Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia
- Published
- Accepted
- Subject Areas
- Biogeography, Ecology, Microbiology, Freshwater Biology
- Keywords
- biofilm, co-occurrence, hydrology, dissimilarity, modules, microbial community
- Copyright
- © 2019 Ren et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia. PeerJ Preprints 7:e27887v1 https://doi.org/10.7287/peerj.preprints.27887v1
Abstract
Bacterial and fungal communities in biofilms are important components in driving biogeochemical processes in stream ecosystems. Previous studies have well documented the patterns of bacterial alpha diversity in stream biofilms in glacier-fed streams, where, however, beta diversity of the microbial communities has received much less attention especially considering both bacterial and fungal communities. A focus on beta diversity can provide insights into the mechanisms driving community changes associated to large environmental fluctuations and disturbances, such as in glacier-fed streams. Moreover, modularity of co-occurrence networks can reveal more ecological and evolutionary properties of microbial communities beyond taxonomic groups. Here, integrating beta diversity and co-occurrence approach, we explored the network topology and modularity of the bacterial and fungal communities with consideration of environmental variation in glacier-fed streams in Central Asia. Combining results from hydrological modeling and normalized difference of vegetation index, this study highlighted that hydrological variables and vegetation status are major variables determining the environmental heterogeneity of glacier-fed streams. Bacterial communities formed a more complex and connected network, while the fungal communities formed a more clustered network. Moreover, the strong interrelations among the taxonomic dissimilarities of bacterial community and modules suggest they had common processes in driving diversity and taxonomic compositions across the heterogeneous environment. In contrast, fungal community and modules generally showed distinct driving processes to each other. Moreover, bacterial and fungal communities also had different driving processes. Furthermore, the variation of bacterial community and modules were strongly correlated with hydrological properties and vegetation status but not with nutrients, while fungal community and modules (except one module) were not associated with environmental variation. Our results suggest that bacterial and fungal communities had distinct mechanisms in structuring microbial networks, and environmental variation had strong influences on bacterial communities but not on fungal communities. The fungal communities have unique assembly mechanisms and physiological properties which might lead to their insensitive responses to environmental variations compared to bacterial communities. Overall, beyond alpha diversity in previous studies, these results add our knowledge that bacterial and fungal communities have contrasting assembly mechanisms and respond differently to environmental variation in glacier-fed streams.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Supplementary Figures
Figure S1 Distributions of OTUs across sample sites for bacterial modules
Figure S2 Distributions of OTUs across sample sites for fungal modules
Supplementary Tables
Table S1 Pairwise dissimilarity tests of taxonomic composition among bacterial modules using PERMANOVA (adonis function in vegan package 2.5-3). R2 and P-values (in bracket) are shown
Table S2 Pairwise dissimilarity tests of taxonomic composition among fungal modules using PERMANOVA (adonis function in vegan package 2.5-3). R2 and P-values (in bracket) are shown.