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Author | Lévêque Jean-Jacques, Maggi Alessia, Souriau Annie, | ||||
Title | Seismological constraints on ice properties at Dome C, Antarctica, from horizontal to vertical spectral ratios | Type | Journal Article | ||
Year | 2010 | Publication | Antarctic Science | Abbreviated Journal | Antarct. Sci. |
Volume | 22 | Issue | 05 | Pages | 572 -579 |
Keywords | Antarctic seismological stations, Concordia, firn, seismic ambient noise, | ||||
Abstract | The French-Italian Concordia (CCD) seismological station at Dome C is one of two observatories setup on the ice cap in the interior of the Antarctic continent. We analysed the seismic signal due to ambient noise at this station and at three temporary stations 5 km away from Concordia, in order to specify the ice properties beneath them. A method based on the horizontal to vertical (H/V) spectral ratio, commonly used to analyse soil response in seismic regions, was applied to the Antarctic stations. The main peak in the spectral ratios is observed at frequencies 6.7–8 Hz at the Dome C stations, but it is not observed at another station on the ice cap, QSPA, where the sensor is buried at 275 m depth. This peak can be explained by a 23 m thick unconsolidated snow or firn layer with a low S-wave velocity of 0.7 km s-1, overlying a consolidated layer with S-wave velocity 1.8 km s-1. Despite the non-uniqueness of the solutions obtained by fitting the H/V spectra, this model is preferred because the depth of the velocity contrast coincides with the density at which ice particles arrange themselves in a continuous, dense lattice. A small variability of this structure is observed around Dome C. | ||||
Programme | 133;906 | ||||
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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 | 0954-1020 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 89 | |||
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Author | Ertz D., Søchting U., Gadea A., Charrier M., Poulsen R.S. | ||||
Title | Ducatina umbilicata gen. et sp. nov., a remarkable Trapeliaceae from the subantarctic islands in the Indian Ocean | Type | Journal Article | ||
Year | 2016 | Publication | The Lichenologist | Abbreviated Journal | |
Volume | 49 | Issue | 2 | Pages | 127-140 |
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Abstract | AbstractThe new genus and species Ducatina umbilicata is described from Îles Crozet and Îles Kerguelen. This lichen is characterized by an umbilicate thallus with a black verrucose lower surface and a greyish to dark olivaceous smooth upper surface having large verrucae, large semi-immersed cephalodia, semi-immersed apothecia with a prominent thalline margin, simple, mainly ellipsoid ascospores of 23–42×12–25 µm and the presence of unknown chemical compounds. Phylogenetic analyses using nuLSU and mtSSU sequences place Ducatina in the Trapeliaceae (Baeomycetales). The new taxon is closely related to Orceolina antarctica and O. kerguelensis, two other lichens endemic to these subantarctic islands, differing by its morphology and the lack of chemical compounds. Ducatina is the only genus in the Trapeliaceae to develop a large umbilicate thallus. | ||||
Programme | 136 | ||||
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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 | 0024-2829 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 6481 | |||
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Author | Gagnevin D.; Ethien R.; Bonin B.; Moine B.; Feraud G.; Gerbe M.C.; Cottin J.Y.; Michon G.; Tourpin S.; Mamias G.; Perrache C.; Giret A. | ||||
Title | Open-system processes in the genesis of silica-oversaturated alkaline rocks of the Rallier-du Baty Peninsula, Kerguelen Archipelago (Indian Ocean) | Type | Journal Article | ||
Year | 2003 | Publication | Journal of volcanology and geothermal research | Abbreviated Journal | |
Volume | 123 | Issue | 3-4 | Pages | 267-300 |
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Abstract | The Rallier-du-Baty Peninsula forms the southwestern part of the Kerguelen Archipelago (Indian Ocean), whose magmatic activity is related to the long-lived 115-Ma Kerguelen plume. The peninsula is mostly made of alkaline rocks constituting two well-defined ring complexes. This paper focuses on the northern ring complex, which is not yet known. Recent field studies have revealed seven discrete syenitic ring dykes ranging in age from 6.2 to 4.9 Ma, and two later volcanic systems. 40Ar/39 Ar dating of a trachytic ignimbrite linked to the Dôme Carva volcano complex yields an age of 26 ± 3 Ka. This represents the last major eruptive event on the Kerguelen Archipelago. The volcanism is bimodal with trachybasalts and trachyandesites constituting the mafic lavas and trachytes and rhyolites constituting the felsic lavas. The volume of erupted felsic magma is by far the larger, and is represented by abundant pyroclastic deposits and lava flows. Boulders of plutonic rocks are found to the northwest of Dôme Carva, and represent intermediate rocks (i.e. monzogabbros and monzonites) that are not present at the surface. Basic rocks are mostly trachybasalts and trachyandesites, while true basalts are scarce. Their mineralogy consists chiefly of plagioclase, olivine, diopside and oxides. Sieve-textured plagioclase is common, as well as corroded olivine and diopside phenocrysts. Peralkaline commenditic trachytes are the most abundant type of acid volcanic rocks. They consist of abundant sanidine, augite and magnetite phenocrysts and interstitial quartz, aegerinic pyroxenes and Na-amphiboles. Ring dykes of quartz-poor alkali feldspar syenites display the same mineralogy, except hornblende is common and replaces diopside. Hornblende is particularly abundant in intermediate monzogabbros. Major and trace element variations of volcanic rocks emphasise the predominant role of fractional crystallisation with a general decrease of MgO, CaO, P2O5, TiO2, FeO. Ba, Sr and Ni from basic to felsic rocks. However, the scattering of the data from the basic rocks indicates that other processes have operated. The overall evolution from trachyte to rhyolite is in agreement with the fractionation of sanidine as the major control. An increase of incompatible elements from trachyte to rhyolite is observed. The felsic lavas display an increase of 87Sr/86Sr(i) without any significant variations in the Nd isotopic composition. The genesis of the basic rocks is complex and reflects concomitant processes of fractional crystallisation, mixing between different basic magmas and probable assimilation of Ba-rich oceanic crust. Major and trace element modelling confirms the possibility of producing the trachytes through continuous differentiation from a basaltic alkaline parent. Discrepancies observed for some trace elements can be explained by the crystallisation of amphibole at an intermediate stage of magma evolution. | ||||
Programme | 251;444 | ||||
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Publisher | Place of Publication | Editor | |||
Language | Summary Language | Original Title | |||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0377-0273 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 3877 | |||
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Author | Lang M., Glasmacher U.A., Moine B., Müller C., Neumann R. & Wagner G.A. | ||||
Title | Artificial ion tracks in volcanic dark mica simulating natural radiation damage: a scanning force microscopy study. | Type | Journal Article | ||
Year | 2002 | Publication | Nuclear Instruments and Methods in Physics Research Section B | Abbreviated Journal | |
Volume | 191 | Issue | 1-4 | Pages | 346-351 |
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Abstract | A new dating technique uses alpha-recoil tracks (ART), formed by the natural /?-decay of U, Th and their daughter products, to determine the formation age of Quaternary volcanic rocks (/<106 a). Visualization of etched ART by scanning force microscopy (SFM) enables to access track densities beyond 108cm-2 and thus extend the new ART-dating technique to an age range />106 a. In order to simulate natural radiation damage, samples of phlogopite, originating from Quaternary and Tertiary volcanic rocks of the Eifel (Germany) and Kerguelen Islands (Indian Ocean) were irradiated with U, Ni (11.4 MeV/u), Xe, Cr, Ne (1.4 MeV/u) and Bi (200 keV) ions. After irradiation and etching with HF at various etching times, phlogopite surfaces were visualized by SFM. Hexagonal etch pits are typical of U, Xe and Cr ion tracks, but the etch pits of Ni, Ne and Bi ion tracks are triangular. Surfaces irradiated with U, Xe, Cr and Ni ions do not show any significant difference between etch pit density and irradiation fluence, whereas the Ne-irradiated surface show /~14 times less etch pit density. The etching rate vH (parallel to cleavage) depends on the chemical composition of the phlogopite. The etching rate vT' (along the track) increases with energy loss. | ||||
Programme | 251 | ||||
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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 | 0168-583X | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 2412 | |||
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Author | Liubomira Romanova, Charles Stépanoff, Norbert Telmon, Eric Crubézy | ||||
Title | Health access inequities and magic medicine: the first ancient evidence? | Type | Journal | ||
Year | 2020 | Publication | The Lancet | Abbreviated Journal | |
Volume | 395 | Issue | 10233 | Pages | 1343-1344 |
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Abstract | Inequities in access to the latest advances in health care and effective drugs constitute public health problems today,1 but was this also the case in ancient societies when practitioners used traditional medicines with limited means? The excavation of frozen graves in Yakutia (present day eastern Siberia, Russia) dating from 1700 CE2 led to the identification of a woman, buried almost naked, covered with a magnificent robe and with half a horse bit in her mouth (figure). The other half of the horse bit was found in the trunk behind her head with her earrings, bracelets, and signet rings. | ||||
Programme | 1038 | ||||
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Corporate Author | Thesis | Bachelor's thesis | |||
Publisher | Elsevier | Place of Publication | Editor | ||
Language | Summary Language | Original Title | |||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | ISBN | 0140-6736, 1474-547X | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 7666 | |||
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Author | Marie L. Verheye, Thierry Backeljau, Cédric d'Udekem d'Acoz | ||||
Title | Locked in the icehouse: Evolution of an endemic Epimeria (Amphipoda, Crustacea) species flock on the Antarctic shelf | Type | Journal | ||
Year | 2017 | Publication | Molecular Phylogenetics and Evolution | Abbreviated Journal | |
Volume | 114 | Issue | Pages | 14-33 | |
Keywords | Amphipoda Divergence times Diversification Historical biogeography Phylogeny Southern ocean | ||||
Abstract | The Antarctic shelf’s marine biodiversity has been greatly influenced by the climatic and glacial history of the region. Extreme temperature changes led to the extinction of some lineages, while others adapted and flourished. The amphipod genus Epimeria is an example of the latter, being particularly diverse in the Antarctic region. By reconstructing a time-calibrated phylogeny based on mitochondrial (COI) and nuclear (28S and H3) markers and including Epimeria species from all oceans, this study provides a temporal and geographical framework for the evolution of Antarctic Epimeria. The monophyly of this genus is not supported by Bayesian Inference, as Antarctic and non-Antarctic Epimeria form two distinct well-supported clades, with Antarctic Epimeria being a sister clade to two stilipedid species. The monophyly of Antarctic Epimeria suggests that this clade evolved in isolation since its origin. While the precise timing of this origin remains unclear, it is inferred that the Antarctic lineage arose from a late Gondwanan ancestor and hence did not colonize the Antarctic region after the continent broke apart from the other fragments of Gondwanaland. The initial diversification of the clade occurred 38.04Ma (95% HPD [48.46Ma; 28.36Ma]) in a cooling environment. Adaptation to cold waters, along with the extinction of cold-intolerant taxa and resulting ecological opportunities, likely led to the successful diversification of Epimeria on the Antarctic shelf. However, there was neither evidence of a rapid lineage diversification early in the clade’s history, nor of any shifts in diversification rates induced by glacial cycles. This suggests that a high turnover rate on the repeatedly scoured Antarctic shelf could have masked potential signals of diversification bursts. | ||||
Programme | 281,1124,1142 | ||||
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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 | 1055-7903 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 8274 | |||
Permanent link to this record | |||||
Author | Juliana A. Vianna, Daly Noll, Gisele P. M. Dantas, Maria Virginia Petry, Andrés Barbosa, Daniel González-Acuña, Céline Le Bohec, Francesco Bonadonna, Elie Poulin | ||||
Title | Marked phylogeographic structure of Gentoo penguin reveals an ongoing diversification process along the Southern Ocean | Type | Book Chapter | ||
Year | 2017 | Publication | Molecular phylogenetics and evolution | Abbreviated Journal | |
Volume | 107 | Issue | Pages | 486-498 | |
Keywords | Climate change Demographic history Polar region Population structure Seabirds | ||||
Abstract | Two main hypotheses have been debated about the biogeography of the Southern Ocean: (1) the Antarctic Polar Front (APF), acting as a barrier between Antarctic and sub-Antarctic provinces, and (2) the Antarctic Circumpolar Current (ACC), promoting gene flow among sub-Antarctic areas. The Gentoo penguin is distributed throughout these two provinces, separated by the APF. We analyzed mtDNA (HVR1) and 12 microsatellite loci of 264 Gentoo penguins, Pygoscelis papua, from 12 colonies spanning from the Western Antarctic Peninsula and the South Shetland Islands (WAP) to the sub-Antarctic Islands (SAI). While low genetic structure was detected among WAP colonies (mtDNA ФST=0.037–0.133; microsatellite FST=0.009–0.063), high differentiation was found between all SAI and WAP populations (mtDNA ФST=0.678–0.930; microsatellite FST=0.110–0.290). These results suggest that contemporary dispersal around the Southern Ocean is very limited or absent. As predicted, the APF appears to be a significant biogeographical boundary for Gentoo penguin populations; however, the ACC does not promote connectivity in this species. Our data suggest demographic expansion in the WAP during the last glacial maximum (LGM, about 20kya), but stability in SAI. Phylogenetic analyses showed a deep divergence between populations from the WAP and those from the SAI. Therefore, taxonomy should be further revised. The Crozet Islands resulted as a basal clade (3.57Mya), followed by the Kerguelen Islands (2.32Mya) as well as a more recent divergence between the Falkland/Malvinas Islands and the WAP (1.27Mya). Historical isolation, local adaptation, and past climate scenarios of those Evolutionarily Significant Units may have led to different potentials to respond to climate changes. | ||||
Programme | 137,354 | ||||
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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 | 1055-7903 | ISBN | 1055-7903 | Medium | |
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 6578 | |||
Permanent link to this record | |||||
Author | Lautrédou A-C, Hinsinger DD, Gallut C, Cheng C-HC, Berkani M, Ozouf-Costaz C, Cruaud C, Lecointre G, Dettai A, | ||||
Title | Phylogenetic footprints of an Antarctic radiation: The Trematominae (Notothenioidei, Teleostei) | Type | Journal Article | ||
Year | 2012 | Publication | Molecular Phylogenetics and Evolution | Abbreviated Journal | Mol. Phylogenet. Evol. |
Volume | 65 | Issue | 1 | Pages | 87-101 |
Keywords | Antarctica, Notothenioidei, Trematominae, Trematomus, | ||||
Abstract | The teleost suborder Notothenioidei is restricted to the Southern Ocean and has been described as a species flock spanning the whole of it. Within the suborder, the subfamily Trematominae is important for coastal Antarctic ecosystems. The eleven Trematomus species occupy a large range of ecological niches. The genus is monophyletic if the genus Pagothenia (two additional species) and Cryothenia amphitreta, also nested within it, are included. Although the Trematominae have received much interest, the relationships among these fourteen species are still unclear. | ||||
Programme | 1124 | ||||
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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 | 1055-7903 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 4022 | |||
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Author | Thierry Anne-Mathilde, Brajon Sophie, Massemin Sylvie, Handrich Yves, Chastel Olivier, Raclot Thierry, |
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Title | Decreased prolactin levels reduce parental commitment, egg temperatures, and breeding success of incubating male Adélie penguins |
Type | Journal Article | ||
Year | 2013 | Publication | Hormones and Behavior | Abbreviated Journal | |
Volume | 64 | Issue | 4 | Pages | 737-747 |
Keywords | Bromocriptine, Corticosterone, Egg temperature, Egg rotation rate, Incubation behavior, Parental care, Pygoscelis adeliae, Prolactin, Seabird, |
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Abstract | Hormones regulate many aspects of an individual's phenotype, including various physiological and behavioral traits. Two hormones have been described as important players in the regulation of parental investment in birds: the glucocorticoid hormone corticosterone and prolactin, a pituitary hormone, widely involved in mediating parental behavior. In comparison with corticosterone, the role of prolactin on parental investment remains poorly documented, and most studies so far have been correlative. In this study, the effects of an experimental decrease of prolactin levels on the incubation behavior of a long-lived seabird species were assessed. Male Adelie penguins were treated with self-degradable bromocriptine pellets, inhibiting prolactin secretion. Filming and subsequent video analysis allowed the determination of a behavioral time budget for birds and their position on the nest, while dummy eggs recorded incubation parameters. Incubation duration and breeding success at hatching were also monitored. As expected, bromocriptine-treatment significantly decreased plasma prolactin levels, but did not affect corticosterone levels. The behavioral time budget of penguins was not affected by the treatment. However, treated birds spent significantly more time in an upright position on the nest. These birds also incubated their eggs at lower temperatures and turned their eggs more frequently than controls, resulting in a lengthened incubation period. Despite this, the treatment was insufficient to trigger nest desertion and eggs of treated birds still hatched, indicating that several endocrine signals are required for the induction of nest abandonment. We suggest that the decreased prolactin levels in treated birds offset their timeline of breeding, so that birds displayed behavior typical of early incubation. |
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Programme | 394,1091 | ||||
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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 | 0018-506X | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 4735 | |||
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Author | Thierry Anne-Mathilde, Massemin Sylvie, Handrich Yves, Raclot Thierry, |
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Title | Elevated corticosterone levels and severe weather conditions decrease parental investment of incubating Adélie penguins |
Type | Journal Article | ||
Year | 2013 | Publication | Hormones and Behavior | Abbreviated Journal | |
Volume | 63 | Issue | 3 | Pages | 475-483 |
Keywords | Egg temperature and rotation rate, Glucocorticoids, Incubation behaviour, Pygoscelis adeliae, Seabird, Weather conditions, |
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Abstract | Corticosterone, the main stress hormone in birds, mediates resource allocation, allowing animals to adjust their physiology and behaviour to changes in the environment. Incubation is a time and energy-consuming phase of the avian reproductive cycle. It may be terminated prematurely, when the parents' energy stores are depleted or when environmental conditions are severe. In this study, the effects of experimentally elevated baseline corticosterone levels on the parental investment of incubating male Adelie penguins were investigated. Incubation duration and reproductive success of 60 penguins were recorded. The clutches of some birds were replaced by dummy eggs, which recorded egg temperatures and rotation rates, enabling a detailed investigation of incubation behaviour. Corticosterone levels of treated birds were 2.4-fold higher than those of controls 18 days post treatment. Exogenous corticosterone triggered nest desertion in 61% of the treated birds; consequently reducing reproductive success, indicating that corticosterone can reduce or disrupt parental investment. Regarding egg temperatures, hypothermic events became more frequent and more pronounced in treated birds, before these birds eventually abandoned their nest. The treatment also significantly decreased incubation temperatures by 1.3 degrees C and lengthened the incubation period by 2.1 days. However, the number of chicks at hatching was similar among successful nests, regardless of treatment. Weather conditions appeared to be particularly important in determining the extent to which corticosterone levels affected the behaviour of penguins, as treated penguins were more sensitive to severe weather conditions. This underlines the importance of considering the interactions of organisms with their environment in studies of animal behaviour and ecophysiology. |
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Programme | 394,1091 | ||||
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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 | 0018-506X | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | yes | |||
Call Number | Serial | 4738 | |||
Permanent link to this record |