Benthic bacterial diversity from freshwater tufas of the Iberian Range (Spain)

Abstract

Aiming to characterize the bacterial diversity of modern tufa systems of the Iberian Range (Spain), we surveyed the 16S rRNA gene sequence diversity from 24 sites within three rivers (Añamaza, Mesa and Piedra). These tufas record substantial calcareous growth under different physicochemical conditions and are part of an important, regional landscape-building system. The bacterial community structure and composition, richness and diversity were quantified from denaturing gradient gel electrophoresis fingerprints. Retrieved DNA sequences could be assigned to 10 bacterial phyla and included a variety of phototrophic and heterotrophic groups. Cyanobacteria, mainly filamentous taxa, constituted 43% of all the retrieved sequences, followed by Firmicutes (11%), Gammaproteobacteria (10%), Alphaproteobacteria (7%), Acidobacteria (6%), Bacteroidetes (5%), Betaproteobacteria (4%), Planctomycetes (4%), Actinobacteria (3%) and Deltaproteobacteria (2%). Diatom and Xanthophyceae chloroplast sequences were also detected. Physicochemical variables measured at each site were modelled with multivariate statistics. Principal component analyses yielded the highest variance for salinity-related variables (conductivity; Na(+) , Cl(-) and SO4(2-) concentrations), which correlated negatively and significantly with diversity indices. However, the highest variance explained by individual principal components was relatively low (< 34%). Overall, we show that these young fluvial tufas are inhabited by a large variety of bacteria in diverse and widespread communities.

Deciphering biodiversity and interactions between bacteria and microeukaryotes within epilithic biofilms from the Loue River, France

“…Indeed, 26% of the bacterial reads correspond to potentially photosynthetic microorganisms belonging to the Rhodobacteraceae family, confirming previous studies highlighting the large abundance of purple non-sulfur bacteria ( e . g ., refs 10, 14–16). Even if most of these bacteria can also be considered heterotrophic 17 , with their photoautotrophic metabolisms depending on environmental conditions (anaerobic conditions, for example), this finding suggests that it might be interesting to estimate their contribution to primary production in river biofilms by using, for instance, an isotope labeling approach.…”

“…These pioneer microorganisms facilitate the establishment of the next arrivals, including heterotrophic and photosynthetic microorganisms 7 , such as bacteria belonging to Alphaproteobacteria and Bacteroidetes 3 , cyanobacteria, microalgae 7–9 , and other microorganisms ( i . e ., archaea, fungi, protozoa, small metazoans, and viruses 1, 10, 11 ).…”

“…g ., refs 10, 14–16). Among them, members of the Rhodobacter genus are able to grow under anaerobic (phototrophic) and aerobic (chemoheterotrophic) conditions 17 .…”

Intrinsic and extrinsic controls of spatial and temporal variations in modern fluvial tufa sedimentation: A thirteen‐year record from a semi‐arid environment

“…Most studies of present fluvial tufas deal with stable‐isotope geochemistry (Hori et al ., ; Kawai et al ., ; Osácar et al ., ), sedimentology (Drysdale & Gillieson, ; Gradziński, ; Pedley & Rogerson, ; Manzo et al ., ) and hydrochemistry (Lorah & Herman, ; Liu et al ., ; Kano et al ., ; Kawai et al ., ; Auqué et al ., ). Biological investigations, although much fewer in number, are also significant for understanding the role of organisms (for example, plants and prokaryotes) in tufa formation (Shiraishi et al ., ; Pedley et al ., ; Santos et al ., ; Beraldi‐Campesi et al ., ), primarily through photosynthesis and extracellular polymeric substance (EPS) mediation (Arp et al ., ; Pedley & Rogerson, ; Shiraishi et al ., ). Some geochemical studies of recent and ancient tufas have demonstrated that tufas are excellent archives of seasonal and interannual environmental conditions and, hence, tufas are considered to be high‐resolution records (Lojen et al ., ; Andrews, ; Brasier et al ., ; Osácar et al ., ).…”

How environment selects: Resilience and survival of microbial mat community within intermittent karst spring Krčić (Croatia)

“…In almost all seasons, filamentous Cyanobacteria belonging to the Oscillatoriales were predominant bacterial microorganisms, thus confirming their key role within the community. Oscillatoriales, that included populations of Microcoleus and Phormidum species, is widely distributed lineage, preferentially in colder environments (Casamatta, Johansen, Vis, & Broadwater, ; Jungblut, Lovejoy, & Vincent, ; Tang, Tremblay, & Vincent, ), designated as most abundant Cyanobacteria in calcifying freshwater microbial mats (Cadel‐Six et al, ; Bissett, Reimer, de Beer, Shiraishi, & Arp, ; Beraldi‐Campesi et al, ; Perri, Manzo, & Tucker, ; Wood, Smith, et al, ; Schneider, Reimer, Hahlbrock, Arp, & Rolf, ). Interestingly, mat community harboured one abundant population of cyanobacteria (in average 20%) related to the uncultured Antarctic cyanobacterium, giving a clue to the specific extreme environmental condition defining Krčić.…”