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Boulinier, T., Betoulle, S., Caza, F., St Pierre, Y., Tornos, J., Gamble, A. &Amp; Tasiemski, A. (2020). Panorama des recherches et des derniers résultats sur les pathogènes en milieu polaire. Bachelor's thesis, , .
Abstract: Approches complémentaires des interactions hôte-parasite en zones polaire: de la détection de parasites et agents infectieux à l'étude fonctionnelle, écologique et évolutive de leurs interactions avec leurs hôtes.
Programme: 333,1151
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Matthis Auger, Rosemary Morrow, Elodie Kestenare, Jean-Baptiste Sallée, Rebecca Cowley. (2020). Southern Ocean in-situ temperature trends over 25 years emerge from interannual variability (Vol. 12).
Abstract: Despite playing a major role in global ocean heat storage, the Southern Ocean remains the most sparsely measured region of the global ocean. Here, a unique 25-year temperature time-series of the upper 800 m, repeated several times a year across the Southern Ocean, allows us to document the long-term change within water-masses and how it compares to the interannual variability. Three regions stand out as having strong trends that dominate over interannual variability: warming of the subantarctic waters (0.29 ± 0.09 °C per decade); cooling of the near-surface subpolar waters (−0.07 ± 0.04 °C per decade); and warming of the subsurface subpolar deep waters (0.04 ± 0.01 °C per decade). Although this subsurface warming of subpolar deep waters is small, it is the most robust long-term trend of our section, being in a region with weak interannual variability. This robust warming is associated with a large shoaling of the maximum temperature core in the subpolar deep water (39 ± 09 m per decade), which has been significantly underestimated by a factor of 3 to 10 in past studies. We find temperature changes of comparable magnitude to those reported in Amundsen–Bellingshausen Seas, which calls for a reconsideration of current ocean changes with important consequences for our understanding of future Antarctic ice-sheet mass loss.
Programme: 694
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Sonja Siljak-Yakovlev, Françoise Lamy, Najat Takvorian, Nicolas Valentin, Valérie Gouesbet, Françoise Hennion, Thierry Robert. (2020). Genome size and chromosome number of ten plant species from Kerguelen Islands (Vol. 43).
Abstract: Kerguelen Islands harbor a unique, probably very ancient flora with a high rate of endemism. However, the evolutionary history and characteristics of this flora still require investigation. This concerns in particular genome size and ploidy level variation, despite the evolutionary and ecological significance of those traits. Here we report the first assessment of genome size, using flow cytometry, for eight plant species of which two are endemics of Kerguelen Islands and four of the South Indian Ocean Province. The 2C DNA value ranged from 1.08 pg for Pringlea antiscorbutica to 11.88 pg for Ranunculus biternatus. The chromosome numbers of Colobanthus kerguelensis (2n = 80), Lyallia kerguelensis (2n = 96) and Poa kerguelensis (2n = 28) were also reported in this study for the first time. Overall, our data allowed to infer that all Kerguelen studied species are polyploid (from tetra- to octopolyploid). Intra-genus comparisons showed significant differences of 2C DNA values among Poa and among Ranunculus species, despite their identical ploidy level. In addition, our data highlight the existence of an intraspecific variability of genome size for the two octoploid species Colobanthus kerguelensis and Lyallia kerguelensis. Finally, our data also support the hypothesis regarding which polyploidy may have played a major role in the adaptation of flowering plants to high latitudes, as it has been suggested for arctic species.
Programme: 1116
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Thomas Frederikse, Maya K. Buchanan, Erwin Lambert, Robert E. Kopp, Michael Oppenheimer, D. J. Rasmussen, Roderik S. W. van de Wal. (2020). Antarctic Ice Sheet and emission scenario controls on 21st-century extreme sea-level changes (Vol. 11).
Abstract: Uncertainties in Representative Concentration Pathway (RCP) scenarios and Antarctic Ice Sheet (AIS) melt propagate into uncertainties in projected mean sea-level (MSL) changes and extreme sea-level (ESL) events. Here we quantify the impact of RCP scenarios and AIS contributions on 21st-century ESL changes at tide-gauge sites across the globe using extreme-value statistics. We find that even under RCP2.6, almost half of the sites could be exposed annually to a present-day 100-year ESL event by 2050. Most tropical sites face large increases in ESL events earlier and for scenarios with smaller MSL changes than extratropical sites. Strong emission reductions lower the probability of large ESL changes but due to AIS uncertainties, cannot fully eliminate the probability that large increases in frequencies of ESL events will occur. Under RCP8.5 and rapid AIS mass loss, many tropical sites, including low-lying islands face a MSL rise by 2100 that exceeds the present-day 100-year event level.
Programme: 688
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Sarah Safieddine, Marie Bouillon, Ana-Claudia Paracho, Julien Jumelet, Florent Tencé, Andrea Pazmino, Florence Goutail, Catherine Wespes, Slimane Bekki, Anne Boynard, Juliette Hadji‐Lazaro, Pierre-François Coheur, Daniel Hurtmans, Cathy Clerbaux. (2020). Antarctic Ozone Enhancement During the 2019 Sudden Stratospheric Warming Event (Vol. 47).
Abstract: We analyze the 2019 sudden stratospheric warming event that occurred in the Southern Hemisphere through its impact on the Antarctic ozone. Using temperature, ozone, and nitric acid data from the Infrared Atmospheric Sounding Interferometer (IASI), our results show that the average increase in stratospheric temperature reached a maximum of 34.4° on 20 September in the [60–90]°S latitude range when compared to the past 3 years. Dynamical parameters suggest a locally reversed and weakened zonal winds and a shift in the location of the polar jet vortex. This led to air masses mixing, to a reduced polar stratospheric clouds formation detected at a ground station, and as such to lower ozone and nitric acid depletion. 2019 total ozone columns for the months of September, October, and November were on average higher by 29%, 28%, and 26%, respectively, when compared to the 11-year average of the same months.
Programme: 209
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Agnieszka Beszczynska-Möller, Hanne Sagen, Peter Voss, Mikael K. Sejr, Thomas Soltwedel, Truls Johannessen, M.-N. Houssais, Andreas Rogge, Ian Allan, Frank Nilsen, Angelika Renner, L. H. Smedsrud, Nicholas Roden, Jean-Pierre Gattuso, Laurent Chauvaud, Claudie Marec, B. Cheng, Andrew King, Christine Provost, Marcel Babin, Mathilde Sorensen. (2020). Enhancement of ocean and sea ice in situ observations in the Arctic under the Horizon2020 project INTAROS.
Abstract: The H2020 project Integrated Arctic Observation System (INTAROS) aspires to increase the temporal and geographic coverage of in situ observations and add new key geophysical and biogeochemical variables in selected regions of the Arctic. By using a combination of mature and new instruments and sensors in integration with existing observatories, INTAROS aims to fill selected gaps in the present-day system and build additional capacity of the Arctic monitoring networks for ocean and sea ice. Three reference sites have been selected as key locations for monitoring ongoing Arctic changes: Costal Greenland, paramount for freshwater output from the Greenland ice sheet; North of Svalbard (covering the region from shelf to deep basin) – the hot-spot for ocean-air-sea ice interactions, and heat and biological energy input to the European Arctic; and Fram Strait – the critical gateway for exchanges between the Arctic and the World oceans. The existing observatories in the reference sites have been extended with new moorings and novel autonomous instrumentation, in particular for biogeochemical measurements and sea ice observations. Bottom-mounted instruments have been also implemented for seismic observations. A distributed observatory for ocean and sea ice in the Arctic Ocean and sub-Arctic seas includes non-stationary components such as ice-tethered observing platforms, float, gliders, and ships of opportunities, collecting multidisciplinary observations, still missing from the Arctic regions. New sensors, integrated platforms and experimental set-ups are currently under implementation during a two-year long deployment phase (2018-2020) with an aim to evaluate their sustained use in a future iAOS. New observations will be used for integration of new data products, demonstration studies and stakeholder consultations, contributing also to ongoing and future long-term initiatives (e.g. SAON).
Programme: 1141
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Detlev Helmig, Daniel Liptzin, Jacques Hueber, Joel Savarino. (2020). Impact of exhaust emissions on chemical snowpack composition at Concordia Station, Antarctica (Vol. 14). Bachelor's thesis, , .
Abstract: The chemistry of reactive gases inside the snowpack and in the lower atmosphere was investigated at Concordia Station (Dome C), Antarctica, from December 2012 to January 2014. Measured species included ozone, nitrogen oxides, gaseous elemental mercury (GEM), and formaldehyde, for study of photochemical reactions, surface exchange, and the seasonal cycles and atmospheric chemistry of these gases. The experiment was installed ≈1 km from the station main infrastructure inside the station clean air sector and within the station electrical power grid boundary. Ambient air was sampled continuously from inlets mounted above the surface on a 10 m meteorological tower. In addition, snowpack air was collected at 30 cm intervals to 1.2 m depth from two manifolds that had both above- and below-surface sampling inlets. Despite being in the clean air sector, over the course of the 1.2-year study, we observed on the order of 50 occasions when exhaust plumes from the camp, most notably from the power generation system, were transported to the study site. Continuous monitoring of nitrogen oxides (NOx) provided a measurement of a chemical tracer for exhaust plumes. Highly elevated levels of NOx (up to 1000 × background) and lowered ozone (down to ≈50 %), most likely from reaction of ozone with nitric oxide, were measured in air from above and within the snowpack. Within 5–15 min from observing elevated pollutant levels above the snow, rapidly increasing and long-lasting concentration enhancements were measured in snowpack air. While pollution events typically lasted only a few minutes to an hour above the snow surface, elevated NOx levels were observed in the snowpack lasting from a few days to ≈ 1 week. GEM and formaldehyde measurements were less sensitive and covered a shorter measurement period; neither of these species' data showed noticeable concentration changes during these events that were above the normal variability seen in the data. Nonetheless, the clarity of the NOx and ozone observations adds important new insight into the discussion of if and how snow photochemical experiments within reach of the power grid of polar research sites are possibly compromised by the snowpack being chemically influenced (contaminated) by gaseous and particulate emissions from the research camp activities. This question is critical for evaluating if snowpack trace chemical measurements from within the camp boundaries are representative for the vast polar ice sheets.
Programme: 1177
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Mioara Mandea, Aude Chambodut. (2020). Geomagnetic Field Processes and Their Implications for Space Weather (Vol. 41).
Abstract: Understanding the magnetic environment of our planet and the geomagnetic field changes in time and space is a very important issue for assessing the Sun–Earth interactions. All changes in solar activity impact the delicate balance between influences of interplanetary magnetic field and of geomagnetic field. The most dynamic events eventually result in disturbances in the magnitude and direction of the Earth’s magnetic field and therefore impact our planet and its magnetosphere as a whole. The dynamics of the ionosphere and thermosphere during magnetic storms and substorms involves the heating, expansion, and composition changes at high latitudes, but also the surface-level response in terms of geomagnetically induced currents and other geomagnetic and geoelectric disturbances. Here, we provide a short overview of the current knowledge of the Earth’s magnetic field, its present shape and the way it responds to external forces. The main aim of the paper is not to present the complexity of the space weather processes, but rather to bring the attention of the geohazard community to the possible dramatic effects of space weather events. For this, the paper highlights some societal implications of space weather on our increasingly technology-dependent society, including some possible effects of geomagnetically induced currents, the disruption of satellite communications and navigation, and risks of radiation damage both in space and in aviation.
Programme: 139
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Albane Barbero, Camille Blouzon, Joël Savarino, Nicolas Caillon, Aurélien Dommergue, Roberto Grilli. (2020). A compact incoherent broadband cavity-enhanced absorption spectrometer for trace detection of nitrogen oxides, iodine oxide and glyoxal at levels below parts per billion for field applications (Vol. 13). Bachelor's thesis, , .
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Rémi Bigonneau, Romain Bazire, Cédric Marteau, Christophe Barbraud, Joan Ferrer-Obiol, Karine Delord. (2020). First record of Black-winged Pratincole Glareola nordmanni for Amsterdam Island, Indian Ocean (Vol. 27). Bachelor's thesis, , .
Abstract: Première mention de la Glaréole à ailes noires Glareola nordmanni pour l’Île Amsterdam, Océan Indien. Une Glaréole à ailes noires Glareola nordmanni de premier hiver à été observée sur l’Île Amsterdam, dans le sud de l’Océan indien, les 12–16 novembre 2013. Il s’agît de la première donnée de cette espèce paléarctique pour l’île. Les mentions antérieures les plus proches proviennent de l’île d’Alphonse, aux Seychelles, à environ 4.200 km de l’Île Amsterdam.
Programme: 109
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