Individual physiological adaptations enable selected bacterial taxa to prevail during long-term incubations
2019
Enclosure experiments are frequently used to investigate the impact of changing environmental conditions on microbial assemblages. Yet, how the incubation itself challenges complex bacterial communities is thus far unknown. In this study, metaproteomic profiling, 16S rRNA gene analyses and cell counts were combined to evaluate bacterial communities derived from marine, mesohaline and oligohaline conditions after long-term batch incubations. Early in the experiment, the three bacterial communities were highly diverse and differed significantly in their composition. Manipulation of the enclosures with terrigenous dissolved organic carbon resulted in notable differences compared to the control enclosures at this early phase of the experiment. However, after 55 days, bacterial communities in the manipulated and the control enclosures at marine and mesohaline conditions were all dominated by gammaproteobacterial Spongiibacter . In the oligohaline enclosures, actinobacterial hgc-I remained abundant in the late phase of the incubation. Metaproteome analyses suggested that the ability to use outer membrane-based internal energy stores, in addition to the previously described grazing resistance, may enable the gammaproteobacterial Spongiibacter to prevail in long time incubations. Under oligohaline conditions the utilization of external recalcitrant carbon seem to be more important (hgc-I). Enclosure experiments with complex natural microbial communities are important tools to investigate the effects of manipulations. However, species-specific properties, such as individual carbon storage strategies can cause manipulation-independent effects and need to be considered when interpreting results from enclosures. Importance In microbial ecology, enclosure studies are often used to investigate the effect of single environmental factors on complex bacterial communities. However, in addition to the manipulation, unintended effects (“bottle effect”) may occur due to the enclosure itself. In this study we analyzed the bacterial communities that originated from three different salinities of the Baltic Sea, comparing their composition and physiological activity both at the early stage and after 55 days of incubation. Our results suggested that internal carbon storage strategies impact the success of certain bacterial species, independent of the experimental manipulation. Thus, while enclosure experiments remain valid tools in environmental research, microbial community composition shifts must be critically followed. This investigation of the metaproteome during long-term batch enclosures expanded our current understanding of the so-called “bottle effect”, which is well-known to occur during enclosure experiments.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
71
References
0
Citations
NaN
KQI