Bacterial diversity patterns in rivers

In various projects, ESA researchers want to unravel the drivers of bacterial community assembly and heterotrophic activity over space and time in the water column of various western European rivers.

In the last years, ESA has investigated the bacterial community composition (BCC) along the course of the Seine River (France) from upstream Paris to downstream Paris. The possible impact of various pollutants (metals, organic micropollutants,…) was studied (Barjhoux et al., 2018).

Studies were also conducted on the BCC of the Zenne River (Belgium). This small river is crossing Brussels where it receives the effluents of two large wastewater treatment plants which largely impact the river bacterial community as previously described by our lab (Garcia-Armisen et al. 2014).

Presently, BCC is studied in a medium-sized western European river watershed, the Meuse watershed. It has been chosen because several studies by our laboratory have shown dynamic patterns of phytoplankton and bacterioplankton in the Belgian course of the Meuse River (Servais 1989; Servais et al. 2000). Moreover, its geology and land use are diverse and the impact of (treated) wastewater outfalls potentially sizable due to high population density in some areas of the watershed.

More specifically, we focus on three aspects:

–          Analysis of spatio-temporal patterns of total and active bacterial community composition (BCC) in relation to its physico-chemical and hydrological parameters. The sampling strategy combines 50 stations sampled 4 times a year and a limited number of stations sampled every week or every 24 hours.

–          Characterizing the BCC and metabolic diversity at coalescence points (river confluences and wastewater inputs), which -based on previous work in our lab (Garcia-Armisen et al. 2014)- could be local hotspots of taxonomic and functional diversity.

–          identifying the factors responsible for the observed BCC at point coalescence events (and downstream), from the mixing ratio of the two water masses to intrinsic properties of the source communities (richness/evenness, presence of specific taxa, size, potential intracommunity interactions, and activity)

Period of the study: October 2011- September 2024

ESA members participating to the project: Barberoux V., Servais P., George, I.

Publications:

Barjhoux, I., Fechner, L.C., Lebrun, J.D., Anzil, A., Ayrault, S., Budzinski, H., Cachot, J., Charron, L., Chaumot, A., Clérandeau, C., Dedourge-Geffard, O., Faburé, J., François, A., Geffard, O., George, I., Labadie, P., Lévi, Y., Munoz, G., Noury, P., Oziol, L., Quéau, H., Servais, P., Uher, E., Urien, N. & Geffard, A. 2018. Application of a multidisciplinary and integrative Weight-of-Evidence approach to a one-year monitoring survey of the Seine River. Environmental Science and Pollution Research.  25(24): 23404-23429.