse, MAD-Ridge and Walters Shoal). Mesopelagic fish from three families accounted for 80% by number of the total catch (5714 specimens, 121 taxa), namely myctophids (59%), gonostomatids (12%) and sternoptychids (9%). Whereas the gonostomatid Sigmops elongatus was the most abundant species around La Pérouse seamount, myctophids were the most diverse and dominant group by number in all three studied areas. Most myctophids were high-oceanic species, which included the numerically dominant Benthosema suborbitale, Ceratoscopelus warmingii, Diaphus perspicillatus, Hygophum hygomii, and Lobianchia dofleini. The few remaining myctophids (Diaphus suborbitalis being the most abundant) were pseudoceanic fish, highlighting the association with landmasses. The study adds one myctophid species new to the Indian Ocean (Diaphus bertelseni), and a second record in the literature of the recently described sternoptychid Argyripnus hulleyi.  
  Programme 109  
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  Series Volume Series Issue Edition  
  ISSN (up) 0967-0645 ISBN 0967-0645 Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8073  
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Author C. A. González-Wevar, N. I. Segovia, S. Rosenfeld, D. Noll, C. S. Maturana, M. Hüne, J. Naretto, K. Gérard, A. Díaz, H. G. Spencer, T. Saucède, J. -P. Féral, S. A. Morley, P. Brickle, N. G. Wilson, E. Poulin doi  openurl
  Title Contrasting biogeographical patterns in Margarella (Gastropoda: Calliostomatidae: Margarellinae) across the Antarctic Polar Front Type Journal
  Year 2020 Publication Molecular Phylogenetics and Evolution Abbreviated Journal  
  Volume 156 Issue Pages 107039  
  Keywords Antarctic Polar Front Benthic-protected development Long-distance dispersal Rafting Southern Ocean  
  Abstract Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Molecular reconstructions and species-delimitation analyses recognized only four species: M. antarctica (the Antarctic Peninsula), M. achilles (endemic to South Georgia), M. steineni (South Georgia and Crozet Island) and the morphologically variable M. violacea (=M. expansa, M. porcellana and M. pruinosa), with populations in southern South America, the Falkland/Malvinas, Crozet and Kerguelen Islands. Margarella violacea and M. achilles are sister species, closely related to M. steineni, with M. antarctica sister to all these. This taxonomy reflects contrasting biogeographic patterns on either side of the APF in the Southern Ocean. Populations of Margarella north of the APF (M. violacea) showed significant genetic variation but with many shared haplotypes between geographically distant populations. By contrast, populations south of the APF (M. antarctica, M. steineni and M. achilles) exhibited fewer haplotypes and comprised three distinct species, each occurring across a separate geographical range. We hypothesize that the biogeographical differences may be the consequence of the presence north of the APF of buoyant kelps – potential long-distance dispersal vectors for these vetigastropods with benthic-protected development – and their near-absence to the south. Finally, we suggest that the low levels of genetic diversity within higher-latitude Margarella reflect the impact of Quaternary glacial cycles that exterminated local populations during their maxima.  
  Programme 1044  
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  Series Volume Series Issue Edition  
  ISSN (up) 1055-7903 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 8001  
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Author Boulinier, T., Betoulle, S., Caza, F., St Pierre, Y., Tornos, J., Gamble, A. &Amp; Tasiemski, A file  doi
openurl 
  Title Panorama des recherches et des derniers résultats sur les pathogènes en milieu polaire Type Book Chapter
  Year 2020 Publication Ipev 2020: rapport d'activité − campagne 2018 2019 Abbreviated Journal  
  Volume Issue Pages 54-65  
  Keywords  
  Abstract Approches complémentaires des interactions hôte-parasite en zones polaire: de la détection de parasites et agents infectieux à l'étude fonctionnelle, écologique et évolutive de leurs interactions avec leurs hôtes.  
  Programme 333,1151  
  Campaign  
  Address  
  Corporate Author Thesis Bachelor's thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1246-7375 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 6951  
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Author M. O. Naumenko-Dèzes, Y. Rolland, G. Lamarque, G. Duclaux, S. Gallet, J. Bascou, R. P. Ménot doi  openurl
  Title Petrochronology of the Terre Adélie Craton (East Antarctica) evidences a long-lasting Proterozoic (1.7–1.5 Ga) tectono-metamorphic evolution — Insights for the connections with the Gawler Craton and Laurentia Type Journal
  Year 2020 Publication Gondwana Research Abbreviated Journal  
  Volume 81 Issue Pages 21-57  
  Keywords Ar/Ar dating East Antarctica HT metamorphism Mafic magmatism P-T modelling Shear zones  
  Abstract The Terre Adélie Craton displays superimposed strain fields related to the Neoarchean (2.6–2.4 Ga, M1) and Paleo-Mesoproterozoic (1.7–1.5 Ga, M2) metamorphic events. M1 is a regional granulite facies event, constrained by P-T modelling at ~0.8–1.0 GPa – 800–850 °C, followed by a decompressional retrogression in the upper amphibolite facies at ~0.6 GPa – 750 °C. M2 Stage 1 P-T peak is constrained at 0.6–0.7 GPa – 670–700 °C, followed by a steep P-T path down to 0.3 GPa – 550 °C. Retrogression after M2 PT peak occurred in a context of dextral shearing along the Mertz Shear Zone along with thrust motions within the eastern Terre Adélie Craton. In this paper, we present a series of 63 new 40Ar/39Ar ages of biotite and amphibole pairs in mafic rocks from a complete traverse of the Terre Adélie Craton. 40Ar/39Ar dating constrains M2 amphibolite facies metamorphism at a regional scale between 1700 and 1650 Ma, during stage 1 peak metamorphism. During retrogression, lower amphibolite facies recrystallization mainly occurred along vertical shear zones and mafic dykes between 1650 and 1600 Ma (Stage 2), followed by amphibolite to greenschist facies metamorphism until after 1500 Ma (Stage 3). At the scale of the Mawson continent, this event is related to the growth of an active margin above an oblique subduction zone. The supra-subduction model best explains opening of Dumont D'Urville and Hunter basins at 1.71 Ga followed by their rapid closure and metamorphism at 1.70 Ga. In this context, episodic shear zone reactivation and magmatic dyke emplacement led to a partial reequilibration of the 40Ar/39Ar system until <1500 Ma. This latter phase of mafic magmatism largely coincides with a hot spot event at the scale of the Gawler Craton and western Laurentia paleocontinent.  
  Programme 1003  
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  Series Volume Series Issue Edition  
  ISSN (up) 1342-937X ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7643  
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Author Stéphanie Jenouvrier, Marika Holland, David Iles, Sara Labrousse, Laura Landrum, Jimmy Garnier, Hal Caswell, Henri Weimerskirch, Michelle LaRue, Rubao Ji, Christophe Barbraud doi  openurl
  Title The Paris Agreement objectives will likely halt future declines of emperor penguins Type Journal
  Year 2020 Publication Global Change Biology Abbreviated Journal  
  Volume 26 Issue 3 Pages 1170-1184  
  Keywords Antarctica climate change mitigation dispersion emission reduction pledges seabirds  
  Abstract The Paris Agreement is a multinational initiative to combat climate change by keeping a global temperature increase in this century to 2°C above preindustrial levels while pursuing efforts to limit the increase to 1.5°C. Until recently, ensembles of coupled climate simulations producing temporal dynamics of climate en route to stable global mean temperature at 1.5 and 2°C above preindustrial levels were not available. Hence, the few studies that have assessed the ecological impact of the Paris Agreement used ad-hoc approaches. The development of new specific mitigation climate simulations now provides an unprecedented opportunity to inform ecological impact assessments. Here we project the dynamics of all known emperor penguin (Aptenodytes forsteri) colonies under new climate change scenarios meeting the Paris Agreement objectives using a climate-dependent-metapopulation model. Our model includes various dispersal behaviors so that penguins could modulate climate effects through movement and habitat selection. Under business-as-usual greenhouse gas emissions, we show that 80% of the colonies are projected to be quasiextinct by 2100, thus the total abundance of emperor penguins is projected to decline by at least 81% relative to its initial size, regardless of dispersal abilities. In contrast, if the Paris Agreement objectives are met, viable emperor penguin refuges will exist in Antarctica, and only 19% and 31% colonies are projected to be quasiextinct by 2100 under the Paris 1.5 and 2 climate scenarios respectively. As a result, the global population is projected to decline by at least by 31% under Paris 1.5 and 44% under Paris 2. However, population growth rates stabilize in 2060 such that the global population will be only declining at 0.07% under Paris 1.5 and 0.34% under Paris 2, thereby halting the global population decline. Hence, global climate policy has a larger capacity to safeguard the future of emperor penguins than their intrinsic dispersal abilities.  
  Programme 109  
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  ISSN (up) 1365-2486 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7675  
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Author David T. Iles, Heather Lynch, Rubao Ji, Christophe Barbraud, Karine Delord, Stephanie Jenouvrier doi  openurl
  Title Sea ice predicts long-term trends in Adélie penguin population growth, but not annual fluctuations: Results from a range-wide multiscale analysis Type Journal
  Year 2020 Publication Global Change Biology Abbreviated Journal  
  Volume 26 Issue 7 Pages 3788-3798  
  Keywords Antarctica environmental variation habitat suitability niche predictability state-space stochastic uncertainty  
  Abstract Understanding the scales at which environmental variability affects populations is critical for projecting population dynamics and species distributions in rapidly changing environments. Here we used a multilevel Bayesian analysis of range-wide survey data for Adélie penguins to characterize multidecadal and annual effects of sea ice on population growth. We found that mean sea ice concentration at breeding colonies (i.e., “prevailing” environmental conditions) had robust nonlinear effects on multidecadal population trends and explained over 85% of the variance in mean population growth rates among sites. In contrast, despite considerable year-to-year fluctuations in abundance at most breeding colonies, annual sea ice fluctuations often explained less than 10% of the temporal variance in population growth rates. Our study provides an understanding of the spatially and temporally dynamic environmental factors that define the range limits of Adélie penguins, further establishing this iconic marine predator as a true sea ice obligate and providing a firm basis for projection under scenarios of future climate change. Yet, given the weak effects of annual sea ice relative to the large unexplained variance in year-to-year growth rates, the ability to generate useful short-term forecasts of Adélie penguin breeding abundance will be extremely limited. Our approach provides a powerful framework for linking short- and longer term population processes to environmental conditions that can be applied to any species, facilitating a richer understanding of ecological predictability and sensitivity to global change.  
  Programme 109  
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  ISSN (up) 1365-2486 ISBN Medium  
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  Notes Approved yes  
  Call Number Serial 7682  
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Author Tuomas Kankaanpää, Eero Vesterinen, Bess Hardwick, Niels M. Schmidt, Tommi Andersson, Paul E. Aspholm, Isabel C. Barrio, Niklas Beckers, Joël Bêty, Tone Birkemoe, Melissa DeSiervo, Katherine H. I. Drotos, Dorothee Ehrich, Olivier Gilg, Vladimir Gilg, Nils Hein, Toke T. Høye, Kristian M. Jakobsen, Camille Jodouin, Jesse Jorna, Mikhail V. Kozlov, Jean-Claude Kresse, Don-Jean Leandri-Breton, Nicolas Lecomte, Maarten Loonen, Philipp Marr, Spencer K. Monckton, Maia Olsen, Josée-Anne Otis, Michelle Pyle, Ruben E. Roos, Katrine Raundrup, Daria Rozhkova, Brigitte Sabard, Aleksandr Sokolov, Natalia Sokolova, Anna M. Solecki, Christine Urbanowicz, Catherine Villeneuve, Evgenya Vyguzova, Vitali Zverev, Tomas Roslin doi  openurl
  Title Parasitoids indicate major climate-induced shifts in arctic communities Type Journal
  Year 2020 Publication Global Change Biology Abbreviated Journal  
  Volume 26 Issue 11 Pages 6276-6295  
  Keywords Arctic climate change DNA barcoding Dryas food webs functional traits host–parasitoid interactions insect herbivory pollinators  
  Abstract Climatic impacts are especially pronounced in the Arctic, which as a region is warming twice as fast as the rest of the globe. Here, we investigate how mean climatic conditions and rates of climatic change impact parasitoid insect communities in 16 localities across the Arctic. We focus on parasitoids in a widespread habitat, Dryas heathlands, and describe parasitoid community composition in terms of larval host use (i.e., parasitoid use of herbivorous Lepidoptera vs. pollinating Diptera) and functional groups differing in their closeness of host associations (koinobionts vs. idiobionts). Of the latter, we expect idiobionts—as being less fine-tuned to host development—to be generally less tolerant to cold temperatures, since they are confined to attacking hosts pupating and overwintering in relatively exposed locations. To further test our findings, we assess whether similar climatic variables are associated with host abundances in a 22 year time series from Northeast Greenland. We find sites which have experienced a temperature rise in summer while retaining cold winters to be dominated by parasitoids of Lepidoptera, with the reverse being true for the parasitoids of Diptera. The rate of summer temperature rise is further associated with higher levels of herbivory, suggesting higher availability of lepidopteran hosts and changes in ecosystem functioning. We also detect a matching signal over time, as higher summer temperatures, coupled with cold early winter soils, are related to high herbivory by lepidopteran larvae, and to declines in the abundance of dipteran pollinators. Collectively, our results suggest that in parts of the warming Arctic, Dryas is being simultaneously exposed to increased herbivory and reduced pollination. Our findings point to potential drastic and rapid consequences of climate change on multitrophic-level community structure and on ecosystem functioning and highlight the value of collaborative, systematic sampling effort.  
  Programme 1036  
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  Series Volume Series Issue Edition  
  ISSN (up) 1365-2486 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial 7686  
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