Influence du changement climatique sur les tapis microbiens des marais salants / Influence of climate change on salt ponds microbial mats

Mazière Camille, Maëlle Bodo, Marie Anaïs Perdrau, Cristiana Cravo-Laureau, Robert Duran, Christine Dupuy, et Cédric Hubas. 2022. « Climate Change Influences Chlorophylls And Bacteriochlorophylls Metabolism In Hypersaline Microbial Mat ». Science Of The Total Environment, 802: 149787. https://doi.org/10.1016/j.scitotenv.2021.149787

This study aimed to determine the effect of climate change on the phototrophic communities of salterns microbial mats. Among the parameters tested (decrease in pH, increase in temperature and a combination of both), the decrease in pH in seawater induced a modification of the pigment composition of the microbial mats, which resulted in a significant decrease in the relative quantity of chlorophyll a and an increase in bacteriochlorophylls. The drop in pH would therefore favor anoxygenic photosynthesis (i.e., which does not produce oxygen) in these ecosystems. However, these microbial communities are naturally confronted with environmental conditions (pH, light, temperature, salinity, etc.) that fluctuate, sometimes on a daily basis, well beyond IPCC predictions for 2100. This probably explains why the photosynthetic capacities of oxygenic microorganisms were not altered during this experiment. This study represents a preliminary step in understanding the long-term impact of climate change on salt ponds microbial communities.

BOREA contact: Cédric Hubas, assistant professor MNHN, cedric.hubas@mnhn.fr

Photo titles :

Main ill.: Photographie de la zone d’étude : un marais salant de l’île de Ré où se développent des tapis microbiens / Photography of the studied area: a salt marsh in Ré Island where microbial mats are observed. © Alice Baldy et Camille Mazière 

Photo 1 : Photographie d’un tapis microbien prélevé dans un marais salant de l’île de Ré / Photography of a microbial mat sampled in a salt marsh of Ré Island. © Alice Baldy et Camille Mazière

Photo 2 : Photographie des mésocosmes où a été simulé le changement climatique (acidification et réchauffement de l’eau) sur les tapis microbiens (sans le système lumineux) / Photography of the mesocosms' system where climate change (ocean acidification and warming) was simulated on microbial mats, without the light system. © Cristiana Cravo-Laureau et Camille Mazière