A pioneer in ocean science, IFREMER’s cutting-edge research is grounded in sustainable development and open science. Our vision is to advance science, expertise and innovation to:

• Protect and restore the ocean
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With more than 1,500 personnel spread along the French coastline in more than 20 sites, the Institute explores the 3 great oceans: the Indian, Atlantic and Pacific oceans. A leader in ocean science, IFREMER is managing the French Oceanographic Fleet and its dedicated scientists create ground-breaking technology to push the boundaries of ocean exploration and knowledge, from the abyss to the atmosphere-ocean interface.

Well-established in the international scientific community, our scientists, engineers and technicians are committed to advance knowledge about our planet’s last unexplored frontiers. They provide the science we need for informed decision-making and public policy and they transfer this knowledge and technology to businesses to fulfill public and private needs. Core to our mission is also to strengthen public awareness about the importance of understanding the ocean and its resources, and empowering future generations of leaders through education and outreach national campaigns.

Founded in 1984, IFREMER is a French public organization and its budget approximates 240 million euros. It is operating under the joint authority of the French Ministry for Higher Education, Research and Innovation, the french Ministry of the Sea, the French Ministry for the Ecological and Solidary Transition, and the French Ministry of Agriculture and Food.

General areas of responsibility

We are seeking a talented candidate to join our team specialized in marine microalgae toxicity and taxonomy. This postdoctoral project aims to determine toxicity and mode of action of marine microalgae to shellfish, using bioassays targeting cultured cells. It is part of a research project studying the relationships between ichthyotoxicity, chemodiversity and genetic diversity of marine microalgae in France, involving biologists, chemists and bioinformaticians.

Key words: cell culture, bioassays, toxic microalgae, marine molluscs.
Duration: 6 months, starting preferably in November 2021
Location: IFREMER (French Research Institute for Exploitation of the Sea), at the Environment & Resources Laboratory of Western Brittany (LER-BO) located in the Concarneau marine station (Concarneau, France)
Supervisors: Malwenn Lassudrie (IFREMER LER-BO) and Stéphanie Auzoux-Bordenave (UPMC-MNHN)

Project description

Harmful Algal Blooms (HABs) occur worldwide, affecting the ecology of coastal ecosystems and associated socio-economical activities. Among them, ichthyotoxic microalgae can cause marine organism mortalities and lead to considerable economic loss in the fish and shellfish industry (e.g. Chili 800M$ in 2016). In France, dinoflagellates from the Kareniacea family, which includes species known to be ichthyotoxic, are regularly detected (Nézan et al. 2014). Mortality events, recruitment and growth failures in fish and shellfish were occasionally observed on the French coast following blooms of Karenia and Karlodinium spp. (Chauvaud et al. 1998; Paulmier et al. 1995). Karlodinium species have induced important fish and shellfish mortality events in many other countries worldwide (Place et al. 2012), particularly by affecting gills of fish. The toxicity of French Karlodinium strains, however, is not well known and needs to be assessed to determine the risk they represent to aquaculture in France and particularly to shellfish farming.

Ichthyotoxic activity can be identified from lytic and cytotoxic properties of microalgae, measured using cellular bioassays that are more ethical and simpler to perform than in vivo assays. They usually target fish blood cells or fish gill cells lines (Dorantes-Aranda et al. 2011; Eschbach et al. 2001). Some studies have assessed the effect of toxic microalgae to shellfish cells, particularly circulating hemocytes and gametes (Gaillard et al. 2020; Lassudrie et al. 2020; Castrec et al. 2021). However, immortal cell lines from marine molluscs are not available to ensure experimental reproducibility. Primary cell cultures of molluscs, already used before in ecotoxicological studies (Avella et al. 1994; Gaume et al. 2012), would represent a suitable alternative to meet reproducibility purposes for a limited period. Maintaining those cells would allow studying the mechanisms involved in microalgae toxicity to bivalves.

The aim of this project is to characterize the ichthyotoxic activity of French Karlodinium spp. to bivalves by answering two main questions:

1. Which French Karlodinium species can be deleterious to bivalves ?
2. What are the mode of action of these microalgae on bivalve cells?

To answer these questions, this project proposes to:

• Establish primary cell cultures of bivalves following methods described in the literature.
• Study the cytotoxic mode of action of microalgae cultures or extracts using bioassays targeting bivalve cultured cells. Approaches combining viability assays and analyses of several phenotypic and metabolic variables will be considered.

This study will contribute to determine the risk induced by these microalgae to French shellfish farming.

Required Knowledge, skills, and characteristics

Education:

• PhD in Biology

Desired skills:

• Cellular bioassays
• Experience in ecotoxicology or toxicology
• Experience with marine models
• Animal cell culture
• Statistical analyses
• Excellent oral and writing skills in English
• Autonomy and team work ability

Eligibility criteria (required from the funding agencies):

The candidate must have spent at least 18 months out from France between May 1st 2016 and the beginning of the project. He/she should have completed his/her PhD for no more than 4 years, out from the French regions Bretagne and Pays de la Loire.

Learn more about this position and how to apply.
Deadline for applications: September 30, 2021