La Rochelle Université – Post-doctoral fellowship

La Rochelle University is recruiting a post-doctoral fellow on a 12-month fixed-term contract, which may extend to 24 months depending on funding renewal.

Employer description

What about joining a daring and innovative university?

La Rochelle University was founded in 1993 as a result of a proactive initiative by the local authorities, led by Michel Crépeau, to set itself apart from the competition.

Thirty years later, in an ever-changing university landscape, it continues to assert an original proposition, based on a strong identity and bold projects, in a human-scale establishment located in an exceptional setting.

Internationally recognized for its research and exchange programs, as well as for the quality of its teaching, La Rochelle University’s 8,700 students include around 1,000 foreign students of more than 90 different nationalities, and employs nearly 1,000 staff (teachers, research professors and administrative and support staff).

Anchored in a coastal region, La Rochelle University has turned this singularity into a veritable signature, in the service of a new model. Its research is focused on the theme of Urban, Sustainable and Intelligent Coastlines (LUDI).

Website : click here

Research structure description

The project will be carried out in collaboration between the Centre d’Etudes Biologiques de Chizé (CEBC) and the PELAGIS Center.

The Centre d’Etudes Biologiques de Chizé (CNRS UMR 7372 – Université de La Rochelle) is a nationally and internationally recognized scientific research center of excellence. The CEBC’s research is based on the study of the biology, ecology, demography and evolution of wild vertebrate individuals and populations. In particular, the Marine Predators research group is world-renowned for the quality of its research on marine birds and mammals, especially in Antarctic and sub-Antarctic areas. Since the creation of this research group, the CEBC has been a major player in French research in the southern territories, and has developed high-quality research programs, including long-term ones, many of which rely on the use of biologging.

The Pelagis Observatory (UAR 3462, CNRS and La Rochelle University) is an observatory of marine megafauna populations in French waters. Its activities help to improve our knowledge of the conservation status of these species, and are largely based on the acquisition of standardised data on the distribution and abundance of marine predators from campaigns on oceanographic vessels and dedicated aerial campaigns, as well as the monitoring of marine mammal strandings on the French coast, and the collection, storage and analysis of biological samples.

Research project

The successful candidate will work on a project that investigates the impact of marine mammals on nutrient recycling in land ecosystems dynamics in a context of sea-to-land-continuum. Nutrients (nitrogen, phosphorus, iron, zinc, ….) are essential biochemical constituents for all life forms. The recycling and transfer of nutrients are therefore essential for ecosystem functionning, as well as the structuring, productivity and stability of trophic assemblages, from bacterial biomass and primary producers (plants) to top predators. Animals recycle nutrients trapped in organic matter (living, slow-decomposing matter) through consumption, digestion and metabolism. These processes result in release of nutrient-rich matter (faeces and urine) available to plants and thus transferred back to higher trophic levels (herbivorous invertebrates, carnivores, etc). In addition, species can feed at sea but reproduce and rest on land, thus providing a supply of sea-based nutrients to terrestrial ecosystems. This sea-land input is undoubtedly essential to the functioning of coastal ecosystems, yet still poorly understood.

To better understand these transfers of nutrients from sea to land, this project is studying the role of marine predators such as the Antarctic fur seal (Arctocephalus gazella), the southern elephant seal (Mirounga leonina) and the penguin (Pygoscelis papua) in the transfer of nutrients from the rich, productive ocean waters of the Kerguelen Plateau, to the oligotrophic coastal zones of Kerguelen Island, and in the structuring of these interfaces between terrestrial and marine environments. The aim of this project is therefore to 1) determine how the seasonal presence of marine predators influences nutrient flows and the structuring dynamics of terrestrial ecosystems in the vicinity of colonies on Kerguelen Island, and 2) characterize and quantify these influences. We therefore expect to observe ecosystems enriched with nutrients of marine origin in the vicinity of colonies, and ecosystems with different characteristics (diversity, assemblages and phenotypes) as we move away from the heart of the colonies.

Main tasks

The candidate will work on previously collected soil, invertebrate and plant samples, which will have to be analyzed during the tenure of the fellowship, including :

1. isotopic analyses (carbon and nitrogen) of all samples collected identify and quantify the integration of nutrients of marine origin within soil, primary producers and first levels of the terrestrial food web;
2. elemental composition analyses (concentrations of trace elements) of the various compartments and their relative enrichment;
3. microbial biomass of the soil quantification as an indicator of biological activity.

Finally, plant traits (height, specific leaf area, leaf dry matter content) and invertebrates (length and width of thorax and abdomen, length of antennae) will be measured to characterize the effect of marine nutrient inputs on the phenotype of the different trophic levels. For example, the height and leaf area of a plant are indicators of the plant’s ability to exploit the resources available to it.

She/he will then statistically analyze the results obtained, combined with the diversity and relative abundance data. Multiple factors can affect the parameters measured (in particular species diversity and assemblages) such as proximity to the coast, exposure (wind, sun) and slope. However, all data on abiotic conditions and nature of the field environment were recorded, so these factors can be taken into account during analyses or results interpretation. In addition, isotopy will help account for influence from the marine environment.

In addition to supervisors from CEBC and PELAGIS, the successful candidate will work in collaboration with David Renault (ECOBIO lab, Professor, University of Rennes) and with Anne-Kristel Bittebiere (Senior Lecturer, Lyon 1 University) to perform these tasks, and may have to spend periods of times in these different laboratories during the course of the fellowship. He/She will also be in charge of supervising interns involved in the project and be disseminate the results of this work in scientific peer review journal(s), in conference/symposiums and to a general audience.