Clément Coclet (MEB team) will support his thesis on Wednesday 26 June at 13h30 at the M building (La Garde Campus).

On the following subject: :

Impacts of multiple contamination of trace metal elements on the microbial communities in a highly anthropized coastal environment: the Toulon bay

Toulon Bay is a highly anthropized coastal ecosystem that present multiple trace metal contamination gradients, and was considered as a model system. The coupling of field campaigns and laboratory experiments were used to study the impact of trace metal contamination on both planktonic and biofilm microbial communities. Chemical analyses, flux cytometry, and metabarcoding were used to study several characteristics of communities, as abundance and taxonomic diversity in response to trace metal contamination in the Toulon Bay. Then, both ultraphytoplankton and bacterioplankton showed strong spatial patterns along the trace metal contamination gradients. Laboratory experiments showed that trace metals played an important role on both abundance and diversity patterns of ultraplanktonic communities, by both potential direct (toxicity) and indirect (phytoplankton-bacterioplankton interactions). Conversely to planktonic communities, trace metal contamination had limited impact on microbial biofilm community. In contrast, microbial biofilm community seemed to be influenced by surrounding sediments, and by potential colonizer taxa from benthic compartment resuspended during sediment resuspension events. In conclusion, trace metals seemed to have impacts on all the microbial communities of Toulon Bay, with variations of influence depending on the compartment.

Keywords: Trace metal elements, microbial communities, bacterioplankton, ultraphytoplankton, microbial biofilm, coastal ecosystem, Toulon bay