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Lemonnier C, Schull Q, Stier A, Boonstra R, Delahanty B, Lefol E, Durand L, Robin J-p, Criscuolo F, Bize P &Amp; Va Viblanc. (2021). Coping with socially stressful environment in colonial seabirds: a test of adaptive phenotype programming in king penguins.
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David Byrne, Jeff Polton, Colin Bell. (2021). Creation of a global tide analysis dataset: Application of NEMO and an offline objective analysis scheme.
Abstract: The accurate prediction of tides is vital for the operation of many industries, early warning of coastal flooding and scientific understanding of ocean processes. In this paper, we describe the creation method of a global dataset of tidal harmonics using NEMO (Nucleus for European Modelling of the Ocean) for the first time and an offline objective analysis scheme. Data are assimilated as part of a post-processing step, reducing the computational resources required. A reduced ensemble of tidal harmonics is generated, where each member is run for a shorter period of time than a central background state. This ensemble is used to estimate a single background covariance state, which is used for analysis. Output is validated using an ensemble of objective analyses. For each ensemble member, random selections of observations are omitted and validation is performed at these locations. Improvements in both Mean Absolute Error (MAE) and correlation coefficients (R2) are seen across all 6 of the largest diurnal and semi-diurnal constituents. MAEs in amplitude and phase are reduced by up to 78% and 89%, respectively, and correlations by as much as 0.14. In addition, the majority of locations (between 70 and 80%) see significant improvement.
Programme: 688
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Lucie Aulus-Giacosa. (2021). Spatio-temporal evolution of life history traits related to dispersal. Brown trout (Salmo trutta L.) colonization of the sub-Antarctic Kerguelen Islands. // Evolution de l'anadromie chez la truite commune (Salmo trutta) L. dans le cadre de l'expansion des populations introduites dans les îles Kerguelen..
Abstract: Grâce à ses capacités dispersives et adaptatives, la truite commune (Salmo trutta L.), poisson anadrome facultatif, est un bon candidat à la colonisation de nouveaux milieux. L'introduction de l'espèce dans les années 1950 dans les îles subantarctiques de Kerguelen fournit un modèle d'étude unique pour comprendre les causes et les mécanismes de la dispersion, grâce à l'étude des traits d'histoire de vie en lien avec la migration (e.g. croissance, âge à la migration). L'étude de leur évolution temporelle le long d'un front de colonisation est le cœur de ce travail de thèse. A travers l’étude des écailles recueillies dans le cadre de ce programme à long terme, les histoires de vie de près de 5000 poissons ont été reconstruites. Ce travail démontre l’importance de la méthodologie utilisée afin de reconstruire les traits de vie individuel. La modélisation de l’évolution de la croissance en eau douce, de la taille à l’âge et de l’âge à la première migration démontre que des processus évolutifs sont en œuvre dans les populations en expansion. Notamment, le ralentissement de la croissance avec le temps ainsi que la diminution de la taille à l’âge le long du front de colonisation laissent à penser que la capacité de dispersion diminue à mesure que les populations sont en marges de la zone d’expansion. L’évolution de la valeur seuil à la première migration confirme ce résultat, et illustre l’importance de la plasticité phénotypique et de l’adaptation locale dans le choix de la tactique migratoire. Toutefois, l’approche menée dans ce manuscrit se concentre sur l’évolution de la migration, et bénéficierait de l’étude de l’évolution conjointe des traits impliqués dans la valeur sélective (balance coûts-bénéfices), tels que la reproduction, ou la croissance en mer.
Programme: 1041
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Lisa-Marie Mazzolo. (2021). Evolution de la calotte glaciaire du Svalbard par altimétrie laser.
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Stefan Osterwalder, Sarrah M. Dunham-Cheatham, Beatriz Ferreira Araujo, Olivier Magand, Jennie L. Thomas, Foteini Baladima, Katrine Aspmo Pfaffhuber, Torunn Berg, Lei Zhang, Jiaoyan Huang, Aurélien Dommergue, Jeroen E. Sonke, Mae Sexauer Gustin. (2021). Fate of Springtime Atmospheric Reactive Mercury: Concentrations and Deposition at Zeppelin, Svalbard (Vol. 5).
Abstract: Mid-latitude atmospheric elemental mercury (Hg) emissions undergo extensive oxidation to reactive Hg (RM) compounds during Arctic polar sunrise, resulting in enhanced atmospheric deposition that impacts Arctic marine wildlife and humans. It has been difficult to estimate RM dry deposition, because RM concentrations, compounds, and their deposition velocities are ill-defined. Here, we investigate RM concentrations sampled with membrane-based methods and find these to exceed denuder-based RM detection by 5 times at the Zeppelin Observatory on Svalbard (March 26–July 24, 2019). Measured dry deposition of gaseous oxidized Hg was about half of the modeled RM deposition, demonstrating that particulate-bound Hg was an important component of dry deposition. Using thermal membrane desorption, RM chemistry was found to be dominated by Hg–Cl/Br (51%) and Hg–N (45%) compounds. Back-trajectory analysis indicated that Hg–Br/Cl compounds were predominantly advected from within the marine boundary layer (sea ice exposure), while Hg–N originated from the free troposphere. Weekly average RM compound-specific dry deposition velocities ranged from 0.12 to 0.49 cm s–1, with a net RM dry deposition of 1.9 μg m–2 (1.5–2.5 μg m–2; 95% confidence interval) that exceeds the mean annual Hg wet deposition flux in Svalbard. Overall, we find that springtime atmospheric RM deposition has been underestimated in the Arctic marine environment.
Programme: 1028
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Martin Beal, Maria P. Dias, Richard A. Phillips, Steffen Oppel, Carolina Hazin, Elizabeth J. Pearmain, Josh Adams, David J. Anderson, Michelle Antolos, Javier A. Arata, José Manuel Arcos, John P. Y. Arnould, Jill Awkerman, Elizabeth Bell, Mike Bell, Mark Carey, Ryan Carle, Thomas A. Clay, Jaimie Cleeland, Valentina Colodro, Melinda Conners, Marta Cruz-Flores, Richard Cuthbert, Karine Delord, Lorna Deppe, Ben J. Dilley, Herculano Dinis, Graeme Elliott, Fernanda De Felipe, Jonathan Felis, Manuela G. Forero, Amanda Freeman, Akira Fukuda, Jacob González-Solís, José Pedro Granadeiro, April Hedd, Peter Hodum, José Manuel Igual, Audrey Jaeger, Todd J. Landers, Matthieu Le Corre, Azwianewi Makhado, Benjamin Metzger, Teresa Militão, William A. Montevecchi, Virginia Morera-Pujol, Leia Navarro-Herrero, Deon Nel, David Nicholls, Daniel Oro, Ridha Ouni, Kiyoaki Ozaki, Flavio Quintana, Raül Ramos, Tim Reid, José Manuel Reyes-González, Christopher Robertson, Graham Robertson, Mohamed Salah Romdhane, Peter G. Ryan, Paul Sagar, Fumio Sato, Stefan Schoombie, R. Paul Scofield, Scott A. Shaffer, Nirmal Jivan Shah, Kim L. Stevens, Christopher Surman, Robert M. Suryan, Akinori Takahashi, Vikash Tatayah, Graeme Taylor, David R. Thompson, Leigh Torres, Kath Walker, Ross Wanless, Susan M. Waugh, Henri Weimerskirch, Takashi Yamamoto, Zuzana Zajkova, Laura Zango, Paulo Catry. (2021). Global political responsibility for the conservation of albatrosses and large petrels (Vol. 7).
Abstract: Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm.
Programme: 109
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Zhuang Jiang, Becky Alexander, Joel Savarino, Joseph Erbland, Lei Geng. (2021). Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study (Vol. 15).
Abstract: Abstract. Atmospheric Information Embedded In Ice-core Nitrate Is Disturbed By Post-depositional Processing. Here We Used A Layered Snow Photochemical Column Model To Explicitly Investigate The Effects Of Post-depositional Processing On Snow Nitrate And Its Isotopes (δ15n And Δ17o) At Summit, Greenland, Where Post-depositional Processing Was Thought To Be Minimal Due To The High Snow Accumulation Rate. We Found Significant Redistribution Of Nitrate In The Upper Snowpack Through Photolysis, And Up To 21 % Of Nitrate Was Lost And/or Redistributed After Deposition. The Model Indicates Post-depositional Processing Can Reproduce Much Of The Observed δ15n Seasonality, While Seasonal Variations In δ15n Of Primary Nitrate Are Needed To Reconcile The Timing Of The Lowest Seasonal δ15n. In Contrast, Post-depositional Processing Can Only Induce Less Than 2.1 ‰ Seasonal Δ17o Change, Much Smaller Than The Observation (9 ‰) That Is Ultimately Determined By Seasonal Differences In Nitrate Formation Pathway. Despite Significant Redistribution Of Snow Nitrate In The Photic Zone And The Associated Effects On δ15n Seasonality, The Net Annual Effect Of Post-depositional Processing Is Relatively Small, Suggesting Preservation Of Atmospheric Signals At The Annual Scale Under The Present Summit Conditions. But At Longer Timescales When Large Changes In Snow Accumulation Rate Occur This Post-depositional Processing Could Become A Major Driver Of The δ15n Variability In Ice-core Nitrate.
Programme: 1177
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Paul Tixier, Nicolas Gasco, Jared R. Towers, Christophe Guinet. (2021). Killer whales of the Crozet Archipelago and adjacent waters: photo-identification catalogue, population status and distribution in 2020.
Abstract: Three forms of killer whales (Orcinus orca) occur around the subantarctic islands of the southern Indian Ocean (42-53°S; 34-74°E). The form encountered in both inshore and offshore waters, described as generalist in its feeding preferences (seals, whales, penguins and fish as prey) and known to depredate toothfish from longliners has been opportunistically photo-identified around the Crozet archipelago since the 1960s. Together with photo-identification data collected in the Prince Edward/Marion EEZ, Kerguelen EEZ and international waters, this report provides up to date information on the abundance and distribution of the Crozet killer whales. In total, 124,313 photographs taken during 2,109 encounters since 1964 were analysed, allowing for 299 individuals to be identified. Most encounters with available data were from the Crozet EEZ (1,432 from longliners, 602 from Île de la Possession) and occurred after 2003 when photo-identification was implemented in the fishery observer program. Among the 188 individuals recorded in the Crozet EEZ since 2003, 22 (12%) were also photographed in the Kerguelen EEZ, 13 (7%) in the Prince Edward/Marion EEZ and 13 (7%) in adjacent international waters. The frequently encountered subset of the Crozet killer whale population was composed of 23 social units (maternal groups), 19 of which included individuals alive in 2020. These social units ranged in size from 1 to 11 individuals with a mean (± SD) of 4 ± 3 per unit. As of June 2020 when the latest photographs included in the study were taken, abundance of this subset was 89-94 individuals. However, detailed analysis of data collected between 2005 and 2020 shows that the number of confirmed deaths (n = 51) exceeds the number of recorded births (n = 46), resulting in a 5% decrease of the population size over this period. These deaths were distributed across the population with the majority occurring in the most common sex and age classes – adult females and juveniles. Factors contributing to mortalities are unclear, but may include lethal interactions with illegal fisheries. When paired with the fact that the Crozet killer whales already underwent a severe mortality episode in the 1990s, these findings raise strong concerns about the future of the population and stress the necessity of conservation actions while maintaining an intensive monitoring effort.
Programme: 109
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Lavrillier A. (2021). Le pas léger sur la Terre des peuples des neiges (Vol. Hors-Série).
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Grégoire Mureau. (2021). Étude des impacts des événements extrêmes sur le massif dunaire de la plage de Sanvík (Islande) (Vol. https://www-iuem.univ-brest.fr/pops/attachments/26).
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