Research

Research Interests

At the boundary between biogeochemistry and marine ecology, my research interests are in tracing organic matter (OM) origin, dynamics and fate in coastal systems especially regarding its transfer within trophic networks. I am interested in how natural or human induced changes (e.g. climate change, eutrophication) in basal OM quantity and quality would affects food webs at different levels: from individual body condition to trophic interactions and its consequences on ecosystem functioning. Currently, my main research is focused on coastal environments.

Tool box

Stable isotopes of carbon and nitrogen (δ13C, δ15N) are used as organic matter tracers in a wide range of environments, especially to study trophic relationships. I have been using stables isotopes of bulk OM but also fatty acids techniques since my Ms.C project were these biomarkers were used together to reveal pelagic fish larvae diet [1]. Coupled with numerical and statistical analyses (e.g. isotopic mixing models (MixSIAR), multivariate statistics), theses biomarkers helped me during my Ph.D to reveal particulate organic matter origin and quantify its composition in a set of coastal systems over the French littoral [2], [3], [5].

Organic matter tracers are commonly used to determine organisms’ diet but can also be used in fields such as ecotoxicology or physiology. During my postdoc, I keep playing with stables isotopes, together with environmental data, to study how Mytilus edulis diet and body condition changes over the pas 25 years in the Baltic Sea. I am also learning a stable isotope compound specific isotope approach on amino acids (CSIA-AA) in collaboration with Center for Physical Sciences and Technology in Vilnius (Lithuania).

Current and past projects

Environmental Changes in the Baltic Sea Benthic Ecosystem: a focus on the Blue Mussel Mytilus edulis (2018-2020) – Project leader: Agnes Karlson.

Archive samples of Mytilus edulis  from the last 25 years (Swedish National yearly monitoring program of phytobenthic community) in the Baltic Sea are studied for elemental and isotopic ratios measurement. By combining blue mussel body condition, bulk and amino acid isotope data and isotopic niche metrics with existing biotic and abiotic datasets on phytoplankton communities, eutrophication and other environmental related variables, we will test specific hypotheses on Mytilus diet, condition and growth status in order to better understand blue mussels and ecosystem responses to environmental changes.

See more details and follow project updates on the Research Gate project page, twitter or in my blog section !

MOSLIT (2014-2016) – La matière Organique Particulaire dans les Systèmes LIToraux : composition, dynamique et forçages (EC2CO – DRIL) – Project leader: Nicolas Savoye (UMR EPOC, Université de Bordeaux / CNRS).

Particulate organic matter (POM) is deeply involved in biogeochemical cycles and constitutes the base of food webs. In coastal systems, POM is a composite pool fueled by autochthonous and allochthonous sources from pelagic, benthic and continental origin, and whose relative contributions highly vary over time and space. Twelve systems (three littoral systems, eight embayments and semi-enclosed systems, and one estuary) distributed along the three maritime façades of France were studied for one to eight years in order to quantify the relative contribution of organic matter sources to the surface-water POM and to assess the drivers of their spatial and temporal variability [3], [4]. Bacterial contribution to POM has been studied focusing on 3 systems along the continent to ocean gradient [5].

SOMLIT (2014-2016) – Service d’Observation en Milieu LITtoral (INSU, since 1996). National leader: Nicolas Savoye (UMR EPOC, Université Bordeaux / CNRS).

For two years I was involved in field sampling for the sites of Aquitaine (Arcachon lagoon and Gironde estuary) and in sample analysis (pH, chlorophyll a by fluorimetry, δ13CCOP, δ15NNOP). As a part of my PhD, I contributed to the database cleaning and the scientific valorisation of the work performed by the SOMLIT.

PERMALA-LIGA (2013-2015) – Perturbations et Milieux Aquatiques Littoraux Aquitains (Conseil Regional Aquitain). Project leader: Philippe Gaudin (MIRA – Université de Pau et des Pays de l’Adour).

The French Basque coast is characterized by the occurence of a viscous TEP-like material that appears discontinuously from late winter/early spring to late summer/early fall. Using stables isotopes of C and N our aims were to assess POM origin and composition in this system [2].

Trophic ecology of leptocephali in the South-West Pacific (2013) – Collaboration between the UMR BOREA at the Museum National d’Histoire Naturelle (Tarik Meziane and Eric Feunteun) and the Japanese Teams of the AORI and Department of Aquatic Biosciences of the University of Tokyo and the Eel Science laboratory of Nihon University.

Leptocephali are pelagic larvae of Anguilliform fish that are dispersed by currents toward adult habitats. Despite an extensive literature on their morphology and distribution area, their feeding ecology is still partly unknown. One current hypothesis suggests those larvae are feeding on particulate organic matter (POM) and assimilating some specific compounds. Fatty acids and stables isotopes of C and N were combined to investigate trophic habits of three families of leptocephali (Muraenidae, Nemichthyidae, Serrivomeridae) caught in the waters south Pacific [1].

 

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