• Acronyme :
    ASSET
  • Référence :
    1182
  • Domaine de recherche :
    Vie
  • Région :
    Antarctique, Dumont D'Urville
  • Site :
    Museum national d'histoire naturelle :
  • Responsable du projet :
    Charrassin Jean-benoit

Antarctic Seals and the Sea-ice EnvironmenT (ASSET)

Given the sensitivity of
the sea-ice zone to global warming (IPCC 2013), there is an urgent need for
determining how top predators use their physical and biological environment, in
order to understand and predict their response to climate change in the different
Antarctic regions. Events
such as calving of large icebergs provide a framework for natural experiments
to study the consequences of habitat variations on higher trophic level
populations. Because the occurrence of such extreme events around Antarctica is
predicted to increase due to global warming, it is now timely to study the
ecological response of higher trophic levels to calving of large icebergs and
their oceanographic consequences. We propose to take advantage of the
unique opportunity offered by the recent Mertz Glacier Tongue calving in Adélie
Land (Feb. 2010) to continue an unprecedented time-series on the winter
foraging movements and in-situ oceanographic conditions of an
ice-dependent top predator, the Weddell seal, spanning over 13 years and
encompassing this significant climate event. Using vertical T/S/chlorophyll
profiles collected by the seals during their dives in winter, we will link
their foraging behaviour to in
situ hydrographic conditions
before and after the Mertz Glacier calving, and assess impact of the Mertz
Glacier calving on ocean/sea ice interactions and primary production in the
Dumont d’Urville region, and their potential consequences on the seals foraging
behaviour. We will also complete our time-series on the foraging ecology of
Weddell seals during summer (post breeding), during which ice retreat
stimulates primary production. Finally, we propose to develop new seal-borne
sensors to measure otherwise poorly sampled key sea-ice parameters such as
sea-ice thickness and sea-ice algae biomass. By so doing, we will
simultaneously address urgent questions on upper trophic levels ecology,
primary production processes in and below sea-ice, and sea-ice/ocean
interactions in an innovative and cost-efficient way.