Campaign
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Université Libre
de Bruxelles - Glaciology Unit of the Department of Earth and
Environmental Sciences
Jean-Louis Tison, Véronique Verbeke
- Antarctic campaign
- Begin date: jan 2003– end date: feb 2003
- Polar zone: Ross Island
- Title: McMurdo Land-fast Sea Ice
- Summary: This field trip is part of the
SIBClim project. In this collaborative work with the New Zealand
glaciologists from the Physics Department of the University
of Dunedin (Dr. Pat Langhorne) and Industrial Research Ltd.
we focused on sea ice biogeochemistry in a coastal environment
(land-fast sea ice, as opposed to pack ice). Processes are
likely to be quite different here due to the proximity of a)
the Ross Ice Shelf (potential of platelet ice production in
the rising plume of Ice Shelf Water that reaches the ice shelf
front) and b) bedrock sources that might considerably affect
the iron input to the sea ice and, therefore its availability
for the primary producers. This is in fact the third phase
of this sub-project, involving a visit in the middle of the
summer. The first two phases (mid-October 1999 and mid-November
2001) were focused on early and late spring, with the secret
wish of maximizing the potential variability of species in
algal blooms. Given the smaller size of the team, the biological
component was limited to the pre-treatment of melted samples
for algal speciation, Chl-a, Pigments and bacterial countings.
However, a total of 120 meters of ice cores were collected
on 7 stations and brought back to Brussels at -30°C to
study the following variables: temperature profile (in situ),
salinity profile, texture and fabrics, stable isotopes, minor
elements (Fe, Mn), total gas content and gas composition. In
addition, samples of surface snow and under ice waters have
been collected, in clean conditions, to check for a potential
drive of iron input on the biological productivity. Finally,
live algae samples have been retrieved and brought back to
Brussels for cultures and experimental procedures addressing
environmental stresses (light, temperature, trace elements°)
on algal metabolism.
A major feature (although not initially planned!) of this three
years sampling program is that it occurred during a period
of relative blockage of the water circulation in McMurdo Sound,
due to the anchoring of iceberg B15 (launched May 2000) at
the entrance of the Sound. Although it has the disadvantage
of focusing the sampling on a period that is not representative
of a “normal” situation, it has allowed a precious
documentation of the impact on the sea ice cover conditions
in the Sound.
- Base: Scott Base (New Zealand)
Belgian projects
Participants :
Jean-Louis
Tison, Véronique
Verbeke
Complementary
resources: -
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