Justine Louis

My role in Medsea Villefranche :

During this secojustinend experiment Medsea at Villefranche sur mer, my role remains the same that in Medsea Stareso : I take an interest in the impact of ocean acidification (OA) on biogeochemical elements cycles and in particular nutrient at nanomolar level (nitrate, phosphate, iron) in Mediterranean sea. The aim of these experiments is to know if climate change can alter the nutrient speciation and so it could modify their bioavaibility and phytoplankton community.

Every day, the samples will be filtered at 0.2µm in order to let go of particulate matter. To study the potential effect of OA on physical speciation of nutrient, the samples will be also filtered at 0.015µm to differentiate colloïdal form from dissolved form. Regarding the chemical speciation, the samples will be irradiated by UV and that can allow us to compare the inorganic form (DIN ; DIP) to organic form (DON ; DOP). Every samples will be analyzed in cleaned conditions, by FIA (for iron analysis) and by spectrophotometry LWCC (for nitrate and phosphate). .

Given that the hydrological and biological conditions in February-March at Villefranche sur mer differ from those during summer at Calvi, it will be really interesting to evaluate the impact of OA between oligotrophic and post-bloom conditions. The only disadvantage is that the temperature of seawater is colder and I think that the cubi battles will be less numerous !!!!!

More about my research  :

At the present time, I’m PhD student at LOV, and It is just my first year … thus I can’t write reams about my research activities … but last year I had the opportunity to do my training course at LOV (with Cecile Guieu and Matthieu Bressac) and thereby I set up the nitrate analysis at nanomolar level and I studied the seasonal variation of nitrate release from Saharan dust in abiotic conditions. After Medsea, I will continue to study the impact of OA but this time in abiotic conditions coupled in atmospheric forcing : Saharan dust.

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