Abstract: Significant environmental changes have already been documented in the Southern Ocean (e.g. sea water temperature increase and salinity drop) but its marine life is still incompletely known given the heterogeneous nature of biogeographic data. However, to establish sustainable conservation areas, understanding species and communities distribution patterns is critical. For this purpose, the ecoregionalization approach can prove useful by identifying spatially explicit and well-delimited regions of common species composition and environmental settings. Such regions are expected to have similar biotic responses to environmental changes and can be used to define priorities for the designation of Marine Protected Areas. In the present work, a benthic ecoregionalization of the Southern Ocean is proposed based on echinoids distribution data and abiotic environmental parameters. Echinoids are widely distributed in the Southern Ocean, they are taxonomically and ecologically well diversified and documented. Given the heterogeneity of the sampling effort, predictive spatial models were produced to fill the gaps in between species distribution data. A first procedure was developed using Gaussian Mixture Models (GMM) to combine individual species models into ecoregions. A second, integrative procedure was implemented using the Generalized Dissimilarity Models (GDM) to model and assemble species distributions. Both procedures were compared to propose benthic ecoregions at the scale of the entire Southern Ocean.

Abstract: High juvenile mortality rates are typical of many long-lived marine vertebrate predators. Insufficient development in dive and forage ability is considered a key driver of this. However, direct links to survival outcome are sparse, particularly in free-ranging marine animals that may not return to land. In this study, we conduct exploratory investigations toward early mortality in juvenile southern elephant seals Mirounga leonina. Twenty postweaning pups were equipped with (a) a new-generation satellite relay data tag, capable of remotely transmitting fine-scale behavioral movements from accelerometers, and (b) a location transmitting only tag (so that mortality events could be distinguished from device failures). Individuals were followed during their first trip at sea (until mortality or return to land). Two analyses were conducted. First, the behavioral movements and encountered environmental conditions of nonsurviving pups were individually compared to temporally concurrent observations from grouped survivors. Second, common causes of mortality were investigated using Cox's proportional hazard regression and penalized shrinkage techniques. Nine individuals died (two females and seven males) and 11 survived (eight females and three males). All but one individual died before the return phase of their first trip at sea, and all but one were negatively buoyant. Causes of death were variable, although common factors included increased horizontal travel speeds and distances, decreased development in dive and forage ability, and habitat type visited (lower sea surface temperatures and decreased total [eddy] kinetic energy). For long-lived marine vertebrate predators, such as the southern elephant seal, the first few months of life following independence represent a critical period, when small deviations in behavior from the norm appear sufficient to increase mortality risk. Survival rates may subsequently be particularly vulnerable to changes in climate and environment, which will have concomitant consequences on the demography and dynamics of populations.

Abstract: Topographic, granulometric, morphometric, petrographic and vegetation surveys were conducted on the slopes of Tasiapik Valley, near Umiujaq (Nunavik), to document mass wasting processes and their geomorphological impact. Talus slopes, widespread at the foot of the steep rockwalls of Tasiapik Valley, are an important landscape feature in the area. The lithology of the slope deposits attest their local origin, namely the result of rockfalls coming from the adjacent wall. Locally, poor vegetation covering the clasts exhibits recently fallen debris; elsewhere, dense shrub cover has colonized the slopes demonstrating the low activity nowadays. On-going periglacial processes have led to extensive dismantling of the rockface, enabling for debris supply. Following the last deglaciation, paraglacial processes have potentially favoured slope instabilities. The use of automatic cameras during the winter 2017–2018 resulted in the observation of many snow-avalanche events; however few rockfall events have been observed. Spring snow avalanches have carried rock debris to the talus at the foot of the slope; snow also enabled debris redistribution on the slopes.