| DMSP as a Reactive Oxygen Species scavenger for phytoplankton cel |
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- Université Libre de Bruxelles (ULB), more, partner
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| Abstract |
| The goal of this thesis is to improve knowledge about the role of dimethylsulphonopropionate (DMSP) and dimethyl sulfoxide (DMSO) as antioxidant for phytoplankton and the impact of light intensity on their production and degradation by phytoplankton. In addition to their antioxidant role for the phytoplankton, DMS(P,O) are the precursors of the dimethylsulfide (DMS), a gas affecting the climate through the production of atmospheric aerosols. The production of DMS(P,O) by phytoplankton is specific and varies with environmental conditions in particular light. The research methodology will combine laboratory experiments, field measurement and mathematical modelling. DMS(P,O) production processes and related enzymatic pathways will be studied in laboratory experiments based on monospecific cultures of key phytoplankton species in different light conditions. Proces s level studies will carried out using two complementary techniques; (1) the expression of several candidate genes implied in DMSP production will be examined using molecular techniques in parallel to (2) the production/degradation of DMSP and DMSO measured by gas chromatography for different key phytoplankton species of the Southern North Sea (SNS) in different environmental conditions of light. Reactive oxygen species (ROS; OH-, O2-, H2O2) relative production will also be measured to estimate their variability in different light conditions. Field measurements will allow to quantify the importance of DMS(P,O) production and DMS emission in the SNS area related to phytoplankton diversity and environmental factors. Data from laboratory experiments and field measurements will then be used to calibrate and validate the DMS(P,O) dynamics in the biogeochemical MIRO-DMS model applied to the SNS. Model simulations will allow to (i) determine the relative importance of biotic and abiotic fa ctors in the production of DMS(P,O) by aquatic ecosystems and (ii) improve the prediction of current and future emissions of DMS. |
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