Homogeneous Environmental Selection Structures the Bacterial Communities of Benthic Biofilms in Proglacial Floodplain Streams.

Détails

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Etat: Public
Version: Final published version
Licence: CC BY 4.0
ID Serval
serval:BIB_FD32F91019F6
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Homogeneous Environmental Selection Structures the Bacterial Communities of Benthic Biofilms in Proglacial Floodplain Streams.
Périodique
Applied and environmental microbiology
Auteur⸱e⸱s
Brandani J., Peter H., Fodelianakis S., Kohler T.J., Bourquin M., Michoud G., Busi S.B., Ezzat L., Lane S., Battin T.J.
ISSN
1098-5336 (Electronic)
ISSN-L
0099-2240
Statut éditorial
Publié
Date de publication
29/03/2023
Peer-reviewed
Oui
Volume
89
Numéro
3
Pages
e0201022
Langue
anglais
Notes
Publication types: Journal Article
Publication Status: ppublish
Résumé
In proglacial floodplains, glacier recession promotes biogeochemical and ecological gradients across relatively small spatial scales. The resulting environmental heterogeneity induces remarkable microbial biodiversity among proglacial stream biofilms. Yet the relative importance of environmental constraints in forming biofilm communities remains largely unknown. Extreme environmental conditions in proglacial streams may lead to the homogenizing selection of biofilm-forming microorganisms. However, environmental differences between proglacial streams may impose different selective forces, resulting in nested, spatially structured assembly processes. Here, we investigated bacterial community assembly processes by unraveling ecologically successful phylogenetic clades in two stream types (glacier-fed mainstems and non-glacier-fed tributaries) draining three proglacial floodplains in the Swiss Alps. Clades with low phylogenetic turnover rates were present in all stream types, including Gammaproteobacteria and Alphaproteobacteria, while the other clades were specific to one stream type. These clades constituted up to 34.8% and 31.1% of the community diversity and up to 61.3% and 50.9% of the relative abundances in mainstems and tributaries, respectively, highlighting their importance and success in these communities. Furthermore, the proportion of bacteria under homogeneous selection was inversely related to the abundance of photoautotrophs, and these clades may therefore decrease in abundance with the future "greening" of proglacial habitats. Finally, we found little effect of physical distance from the glacier on clades under selection in glacier-fed streams, probably due to the high hydrological connectivity of our study reaches. Overall, these findings shed new light on the mechanisms of microbial biofilm assembly in proglacial streams and help us to predict their future in a rapidly changing environment. IMPORTANCE Streams draining proglacial floodplains harbor benthic biofilms comprised of diverse microbial communities. These high-mountain ecosystems are rapidly changing with climate warming, and it is therefore critical to better understand the mechanisms underlying the assembly of their microbial communities. We found that homogeneous selection dominates the structuring of bacterial communities in benthic biofilms in both glacier-fed mainstems and nonglacier tributary streams within three proglacial floodplains in the Swiss Alps. However, differences between glacier-fed and tributary ecosystems may impose differential selective forces. Here, we uncovered nested, spatially structured assembly processes for proglacial floodplain communities. Our analyses additionally provided insights into linkages between aquatic photoautotrophs and the bacterial taxa under homogeneous selection, potentially by providing a labile source of carbon in these otherwise carbon-deprived systems. In the future, we expect a shift in the bacterial communities under homogeneous selection in glacier-fed streams as primary production becomes more important and streams become "greener".
Mots-clé
Ecosystem, Phylogeny, Biodiversity, Bacteria/genetics, Microbiota, Biofilms, 16S and 18S rRNA amplicons, assembly processes, benthic biofilms, climate change, microbial diversity, proglacial floodplains
Pubmed
Web of science
Open Access
Oui
Création de la notice
13/03/2023 17:16
Dernière modification de la notice
12/04/2023 5:54
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