In recent years, the international “Southern Elephant
seals as Oceanographic Samplers” (SEaOS) project has
deployed miniaturized conductivity-temperature-depth
satellite-relayed data loggers (CTD-SRDL) on elephant
seals 1) to study their winter foraging ecology in
relation to oceanographic conditions, and 2) to collect
hydrographic data from polar regions, which are
otherwise sparsely sampled. We summarize here the
main results that have been published in both science
components since 2003/2004. Instrumented southern
elephant seals visit different regions within the Southern
Ocean (frontal zones, continental shelf, and/or ice
covered areas) and forage in a variety of different water
masses (e.g. Circumpolar Deep Water upwelling
regions, High Salinity Shelf Water), depending on their
geographic distribution. Adult females and juvenile
males from Kerguelen Is. forage pelagically in frontal
zones of the Southern Indian Ocean, while adult males
forage benthically over the Kerguelen Plateau and the
Antarctic Continental Shelf, with the two groups feeding
at different trophic levels as shown by stable isotopes
analysis. Oceanographic studies using the data
collected from the seals have, to date, concentrated on
circumpolar and regional studies of the Antarctic
Circumpolar Current (ACC) circulation. The
temperature and salinity profiles documented by
elephant seals at high latitudes, including below sea ice,
have permitted quasi-circumpolar mapping of the
southernmost fronts of the ACC. By merging
conventional data and the high temporal and spatial
resolution data collected by seal-borne SRDLs, it has
been possible to describe precisely 1) the large-scale
features of the ACC in the South Atlantic and its
variability; 2) the circulation pattern over the
Kerguelen plateau, revealing that the poorly known
Fawn Trough concentrates an important proportion of
the ACC flow in that region. Seals that foraged in ice
covered areas have made eulerian time series available
that have allowed for the estimation of sea ice formation
rates, a parameter that is otherwise difficult to obtain,
while also providing a unique description of the
wintertime ocean circulation over the central Weddell
Sea continental shelf. Finally, we present the first data
collected by a newly-developed fluorescence sensor that
has been embedded in the regular CTD-SRDL and
deployed on elephant seals at Kerguelen. The
fluorometer data obtained have offered the first synoptic
view of the 3 dimensional distribution of temperature,
salinity and fluorescence over a vast sector of the
Southern Indian Ocean, allowing us to describe both
vertical and horizontal variations in chlorophyll.
This paper will make a core contribution to the Plenary
Sessions 2C, 3A and 4A, and will be relevant to 2A and 2