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Jennifer A. Burt, Diana Dragomir, Paul Mollière, Allison Youngblood, Antonio García Muñoz, John McCann, Laura Kreidberg, Chelsea X. Huang, Karen A. Collins, Jason D. Eastman, Lyu Abe, Jose M. Almenara, Ian J. M. Crossfield, Carl Ziegler, Joseph E. Rodriguez, Eric E. Mamajek, Keivan G. Stassun, Samuel P. Halverson, Steven Villanueva, R. Paul Butler, Sharon Xuesong Wang, Richard P. Schwarz, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Abdelkrim Agabi, Xavier Bonfils, David Ciardi, Marion Cointepas, Jeffrey D. Crane, Nicolas Crouzet, Georgina Dransfield, Fabo Feng, Elise Furlan, Tristan Guillot, Arvind F. Gupta, Steve B. Howell, Eric L. N. Jensen, Nicholas Law, Andrew W. Mann, Wenceslas Marie-Sainte, Rachel A. Matson, Elisabeth C. Matthews, Djamel Mékarnia, Joshua Pepper, Nic Scott, Stephen A. Shectman, Joshua E. Schlieder, François-Xavier Schmider, Daniel J. Stevens, Johanna K. Teske, Amaury H. M. J. Triaud, David Charbonneau, Zachory K. Berta-Thompson, Christopher J. Burke, Tansu Daylan, Thomas Barclay, Bill Wohler, C. E. Brasseur |
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Title |
TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399 |
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Year |
2021 |
Publication |
The Astronomical Journal |
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Volume |
162 |
Issue |
3 |
Pages |
87 |
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Abstract |
We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby (d = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the Antarctica Search for Transiting ExoPlanets program. Combining the photometric data sets, we find that the newly discovered planet has a radius of and an orbital period of 24.246 days. Radial velocity measurements obtained with the Planet Finder Spectrograph on the Magellan Clay telescope confirm the existence of the planet and lead to a mass measurement of 15.5 ± 3.3 M ⊕. With an equilibrium temperature of just 330 K, TOI-1231 b is one of the coolest small planets accessible for atmospheric studies thus far, and its host star’s bright near-infrared brightness (J = 8.88, K s = 8.07) makes it an exciting target for the Hubble Space Telescope and the James Webb Space Telescope. Future atmospheric observations would enable the first comparative planetology efforts in the 250–350 K temperature regime via comparisons with K2-18 b. Furthermore, TOI-1231's high systemic radial velocity (70.5 km s−1) may allow for the detection of low-velocity hydrogen atoms escaping the planet by Doppler, shifting the H i Lyα stellar emission away from the geocoronal and interstellar medium absorption features. |
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1066 |
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1538-3881 |
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yes |
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8196 |
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Yves Cherel |
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?Mastigoteuthis B Clarke, 1980, is a junior synonym of Asperoteuthis acanthoderma (Lu, 1977) (Cephalopoda, Oegopsida, Chiroteuthidae), a rare cosmopolitan deep-sea squid |
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Year |
2021 |
Publication |
Marine Biodiversity |
Abbreviated Journal |
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Volume |
51 |
Issue |
1 |
Pages |
14 |
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Abstract |
The present work resolved the long-standing taxonomic problem associated with the enigmatic ?Mastigoteuthis B Clarke, 1980, by demonstrating that these lower beaks correspond to those of the large deep-sea chiroteuthid Asperoteuthis acanthoderma (Lu, 1977). A review of the existing literature listed 22 specimens of A. acanthoderma, but synonymizing ?Mastigoteuthis B with A. acanthoderma increased 14 times the species record worldwide. Pooling the data from both specimens and beaks (a total of 329 individuals) indicates that the species has a circumglobal distribution, since it occurs in tropical and subtropical waters of the Atlantic, Indian and Pacific Oceans. The synonymization also highlights trophic relationships of the species as a prey of top marine predators. Lower beaks of A. acanthoderma were mostly found in stomachs of sperm whales, but a few beaks were also recorded from stomach contents of sharks, swordfish and the wandering albatross. |
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109 |
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1867-1624 |
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yes |
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Serial |
8208 |
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A. Corbeau, J. Collet, F. Orgeret, P. Pistorius, H. Weimerskirch |
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Title |
Fine-scale interactions between boats and large albatrosses indicate variable susceptibility to bycatch risk according to species and populations |
Type |
Journal |
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Year |
2021 |
Publication |
Animal Conservation |
Abbreviated Journal |
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Volume |
24 |
Issue |
4 |
Pages |
689-699 |
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Keywords |
albatross populations biologging bycatch assessment bycatch risk ecological trap fisheries fishing boat bycatch seabirds |
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Abstract |
Many seabirds are attracted to fishing boats where they exploit foraging opportunities, often involving bycatch-related mortality. Bycatch risk is generally estimated by overlapping seabirds foraging ranges with coarse-scale monthly maps of fishing efforts, but a more direct estimation would be the time birds actually spend attending fishing boats. Here we matched data from Automatic Identification Systems from all declared boats in the Southern Ocean, with 143 simultaneous foraging trips from all populations of large albatrosses (Diomedea amsterdamensis and Diomedea exulans) breeding in the Indian Ocean (Marion, Crozet, Kerguelen, Amsterdam islands). We quantified and compared real-time co-occurrence between boats and albatrosses, at different scales (100, 30 and 5 km). We also examined to what extent co-occurrence at a large-scale (5×5° grid cell) predicted fine-scale attendance (5 km). Albatrosses on average spent about 3 h per trip attending fishing boats (<5 km) at both Amsterdam and Marion and about 30 h per trip at Kerguelen. In all populations, >90% of declared fishing boat attendances occurred within Economic Exclusive Zones (EEZ) where bycatch mitigation measures are enforced. Outside EEZs, birds from all populations to a large extent also attended non-fishing boats. Fishing boat density at a large scale (5 × 5°, 100 km) was a poor predictor of time spent attending fishing boats (<5 km) across populations. Our results indicate a large variation in fishing boat densities within the foraging ranges of different populations and in the time birds spent attending boats. We discuss the pros and cons of considering bycatch risk at a large geographical scale and methods that can be implemented to improve the estimation of seabird vulnerability to fishing activities when fine-scale data are available, particularly for the conservation of those highly threatened species. |
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109 |
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1469-1795 |
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yes |
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Call Number |
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Serial |
8209 |
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Maud Quéroué, Christophe Barbraud, Frédéric Barraquand, Daniel Turek, Karine Delord, Nathan Pacoureau, Olivier Gimenez |
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Title |
Multispecies integrated population model reveals bottom-up dynamics in a seabird predator–prey system |
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Journal |
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Year |
2021 |
Publication |
Ecological Monographs |
Abbreviated Journal |
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Volume |
91 |
Issue |
3 |
Pages |
e01459 |
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Keywords |
Bayesian inference demography environmental variation integrated population model matrix population model Nimble predator–prey interactions |
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Abstract |
Assessing the effects of climate and interspecific relationships on communities is challenging because of the complex interplay between species population dynamics, their interactions, and the need to integrate information across several biological levels (individuals, populations, communities). Usually used to quantify single-species demography, integrated population models (IPMs) have recently been extended to communities. These models allow fitting multispecies matrix models to data from multiple sources while simultaneously accounting for uncertainty in each data source. We used multispecies IPMs accommodating climatic variables to quantify the relative contribution of climate vs. interspecific interactions on demographic parameters, such as survival and breeding success, in the dynamics of a predator–prey system. We considered a stage-structured predator–prey system combining 22 yr of capture–recapture data and population counts of two seabirds, the Brown Skua (Catharacta lönnbergi) and its main prey the Blue Petrel (Halobaena caerulea), both breeding on the Kerguelen Islands in the Southern Ocean. Our results showed that climate and predator–prey interactions drive the demography of skuas and petrels in different ways. The breeding success of skuas appeared to be largely driven by the number of petrels and to a lesser extent by intraspecific density dependence. In contrast, there was no evidence of predation effects on the demographic parameters of petrels, which were affected by oceanographic factors. We conclude that bottom-up mechanisms are the main drivers of this skua–petrel system. |
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Programme |
109 |
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Bachelor's thesis |
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ISSN |
1557-7015 |
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yes |
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Serial |
8210 |
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Author |
N. Ribeiro, L. Herraiz-Borreguero, S. R. Rintoul, C. R. McMahon, M. Hindell, R. Harcourt, G. Williams |
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Title |
Warm Modified Circumpolar Deep Water Intrusions Drive Ice Shelf Melt and Inhibit Dense Shelf Water Formation in Vincennes Bay, East Antarctica |
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Year |
2021 |
Publication |
Journal of Geophysical Research: Oceans |
Abbreviated Journal |
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Volume |
126 |
Issue |
8 |
Pages |
e2020JC016998 |
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Keywords |
AABW Antarctic Coastal Circulation Antarctic Margins basal melt mCDW intrusions seal CTD |
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Abstract |
Antarctic Bottom Water (AABW) production supplies the deep limb of the global overturning circulation and ventilates the deep ocean. While the Weddell and Ross Seas are recognized as key sites for AABW production, additional sources have been discovered in coastal polynya regions around East Antarctica, most recently at Vincennes Bay. Vincennes Bay, despite encompassing two distinct polynya regions, is considered the weakest source, producing Dense Shelf Water (DSW) only just dense enough to contribute to the lighter density classes of AABW found offshore. Here we provide the first detailed oceanographic observations of the continental shelf in Vincennes Bay (104-111°E), using CTD data from instrumented elephant seals spanning from February to November of 2012. We find that Vincennes Bay has East Antarctica’s warmest recorded intrusions of modified Circumpolar Deep Water (mCDW) and that warm mCDW drives basal melt under Vanderford and Underwood ice shelves. Our study also provides the first direct observational evidence for the inflow of meltwater to this region, which increases stratification and hinders DSW formation, and thus AABW production. The Vincennes Bay glaciers, together with the Totten Glacier, drain part of the Aurora Basin, which holds up to 7 m of sea level rise equivalent. Our results highlight the vulnerability of the East Antarctic Ice Sheet to intrusions of mCDW. |
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109 |
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ISSN |
2169-9291 |
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yes |
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Call Number |
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Serial |
8211 |
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Author |
Jilda Alicia Caccavo, Thierry Raclot, Timothée Poupart, Yan Ropert-Coudert, Frédéric Angelier |
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Title |
Anthropogenic activities are associated with shorter telomeres in chicks of Adélie penguin (Pygoscelis adeliae) |
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Journal |
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Year |
2021 |
Publication |
Polar Biology |
Abbreviated Journal |
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Volume |
44 |
Issue |
7 |
Pages |
1391-1399 |
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Abstract |
Defining the impact of anthropogenic stressors on Antarctic wildlife is an active aim for investigators. Telomeres represent a promising molecular tool to investigate the fitness of wild populations, as their length may predict longevity and survival. We examined the relationship between telomere length and human exposure in Adélie penguin chicks (Pygoscelis adeliae) from East Antarctica. Telomere length was compared between chicks from areas with sustained human activity and on neighboring protected islands with little or no human presence. Adélie penguin chicks from sites exposed to human activity had significantly shorter telomeres than chicks from unexposed sites in nearby protected areas, with exposed chicks having on average 3.5% shorter telomeres than unexposed chicks. While sampling limitations preclude our ability to draw more sweeping conclusions at this time, our analysis nonetheless provides important insights into measures of colony vulnerability. More data are needed both to understand the proximate causes (e.g., stress, feeding events) leading to shorter telomeres in chicks from human exposed areas, as well as the fitness consequences of reduced telomere length. We suggest to further test the use of telomere length analysis as an eco-indicator of stress in wildlife among anthropized sites throughout Antarctica. |
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1091 |
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ISSN |
1432-2056 |
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yes |
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Call Number |
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Serial |
8224 |
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Author |
O. Alemany, P. Talalay, P. Boissonneau, J. Chappellaz, J. F. Chemin, R. Duphil, E. Lefebvre, L. Piard, P. Possenti, J. Triest |
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Title |
The SUBGLACIOR drilling probe: hydraulic considerations |
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Journal |
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Year |
2021 |
Publication |
Annals of Glaciology |
Abbreviated Journal |
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Volume |
62 |
Issue |
84 |
Pages |
131-142 |
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Keywords |
Glaciological instruments and methods ice coring ice engineering paleoclimate |
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Abstract |
Using significant technological breakthroughs and unconventional approaches, the goal of the in situ probing of glacier ice for a better understanding of the orbital response of climate (SUBGLACIOR) project is to advance ice core research by inventing, constructing and testing an in situ probe to evaluate if a target site is suitable for recovering ice as old as 1.5 million years. Embedding a laser spectrometer, the probe is intended to make its own way down into the ice and to measure, in real time and down to the bedrock, the depth profiles of the ice δD water isotopes as well as the trapped CH4 gas concentration and dust concentration. The probe descent is achieved through electromechanical drilling combined with continuous meltwater sample production using a central melting finger in the drill head. A key aspect of the project lies in the design and implementation of an efficient method to continuously transfer to the surface the ice chips being produced by the drill head and from the refreezed water expulsed downstream from the melting finger, into the borehole. This paper presents a detailed calculation and analysis of the flow rates and pressure conditions required to overcome friction losses of the drilling fluid and to effectively transport ice chips to the surface. |
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Programme |
119 |
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ISSN |
0260-3055, 1727-5644 |
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yes |
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Serial |
8234 |
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Author |
Chiara Papetti, Massimiliano Babbucci, Agnes Dettai, Andrea Basso, Magnus Lucassen, Lars Harms, Celine Bonillo, Franz Maximilian Heindler, Tomaso Patarnello, Enrico Negrisolo |
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Title |
Not Frozen in the Ice: Large and Dynamic Rearrangements in the Mitochondrial Genomes of the Antarctic Fish |
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Journal |
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Year |
2021 |
Publication |
Genome Biology and Evolution |
Abbreviated Journal |
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Volume |
13 |
Issue |
3 |
Pages |
evab017 |
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Abstract |
The vertebrate mitochondrial genomes generally present a typical gene order. Exceptions are uncommon and important to study the genetic mechanisms of gene order rearrangements and their consequences on phylogenetic output and mitochondrial function. Antarctic notothenioid fish carry some peculiar rearrangements of the mitochondrial gene order. In this first systematic study of 28 species, we analyzed known and undescribed mitochondrial genome rearrangements for a total of eight different gene orders within the notothenioid fish. Our reconstructions suggest that transpositions, duplications, and inversion of multiple genes are the most likely mechanisms of rearrangement in notothenioid mitochondrial genomes. In Trematominae, we documented an extremely rare inversion of a large genomic segment of 5,300 bp that partially affected the gene compositional bias but not the phylogenetic output. The genomic region delimited by nad5 and trnF, close to the area of the Control Region, was identified as the hot spot of variation in Antarctic fish mitochondrial genomes. Analyzing the sequence of several intergenic spacers and mapping the arrangements on a newly generated phylogeny showed that the entire history of the Antarctic notothenioids is characterized by multiple, relatively rapid, events of disruption of the gene order. We hypothesized that a pre-existing genomic flexibility of the ancestor of the Antarctic notothenioids may have generated a precondition for gene order rearrangement, and the pressure of purifying selection could have worked for a rapid restoration of the mitochondrial functionality and compactness after each event of rearrangement. |
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Programme |
1124 |
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ISSN |
1759-6653 |
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yes |
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Serial |
8235 |
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Author |
Mark A. Hindell, Clive R. McMahon, Ian Jonsen, Robert Harcourt, Fernando Arce, Christophe Guinet |
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Title |
Inter- and intrasex habitat partitioning in the highly dimorphic southern elephant seal |
Type |
Journal |
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Year |
2021 |
Publication |
Ecology and Evolution |
Abbreviated Journal |
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Volume |
11 |
Issue |
4 |
Pages |
1620-1633 |
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Keywords |
Antarctic Shelf foraging and diving behavior Kerguelen Plateau mid-year haul out predation risk Southern Ocean |
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Abstract |
Partitioning resources is a key mechanism for avoiding intraspecific competition and maximizing individual energy gain. However, in sexually dimorphic species it is difficult to discern if partitioning is due to competition or the different resource needs of morphologically distinct individuals. In the highly dimorphic southern elephant seal, there are intersexual differences in habitat use; at Iles Kerguelen, males predominantly use shelf waters, while females use deeper oceanic waters. There are equally marked intrasexual differences, with some males using the nearby Kerguelen Plateau, and others using the much more distant Antarctic continental shelf ( 2,000 km away). We used this combination of inter and intrasexual behavior to test two hypotheses regarding habitat partitioning in highly dimorphic species. (a) that intersexual differences in habitat use will not appear until the seals diverge in body size and (b) that some habitats have higher rates of energy return than others. In particular, that the Antarctic shelf would provide higher energy returns than the Kerguelen Shelf, to offset the greater cost of travel. We quantified the habitat use of 187 southern elephant seals (102 adult females and 85 subadult males). The seals in the two groups were the same size ( 2.4 m) removing the confounding effect of body size. We found that the intersexual differences in habitat use existed before the divergence in body size. Also, we found that the amount of energy gained was the same in all of the major habitats. This suggests that the use of shelf habitats by males is innate, and a trade-off between the need to access the large benthic prey available on shelf waters, against the higher risk of predation there. Intrasexual differences in habitat use are another trade-off; although there are fewer predators on the Antarctic shelf, it is subject to considerable interannual fluctuations in sea-ice extent. In contrast, the Kerguelen Plateau presents more consistent foraging opportunities, but contains higher levels of predation. Habitat partitioning in this highly dimorphic species is therefore the result of complex interplay of life history strategies, environmental conditions and predation pressure. |
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Programme |
109,1201 |
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Thesis |
Bachelor's thesis |
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Edition |
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ISSN |
2045-7758 |
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Approved |
yes |
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Call Number |
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Serial |
8243 |
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| Permanent link to this record |
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Author |
J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J. D. Carrillo-Sánchez, P. Pokorný, J. M. C. Plane |
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Title |
The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth |
Type |
Journal |
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Year |
2021 |
Publication |
Earth and Planetary Science Letters |
Abbreviated Journal |
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Volume |
560 |
Issue |
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Pages |
116794 |
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Antarctic micrometeorites atmospheric entry cosmic spherules extraterrestrial flux interplanetary dust particles zodiacal cloud |
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Abstract |
The annual flux of extraterrestrial material on Earth is largely dominated by sub-millimetre particles. The mass distribution and absolute value of this cosmic dust flux at the Earth's surface is however still uncertain due to the difficulty in monitoring both the collection efficiency and the exposure parameter (i.e. the area-time product in m2.yr). In this paper, we present results from micrometeorite collections originating from the vicinity of the CONCORDIA Station located at Dome C (Antarctica), where we performed several independent melts of large volumes of ultra-clean snow. The regular precipitation rate and the exceptional cleanliness of the snow from central Antarctica allow a unique control on both the exposure parameter and the collection efficiency. A total of 1280 unmelted micrometeorites (uMMs) and 808 cosmic spherules (CSs) with diameters ranging from 30 to 350 μm were identified. Within that size range, we measured mass fluxes of 3.0 μg.m−2.yr−1 for uMMs and 5.6 μg.m−2.yr−1 for CSs. Extrapolated to the global flux of particles in the 12-700 μm diameter range, the mass flux of dust at Earth's surface is 5,200±12001500 tons.yr−1 (1,600±500 and 3,600±7001000 tons.yr−1 of uMMs and CSs, respectively). We indicate the statistical uncertainties expected for collections with exposure parameters in the range of 0.1 up to 105 m2.yr. In addition, we estimated the flux of altered and unaltered carbon carried by heated and un-heated particles at Earth's surface. The mass distributions of CSs and uMMs larger than 100 μm are fairly well reproduced by the CABMOD-ZoDy model that includes melting and evaporation during atmospheric entry of the interplanetary dust flux. These numerical simulations suggest that most of the uMMs and CSs originate from Jupiter family comets and a minor part from the main asteroid belt. The total dust mass input before atmospheric entry is estimated at 15,000 tons.yr−1. The existing discrepancy between the flux data and the model for uMMs below 100 μm suggests that small fragile uMMs may evade present day collections, and/or that the amount of small interplanetary particles at 1 AU may be smaller than expected. |
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1120 |
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0012-821X |
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yes |
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8244 |
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