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Lenourry L. (2023). Adélie penguin (Pygoscelis adeliae) colony structuration in space and time: identifying selective pressures that shape colonial reproductive strategies.
Abstract: Cosupervision: Bonadonna & Le Bohec
Programme: 137
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Lissa Gourillon . (2023). Evolution des deltas et prodeltas du Lovenbreen depuis 2009.
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Lizhou Sha, Andrew M Vanderburg, Chelsea X Huang, David J Armstrong, Rafael Brahm, Steven Giacalone, Mackenna L Wood, Karen A Collins, Louise D Nielsen, Melissa J Hobson, Carl Ziegler, Steve B Howell, Pascal Torres-Miranda, Andrew W Mann, George Zhou, Elisa Delgado-Mena, Felipe I Rojas, Lyu Abe, Trifon Trifonov, Vardan Adibekyan, Sérgio G Sousa, Sergio B Fajardo-Acosta, Tristan Guillot, Saburo Howard, Colin Littlefield, Faith Hawthorn, François-Xavier Schmider, Jan Eberhardt, Thiam-Guan Tan, Ares Osborn, Richard P Schwarz, Paul Strøm, Andrés Jordán, Gavin Wang, Thomas Henning, Bob Massey, Nicholas Law, Chris Stockdale, Elise Furlan, Gregor Srdoc, Peter J Wheatley, David Barrado Navascués, Jack J Lissauer, Keivan G Stassun, George R Ricker, Roland K Vanderspek, David W Latham, Joshua N Winn, Sara Seager, Jon M Jenkins, Thomas Barclay, Luke G Bouma, Jessie L Christiansen, Natalia Guerrero, Mark E Rose. (2023). TESS spots a mini- interior to a hot saturn in the TOI-2000 system (Vol. 524).
Abstract: Hot jupiters (P < 10 d, M > 60 M⊕) are almost always found alone around their stars, but four out of hundreds known have inner companion planets. These rare companions allow us to constrain the hot jupiter’s formation history by ruling out high-eccentricity tidal migration. Less is known about inner companions to hot Saturn-mass planets. We report here the discovery of the TOI-2000 system, which features a hot Saturn-mass planet with a smaller inner companion. The mini-neptune TOI-2000 b (2.70 ± 0.15 R⊕, 11.0 ± 2.4 M⊕) is in a 3.10-d orbit, and the hot saturn TOI-2000 c ($8.14{-0.30}^{+0.31}$ R⊕ , $81.7{-4.6}^{+4.7}$ M⊕) is in a 9.13-d orbit. Both planets transit their host star TOI-2000 (TIC 371188886, V = 10.98, TESS magnitude = 10.36), a metal-rich ([Fe/H] = 0.439 $_{-0.043}^{+0.041}$) G dwarf 173 pc away. TESS observed the two planets in sectors 9–11 and 36–38, and we followed up with ground-based photometry, spectroscopy, and speckle imaging. Radial velocities from CHIRON, FEROS, and HARPS allowed us to confirm both planets by direct mass measurement. In addition, we demonstrate constraining planetary and stellar parameters with MIST stellar evolutionary tracks through Hamiltonian Monte Carlo under the PyMC framework, achieving higher sampling efficiency and shorter run time compared to traditional Markov chain Monte Carlo. Having the brightest host star in the V band among similar systems, TOI-2000 b and c are superb candidates for atmospheric characterization by the JWST, which can potentially distinguish whether they formed together or TOI-2000 c swept along material during migration to form TOI-2000 b.
Programme: 1066
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Loïc Le Ster, Hervé Claustre, Francesco d’Ovidio, David Nerini, Baptiste Picard, Christophe Guinet. (2023). Improved accuracy and spatial resolution for bio-logging-derived chlorophyll a fluorescence measurements in the Southern Ocean (Vol. 10).
Abstract: The ocean’s meso- and submeso-scales (1-100 km, days to weeks) host features like filaments and eddies that have a key structuring effect on phytoplankton distribution, but that due to their ephemeral nature, are challenging to observe. This problem is exacerbated in regions with heavy cloud coverage and/or difficult access like the Southern Ocean, where observations of phytoplankton distribution by satellite are sparse, manned campaigns costly, and automated devices limited by power consumption. Here, we address this issue by considering high-resolution in-situ data from 18 bio-logging devices deployed on southern elephant seals (Mirounga leonina) in the Kerguelen Islands between 2018 and 2020. These devices have submesoscale-resolving capabilities of light profiles due to the high spatio-temporal frequency of the animals’ dives (on average 1.1 +-0.6 km between consecutive dives, up to 60 dives per day), but observations of fluorescence are much coarser due to power constraints. Furthermore, the chlorophyll a concentrations derived from the (uncalibrated) bio-logging devices’ fluorescence sensors lack a common benchmark to properly qualify the data and allow comparisons of observations. By proposing a method based on functional data analysis, we show that a reliable predictor of chlorophyll a concentration can be constructed from light profiles (14 686 in our study). The combined use of light profiles and matchups with satellite ocean-color data enable effective (1) homogenization then calibration of the bio-logging devices’ fluorescence data and (2) filling of the spatial gaps in coarse-grained fluorescence sampling. The developed method improves the spatial resolution of the chlorophyll a field description from ~30 km to ~12 km. These results open the way to empirical study of the coupling between physical forcing and biological response at submesoscale in the Southern Ocean, especially useful in the context of upcoming high-resolution ocean-circulation satellite missions.
Programme: 109
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Loïc Le Ster, Hervé Claustre, Francesco d’Ovidio, David Nerini, Baptiste Picard, Christophe Guinet. (2023). Improved accuracy and spatial resolution for bio-logging-derived chlorophyll a fluorescence measurements in the Southern Ocean (Vol. 10).
Abstract: The ocean’s meso- and submeso-scales (1-100 km, days to weeks) host features like filaments and eddies that have a key structuring effect on phytoplankton distribution, but that due to their ephemeral nature, are challenging to observe. This problem is exacerbated in regions with heavy cloud coverage and/or difficult access like the Southern Ocean, where observations of phytoplankton distribution by satellite are sparse, manned campaigns costly, and automated devices limited by power consumption. Here, we address this issue by considering high-resolution in-situ data from 18 bio-logging devices deployed on southern elephant seals (Mirounga leonina) in the Kerguelen Islands between 2018 and 2020. These devices have submesoscale-resolving capabilities of light profiles due to the high spatio-temporal frequency of the animals’ dives (on average 1.1 +-0.6 km between consecutive dives, up to 60 dives per day), but observations of fluorescence are much coarser due to power constraints. Furthermore, the chlorophyll a concentrations derived from the (uncalibrated) bio-logging devices’ fluorescence sensors lack a common benchmark to properly qualify the data and allow comparisons of observations. By proposing a method based on functional data analysis, we show that a reliable predictor of chlorophyll a concentration can be constructed from light profiles (14 686 in our study). The combined use of light profiles and matchups with satellite ocean-color data enable effective (1) homogenization then calibration of the bio-logging devices’ fluorescence data and (2) filling of the spatial gaps in coarse-grained fluorescence sampling. The developed method improves the spatial resolution of the chlorophyll a field description from ~30 km to ~12 km. These results open the way to empirical study of the coupling between physical forcing and biological response at submesoscale in the Southern Ocean, especially useful in the context of upcoming high-resolution ocean-circulation satellite missions.
Keywords: bio-logging tag chla fluorescence Sensor calibration Southern elephant seal Southern Ocean Submesoscale
Programme: 1201
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Lucie A. Malard, Benoit Bergk-Pinto, Rose Layton, Timothy M. Vogel, Catherine Larose, David A. Pearce. (2023). Snow Microorganisms Colonise Arctic Soils Following Snow Melt.
Abstract: Arctic soils are constantly subjected to microbial invasion from either airborne, marine, or animal sources, which may impact local microbial communities and ecosystem functioning. However, in winter, Arctic soils are isolated from outside sources other than snow, which is the sole source of microorganisms. Successful colonisation of soil by snow microorganisms depends on the ability to survive and compete of both, the invading and resident community. Using shallow shotgun metagenome sequencing and amplicon sequencing, this study monitored snow and soil microbial communities throughout snow melt to investigate the colonisation process of Arctic soils. Microbial colonisation likely occurred as all the characteristics of successful colonisation were observed. The colonising microorganisms originating from the snow were already adapted to the local environmental conditions and were subsequently subjected to many similar conditions in the Arctic soil. Furthermore, competition-related genes (e.g. motility and virulence) increased in snow samples as the snow melted. Overall, one hundred potentially successful colonisers were identified in the soil and, thus, demonstrated the deposition and growth of snow microorganisms in soils during melt.
Keywords: Airborne dispersal Arctic ecosystems Bacterial diversity Coalescence Microbial colonisation Snow Soils
Programme: 1192
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Manzo Emilie. (2023). Caractérisation des changements morphologiques des populations de Merizodus soledadinus (Coleoptera) suite à la colonisation de nouveaux habitats dans les îles Kerguelen.
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Martin Beal, Paulo Catry, Richard A. Phillips, Steffen Oppel, John P. Y. Arnould, Maria I. Bogdanova, Mark Bolton, Ana P. B. Carneiro, Corey Clatterbuck, Melinda Conners, Francis Daunt, Karine Delord, Kyle Elliott, Aymeric Fromant, José Pedro Granadeiro, Jonathan A. Green, Lewis Halsey, Keith C. Hamer, Motohiro Ito, Ruth Jeavons, Jeong-Hoon Kim, Nobuo Kokubun, Shiho Koyama, Jude V. Lane, Won Young Lee, Sakiko Matsumoto, Rachael A. Orben, Ellie Owen, Vitor H. Paiva, Allison Patterson, Christopher J. Pollock, Jaime A. Ramos, Paul Sagar, Katsufumi Sato, Scott A. Shaffer, Louise Soanes, Akinori Takahashi, David R. Thompson, Lesley Thorne, Leigh Torres, Yutaka Watanuki, Susan M. Waugh, Henri Weimerskirch, Shannon Whelan, Ken Yoda, José C. Xavier, Maria P. Dias. (2023). Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identification (Vol. 281).
Abstract: Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed area-based conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: −0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds.
Keywords: Animal tracking Area-based conservation Biotelemetry Key biodiversity areas Marine spatial planning Protected areas Sampling effort Spatial consistency
Programme: 109
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Mathurin Dongmo Wamba, Jean-Paul Montagner, Barbara Romanowicz. (2023). Imaging deep-mantle plumbing beneath La Réunion and Comores hot spots: Vertical plume conduits and horizontal ponding zones (Vol. 9).
Abstract: Whether the two large low–shear velocity provinces (LLSVPs) at the base of Earth’s mantle are wide compact structures extending thousands of kilometers upward or bundles of distinct mantle plumes is the subject of debate. Full waveform shear wave tomography of the deep mantle beneath the Indian Ocean highlights the presence of several separate broad low-velocity conduits anchored at the core-mantle boundary in the eastern part of the African LLSVP, most clearly beneath La Réunion and Comores hot spots. The deep plumbing system beneath these hot spots may also include alternating vertical conduits and horizontal ponding zones, from 1000-km depth to the top of the asthenosphere, reminiscent of dyke and sills in crustal volcanic systems, albeit at a whole-mantle scale.
Programme: 133
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Matthias Vignon, Mingsha Zhou, Angus R. McIntosh, Cristian Correa, Peter A. H. Westley, Lisa Jacquin, Jacques Labonne, Andrew P. Hendry. (2023). Trait variation in a successful global invader: a large-scale analysis of morphological variance and integration in the brown trout (Vol. 25).
Abstract: In ecology and evolution, the small population paradigm posits that reduced genetic variation will result in limited phenotypic variation that, in turn, will affect population resilience and potential for adaptation. Over the last decade though, such a paradigm has been questioned, with evidence that mechanisms independent of genetic variation may be also important in shaping phenotypic variation. However, there are few large-scale empirical examples, especially from aquatic ecosystems. Using the large-scale natural experiment afforded by the global invasion of brown trout (Salmo trutta), we quantify standing phenotypic variation in morphology among different introduced ranges, relative to the native range. By using shape variation and morphological integration as indicators of phenotypic variation, we show that neither founding population size nor time since founding (i.e., effect of selection regime) are correlated to the amount of morphological variation, contrarily to common expectations. Beyond founding population size and time since founding, the amount of morphological variation is mostly controlled by factors at the population level rather than at the region level, and is not lower in invaded regions compared to the native range. These results suggest that the dynamics of phenotypic variation may be largely independent of population size and mostly determined by site-specific patterns of selection.
Keywords: Invasion Morphological integration Phenotypic variation Population size
Programme: 1041
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