Research group presentation Université Libre de Bruxelles - Ecologie des Systèmes Aquatiques (ESA-ULB) Presentation ESA (Ecologie des Systèmes Aquatiques) is a research unit of the Université Libre de Bruxelles. It is active since 20 years in the study of general aspects of aquatic microbial ecology and has published some 300 papers in international peer-reviewed journals. ESA is currently developing an integrated conceptual methodological approach combining field observations, process-level studies and numerical experimentation that aims to develop a generic mechanistic biogeochemical model of the planktonic ecosystem based on physiological and geochemical principles. When coupled with hydrodynamical models of appropriate spatio-temporal resolution, such a model can address local, regional or more global environmental questions such as the uptake of atmospheric CO2 by the Southern Ocean. To comply with the interdisciplinary nature of its environmental research, ESA is continuously developing national and international collaborations in the scope of joint research projects and membership of international scientific committees or through PhD-student and post-doc exchanges. ESA has the expertise in (i) the study of the microbiological processes in the polar environment and (ii) the development of complex biogeochemical model that can be coupled to ice-ocean 1D and 3D models. To achieve these objectives, ESA is well equipped with laboratory infrastructures required for microbiological studies: temperature and light-controlled culture room, laminar-flow bench, facilities for radio-isotopes work (radioactive room, scintillation counter), microscopes (inverted and epifluorescence) and image analyser, spectrofluorometer, photometer, TOC analyser, optic sensors and molecular biology equipments. For the polar environmental studies, ESA has developed specific methodologies to measure microbiological and biogeochemical processes in the extreme environments and making use of ultraclean techniques to avoid trace metal contamination. In particular, ESA has a temperature- and light- controlled culture room with phytoplankton collection including diatoms and Phaeocystis antarctica maintained at 0°C and a trace-metal clean room. More than 15 years of activity in Antarctic research, has allowed the successful development and testing of the biogeochemical SWAMCO model (describing the C, N, P, Si, Fe cycling through different aggregated chemical and biological compartments of the Antarctic plankton ecosystem) which has been implemented in a 1D and 3D physical resolution. Activities ESA was invited to participate to several international polar expeditions in the Southern Ocean (EPOS-European Polarstern Study, and SO-JGOFS expeditions; AntX/6 and AntXVI/3, Antares 2 and 3, AESOPS-process-IV, ARISE, ISPOL) and in Arctic Fjords. ESA was also actively present at all international Polar conference such as the 5 Gordon Conferences on Polar Marine Science, the SO-JGOFS symposia of Brest (France), the special sessions on polar research held during ASLO meetings. ESA-ULB contributes also to: 1. PADD-II-Support actions: SOLAS cluster. 2005-2007 Main field of activity in polar regions ESA research focuses on the study and modelling of the response of marine ecosystems to climate and anthropogenic changes. This happens throughout the understanding of the interactions between planktonic organisms and marine biogeochemical cycles (C, N, P, Si, Fe). To achieve this objective ESA research activities aim to assess the contribution of biological processes to air-ice-sea exchanges of CO2 and DMS in the Southern Ocean. (i) Sea ice and pelagic microbial eco-physiology in the Southern Ocean Biological
activities of the Ocean can significantly affect the greenhouse
gas, such as CO2. Algae produces particulate organic matter by
the photosynthetic uptake of CO2 and such particles may sink
away from the surface. In this biological process, there is a
net transfer of CO2 from surface waters into the deeper parts
of the ocean (carbon biological pump). Major part of the organic
carbon is decomposed during sinking and can return to the surface
by upwellings. However, another part of the organic carbon is
sequestrated into the deep ocean. The efficiency of carbon biological
pump relies not only on the level of primary production (photosynthetic
CO2 uptake by phytoplankton) but also on the dominant phytoplanktonic
groups which shape the structure of the pelagic food web (microbial
food web versus classical linear food chain) and which are characterised
by different biodegradability and aggregation potential and sinking
rates. (ii) The biogeochemical model SWAMCO. More than 15 year of activity in Antarctic research, has allowed
the successful development and testing of the biogeochemical
SWAMCO-4 model. The SWAMCO-4 model is a complex mechanistic
model of the marine planktonic system describing C, N, P,
Si, Fe cycling within the upper ocean, the export production and
the exchange of CO2 between Ocean and atmosphere. The model
constrained by physical, chemical and biological (grazing
and lysis) controls, explicitly details the dynamic of four relevant
phytoplankton functional groups with respect to C, N, P,
Si, Fe cycling and climate change. These are diatoms, autotrophic
pico-nanophytoplankton, coccolithophorids and Phaeocystis
sp., distinguished on the basis of their physiology (temperature
and light adaptation, nutrient and iron uptake kinetics and
sinking rates) and mode of grazer control (microzooplankton
and mesozooplanton). Actually a simplified version of the SWAMCO-4 model is implemented in the 3D ice-ocean model Orca-LIM in the domain south of 30°S. List of projects
Research Group Team
Publication list - Complementary resources about this research group:
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