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. (2021). Surface ocean microbiota determine cloud precursors (Vol. 11).
Abstract: One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions. This sensitivity of CCN number fluxes to ocean biology is currently unaccounted for in climate models yet our measurements indicate that it influences fluxes by more than one order of magnitude over the range of phytoplankton investigated.
Keywords: Atmospheric science Marine biology
Programme: 1187
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. (2021). Fine-scale spatial segregation in a pelagic seabird driven by differential use of tidewater glacier fronts (Vol. 11).
Abstract: In colonially breeding marine predators, individual movements and colonial segregation are influenced by seascape characteristics. Tidewater glacier fronts are important features of the Arctic seascape and are often described as foraging hotspots. Albeit their documented importance for wildlife, little is known about their structuring effect on Arctic predator movements and space use. In this study, we tested the hypothesis that tidewater glacier fronts can influence marine bird foraging patterns and drive spatial segregation among adjacent colonies. We analysed movements of black-legged kittiwakes (Rissa tridactyla) in a glacial fjord by tracking breeding individuals from five colonies. Although breeding kittiwakes were observed to travel up to ca. 280 km from the colony, individuals were more likely to use glacier fronts located closer to their colony and rarely used glacier fronts located farther away than 18 km. Such variation in the use of glacier fronts created fine-scale spatial segregation among the four closest (ca. 7 km distance on average) kittiwake colonies. Overall, our results support the hypothesis that spatially predictable foraging patches like glacier fronts can have strong structuring effects on predator movements and can modulate the magnitude of intercolonial spatial segregation in central-place foragers.
Keywords: Behavioural ecology Biogeography
Programme: 330
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. (2021). Fine-scale structures as spots of increased fish concentration in the open ocean (Vol. 11).
Abstract: Oceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesopelagic fish concentrations to satellite-derived fine-scale Lagrangian Coherent Structures in the Indian sector of the Southern Ocean. First, we demonstrate that higher fish concentrations occur more frequently in correspondence with strong Lagrangian Coherent Structures. Secondly, we illustrate that, while increased fish densities are more likely to be observed over these structures, the presence of a fine-scale feature does not imply a concomitant fish accumulation, as other factors affect fish distribution. Thirdly, we show that, when only chlorophyll-rich waters are considered, front intensity modulates significantly more the local fish concentration. Finally, we discuss a model representing fish movement along Lagrangian features, specifically built for mid-trophic levels. Its results, obtained with realistic parameters, are qualitatively consistent with the observations and the spatio-temporal scales analysed. Overall, these findings may help to integrate intermediate trophic levels in trophic models, which can ultimately support management and conservation policies.
Keywords: Fisheries Marine biology Physical oceanography
Programme: 109
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Robert E. Anthony, Adam T. Ringler, Michael DuVernois, Kent R. Anderson, David C. Wilson. (2021). Six Decades of Seismology at South Pole, Antarctica: Current Limitations and Future Opportunities to Facilitate New Geophysical Observations (Vol. 92).
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. (2021). Preface to the Focus Section on European Seismic Networks and Associated Services and Products (Vol. 92).
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Garcin N, Viblanc VA, Schull Q, Michaux D, Reichert S, Robin JP, Bize P, Stier A. (2021). Naturally equipped to resist stress.
Abstract: Stress exposure and stress response are likely to vary according to life history strategies and environmental contexts. Although the acute release of glucocorticoids in response to unpredictable environmental conditions may lead to adaptative behavioral and physiological responses, exposure to high glucocorticoid levels on the long-term usually leads to deleterious cascading effects on animal’s physiology, behavior and fitness. Yet, some species may be more adapted to cope with challenging events than others and might naturally possess protective mechanisms limiting the adverse consequences of prolonged exposure to high glucocorticoid levels. King penguin chicks being naturally exposed to harsh weather, prolonged fasting and constant predation pressure, we investigated the life-history, behavioral and physiological consequences of an experimental increase in corticosterone levels on the medium and long-term (after removing implants), predicting to find relatively few costs associated with such treatment. Although non-significant, CORT-treated chicks were slightly larger, fledged slightly earlier and had slightly higher survival chances than placebo chicks. CORT-treated chicks were significantly more aggressive and displayed lower corticosterone response to acute stress on the medium term, while their physical activity and whole-body energetics were not significantly affected. While mitochondrial density was not significantly affected by the CORT treatment, CORT-treated chicks had lower oxidative stress levels on the long-term than placebo ones, and no significant impact was observed on telomere shortening. Finally, the expression of several genes (i.e. CORT receptor, HSP90, mTOR, NRF2 and TERF2) was up regulated in treated chicks, which could potentially mediate the apparent ‘stress’ resistance we observed at the phenotypic level.
Programme: 119
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G. Hubert, S. Aubry. (2021). Study of the Impact of Past Extreme Solar Events on the Modern Air Traffic (Vol. 19).
Abstract: The ancient solar energetic particle (SEP) events of 774/775 CE and 993/994 CE were characterized thanks to radionuclide productions stored in environmental archives as ice cores or tree rings. Primary cosmic ray spectra deduced from these cosmogenic isotope data indicate that the impact of these extreme SEP events would have been much more significant than any of the ones observed during the modern era. However, the impact of these should be studied more accurately in the framework of the ambient dose equivalent impacting aircrew and passengers in the air traffic context by considering physical parameters such as time profile or anisotropy properties. In this study, the impact that 774/775 CE and 993/994 CE past extreme SEP events could have had on modern air traffic is discussed. Possible event spectra for these ancient events are derived from the spectra ground-level enhancement (GLE) 5 and GLE 69, which have been observed during the modern era and have been widely studied/characterized using measurements. The investigations include the impact of the SEP activity on ambient dose equivalent, including detailed analyses considering route, airplane characteristics (departure, arrival, continent, airplane type), and the time occurrence of the SEP event. Statistical analyses show that additional dose levels can reach values on the order of 70 mSv, which is absolutely significant considering the current air traffic recommendations. The orders of magnitude of the ambient dose equivalent induced during past extreme SEP events raises a number of issues, both for aircrews and for avionics hardware. This study demonstrates that simulations can be useful for the evaluation of risks in case of extreme SEP events.
Programme: 1112
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Armelle Decaulne, Najat Bhiry, Fabienne Joliet, Laine Chanteloup, Thora Martina Herrmann, Bruno Persat, Daniel Germain, Orsane Rousset. (2021). TAKUJUQ: Where Art and Science meet in Nunavik.
Abstract: The TUKISIK (Tukisigasuaqatigit: Understanding together) is a scientific program, ongoing since 2014, concerning human-environment interactions, reinforcing links between scientists and several communities.
Programme: 1148
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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.
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. (2021). Precise Transit and Radial-velocity Characterization of a Resonant Pair: The Warm Jupiter TOI-216c and Eccentric Warm Neptune TOI-216b (Vol. 161).
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