Chronic Environmental Perturbation Influences Microbial Community Assembly Patterns

Abstract

Acute environmental perturbations are reported to induce deterministic microbial community assembly, while it is hypothesized that chronic perturbations promote development of alternative stable states. Such acute or chronic perturbations strongly impact on the pre-adaptation capacity to the perturbation. To determine the importance of the level of microbial pre-adaptation and the community assembly processes following acute or chronic perturbations in the context of hydrocarbon contamination, a model system of pristine and polluted (hydrocarbon-contaminated) sediments was incubated in the absence or presence (discrete or repeated) of hydrocarbon amendment. The community structure of the pristine sediments changed significantly following acute perturbation, with selection of different phylotypes not initially detectable. Conversely, historically polluted sediments maintained the initial community structure, and the historical legacy effect of chronic pollution likely facilitated community stability. An alternative stable state was also reached in the pristine sediments following chronic perturbation, further demonstrating the existence of a legacy effect. Finally, ecosystem functional resilience was demonstrated through occurrence of hydrocarbon degradation by different communities in the tested sites, but the legacy effect of perturbation also strongly influenced the biotic response. This study therefore demonstrates the importance of perturbation chronicity on microbial community assembly processes and reveals ecosystem functional resilience following environmental perturbation.

Electrokinetic-Enhanced Bioremediation of Trichloroethylene-Contaminated Low-Permeability Soils: Mechanistic Insight from Spatio-Temporal Variations of Indigenous Microbial Community and Biodehalogenation Activity

“…Within 60 d, IR-type populations were enriched mostly, and OHR-type population (OTU_13) decreased first; after 90 d, OHR-type populations turned to dominate (Figure b). The Geobacter assembly process was a typical drift pattern (Figure b), , which could limit the biodehalogenation activity. Obligate OHRB Dehalobacter had an extremely low abundance in the initial soil (0.00,128%), and it was gradually enriched to ∼0.05% at 30 d and to 0.82–2.74% at 195 d (Figure c).…”

“…OTU_43 is closer to Dehalobacter 12 DCA (GB: CP046996.1) than OTU_1481 (Figure S12), which indicated the assembly of Dehalobacter populations into TCE-dehalogenation type under EK-Bio. The Dehalobacter assembly process was a typical selection pattern (Figure c), , which directly enhanced the biodehalogenation activity. Versatile OHRB Anaeromyxobacter was also enriched to a high abundance (Figure S11b), but it is not proven of TCE dehalogenation. , …”

Stronger responses of soil protistan communities to legacy mercury pollution than bacterial and fungal communities in agricultural systems

“…The increased interactions within protistan community could be attributed to the adaption to long-term Hg pollution. For example, chronic environmental perturbation like hydrocarbon contamination maintained the initial microbial community structure [ 82 ]. Consistently, soil microbial community gradually recovered after a fumigation in facility agricultural systems [ 83 ].…”

Gender Effects of Dioecious Plant Populus cathayana on Fungal Community and Mycorrhizal Distribution at Different Arid Zones in Qinghai, China

“…With governing soil carbon cycling, plant pathology, and nutrition, fungi are integral ecosystem agents [ 12 ]. Although it has been widely known that fungal communities in the specific ecosystem are not a random combination of species, researchers still seek to understand the process of shaping community assembly [ 13 , 14 ].…”