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12 / MONACO AT THE HEART OF CLIMATE CHANGE DEBATES

Hervé Claustre
CNRS Research Director at the Villefranche sur Mer
Oceanographic Laboratory (UPMC/CNRS)

Why should we take an interest in the ocean?
We need to increase our understanding of CO fixation mechanisms by
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phytoplankton and its possible transfer by the trophic chain to the ocean beds.
The average ocean depth is 3800 meters. Storms, high pressure and the
absence of light in the major ocean beds make them difficult to explore: areas
as large as France are completely unknown to us. Half of the anthropogenic
carbon which enters the ocean is «pumped» by the Southern Ocean.
We still have very little information regarding this far-off ocean which is difficult
to access via boat. However, we owe it to ourselves to improve
and increase our observation techniques.

Why turn to robots?
The meteorological conditions in the Southern Ocean, where we are
researching, make oceanographic research difficult; robots provide an
alternative research method. The Argo ocean surveillance project is based
on a group of almost 4000 robots. The drifting-profiling floats record precise
temperature and salinity measurements for the entire area from the water’s
surface to 2 km in depth. Each robot records the measurements every
10 days. In addition to this data, the Biogeochemical-Argo programme which is
currently based on almost 200 floats is already informing us about the ocean’s
biogeochemical characteristics. Other parameters are measured, such as
particle levels, light, oxygen, pH and nitrate and chlorophyll concentration levels
which are plant biomass indicators. All these measurements are transferred in
real time (less than 24 hours) and can, in particular, be compared to satellite
measurements.

Which results are you expecting from the Southern Ocean?
We have chosen to launch an exploration campaign in certain zones south of
© David Luquet Observatoire Océanologique de Villefranche winter. This is a potentially unique source of information.
the Kerguelen plateau. Some of these robots are able to continue collecting
data from underneath winter ice floes. During the spring ice melt, the robot
comes up to the surface and transmits all the data which it collected during the