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Author |
Winton V.H.L., Ming A., Caillon N., Hauge L. Jones A.E., Savarino J., Yang X., Frey M.M. |
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Title |
Deposition, recycling, and archival of nitrate stable isotopes between the air–snow interface: comparison between Dronning Maud Land and Dome C, Antarctica |
Type |
Journal |
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Year |
2020 |
Publication |
Atmospheric Chemistry and Physics |
Abbreviated Journal |
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Volume  |
20 |
Issue |
9 |
Pages |
5861–5885 |
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Keywords |
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Abstract |
The nitrogen stable isotopic composition in nitrate (δ15N-NO−3) measured in ice cores from low-snow-accumulation regions in East Antarctica has the potential to provide constraints on past ultraviolet (UV) radiation and thereby total column ozone (TCO) due to the sensitivity of nitrate (NO−3) photolysis to UV radiation. However, understanding the transfer of reactive nitrogen at the air–snow interface in polar regions is paramount for the interpretation of ice core records of δ15N-NO−3 and NO−3 mass concentrations. As NO−3 undergoes a number of post-depositional processes before it is archived in ice cores, site-specific observations of δ15N-NO−3 and air–snow transfer modelling are necessary to understand and quantify the complex photochemical processes at play. As part of the Isotopic Constraints on Past Ozone Layer Thickness in Polar Ice (ISOL-ICE) project, we report new measurements of NO−3 mass concentration and δ15N-NO−3 in the atmosphere, skin layer (operationally defined as the top 5 mm of the snowpack), and snow pit depth profiles at Kohnen Station, Dronning Maud Land (DML), Antarctica. We compare the results to previous studies and new data, presented here, from Dome C on the East Antarctic Plateau. Additionally, we apply the conceptual 1D model of TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow (TRANSITS) to assess the impact of NO−3 recycling on δ15N-NO−3 and NO−3 mass concentrations archived in snow and firn. We find clear evidence of NO−3 photolysis at DML and confirmation of previous theoretical, field, and laboratory studies that UV photolysis is driving NO−3 recycling and redistribution at DML. Firstly, strong denitrification of the snowpack is observed through the δ15N-NO−3 signature, which evolves from the enriched snowpack (−3 ‰ to 100 ‰), to the skin layer (−20 ‰ to 3 ‰), to the depleted atmosphere (−50 ‰ to −20 ‰), corresponding to mass loss of NO−3 from the snowpack. Based on the TRANSITS model, we find that NO−3 is recycled two times, on average, before it is archived in the snowpack below 15 cm and within 0.75 years (i.e. below the photic zone). Mean annual archived δ15N-NO−3 and NO−3 mass concentration values are 50 ‰ and 60 ng g−1, respectively, at the DML site. We report an e-folding depth (light attenuation) of 2–5 cm for the DML site, which is considerably lower than Dome C. A reduced photolytic loss of NO−3 at DML results in less enrichment of δ15N-NO−3 than at Dome C mainly due to the shallower e-folding depth but also due to the higher snow accumulation rate based on TRANSITS-modelled sensitivities. Even at a relatively low snow accumulation rate of 6 cm yr−1 (water equivalent; w.e.), the snow accumulation rate at DML is great enough to preserve the seasonal cycle of NO−3 mass concentration and δ15N-NO−3, in contrast to Dome C where the depth profiles are smoothed due to longer exposure of surface snow layers to incoming UV radiation before burial. TRANSITS sensitivity analysis of δ15N-NO−3 at DML highlights that the dominant factors controlling the archived δ15N-NO−3 signature are the e-folding depth and snow accumulation rate, with a smaller role from changes in the snowfall timing and TCO. Mean TRANSITS model sensitivities of archived δ15N-NO−3 at the DML site are 100 ‰ for an e-folding depth change of 8 cm, 110 ‰ for an annual snow accumulation rate change of 8.5 cm yr−1 w.e., 10 ‰ for a change in the dominant snow deposition season between winter and summer, and 10 ‰ for a TCO change of 100 DU (Dobson units). Here we set the framework for the interpretation of a 1000-year ice core record of δ15N-NO−3 from DML. Ice core δ15N-NO−3 records at DML will be less sensitive to changes in UV than at Dome C; however the higher snow accumulation rate and more accurate dating at DML allows for higher-resolution δ15N-NO−3 records. |
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Programme |
1177 |
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Thesis |
Bachelor's thesis |
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ISSN |
1680-7316 |
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yes |
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Call Number |
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Serial |
7855 |
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Author |
E. Crubezy, O. Melnichuk, A. Alexeev |
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Title |
Archaelogy, genetics and history 15 years of research in Yakutia (2002–2017) |
Type |
Journal |
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Year |
2020 |
Publication |
Vestnik arheologii, antropologii i etnografii |
Abbreviated Journal |
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Volume |
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Issue |
4 (51) |
Pages |
110-119 |
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Keywords |
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Abstract |
For the past 15 years, our research has focused on the evolution of the first Yakut populations, their interaction with local tribes as well as with the Russian population, which marks the beginning of Yakutia's development from the first half of the 17th century. We conducted the excavation of tombs and we analysed the cultural, historical and paleogenetic data uncovered. A review and a synthesis of the main results published in articles and monographs informs our research directions for the future. |
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Programme |
1038 |
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Address |
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Corporate Author |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1811-7465 |
ISBN |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
7936 |
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| Permanent link to this record |
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Author |
Louis Le Toumelin, Charles Amory, Vincent Favier, Christoph Kittel, Stefan Hofer, Xavier Fettweis, Hubert Gallée, Vinay Kayetha |
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Title |
Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica |
Type |
Journal |
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Year |
2020 |
Publication |
The Cryosphere |
Abbreviated Journal |
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Volume |
15 |
Issue |
8 |
Pages |
3595-3614 |
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Keywords |
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Abstract |
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Programme |
411,1013 |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Original Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
1994-0416 |
ISBN |
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Medium |
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Area |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
7946 |
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| Permanent link to this record |
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Author |
Luis R. Pertierra, Nicolás I. Segovia, Daly Noll, Pablo A. Martinez, Patricio Pliscoff, Andrés Barbosa, Pedro Aragón, Andrea Raya Rey, Pierre Pistorius, Phil Trathan, Andrea Polanowski, Francesco Bonadonna, Céline Le Bohec, Ke Bi, Cynthia Y. Wang-Claypool, Daniel González-Acuña, Gisele P. M. Dantas, Rauri C. K. Bowie, Elie Poulin, Juliana A. Vianna |
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Title |
Cryptic speciation in gentoo penguins is driven by geographic isolation and regional marine conditions: Unforeseen vulnerabilities to global change |
Type |
Journal |
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Year |
2020 |
Publication |
Diversity and distributions |
Abbreviated Journal |
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Volume |
26 |
Issue |
8 |
Pages |
958-975 |
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Keywords |
diversification ecological niche overlap gentoo penguin subspecies |
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Abstract |
Aim The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of gentoo penguins (Pygoscelis papua) distributed across Antarctica and sub-Antarctic Islands are subject to spatially explicit ecological conditions that have limited gene flow, facilitating genetic differentiation, and thereby speciation processes. Location Antarctica and sub-Antarctic area. Methods We identify divergent lineages for gentoo penguins using ddRAD-seq and mtDNA, and generated species distribution models (SDMs) based on terrestrial and marine parameters. Results Analyses of our genomic data supports the existence of four major lineages of gentoo penguin: (i) spanning the sub-Antarctic archipelagos north of the Antarctic Polar Front (APF); (ii) Kerguelen Island; (iii) South America; and (iv) across maritime Antarctic and the Scotia Arc archipelagos. The APF, a major current system around Antarctica, acts as the most important barrier separating regional sister lineages. Our ecological analyses spanning both the terrestrial (breeding sites) and marine (feeding sites) realms recover limited niche overlap among the major lineages of gentoo penguin. We observe this pattern to correspond more closely with regional differentiation of marine conditions than to terrestrial macroenvironmental features. Main conclusions Recognition of regional genetic lineages as discrete evolutionary entities that occupy distinct ecological niches and also differ morphologically should be considered a priority for conservation. Gentoo penguins provide a good example of how conservation policy can be directly impacted by new insights obtained through the integration of larger genomic datasets with novel approaches to ecological modelling. This is particularly pertinent to polar environments that are among the most rapidly changing environments on earth. |
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Programme |
137,354 |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Language |
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Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1472-4642 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
7950 |
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| Permanent link to this record |
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Author |
Audrey Jaeger, Amandine Gamble, Erwan Lagadec, Camille Lebarbenchon, Vincent Bourret, Jérémy Tornos, Christophe Barbraud, Karin Lemberger, Karine Delord, Henri Weimerskirch, Jean-Baptiste Thiebot, Thierry Boulinier, Pablo Tortosa |
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Title |
Impact of Annual Bacterial Epizootics on Albatross Population on a Remote Island |
Type |
Journal |
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Year |
2020 |
Publication |
EcoHealth |
Abbreviated Journal |
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Volume |
17 |
Issue |
2 |
Pages |
194-202 |
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Keywords |
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Abstract |
The reduced species richness typical of oceanic islands provides an interesting environmental setup to examine in natura the epidemiological dynamics of infectious agents with potential implications for public health and/or conservation. On Amsterdam Island (Indian Ocean), recurrent die-offs of Indian yellow-nosed albatross (Thalassarche carteri) nestlings have been attributed to avian cholera, caused by the bacterium Pasteurella multocida. In order to help implementing efficient measures for the control of this disease, it is critical to better understand the local epidemiology of P. multocida and to examine its inter- and intra-annual infection dynamics. We evaluated the infection status of 264 yellow-nosed albatrosses over four successive breeding seasons using a real-time PCR targeting P. multocida DNA from cloacal swabs. Infection prevalence patterns revealed an intense circulation of P. multocida throughout the survey, with a steady but variable increase in infection prevalence within each breeding season. These epizootics were associated with massive nestling dies-offs, inducing very low fledging successes (≤ 20%). These results suggest important variations in the transmission dynamics of this pathogen. These findings and the developed PCR protocol have direct applications to guide future research and refine conservation plans aiming at controlling the disease. |
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Programme |
109, 1151 |
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Corporate Author |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Language |
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Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1612-9210 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
7961 |
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| Permanent link to this record |
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Author |
Julie Mestre, Matthieu Authier, Yves Cherel, Rob Harcourt, Clive R. McMahon, Mark A. Hindell, Jean-Benoît Charrassin, Christophe Guinet |
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Title |
Decadal changes in blood δ13C values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands |
Type |
Journal |
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Year |
2020 |
Publication |
Proceedings of the Royal Society B: Biological Sciences |
Abbreviated Journal |
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Volume |
287 |
Issue |
1933 |
Pages |
20201544 |
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Keywords |
bio-logging decadal change foraging habitat Indian sector of the Southern Ocean population strategies stable isotopes |
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Abstract |
Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004–2018) using tracking, weaning mass, and blood δ13C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006–2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers' pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood δ13C values decreased by 1.1‰ over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in δ13C is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations. |
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Programme |
109,1201 |
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Corporate Author |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Edition |
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ISBN |
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Area |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
8006 |
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| Permanent link to this record |
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Author |
Guillaumot Charlène, Danis Bruno, Saucède Thomas |
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Title |
Selecting environmental descriptors is critical for modelling the distribution of Antarctic benthic species |
Type |
Journal |
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Year |
2020 |
Publication |
Polar Biology |
Abbreviated Journal |
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Volume |
43 |
Issue |
9 |
Pages |
1363-1381 |
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Keywords |
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Abstract |
Species distribution models (SDMs) are increasingly used in ecological and biogeographic studies by Antarctic biologists, including for conservation and management purposes. During the modelling process, model calibration is a critical step to ensure model reliability and robustness, especially in the case of SDMs, for which the number of selected environmental descriptors and their collinearity is a recurring issue. Boosted regression trees (BRT) was previously considered as one of the best modelling approach to correct for this type of bias. In the present study, we test the performance of BRT in modelling the distribution of Southern Ocean species using different numbers of environmental descriptors, either collinear or not. Models are generated for six sea star species with contrasting ecological niches and wide distribution ranges over the entire Southern Ocean. For the six studied species, overall modelling performance is not affected by the number of environmental descriptors used to generate models, BRT using the most informative descriptors and minimizing model overfitting. However, removing collinear descriptors also helps reduce model overfitting. Our results confirm that BRTs may perform well and are relevant to deal with complex and redundant environmental information for Antarctic biodiversity distribution studies. Selecting a limited number of non-collinear descriptors before modelling may generate simpler models and facilitate their interpretation. The modelled distributions do not differ noticeably between the different species despite contrasting species ecological niches. This unexpected result stresses important limitations in using SDMs for broad scale spatial studies, based on limited, spatially aggregated data, and low-resolution descriptors. |
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Programme |
1044,1124 |
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Thesis |
Bachelor's thesis |
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Place of Publication |
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Language |
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Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1432-2056 |
ISBN |
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Medium |
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Area |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
8184 |
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Author |
Chuxian Li, Jeroen E. Sonke, Gaël Le Roux, Nathalie Van der Putten, Natalia Piotrowska, Catherine Jeandel, Nadine Mattielli, Mathieu Benoit, Giles F. S. Wiggs, François De Vleeschouwer |
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Title |
Holocene dynamics of the southern westerly winds over the Indian Ocean inferred from a peat dust deposition record |
Type |
Journal |
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Year |
2020 |
Publication |
Quaternary Science Reviews |
Abbreviated Journal |
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Volume |
231 |
Issue |
|
Pages |
106169 |
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Keywords |
Amsterdam Island Anthropogenic activities Dust sources Peat Southern westerly winds |
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Abstract |
The southern westerly winds (SWW) play a major role in climate variability in Southern Hemisphere mid- and high-latitudes, regulating rainfall, ocean circulation, and the Southern Ocean carbon sink. Despite their importance, little is known about millennial scale changes in the SWW and how they have influenced the climate system in the past and interacted with the Earth’s surface elements, such as dust, nutrients and carbon. Here we present a dust record from a 6.6 kyr old peat core in Amsterdam Island (AMS) situated at the northern edge of the SWW (37°S) in the Southern Indian Ocean. Mineral dust flux was used to track atmospheric dust production, long-distance transport and subsequent deposition. Dust provenance was determined from rare earth element (REE) and Nd isotopic signatures (εNd) in the peat core, compared with a reference dataset of Southern Hemisphere dust sources. Using a multi-proxy mixing model, the εNd and REE ratios show a relatively uniform mixture of ca. 40% local, 15% Southern African and 45% Southern South American dust sources since 6.6 cal kyr BP. However, from 1910 AD onwards, there is a doubling in the contribution from Southern Africa (32%). Two mineral dust flux minima occur at 6.2–4.9 cal kyr BP and 3.9–2.7 cal kyr BP, interpreted as periods with equatorward-shifted and/or strengthened SWW at the northern edge of the wind belt. Conversely, periods of higher dust flux at 6.6–6.2 cal kyr BP, 4.9–3.9 cal kyr BP, and 1.4 cal kyr BP onwards are interpreted as poleward-shifted and/or weakened SWW. These interpretations are based on the findings that higher (lower) wind speeds lead to enhanced (less) removal of distal dust on the way to AMS, by wet deposition and turbulence. Published Holocene SWW records at the northern edge of the wind belt (33–41°S) covering South-America, Southern-Africa and Australia, show much variability over the last 6.6 kyr. We suggest this reflects complex regional climate variability in the different SH longitudinal sectors, indicating that SWW are not zonally homogeneous at the northern edge of the wind belt. The recent shift in dust provenance is not accompanied by enhanced total dust deposition at AMS. We therefore suggest that human impact (e.g., land use changes) and drier climate conditions in Southern Africa have led to enhanced dust mobilization. |
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Programme |
1065,1133 |
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Thesis |
Bachelor's thesis |
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Series Issue |
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ISSN |
0277-3791 |
ISBN |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
8193 |
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| Permanent link to this record |
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Author |
Héloïse Barbel, Dominique Todisco, Najat Bhiry |
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Title |
A geochemical investigation of an Early Inuit semi-subterranean winter dwelling in a periglacial context |
Type |
Journal |
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Year |
2020 |
Publication |
Journal of archaeological science: reports |
Abbreviated Journal |
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Volume |
33 |
Issue |
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Pages |
102552 |
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Keywords |
C-N analysis Cryosolic soils geochemistry FTIR ICP-AES Inuit archaeology Nunavik Semi-subterranean house |
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Abstract |
Geochemical investigations using FTIR, ICP-AES and C-N analyses were carried out on a single-family semi-subterranean Inuit house in order to assess the contribution of Inuit domestic activities in the formation of cryosolic soils in a periglacial archaeological context (Kuuvik Bay, Nunavik, Canada). The geochemical elements data were analyzed using box plots and enrichment factors. The information was also summarized and visualized through principal component analysis (PCA). These complementary statistical approaches provided evidence of a moderate but identifiable and significant imprint of Inuit domestic activities on soil geochemistry. The box plots indicate moderate Ca, Mn, Cu and P enrichments and more noticeable Mg, Fe and S enrichments. These enrichment factors and the ICP-AES data show that samples from the peripheral wall and the tunnel entrance of the house and its vicinity are significantly enriched. While FTIR analysis highlighted the main soil element contents (e.g., organic and mineral components), ICP-AES analysis was used to further document variations in the background elements throughout the site. However, the obtained results do not allow us to undertake a spatial analysis of Inuit activities or to describe them in detail. In addition, the data highlight the difficulty of documenting the natural variability of element contents in cryosolic soils, especially in archaeological contexts. Cryo-pedological processes in the active layer as well as house cleaning and nutrient inputs resulting from Inuit occupations may have attenuated chemical signatures of previous Inuit domestic activities. |
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Programme |
1080 |
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Campaign |
LOTECHAIN |
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Address |
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Thesis |
Bachelor's thesis |
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Edition |
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ISSN |
2352-409X |
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yes |
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Call Number |
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Serial |
8206 |
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| Permanent link to this record |
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Author |
Renac Christophe, Moine Bertrand, Goudour Jean-Pierre, LeRomancer Marc, Perrache Chantal |
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Title |
Stable isotope study of rainfall, river drainage and hot springs of the kerguelen archipelago, SW Indian Ocean |
Type |
Journal |
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Year |
2020 |
Publication |
Geothermics |
Abbreviated Journal |
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Volume |
83 |
Issue |
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Pages |
101726 |
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Keywords |
Geothermal springs Kerguelen archipelago Stable isotope composition Water-Rock interaction |
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Abstract |
This study is the first synthesis of chemical composition and stable isotopes values for the Kerguelen archipelago waters. The stable isotope values for rainfall and river waters in the Kerguelen archipelago allow a calculation of the Local Meteoric Water Line (δD rainfall = 8.43 x δ18O rainfall + 11) and a summer runoff line (δD river drainage = 7.45 x δ18O river drainage + 6). Surface waters with low- ion concentrations, chlorine facies and stable isotope values infiltrate through fractures and lava flows recharging deeper groundwaters. Thermal groundwater with low- (7 to 50 °C) and high- (50 to 100 °C) temperatures emerges in different localities in the volcanic archipelago. The low-temperature thermal waters might represent a mixture of high-temperature water with rainfall, thermal gradient changes or shallower infiltration compared to that for high-temperature thermal waters. The Rallier du Baty and Val Travers areas contain geothermal fluids with high-temperature springs, fumaroles and a large water flow. In the Rallier du Baty, the major ion chemistry and O, H, C and S stable isotope ratio of low (7 to 50 °C) temperature spring waters in Rallier du Baty area demonstrate a geothermal-system recharged by meteoric water (δD H2O liquid = 7.0 x δ18O H2O liquid + 0.5) rather than sea water. The chemical and isotopic compositions of elevated temperature spring waters (50 to 100 °C) have a long and complex history of meteoric water interacting with cooling magmas (δD H2O liquid = 1.78 x δ18O H2O liquid – 23). Surficial precipitation of aragonite, kaolinite, pyrite, native sulfur attest to a long livied geothermal system. A temperature of the geothermal reservoir has been estimated between 193 and 259 °C by cation geothermometry. The combination of minerals observed, major ion composition of water with thermodynamic modeling and stable isotope data suggest a geothermal system with a series of water/rock interactions from 50 to 250 °C. The conductive cooling of rising of H2O−CO2-rich fluids have produced a H2O−CO2 phase separation with the precipitation of secondary minerals. |
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Programme |
408,444 |
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Campaign |
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Corporate Author |
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Thesis |
Bachelor's thesis |
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Publisher |
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Place of Publication |
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Language |
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Summary Language |
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Original Title |
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Series Volume |
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Edition |
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ISSN |
0375-6505 |
ISBN |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
8262 |
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