Institut Méditerranéen d’Océanologie
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Séminaire MIO : Enrico Ser-Giacomi, post-doctorant au LOCEAN, donnera un séminaire dans la salle égée le mardi 20 mars de 11 à 12h

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Sur le sujet suivant : ECOLOGICAL PATTERNS OF PLANKTONIC COMMUNITIES AND OCEAN TRANSPORT DYNAMICS FROM A NETWORK PERSPECTIVE

Abstract :
During the first part of the talk I will focus on ecological patterns derived from the examination of Species Abundance Distributions (SADs) of planktonic organisms. Analyzing the dataset gathered by the Tara Oceans expedition for marine microbial eukaryotes (protists) we explore how SADs of planktonic local communities vary across the global ocean. We show that the decay in abundance of more than the 99% of species is commonly governed by a power-law. Moreover, the power-law exponent varies by less than 10% across locations and does not show biogeographical signatures suggesting that large-scale ubiquitous ecological processes could govern the assembly of such communities.
In the second part of the talk I will introduce a Network Theory approach that was developed to characterize fluid transport in the ocean. Discretizing the sea surface in small equal-sized cells we construct networks, called Lagrangian Flow Networks (LFNs), that describe water exchanges between different regions of the seascape. Using Network Theory concepts & tools we can study dispersion and mixing at both local and global scales evidencing relationships between network measures and dynamical properties of the flow. Among possible applications, such framework provides a systematic characterization of the dispersal of planktonic life-stages of marine organisms which helps understanding the connectivity and structural complexity of marine populations.
I will finally present an on-going project which investigates the effects of ocean transport and mixing on planktonic community assembly in the Mediterranean using the LFN methodology.