Clarisse Goar

Clarisse Goar Development of a bioindicator for the preservation of ecosystems associated with massive sulfide deposits: benthic foraminifera. or In the sulfide mountains, studying unicellular organisms capable of providing information about their environment with the aim of preserving it.

Foraminifera are unicellular organisms with a shell, -called a « test » which may be mineral or organic. These organisms evolve in most marine environments and are highly sensitive to changes of their habitat. So, their study gives valuable information on environmental conditions (pollution, temperature variations, oxygen, availability and type of food…). Some species have a strong test. After their death, they are preserved as mineral shells. This keeps the information in the sediment where they lived. This data enables Clarisse to follow the evolution of an environment, both past and present. This is why foraminifera are mostly used as bioindicators or in paleoclimatology studies.

In her thesis, Clarisse studies the nowadays-foraminiferal communities in different environments near the Mid-Atlantic ridge. She is focusing on four environments: areas far from where hydrothermal fluids are emitted, nearby areas, in intermediate environments, and "inactive" areas where vents no longer emit fluids. The aim is to determine which communities are present and how they respond to different environmental contexts.

Why this subject ?

This subject combines knowledge of geology and marine biology, giving a global vision of the environment studied. It aims to provide information on biodiversity around hydrothermal fields, an environment that is still little known but targeted by the mining industry because of the metals present on these sites. This places the subject in an actual context marked by increasing human pressures.