Diversity of active microbial communities subjected to long-term exposure to chemical contaminants along a 40-year-old sediment core.
In estuarine ecosystems, metallic and organic contaminants are mainly associated with fine grain sediments which settle on mudflats. Over time, the layers of sediment accumulate and are then transformed by diagenetic processes mainly controlled by microbial activity, recording the history of the estuary's chemical contamination. In an environment of this specific type, we investigated the evolution of the chemical contamination and the structure of both total and active microbial communities, based on PhyloChip analysis of a 4.6-m core corresponding to a 40-year sedimentary record. While the archaeal abundance remained constant along the core, a decrease by one order of magnitude in the bacterial abundance was observed with depth. Both total and active microbial communities were dominated by Proteobacteria, Actinobacteria, and Firmicutes in all sediment samples. Among Proteobacteria, alpha-Proteobacteria dominated both total (from 37 to 60 %) and metabolically active (from 19.7 to 34.6 %) communities, including the Rhizobiales, Rhodobacter, Caulobacterales, and Sphingomonadales orders. Co-inertia analysis revealed a relationship between polycyclic aromatic hydrocarbons, zinc and some polychlorobiphenyls concentrations, and the structure of total and active microbial communities in the oldest and most contaminated sediments (from 1970 to 1975), suggesting that long-term exposure to chemicals shaped the structure of the microbial community.
Normandie Université, UR, UMR CNRS 6143 M2C, FED 4116, 76821, Mont Saint Aignan, France.
Assia
A
Kaci
Normandie Université, UR, UMR CNRS 6143 M2C, FED 4116, 76821, Mont Saint Aignan, France.
Fabienne
F
Petit
Normandie Université, UR, UMR CNRS 6143 M2C, FED 4116, 76821, Mont Saint Aignan, France.
Matthieu
M
Fournier
Environmental Microbial Genomics Group, Ecole Centrale de Lyon, Laboratoire Ampère UMR5005 CNRS, Ecully, France.
Sébastien
S
Cécillon
IRSN, Laboratoire de Radioécologie de Cherbourg-Octeville (LRC), 50130, Cherbourg-Octeville, France.
Dominique
D
Boust
Normandie Université, UR, UMR CNRS 6143 M2C, FED 4116, 76821, Mont Saint Aignan, France.
Patrick
P
Lesueur
Normandie Université, UR, UMR CNRS 6143 M2C, FED 4116, 76821, Mont Saint Aignan, France. thierry.berthe@univ-rouen.fr.
Thierry
T
Berthe
D001105:Archaea; D044822:Biodiversity; D017753:Ecosystem; D004787:Environmental Pollution; D063366:Estuaries; D005602:France; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D059013:Microbial Consortia / Q000187:drug effects*; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D020560:Proteobacteria; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
Anthropized estuary; Microbial diversity; Organic pollutants; PhyloChip; Sediment core; Trace metals