ena-STUDY-Instituto Antofagasta-24-08-2018-19:25:48:161-145
Connectivity of Bacterial Communities—Case of the Loa River in the Atacama Desert
The Loa River is an exceptional watercourse within the Atacama Desert; it crosses ~440km from East to West and discharges its waters into the Pacific Ocean. However, the roleof this fluvial ecosystem in the dispersal of microorganisms has not yet been studied indetail. In this study, we analysed bacterial communities in the Loa River, using V4 regionsequencing of the 16S rRNA gene from 16 samples of water and surface sediments takenfrom 8 sampling sites along the river. In addition, we used network analysis to identifyinterconnected river microbial assemblages. An average of 2482 Operational TaxonomicUnits (OTUs) were obtained, whose diversity decreased from the headstream down andtended to be greater in sediment than in water. The structure of the bacterial communitywas related along the river, clustering by site and based on substrate type (water orsediment). The communities were dominated by a large variety of Proteobacteria,Bacteroidetes, Cyanobacteria, Planctomycetes, Actinobacteria, and Firmicutes phyla.Further, less abundant communities contained many unique taxa with a high level ofmetabolic diversity. Shifts in community structure were related to the influence of salinity,pH, chlorophyll, and oxygen saturation. The proportions of common taxa along the riverindicated that there is strong connectivity between the bacterial communities upstream anddownstream. Thus, we propose the Loa River is a possible &quot;extreme local reservoir&quot; with agreat ecological importance, emphasising the need for planning its conservation.
The Loa River is an exceptional watercourse within the Atacama Desert; it crosses ~440km from East to West and discharges its waters into the Pacific Ocean. However, the roleof this fluvial ecosystem in the dispersal of microorganisms has not yet been studied indetail. In this study, we analysed bacterial communities in the Loa River, using V4 regionsequencing of the 16S rRNA gene from 16 samples of water and surface sediments takenfrom 8 sampling sites along the river. In addition, we used network analysis to identifyinterconnected river microbial assemblages. An average of 2482 Operational TaxonomicUnits (OTUs) were obtained, whose diversity decreased from the headstream down andtended to be greater in sediment than in water. The structure of the bacterial communitywas related along the river, clustering by site and based on substrate type (water orsediment). The communities were dominated by a large variety of Proteobacteria,Bacteroidetes, Cyanobacteria, Planctomycetes, Actinobacteria, and Firmicutes phyla.Further, less abundant communities contained many unique taxa with a high level ofmetabolic diversity. Shifts in community structure were related to the influence of salinity,pH, chlorophyll, and oxygen saturation. The proportions of common taxa along the riverindicated that there is strong connectivity between the bacterial communities upstream anddownstream. Thus, we propose the Loa River is a possible &quot;extreme local reservoir&quot; with agreat ecological importance, emphasising the need for planning its conservation.