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Melilotus Thyssen

Mélilotus Thyssen CNRS Researcher, Marine microbial Ecologist and Biogeochemist
15
Documents

Présentation

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.

Domaines de recherche


Compétences

Flow cytometry, sea water flowthrough, primary production, big data analysis,

Publications

michel-denis
Image document

Onset of the spring bloom in the northwestern Mediterranean Sea: influence of environmental pulse events on the in situ hourly-scale dynamics of the phytoplankton community structure

Melilotus Thyssen , Gérald Grégori , Jean-Michel Grisoni , Maria-Luiza Pedrotti , Laure Mousseau
Frontiers in Microbiology, 2014, 5, pp.387. ⟨10.3389/fmicb.2014.00387⟩
Article dans une revue hal-01321252v1

The combined effect of ultraviolet B radiation and temperature increase on phytoplankton dynamics and cell cycle using pulse shape recording flow cytometry

Melilotus Thyssen , Gustavo Ferreyra , Sébastien Moreau , Irene Schloss , Michel Denis
Journal of Experimental Marine Biology and Ecology, 2011, pp.95;107. ⟨10.1016/j.jembe.2011.06.015⟩
Article dans une revue hal-00744463v1

Phytoplankton distribution during two contrasted summers in a Mediterranean harbour: combining automated submersible flow cytometry with conventional techniques

Melilotus Thyssen , Nicole Garcia , Michel Denis , Beatriz Beker , Dilek Ediger
Environmental Monitoring and Assessment, 2010, pp.1-16
Article dans une revue hal-01663229v1
Image document

Ultraphytoplankton basin-scale distribution in the eastern Mediterranean Sea in winter : link to hydrodynamism and nutrients

Michel Denis , Melilotus Thyssen , V. Martin , B. Manca , F. Vidussi
Biogeosciences, 2010, 7 (7), pp.2227-2244. ⟨10.5194/bg-7-2227-2010⟩
Article dans une revue hal-00514544v1

Short-term vaiation of phytoplankton assemblages in Mediterranean coastal waters recorded with an automated submerged flow cytometer

Melilotus Thyssen , Delphine Mathieu , Nicole Garcia , Michel Denis
Journal of Plankton Research, 2009, 30 (9), pp.1027-1040. ⟨10.1093/plankt/fbn054⟩
Article dans une revue hal-00363507v1

Microbial community structure along 18°W (39°N–44.5°N) in the NE Atlantic in late summer 2001 (POMME programme)

Camila Fernandez , Melilotus Thyssen , Michel Denis
Journal of Marine Systems, 2008, 71 (1-2), pp.46 - 62. ⟨10.1016/j.jmarsys.2007.06.003⟩
Article dans une revue hal-01886950v1

Heterotrophic nanoflagellate and ciliate bacterivorous activity and growth in the northeast Atlantic Ocean : a seasonal mesoscale study

Hera Karayanni , Urania Christaki , France van Wambeke , Melilotus Thyssen , Michel Denis
Aquatic Microbial Ecology, 2008, 51, pp.169-181. ⟨10.3354/ame01181⟩
Article dans une revue hal-00290748v1

The emergence of automated high-frequency flow cytometry: revealing temporal and spatial phytoplankton variability

Melilotus Thyssen , Glen A. Tarran , Mikhail V. Zubkov , Ross J. Holland , Gérald Grégori
Journal of Plankton Research, 2008, 30, pp.333-343. ⟨10.1093/plankt/fbn005⟩
Article dans une revue hal-00691254v1

Relationship among Several Key Cell Cycle Events in the Developmental Cyanobacterium Anabaena sp. Strain PCC 7120

Samer Sakr , Melilotus Thyssen , Michel Denis , Cheng-Cai Zhang
Journal of Bacteriology, 2006, 188/16, pp.5958-5965
Article dans une revue hal-00092841v1

The bactericidal effect of TiO2 photocatalysis involves adsorption onto catalyst and the loss of membrane integrity

Gaetan Gogniat , Melilotus Thyssen , Michel Denis , Cesar Pulgarin , Sam Dukan
FEMS Microbiology Letters, 2006, 258, pp.18-24
Article dans une revue hal-00092800v1
Image document

Microbial community production, respiration and structure of the microbial food web of an ecosystem in the northeastern Atlantic Ocean

Anne Maixandeau , Dominique Lefèvre , Hera Karayanni , Urania Christaki , France van Wambeke
Journal of Geophysical Research. Oceans, 2005, 110 (C7), pp.C07S17. ⟨10.1029/2004JC002694⟩
Article dans une revue hal-00092669v1
Image document

Spatial distribution of heterotrophic bacteria in the northeast Atlantic (POMME study area) during spring 2001

Melilotus Thyssen , Dominique Lefèvre , Guy Caniaux , Josephine Ras , Camila I. Fernandez
Journal of Geophysical Research, 2005, 110, pp.C07S16-16. ⟨10.1029/2004JC002670⟩
Article dans une revue hal-00092675v1