Abstract: Climate change has been projected to affect species distribution1 and future trends of local populations2, 3, but projections of global population trends are rare. We analyse global population trends of the emperor penguin (Aptenodytes forsteri), an iconic Antarctic top predator, under the influence of sea ice conditions projected by coupled climate models assessed in the Intergovernmental Panel on Climate Change (IPCC) effort4. We project the dynamics of all 45 known emperor penguin colonies5 by forcing a sea-ice-dependent demographic model6, 7 with local, colony-specific, sea ice conditions projected through to the end of the twenty-first century. Dynamics differ among colonies, but by 2100 all populations are projected to be declining. At least two-thirds are projected to have declined by >50% from their current size. The global population is projected to have declined by at least 19%. Because criteria to classify species by their extinction risk are based on the global population dynamics8, global analyses are critical for conservation9. We discuss uncertainties arising in such global projections and the problems of defining conservation criteria for species endangered by future climate change.

Abstract: La côte de la Terre Adélie (Est Antarctique) met à l’affleurement des fragments crustaux d’âge néoarchéen (2.5 Ga) et paléoprotérozoïque (1.7 Ga) qui constituent un ensemble unique au sein du continent Est-Antarctique. Le Craton de Terre Adélie (TAC) se distingue ainsi par l’importance de l’événement paléoprotérozoïque (1.7 Ga) et l’absence de réactivation grenvillienne (1 Ga) et panafricaine (Ross, 0.5 Ga), Ménot et al. 2007.
Les différents blocs du TAC sont marqués par une tectonique en transpression qui se matérialise par des zones à structures horizontales (structures en dômes) au contact de larges couloirs de cisaillement verticaux. Certaines de ces structures sont d’échelle plurikilométrique et trouvent leur continuité au niveau du craton du Gawler au sud de l’Australie. Les structures et la déformation de la Terre Adélie sont étudiées depuis 2009 dans le cadre du programme ArLiTA (Architecture de la Lithosphère de Terre Adélie). La démarche adoptée est pluridisciplinaire et combine différentes méthodes d’analyse et d’interprétation, connectant les observations de terrain aux modèles géodynamiques. La caractérisation des structures est également multi-échelles depuis l’étude des structures cristallines observées au microscope électronique à l’imagerie des structures lithosphériques à partir d’enregistrements sismologiques. Les travaux menés dans le cadre de ce programme permettent ainsi de définir une première image 3D des grandes structures du TAC et de préciser les modalités de la déformation de la croûte continentale à la transition Archéen – Paléoprotérozoïque, période charnière de l’histoire de la Terre.

Abstract: The Mertz shear zone (MSZ) located in George Vth Land (67S, 145E) is a key area to understand tectonic relationships between the Neoarchean-Paleoproterozoic Terre Adélie Craton (TAC) and the Early Paleozoic units of Cape Webb and Penguin Point. The MSZ is therefore a major structure that represents the eastern boundary of the East Antartica Shield. In addition, the MSZ that recorded dextral strike-slip movement estimated at 1.7Ga could be correlated to the Kalinjila shear zone a large scale mylonitic structure outcropping at the east of the Gawler Craton (South Australia). In order to better understand the MSZ dynamics, we developed a
multi-disciplinary approach with the French polar institute (IPEV) through the Arlita program (Architecture de la Lithosphere de Terre Adélie). Four temporary seismic stations were deployed on both sides and above the MSZ from October 2009 to October 2011 to map the deep tectonic structures. We analysed receiver functions to evaluate Moho depth and seismic anisotropy through the splitting of SKS waves to analyze the prolongation of the MSZ structures into the mantle.
Results from receiver functions reveal Moho depths of 40-44km for the TAC, about 36 km under the MSZ and 28km for the Paleozoic domain. These results show that the MSZ delimit two crustal blocks with different thicknesses. Our study is consistent with crustal thicknesses estimated by Fontaine et al. (2012) in South Australia in the Gawler craton (>40km) and in the Delamerian orogen terrains (31km). However, the transition between the thick craton and the Paleozoic crust is sharper at the MSZ than in south Australia. Seismic anisotropy in the MSZ area was studied from events of magnitudes ranging from 5.9 to 7.0. In addition, petrological and crystallographic fabrics of the crust were carry out in order to better constrain the observed SKS delay times. The measurements of the splitting parameters show a fast polarisation direction () parallel to the E-W coast and delay times (dt) ranging 0.5 to 1s at most stations. These results are similar to splitting parameters observed at the permanent Geoscope Dumont D’Urville station (DRV:  = 80N, dt = 1s) located in the Paleoproterozoic (1.7Ga) domain of TAC.
Although we observe an important offset in the Moho depth across the MSZ, no evidence of distinct seismic anisotropy is found. Questions thus remain concerning the prolongation into the mantle of this large strike-slip shear zone.

Abstract: Wandering albatrosses are large long-lived seabirds that inhabit the Southern Ocean. This species uses wind to move at low energetic costs and probably represents one of the best studied life-history models in animals. Here, using both tracking and isotopic data, we report on the lifetime distribution of wandering albatrosses at sea, constructing a synthesis about how their distribution, foraging movements and feeding ecology change throughout all life-history stages (i.e. juvenile, immature, pre breeding adults, breeding adults, sabbatical adults and senescent birds). Males and females exhibit different foraging strategies that change throughout their life. For instance, as males mature from young to old stages, they progressively move from subtropical waters to Antarctic waters. In comparison, females remain in subtropical waters throughout their lives, but increase their speed of travel with age. For both sexes, the first year at sea is a critical period, when the highest mortality occurs. At this stage, juveniles have already fledged and are able to use the wind optimally to maximise movement, but require several months to reach the travelling speed of adults. Immature albatrosses remain in warm subtropical waters, before returning to their birth place and future breeding grounds from where they move as central place foragers. When recruited into the breeding population, they breed every other year. In one year they invest in one long breeding season when males and females use separate foraging zones in the subtropics and sub-Antarctic, respectively. In the subsequent year (termed “sabbatical” year), both sexes disperse across the Southern Ocean, with reduced segregation between sexes. In total, throughout the approximate 50 year lifetime of a wandering albatross, an individual is estimated to travel a mere 8.5 million km. We show that the changes in habitats and foraging strategies observed though the life time of wandering albatrosses are the results of behavioural adjustment to the successive constraints encountered, such as learning processes, breeding or ageing, and have profound consequences on survival and nesting success.