Microbial Ecology

Lya obtained her bachelor's degree in Life and Earth Sciences (SVT) from the University of Southern Brittany (UBS), where she then pursued a master's degree in Biotechnology (Biomolecules, Microorganisms, and Bioresources). It was during her final master's internship in Denmark that she decided to focus on environmental issues and continue her career in research. Drawn to Dr. Lazar's project, she wanted to work on groundwater ecosystems.

​

This doctoral project focuses on the interactions between planktonic microorganisms in aquifers. These environments are challenging for microbial life due to their low organic carbon and nutrient content, as well as limited energy sources. Although abiotic factors (water geochemistry, geology, surface conditions) strongly control these communities, they explain only a small portion of the observed microbial variance. This project therefore examines the hypothesis that biotic interactions (competition, mutualism, predation) explain a major part of this unexplained variance. Three themes will be addressed. The first focuses on syntrophic relationships between groundwater microbes, these metabolic associations essential for survival in these nutrient-poor environments. A second theme aims to study the effect of local abiotic factors on population dynamics, including their temporal evolution and seasonal variations linked to surface conditions. The third theme of the project focuses on identifying the food chains and food webs present in these ecosystems. To achieve these objectives, culture methods will be used to grow planktonic microorganisms, followed by DNA and RNA extraction. Amplicon sequencing will allow for the analysis of the diversity of archaea, bacteria, and eukaryote communities, and some samples will also be used to reconstruct the entire genomes of the populations present.