Research
This research project aims to
assess to which extent ice-covered polar oceans contribute to
processes regulating the Earth’s climate. It involves a
new multidisciplinary consortium combining the expertise of glaciologists,
biologists, geochemists and ecosystems-modelers of the Université Libre
de Bruxelles (ULB).
The main goal of the project is to study, understand and quantify
the physical and biogeochemical processes associated with the
sea ice biota that govern the emissions of marine gases of climatic
significance. These processes are indeed presently unknown and
therefore not integrated into Oceanic Biogeochemical Climate
Models (OBCMs). In this context, particular attention will be
paid to Carbon Dioxide (CO2) and Dimethyl Sulphide (DMS), both
actively involved in the sea ice microbial metabolism. On a global
level, CO2 is well known for its efficient greenhouse gas behavior,
while DMS has the recognized potential to stabilize the climate
against warming by controlling the incident solar energy via
the production of aerosols and cloud condensation nuclei. It
has now been demonstrated that iron can play a crucial role in
controlling phytoplanktonic productivity and the biological carbon
pump in the Southern Ocean. This is, however, yet to be assessed
for the Arctic Ocean. The work programme will thus in addition
focus especially on the biogeochemical cycle of iron (origin,
availability and fate) in the sea ice environment.
The geographical coverage will include, for comparison, both
the Arctic and the Antarctic oceans where the mechanisms controlling
the carbon production and the relative importance of anthropogenic
and marine sulphur compounds in cloud formation processes are
quite contrasted.
The research methodology will be highly interdisciplinary and
combine field investigations, process-oriented studies both “in
situ” and in the laboratory, and modeling work in order
to quantify key biological, geochemical and physical interactions
between sea ice, the ocean and the atmosphere and to elucidate
the controlling mechanisms. Cores collected during field surveys
will be used to characterize the distribution of Fe, CO2, DMS
and other related physico-chemical and biological parameters
in sea ice. Chemical transformation of iron during melting of
sea ice and the associated biological and chemical processes
will also be studied in the field. Investigations on the mechanisms
regulating iron bio-availability and on the iron isotopes bio-signature
will be conducted under laboratory-controlled conditions on cultures
of polar micro-organisms. Each topic will involve the development
of new methodologies including, for example, fluorescent probes,
molecular methods (PCR, DGGE), iron isotope analysis (MC-ICP-MS),
iron flow injection analysis (Fe-FIA), extraction and gas chromatography
for gaseous DMS.
Modeling effort will involve the development of a new sea ice
biogeochemical model (SIMCO). Its parameterization will rely
on the results obtained during the process studies described
above. The online coupling of the SIMCO model with the existing,
and currently being improved, model for the upper layer of the
Southern Ocean (SWAMCO) should yield an original data set of
CO2 and DMS fluxes between the ocean and the atmosphere in polar
oceans. These would then be available to ultimately be fed into
more general circulation models.
Coordinator: Prof. Dr. Jean-Louis Tison
Involved research group:
Involved Partners:
Belgian partners:
Foreign partners: