Current and past research activities
My research currently focuses on the ecology of gelatinous pelagic organisms, their contributions to ecological processes, and their responses to a changing environment.
Gelatinous plankton community in the southern North Sea
Since autumn 2015 I am investigating the interannual variations in the spring bloom dynamics of the ctenophore Pleurobrachia pileus in relation to environmental parameters (climate indices, SST, wind, primary production). This work is based on the analysis of a 20 year time-series from the Southern North Sea.
From autumn 2013 to summer 2015, with Dr Dorothée VINCENT (ULCO LOG-UMR8187) and Dr Elvire ANTAJAN (IFREMER), we have been running year-round monitoring of the gelatinous plankton community in Dunkirk industrial harbour. This programme allowed us to : (1) document the local diversity of gelatinous organisms (ctenophores, hydromedusae, scyphomedusae), (2) study the seasonal dynamics of gelatinous plankton abundance and assess risk of water intake clogging for local industrial plants, and (3) monitor the abundance of potentially invasive species such as the ctenophore Mnemiopsis leidy Work conducted at the Laboratoire d'Océanologie et Géoscience (LOG UMR8187) in Wimereux (France), and funded by a one year post-doctoral fellowship from the Université du Littoral Côte d'Opale and by research contracts with an industrial partner (EDF) renewed in 2014 and 2015. |
Using bio-logging and telemetry to investigate jellyfish behaviors
I have been involved in the first study using 3-axial accelerometers to study jellyfish swimming behaviour. This work lead by Dr Sabrina FOSSETTE and Prof. Graeme HAYS (Swansea University) coupled accelerometry records with direct observations of the swimming orientation of individual medusae and in situ records of current directions. This enabled us to show the existence of a current-oriented swimming behavior in Rhizostoma octopus.
Prior to this, I worked on time-depth records from achival electronic tags deployed on the same species. This dataset, further analysed by others, revealed how these animals are more active than previously thought, with significant distance swam every day, and at times exhibiting complex swimming patterns.
I also have experience with active acoustic tracking techniques which we used with Dr Tom DOYLE to study the horizontal and vertical movements of the Lion's Mane jellyfish (Cyanea capillata) in Dublin Bay, Ireland. This study revealed that although the species broadly followed tidal currents, its vertical swimming behaviours were diverse and changing. This was part of the EcoJel project (EU INTERREG IVa).
|
From 'jellies' to humans...
Bio-logging techniques are also used to study movements in humans. I worked for 18 months as a post-doctoral researcher at the CRNH Rhône-Alpes with Prof. Chantal SIMON, applying telemetry and bio-logging techniques (3-axial accelerometry and GPS) in a clinical-study on the measurement of daily physical activity and sedentary behaviors (SVELTE project, ANR TecSan), and in a different project on urban mobility (Acti-Cités project, INCa). I also investigated whether such data could be a useful proxy for energy expenditure in comparison to respirometry and/or heart-rate measurements.
Collaborations : Lyon Sud University Hospital, INSERM, CRNS, Universities (Lyon, Strasbourg, Paris), CEA, MOVEA (private company). |
Investigating the broad-scale distribution of scyphomedusae in Irish Waters
My PhD research were conducted at the Coastal and Marine Reasearch Centre (CMRC, Cork, Ireland) under the supervisions of Dr Tom DOYLE, Prof. John DAVENPORT, and Dr Rob McALLEN, as part of the EcoJel project (EU INTERREG IVa Ireland-Wales Programme).
My PhD research were conducted at the Coastal and Marine Reasearch Centre (CMRC, Cork, Ireland) under the supervisions of Dr Tom DOYLE, Prof. John DAVENPORT, and Dr Rob McALLEN, as part of the EcoJel project (EU INTERREG IVa Ireland-Wales Programme).
Using fisheries survey 'by-catch' data to access semi-quantitative and quantitative abundance data beyond the littoral fringe.
Data from the 2007-2010 Irish Sea Juvenile and 0-group Gadoid Fish Survey (AFBI Northern-Ireland) provided the first quantitative description of Aurelia aurita and Cyanea spp. late spring abundances across the Irish Sea, revealing constrasting inter-annual patterns within and between regions of the Irish Sea. These data also highlighted the existence of an increasing trends in the average biomass of jellyfish in the Western Irish Sea in link with recent environmental changes.
Bycatch data collected during the 2008-2010 Irish Ground Fish Surveys (Irish Marine Institute) and the 2010 IFREMER's EVHOE survey revealed the widespread autumnal presence of Pelagia noctiluca all across the european western continental shelf, from Britanny to the north of Ireland. This species is of particular concern in Ireland where it can critically impacts salmon farms.
These surveys not only provided me with some insights into fisheries science but also gave me significant experience in practical work at sea including biological and hydrological sampling (MIK net, Gulf VII, CTD).
|
Using ferries to monitor 'jellies'
Two years of regular visual surveys from ships of opportunity, allowed my colleagues and I to describe the seasonnal dynamics of scyphomedusae abundances along a >100 km transect between Ireland and Wales. Those surveys revealed that, at peak season, dense jellyfish aggregations are present all across the Irish Sea. Furthermore, these surface counts could be compared to numerical model outputs and in-situ records from Ferry Box devices.
|
Microrespirometry trials on young medusae and polyps
During my PhD research I had the opportunity to spend 3 weeks working with the group of Dr Veronica FUENTES in Barcelona where, in collaboration with Dr Jennifer PURCELL, I took part to the development phase of microrespirometry trials on young medusae and polyps.
|
Looking into the ecology of the Leatherback turtle
In 2007 and 2008, as an M.Sc. students interested in 'jellyfish', I worked with biologists specialised in the behavioural ecology of their most famous predator: the leatherback turtle.
I analysed jellyfish abundance data from and near a leatherback turtle rookery of French Guyana for Dr Sabrina FOSSETTE and Dr Jean-Yves GEORGES, showing that it would be possible for leatherback turtles to find food during their reproductive/spawning season.
Later on, with Dr Tom DOYLE, we conducted a field study of a known foraging spot of leatherback turtles on the French Atlantic coast, mapping large barrel jellyfish aggregations from aerial and at-sea transects in the Pertuis Breton (near La Rochelle, France). A work that proved useful few years later when we undertook to deploy accelerometers on those jellyfish to study their swimming behaviour.
Finally, under the supervision of Dr Patrick LEHODEY and Dr Jean-Yves GEORGES, I conducted a preliminary analysis to the development of a spatial dynamics population module. for Atlantic leatherback turtles in the global ecosystem model SEAPODYM. This analysis consisted in characterising feeding and spawning habitats based on environmental variables along the satellite tracks of turtles migrating through the North Atlantic Ocean.
|
Before I started working on gelatinous species and their predators, I had been involved in other research projects :
The quantification of CO2 fluxes from the intertidal barnacle Chthamalus montagui during emersion and immersion, a work conducted with Prof. Jacques CLAVIER in Brest, Brittany, France.
Behavioural observations and calculation of time-budget associated to parental cares in a pair of white storks Cicognia cicognia; a work under the direction of Dr Sylvie MASSEMIN-CHALLET, in Strasbourg, France.