Abstract: The selection of an otolith optimal zone where to obtain interpretable chronological data (e.g. chemicaltransect, increment width) and valid age estimation is fundamental if otoliths are to be used as an effectivetool for investigating life history traits or environments experienced by fish. In the remote sub-AntarcticKerguelen Islands (49◦S, 70◦E), introduced brown trout populations are invading the archipelago sincethe 50’s and life histories information is of great interest to understand the invasion dynamics. Unfortu-nately, few studies have used otolith as a tool to estimate brown trout age at these extreme latitudes andlittle is known about otolith growth and annulus formation in these sub-polar conditions. Furthermore,no formal procedure exists at the population level to select an otolith optimal zone where to concomi-tantly extract chronological data aiming at investigating life history traits and growth chronologies. Inthis context, the aims of this study were (1) to validate the otolith age estimation method by the deter-mination of the position of the first annulus and the annual formation of subsequent annuli; (2) to definean optimal zone where chronological data could be coupled to age estimates. A brown trout populationlocated near the Port-au-Franc¸ ais station was studied and sampled repeatedly using mark-recapturemethod and Alizarin Red S marking. After to 2 years of recaptures 53 sagittae were analysed. A compositeindex was created to select an optimal zone where chronological data transects have the maximum prob-abilities to cross readable annuli. Results showed that brown trout forms annuli at the end of September,starting with the first winter after the December hatching. Annulus formation up to 2 years after mark-ing was validated. The area between 80◦and 120◦perpendicular to the rostrum/core axis was optimalfor the positioning of data transect. The proposed formal approach allows distinguishing the zone thatidentifies the best compromise between spatial resolution and precise annulus positioning along otolithchronological series.AcknowledgementsWe thank the French Polar Institute (IPEV, Institut PolairePaul-Emile Victor) for the financial support of the Program 1041SALMEVOL; we thank Jacques Labonne for his management of theprogram from 2008 to 2013.We thank Margaret Lang for providingwriting assistance that lead to the clarity of the English language.We thank Jacques Rives and Franc¸ ois Guéraud for otolith and scaleanalysis. We thank two anonymous reviewers for comments thatlead to substantial improvements in the manuscript. We gratefullyacknowledge the logistical support provided by the TAAF adminis-tration and the Southern French Natural Reserve at Kerguelen. Thefieldwork would not have been possible without the help and sup-port of the IPEV logistics team (Romuald Bellec, Yann Lemeur, NinaMarchand) and all the people involved in the SALMEVOL summercampaign (Stephane Betoulle, Eduardo Vicente Dopico-Rodriguez,Emily Farcy, Franc¸ ois Guéraud, José-Luis Horreo-Escandon, RenaudKaeuffer, Jacques Rives, Thibault Thellier, Julien Tremblay).

Abstract: By accompanying human travels since prehistorical times, the house mouse dispersed widely throughout the world, and colonized many islands. The origin of the travellers determined the phylogenetic source of the insular mice, which encountered diverse ecological and environmental conditions on the various islands. Insular mice are thus an exceptional model to disentangle the relative role of phylogeny, ecology and climate in evolution. Molar shape is known to vary according to phylogeny and to respond to adaptation. Using for the first time a three-dimensional geometric morphometric approach, compared with a classical two-dimensional quantification, the relative effects of size variation, phylogeny, climate and ecology were investigated on molar shape diversity across a variety of islands. Phylogeny emerged as the factor of prime importance in shaping the molar. Changes in competition level, mostly driven by the presence or absence of the wood mouse on the different islands, appeared as the second most important effect. Climate and size differences accounted for slight shape variation. This evidences a balanced role of random differentiation related to history of colonization, and of adaptation possibly related to resource exploitation.

Abstract: Multiple year-round records of bulk and size-segregated compositions of aerosol were obtained at the coastal Dumont d'Urville (DDU) and inland Concordia sites located in East Antarctica. They document the sea-salt aerosol load and composition including, for the first time in Antarctica, the bromide depletion of sea-salt aerosol relative to sodium with respect to seawater. In parallel, measurements of bromide trapped in mist chambers and denuder tubes were done to investigate the concentrations of gaseous inorganic bromine species. These data are compared to simulations done with an off-line chemistry transport model, coupled with a full tropospheric bromine chemistry scheme and a process-based sea-salt production module that includes both sea-ice-sourced and open-ocean-sourced aerosol emissions. Observed and simulated sea-salt concentrations sometime differ by up to a factor of 2 to 3, particularly at DDU possibly due to local wind pattern. In spite of these discrepancies, both at coastal and inland Antarctica, the dominance of sea-ice-related processes with respect to open ocean emissions for the sea-salt aerosol load in winter is confirmed. For summer, observations and simulations point out sea salt as the main source of gaseous inorganic bromine species. Investigations of bromide in snow pit samples do not support the importance of snowpack bromine emissions over the Antarctic Plateau. To evaluate the overall importance of the bromine chemistry over East Antarctica, BrO simulations were also discussed with respect data derived from GOME-2 satellite observations over Antarctica.

Abstract: Abstract. Orbital tuning is central for ice core chronologies beyond annual layer counting, available back to 60 ka (i.e. thousands of years before 1950) for Greenland ice cores. While several complementary orbital tuning tools have recently been developed using δ18Oatm, δO2⁄N2 and air content with different orbital targets, quantifying their uncertainties remains a challenge. Indeed, the exact processes linking variations of these parameters, measured in the air trapped in ice, to their orbital targets are not yet fully understood. Here, we provide new series of δO2∕N2 and δ18Oatm data encompassing Marine Isotopic Stage (MIS) 5 (between 100 and 160 ka) and the oldest part (340–800 ka) of the East Antarctic EPICA Dome C (EDC) ice core. For the first time, the measurements over MIS 5 allow an inter-comparison of δO2∕N2 and δ18Oatm records from three East Antarctic ice core sites (EDC, Vostok and Dome F). This comparison highlights some site-specific δO2∕N2 variations. Such an observation, the evidence of a 100 ka periodicity in the δO2∕N2 signal and the difficulty to identify extrema and mid-slopes in δO2∕N2 increase the uncertainty associated with the use of δO2∕N2 as an orbital tuning tool, now calculated to be 3–4 ka. When combining records of δ18Oatm and δO2∕N2 from Vostok and EDC, we find a loss of orbital signature for these two parameters during periods of minimum eccentricity (∼ 400 ka, ∼ 720–800 ka). Our data set reveals a time-varying offset between δO2∕N2 and δ18Oatm records over the last 800 ka that we interpret as variations in the lagged response of δ18Oatm to precession. The largest offsets are identified during Terminations II, MIS 8 and MIS 16, corresponding to periods of destabilization of the Northern polar ice sheets. We therefore suggest that the occurrence of Heinrich–like events influences the response of δ18Oatm to precession.

Abstract: in Chemical Signals in Vertebrates 13. Recent research on avian chemical signalling has highlighted the need for new appropriate protocols especially for sampling, and analyzing, compounds borne by individuals Although many studies have already examined the chemical substances secreted by birds, only few works have done so from the perspective of chemical communication and none have focused on the actual airborne compounds which make up the final odor. As well as the relative infancy of the field, this gap originates from the absence of an appropriate methodological framework. In this study, we provide a methodological guideline of various combinations of sampling and extraction techniques that have been developed and tested in our research. These include: analysis of (i) uropygial secretion samples by solvent extraction, (ii) feather lipids by solvent extraction, (iii) feather lipids by direct solid-phase thermal desorption, (iv) cotton swab (rubbed on bird) by solid phase microextraction, (v) cotton swab by direct solid-phase thermal desorption and (vi) airborne volatiles by thermal desorption. To achieve this, we used the particular case study of blue petrels (Halobaena caerulea), a Sub-antarctic procellariiform seabird, living on remote islands and known for its good olfactory capabilities. Outcomes from the different methods are presented in terms of chromatographic quality, the number and properties of the analytes resolved and their suitability for the work in isolated locations. Advantages and limitations of each method are discussed together with challenges that remain to make the new protocols presented more robust for field chemo-ecologists.