Long-term dynamic changes in attached and planktonic microbial communities in a contaminated aquifer. (15th May 2021)

• Record Type: Journal Article
• Authors: Mujica-Alarcon, Juan F.; Thornton, Steven F.; Rolfe, Stephen A.
• Is Part Of: Environmental pollution. Volume 277(2021)
• Publication Date: 2021-05-15
• Subjects: Attachment -- Microbial dynamics -- Community preferences; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.116765
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Biodegradation is responsible for most contaminant removal in plumes of organic compounds and is fastest at the plume fringe where microbial cell numbers and activity are highest. As the plume migrates from the source, groundwater containing the contaminants and planktonic microbial community encounters uncontaminated substrata on which an attached community subsequently develops. While attached microbial communities are important for biodegradation, the time needed for their establishment, their relationship with the planktonic community and the processes controlling their development are not well understood. We compare the dynamics of development of attached microbial communities on sterile substrata in the field and laboratory microcosms, sampled simultaneously at intervals over two years. We show that attached microbial cell numbers increased rapidly and stabilised after similar periods of incubation (∼100 days) in both field and microcosm experiments. These timescales were similar even though variation in the contaminant source evident in the field was absent in microcosm studies, implying that this period was an emergent property of the attached microbial community. 16S rRNA gene sequencing showed that attached and planktonic communities differed markedly, with many attached organisms strongly preferring attachment. Successional processes were evident, both in community diversity indices and from community network analysis. Community development was governed by both deterministic and stochastic processes and was related to the predilection of community members for different lifestyles and the geochemical environment. Graphical abstract: Image 1 Highlights: Attached microbial cell numbers took 100 days to stabilise in laboratory microcosms and in situ field incubations. Attached and planktonic communities differed markedly over time. Members of the α-, β- and γ-Proteobacteria showed preferential attachment. Bacteroidia, Clostridia, δ-Proteobacteria and other β-Proteobacteria were preferentially planktonic. Community development was governed by both deterministic and stochastic processes.