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Crouzet N., Guillot T., Abe L., Mékarnia D., Agabi K., Bresson Y., Bailet C., Mauclert N., Heras A., Ferruit P., Triaud A., Lagrange A., Schmider ., Giardino G., Isaak K., Kohley R., Michalik D., Foing B., Pilbratt G., Stankov A., Gondoin P., Birkmann S., O'Rourke L. (2020). Two-colour photometry to search for transiting exoplanets with ASTEP at Dome C, Antarctica.
Abstract: Dome C in Antarctica provides exceptional conditions for photometry thanks to the continuous night during the Antarctic winter, a high clear sky fraction, low wind speeds, and a cold and dry atmosphere. The ASTEP project (Antarctic Search for Transiting ExoPlanets) aims at detecting and characterising transiting exoplanets and qualifying this site for photometry in the visible. The main instrument, a 40 cm telescope, has been designed to perform high precision photometry under the extreme conditions of the Antarctic winter and has operated at the Concordia station since 2010. It will be upgraded with two new cameras and a new camera box in order to provide simultaneous two-colour photometry and substantially increase its throughput. The new setup will be operational for the winter campaign 2021 and will allow us to discover transiting exoplanets orbiting bright stars in particular low mass exoplanets, temperate exoplanets, exoplanets around young stars, and to refine the ephemerides of exoplanets discovered by the TESS mission. These observations will provide targets for first characterisation with the CHEOPS mission and atmospheric studies with the JWST and ARIEL missions. In this talk, I will describe the science goals and the upgrade of the ASTEP telescope.
Programme: 1066
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Crouzet N., Mékarnia D., Agabi K., Guillot T., Abe L., Bayliss D., Deeg H., Murgas F., Palle E., Schmider F. (2020). Searching for long period transiting exoplanets with ASTEP South at Dome C, Antarctica. Bachelor's thesis, , .
Abstract: Much of our understanding of gas giant exoplanets come from those transiting in front of bright stars at short orbital separations (P ~ 3 days, a ~ 0.05 au). However, these
Programme: 1066
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Crouzet, N., Guillot T., Abe L., Mékarnia D., Agabi A., Schmider F.-X., Vauglin I. (2020). Astronomie à Concordia : projets et besoins. Bachelor's thesis, , .
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D. B. Green, S. Bestley, R. Trebilco, S. P. Corney, P. Lehodey, C. R. McMahon, C. Guinet, Mark A. Hindell. (2020). Modelled mid-trophic pelagic prey fields improve understanding of marine predator foraging behaviour (Vol. 43). Bachelor's thesis, , .
Abstract: Biophysical interactions are influential in determining the scale of key ecological processes within marine ecosystems. For oceanic predators, this means foraging behaviour is influenced by processes shaping the distribution of prey. However, oceanic prey is difficult to observe and its abundance and distribution is regionally generalised. We use a spatiotemporally resolved simulation model to describe mid-trophic prey distribution within the Southern Ocean and demonstrate insights that this modelled prey field provides into the foraging behaviour of a widely distributed marine predator, the southern elephant seal. From a five-year simulation of prey biomass, we computed climatologies of mean prey biomass (average prey conditions) and prey biomass variability (meso-scale variability). We also compiled spatially gridded metrics of seal density and diving behaviour from 13 yr of tracking data. We statistically modelled these metrics as non-linear functions of prey biomass (both mean and variability) and used these to predict seal distribution and behaviour. Our predictions were consistent with observations (R2adj = 0.23), indicating that seals aggregate in regions of high mesoscale activity where eddies concentrate prey. Here, seals dived deeper (R2marg = 0.12, R2cond = 0.51) and spent less time hunting (R2marg = 0.05, R2cond = 0.56), likely targeting deep but profitable prey patches. Seals generally avoided areas of low eddy activity where prey was likely dispersed. Most seals foraged south of the Subantarctic Front, despite north of the front exhibiting consistently high simulated prey biomasses. This likely reflects seal prey or habitat preferences, but also emphasises the importance of mesoscale prey biomass variability relative to regionally high mean biomass. This work demonstrates the value of coupling mechanistic representations of prey biomass with predator observations to provide insight into how biophysical processes combine to shape species distributions. This will be increasingly important for the robust prediction of species’ responses to rapid system change.
Keywords: ecosystem modelling kerguelen plateau micronekton predators prey interaction southern elephant seal Southern Indian Ocean
Programme: 109,1201
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David Boertmann, Flemming Merkel, Olivier Gilg. (2020). Seabird Breeding Colonies in East and North Greenland: A Baseline (Vol. 73).
Abstract: This paper presents the results of a number of aircraft- and boat-based surveys for seabird breeding colonies in East and North Greenland carried out in the period 2003 to 2018 and gives the first comprehensive overview of the distribution and size of the seabird breeding colonies in this remote and mainly uninhabited region. Seventeen seabird species breed in approximately 800 sites distributed very unevenly along the coasts, with high concentrations at the polynyas and long stretches with very few breeding seabirds. Climate changes are in full progress in East and North Greenland, especially affecting the sea ice regime, and seabirds are expected to respond to these changes in different ways. For example, since the 1980s, Common Eiders (Somateria mollissima) have extended their breeding range more than two latitudinal degrees towards the north, now reaching the northernmost land on Earth. Lesser Black-backed Gulls (Larus fuscus) and Great Cormorants (Phalacrocorax carbo) have immigrated, and Sabine’s Gulls (Xema sabini) have increased and extended their range. Besides presenting survey results, this report may also serve as a baseline for future studies of the abundance of breeding seabirds in East and North Greenland.
Keywords: climate change colonial seabirds distribution Greenland
Programme: 1036
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David H. Bromwich, Kirstin Werner, Barbara Casati, Jordan G. Powers, Irina V. Gorodetskaya, François Massonnet, Vito Vitale, Victoria J. Heinrich, Daniela Liggett, Stefanie Arndt, Boris Barja, Eric Bazile, Scott Carpentier, Jorge F. Carrasco, Taejin Choi, Yonghan Choi, Steven R. Colwell, Raul R. Cordero, Massimo Gervasi, Thomas Haiden, Naohiko Hirasawa, Jun Inoue, Thomas Jung, Heike Kalesse, Seong-Joong Kim, Matthew A. Lazzara, Kevin W. Manning, Kimberley Norris, Sang-Jong Park, Phillip Reid, Ignatius Rigor, Penny M. Rowe, Holger Schmithüsen, Patric Seifert, Qizhen Sun, Taneil Uttal, Mario Zannoni, Xun Zou. (2020). The Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) (Vol. 101).
Abstract: Abstract The Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) had a special observing period (SOP) that ran from 16 November 2018 to 15 February 2019, a period chosen to span the austral warm season months of greatest operational activity in the Antarctic. Some 2,200 additional radiosondes were launched during the 3-month SOP, roughly doubling the routine program, and the network of drifting buoys in the Southern Ocean was enhanced. An evaluation of global model forecasts during the SOP and using its data has confirmed that extratropical Southern Hemisphere forecast skill lags behind that in the Northern Hemisphere with the contrast being greatest between the southern and northern polar regions. Reflecting the application of the SOP data, early results from observing system experiments show that the additional radiosondes yield the greatest forecast improvement for deep cyclones near the Antarctic coast. The SOP data have been applied to provide insights on an atmospheric river event during the YOPP-SH SOP that presented a challenging forecast and that impacted southern South America and the Antarctic Peninsula. YOPP-SH data have also been applied in determinations that seasonal predictions by coupled atmosphere–ocean–sea ice models struggle to capture the spatial and temporal characteristics of the Antarctic sea ice minimum. Education, outreach, and communication activities have supported the YOPP-SH SOP efforts. Based on the success of this Antarctic summer YOPP-SH SOP, a winter YOPP-SH SOP is being organized to support explorations of Antarctic atmospheric predictability in the austral cold season when the southern sea ice cover is rapidly expanding.
Programme: 1013
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David Renault. (2020). A Review of the Phenotypic Traits Associated with Insect Dispersal Polymorphism, and Experimental Designs for Sorting out Resident and Disperser Phenotypes (Vol. 11). Bachelor's thesis, , .
Abstract: Dispersal represents a key life-history trait with several implications for the fitness of organisms, population dynamics and resilience, local adaptation, meta-population dynamics, range shifting, and biological invasions. Plastic and evolutionary changes of dispersal traits have been intensively studied over the past decades in entomology, in particular in wing-dimorphic insects for which literature reviews are available. Importantly, dispersal polymorphism also exists in wing-monomorphic and wingless insects, and except for butterflies, fewer syntheses are available. In this perspective, by integrating the very latest research in the fast moving field of insect dispersal ecology, this review article provides an overview of our current knowledge of dispersal polymorphism in insects. In a first part, some of the most often used experimental methodologies for the separation of dispersers and residents in wing-monomorphic and wingless insects are presented. Then, the existing knowledge on the morphological and life-history trait differences between resident and disperser phenotypes is synthetized. In a last part, the effects of range expansion on dispersal traits and performance is examined, in particular for insects from range edges and invasion fronts. Finally, some research perspectives are proposed in the last part of the review.
Keywords: fecundity hostile matrix life-history mating morphology movement range expansion reproduction wing-dimorphic wing-monomorphic
Programme: 136
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David T. Iles, Heather Lynch, Rubao Ji, Christophe Barbraud, Karine Delord, Stephanie Jenouvrier. (2020). Sea ice predicts long-term trends in Adélie penguin population growth, but not annual fluctuations: Results from a range-wide multiscale analysis (Vol. 26).
Abstract: Understanding the scales at which environmental variability affects populations is critical for projecting population dynamics and species distributions in rapidly changing environments. Here we used a multilevel Bayesian analysis of range-wide survey data for Adélie penguins to characterize multidecadal and annual effects of sea ice on population growth. We found that mean sea ice concentration at breeding colonies (i.e., “prevailing” environmental conditions) had robust nonlinear effects on multidecadal population trends and explained over 85% of the variance in mean population growth rates among sites. In contrast, despite considerable year-to-year fluctuations in abundance at most breeding colonies, annual sea ice fluctuations often explained less than 10% of the temporal variance in population growth rates. Our study provides an understanding of the spatially and temporally dynamic environmental factors that define the range limits of Adélie penguins, further establishing this iconic marine predator as a true sea ice obligate and providing a firm basis for projection under scenarios of future climate change. Yet, given the weak effects of annual sea ice relative to the large unexplained variance in year-to-year growth rates, the ability to generate useful short-term forecasts of Adélie penguin breeding abundance will be extremely limited. Our approach provides a powerful framework for linking short- and longer term population processes to environmental conditions that can be applied to any species, facilitating a richer understanding of ecological predictability and sensitivity to global change.
Keywords: Antarctica environmental variation habitat suitability niche predictability state-space stochastic uncertainty
Programme: 109
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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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Do Rosario Valentin. (2020). Ecological, biological and physiological effects of climate change on insect species. Master 1 EFCE, Université de Rennes 1 (Encadrement : D. Renault).
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