We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Interrelation prokaryotic community-aquifer in a carbonate coastal environment.
- Authors
Sola, Fernando; Vargas-García, María del Carmen; Vallejos, Angela
- Abstract
Seawater intrusion in coastal aquifers produces strong physico-chemical gradients. The bacterial community can play a significant role in the biogeochemical reactions in these specific environments. The objective of this study was to analyze the prokaryotic community and determine its influence along a vertical saline gradient (from freshwater to saltwater) and pH (from 9 to 5) in 16 m of groundwater column in a carbonate coastal aquifer. Representative samples taken from the freshwater, interface and saltwater were amplified using primers of the hypervariable V3–V4 region of the 16S rRNA gene and sequenced using NGS technology (Next Generation Sequencing) in order to reveal the prokaryotic microbiome, both Bacteria and Archaea. There were clear differences in the prokaryotic community along this profile, in both qualitative and relative quantitative terms. The freshwater layer, in the upper part of the aquifer, was richer in the number of species and was dominated by Proteobacteria which were replaced by Firmicutes and Euryarchaeota as depth and salinity increased. All groundwater levels had, in general, a relatively high diversity of OTUs, most of them showing low relative abundances (< 0.1%). There was a clear interdependence between physicochemical and microbial parameters; firstly, the marine intrusion created a vertical salinity gradient where only the species adapted to these environments could develop. Secondly, the microbial action modified the environment, generating in the upper part an anomalous alkaline pH where specialist species live, such as Desulfonatronum cooperativum. As for the interface and saltwater layers, they were clearly acid due to the activity of several sulfates reducing bacteria species, such as Sulfuriflexus mobilis or Desulfomicrobium baculatum. The latter species is able to oxidize several metals, resulting in a pH decrease in the groundwater and an increase in the concentration of these metals. The acidification mediated by bacteria plays a significant role since it can dissolve the carbonate rock, favoring the landward advance of marine intrusion.
- Subjects
SULFATE-reducing bacteria; CARBONATES; DNA primers; SALTWATER encroachment; INTERDEPENDENCE theory; CARBONATE rocks; WATER table; HYPERVARIABLE regions
- Publication
Aquatic Sciences, 2020, Vol 82, Issue 1, p1
- ISSN
1015-1621
- Publication type
Article
- DOI
10.1007/s00027-019-0686-4