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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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Maxim Lamare, Florent Domine, Jesús Revuelto, Maude Pelletier, Laurent Arnaud, Ghislain Picard. (2023). Investigating the Role of Shrub Height and Topography in Snow Accumulation on Low-Arctic Tundra using UAV-Borne Lidar (Vol. 24).
Abstract: Abstract Expanding shrubs in the Arctic trap blowing snow, increasing snow height and accelerating permafrost warming. Topography also affects snow height as snow accumulates in hollows. The respective roles of topography and erect vegetation in snow accumulation were investigated using a UAV-borne lidar at two nearby contrasted sites in northern Quebec, Canada. The North site featured tall vegetation up to 2.5 m high, moderate snow height, and smooth topography. The South site featured lower vegetation, greater snow height, and rougher topography. There was little correlation between topography and vegetation height at both sites. Vegetation lower than snow height had very little effect on snow height. When vegetation protruded above the snow, snow height was well correlated with vegetation height. The topographic position index (TPI) was well correlated with snow height when it was not masked by the effect of protruding vegetation. The North site with taller vegetation therefore showed a good correlation between vegetation height and snow height, R2 = 0.37, versus R2 = 0.04 at the South site. Regarding topography, the reverse was observed between TPI and snow height, with R2 = 0.29 at the North site and R2 = 0.67 at the South site. The combination of vegetation height and TPI improved the prediction of snow height at the North site (R2 = 0.59) but not at the South site because vegetation height has little influence there. Vegetation was therefore the main factor determining snow height when it protruded above the snow. When it did not protrude, snow height was mostly determined by topography. Significance Statement Wind-induced snow drifting is a major snow redistribution process in the Arctic. Shrubs trap drifting snow, and drifting snow accumulates in hollows. Determining the respective roles of both these processes in snow accumulation is required to predict permafrost temperature and its emission of greenhouse gases, because thicker snow limits permafrost winter cooling. Using a UAV-borne lidar, we have determined snow height distribution over two contrasted sites in the Canadian low Arctic, with varied vegetation height and topography. When snow height exceeds vegetation height, topography is a good predictor of snow height, with negligible effect of buried vegetation. When vegetation protrudes above the snow, combining both topography and vegetation height is required for a good prediction of snow height.
Programme: 1042
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Maxime Bès de Berc, Dimitri Zigone, Peter Danecek, Alain Steyer, Francesco Zanolin, Alessia Maggi, Jean‐Yves Thoré, Armelle Bernard, Hervé Blumentritt, Sophie Lambotte, Jean‐Jacques Lévêque, Luis Rivera, Olivier Alemany, Philippe Possenti, Martin Vallée, Eléonore Stutzmann, Adriano Cavaliere, Nathalie Cotte, Stefano Marino, Baptiste Gombert, Wenceslas Marie‐Sainte, Nicolas Leroy, Constanza Pardo, Frédérick Pesqueira, Céleste Broucke. (2023). A New Posthole Seismometer at Concordia Permanent Research Facility in the Heart of the Icy East Antarctic Plateau.
Abstract: In the Southern Hemisphere, the prevalence of oceans and the difficulty of access to land result in reduced coverage of seismological stations, limiting our detailed knowledge of Earth’s structures and of large earthquakes sources. This situation is exacerbated inside the antarctic continent, where only two permanent seismic stations are currently available (IU.QSPA at South Pole and G.CCD). The CCD station, built in early 2000s with state‐of‐the‐art surface instrumentation and located at the French–Italian Concordia base (75° S, 123° E), has been providing seismological data since 2008. However, it suffers from several problems: the vault is deformed by the hydrostatic pressure of the snow, the firn waveguide traps anthropogenic noise from the base causing strong noise below 1 s, and a coupling defect limits the performance above 30 s on the horizontal channels. To ensure the continuity of CCD and to improve its overall performance, we started in 2014 to plan the installation of a borehole seismometer at the site. In this article, we describe in detail this renovation of CCD and some examples of data analysis. The new borehole sensor shows that short‐period disturbances are largely attenuated (−20 dB at 0.1 s) compared to the surface installation and that the horizontal channels have a lower noise level at long periods (−8 dB at 100 s). Data for all components are below the standard noise model between 0.1 and 0.2 s, which makes this sensor one of the quietest installations in the world for this bandwidth. For periods >600 s we observe atmospheric pressure‐related perturbations on the vertical component. Despite this problem, the new CCD borehole station is a success with better‐than‐expected performances at all periods <600 s. The data produced are now distributed in the world’s data centers as G.CCD.20 and we encourage the scientific community to use the data for all studies requiring seismograms from Antarctica.
Programme: 133
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Maxime Pineaux, Pierrick Blanchard, Léa Ribeiro, Scott A. Hatch, Sarah Leclaire. (2023). A Gull Species Recognizes MHC-II Diversity and Dissimilarity Using Odor Cues (Vol. 15).
Abstract: The major histocompatibility complex (MHC) plays a crucial role in the resistance to parasites in vertebrates and is thus often suggested to be an important force driving social interactions, including mating preference. However, the phenotypic cues used by individuals to assess the MHC characteristics of conspecifics are generally unknown. Here, we used behavioral tests to investigate whether, in black-legged kittiwakes, females use odor cues to distinguish male MHC-II diversity and MHC-II dissimilarity. We found that females took less time to peck at an odor sample coming from a male with high or low MHC-II diversity compared to intermediate MHC-II diversity. However, this result is due to the single individual who has only one MHC-II allele. When excluding this individual, females took less time to peck at an odor sample coming from a male with high MHC-II diversity. In addition, when the odor sample came from a male with higher MHC-II dissimilarity, females took less time to peck at the sample, but once they pecked at it, they delayed the use of the sample. Altogether, our results add evidence for olfactory recognition of MHC characteristics in birds, but further studies are needed to determine whether kittiwakes use this ability to optimize fitness.
Keywords: Birds Black-legged kittiwake Intraspecific communication Major histocompatibility complex Olfaction Rissa tridactyla Sexual selection
Programme: 1162
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