Melilotus Thyssen

I am a marine microbiologist and biogeochemist, dealing with the multiparametric complexity of the ocean and the microorganisms floating inside.I am looking at the very small scales related to phytoplankton organisms, as far as we can. Meaning I study all together their functional diversity (regarding their role in biogeochemical processes), their structural diversity (how the functional groups or species are making a community), and most of all, the dynamical behavior of each entity within the community (hourly to daily physiological changes and abundances variations), surrounded by water in motion. The use of high resolution automated sensors capable of precise single cell observation that can give insight to phytoplankton functional and structural heterogeneity within spatial and temporal variability is part of my job. I use automated flow cytometry in combination with several sensors deciphering the surrounding chemical and physical conditions. I am singularly looking into the very fast reactivity of the smallest phytoplankton size classes (pico-nanophytoplankton) after drastic environmental changes (as an example, after the upper layer mixing linked to strong winds), especially in the oligotrophic regions where low productivity is expected. I also collect basin scale high resolution phytoplankton distribution to understand large scale seasonal changes in hydrological properties affecting phytoplankton community structure and spatial heterogeneity. From the tiny single cell observation at high resolution (km scale/hourly scale) to the large scale observation increases datasets quality and our potential of undertanding. Combination with remote sensing (PHYSAT for example) and modelling will increase the sensitivity of extrapolation and sharpen our understanding.