Since July, Célia Caillibot has joined us at the Ifremer representation office in New Caledonia. Under the supervision of Thierry Jauffrais (IFREMER), Nicolas Lebouvier (UNC), and Philipp Hess (IFREMER), she will be working as part of Work Package 2: Ecological Vulnerability and Biological Impacts.
After completing her initial training in Bordeaux in Chemistry – specializing in Ecotoxicology and Environmental Chemistry – she undertook her first internship during her Master 1 at the Ifremer representation in Concarneau, focusing on the effects of ichthyotoxic dinoflagellates from the genus Karlodinium on oyster gametes. She then completed a second internship during her Master 2 at ISEA (Institute of Exact and Applied Sciences) on reference values for nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), and arsenic (As) in streams flowing through peridotite massifs. With these two initial experiences and her degree in hand, she continued her path with a VSC (volontariat de service civique) at the New Caledonia Laboratory (LNC, DAVAR), where she implemented a multi-residue pesticide analysis method in plants using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS).
Eager to deepen her understanding of the environmental specificities of the New Caledonian context, she successfully obtained a PhD contract along with an Ifremer scholarship. Her thesis project is conducted in partnership with Ifremer (LEAD-NC and PHYTOX teams), the University of New Caledonia (ISEA), and the MaHeWa project.
Célia’s thesis aims to better understand the risk associated with ciguatera in New Caledonia—a foodborne illness caused by consuming fish contaminated with ciguatoxins produced by the microalga Gambierdiscus. Common in tropical regions, this phenomenon is a major public health issue, with 10,000 to 50,000 cases reported annually. It is further exacerbated by climate change, which promotes the proliferation of toxic algae. Given the absence of curative treatment and the variety of symptoms (gastrointestinal, neurological, and cardiovascular), the objective of her research is to adopt a multidisciplinary approach that combines ecophysiology, chemistry, molecular biology, and marine resource management to improve the understanding of this risk and help prevent poisoning in the New Caledonian context.
Célia’s methodology is based on an integrated approach that combines fieldwork with laboratory analysis to better understand the diversity and behavior of toxic microalgae from the genus Gambierdiscus in New Caledonia.
Field campaigns will be conducted at three study sites (Lifou, the Southern Lagoon, and potentially Ouvéa) to assess the impact of seasonal changes and marine heatwaves on microalgal diversity, using SPATT (Solid Phase Absorption Toxin Tracking) and WS (Window Screen) devices to collect microalgae and characterize the toxins present, particularly ciguatoxins.
Fish (both herbivorous and carnivorous) and giant clams will also be sampled four times a year at these sites to analyze the toxicity of commonly consumed species.
In the lab, isolated Gambierdiscus strains will be identified using molecular biology, morphological analysis, and chemotaxonomy techniques, with the goal of building an algal strain library. These strains will then be exposed to different temperature conditions to study their growth, thermal tolerance, toxic potential, and cellular organization, in order to predict how the ciguatera risk might evolve in a warming ocean and to better understand the toxin profiles of local marine species.
We look forward to sharing Célia’s first research results with the MaHeWa community as this very promising project moves forward!
