Thébault Justine

PhD (2017-2020)
Justus-Liebig University (Gieβen, Germany) and Doctoral School of the University of La Rochelle (EUCLIDE)
Original training :
Master Marine Biological Sciences, specialization in Marine Ecosystems; European Institute for Marine Studies, Plouzané, France; 2015-2016

(2017-2020) Mercury contamination and plastic debris residues in Antarctic petrel species

Keywords : ecotoxicology, bioaccumulation, biomagnification, heavy metals, mercury, plastics, phthalates, trophic ecology, bulk stable isotopes, compound specific stable isotopes, Antarctica, Southern Ocean, seabirds

Supervisors :
-  Petra Quillfeldt, researcher, Justus-Liebig University, Gieβen, Allemagne
-  Paco Bustamante, researcher, University of La Rochelle, LIENSs UMR 7266

Funding : Allocation from the German Research Foundation (Deutsche Forschungsgemeinschaft), via their priority program 1158 “Antarctic Research with Comparative Investigations in Arctic Ice Areas”

Mercury contamination and plastic debris residues in Antarctic petrel species
Marine ecosystems are renowned to be major repositories of environmental contaminants, such as heavy metals, persistent organic pollutants and plastic debris. Seabirds are often long-lived meso to top predators, hence particularly at risk of environmental contaminant bioaccumulation and biomagnification. They have therefore been widely used as sentinels in order to monitor the pollution in the ocean. Nevertheless, mercury (Hg) and plastic exposure of petrel species are still poorly documented, especially in remote areas such as polar regions.

In the frame of my PhD, fieldwork is carried out during early and late breeding season, at different sites in Antarctic (King George Island, Adélie Land) and Subantarctic (Diego Ramirez Islands, Kerguelen Island, Falkland Islands) zones. Mercury, stable isotopes and compound specific stable isotopes will be measured from the same birds using feathers and blood samples. The presence of common plasticizers will be determined in the waxy preen oil using a recently established GC-MS protocol. Additionally, plastic exposure of seabirds breeding in the Southern Ocean will be compared with storm petrel breeding in the North-east Pacific (Coronado and Todos Santos Islands, Mexico), an area renowned to display a high plastic contamination.

Research questions:

  • Does the distribution at sea and the trophic level determine the level of Hg and plastic contamination in Antarctic and Subantarctic petrel species?
  • Does the level of contamination change over the breeding period? Is there a carry-over effect from the winter areas?
  • Are the Hg and plastic debris residues body burdens of petrel species breeding in Antarctic and Subantarctic zones lower than those breeding in the Northern Pacific?
  • Are the levels of contamination hazardous for the birds?
  • Is there a temporal variation in the exposure of Antarctic seabirds to Hg?
  • Is there a synergetic effect of Hg and plastics?

The level of contamination:

  • increases with a more northerly breeding and inter-breeding distribution (lower contamination in Antarctic waters) and with a higher trophic level;
  • is higher at the beginning of the breeding season for Antarctic species. Over the course of the season the contamination level drops as birds spend more time in Antarctic waters;
  • is higher in adults than in chicks for Antarctic species;
  • is increasing over time;
  • is highest in the North Pacific, intermediate in the Subantarctic and lowest in the Antarctic species.

Collaborations :
-  Centre d’Etudes Biologiques de Chizé (France)
-  Instituto Antártico Argentino (Argentina)
-  UC Davis Stable Isotope facility (USA)