Biogeochemical and hydrosedimentary functioning of Lake Grand-Lieu
Lowland lakes constitute privileged interfaces between terrestrial and aquatic ecosystems and represent hotspots of biogeochemical activities and diversity, dependent on climatic aleas. Being shallow, they are commonly viewed as homogeneously mixed.
However, these water bodies can have a strong spatial heterogeneity of physico-chemical parameters and communities completely neglected until now. Although these systems are very often mixed by wind, strong thermal gradients (up to 8 ° C) and chemical gradients can be put in place for a few hours, in some parts of the lake. This recurrent fragmentation impacts the biogeochemical functioning of the system, its gas exchange and its plankton communities.
Plankton communities have a key role in cycles (C, N, P and Si) they couple, they have a high reactivity to environmental local conditions and present a huge diversity.
The objective of this study is to characterize the spatio-temporal dynamics (vertical and horizontal) of water masses in a large shallow lake and to highlight the consequences on nutrient concentrations, biomass and diversity of planktonic communities.
Projet en partenariat avec la SNPN
La Société nationale de protection de la nature, chargée par le ministère de l’Environnement d’assurer la gestion de la réserve, nous aide lors des différents échantillonnages et assure le suivi des sondes laissées en place dans le lac.