Thermogenic travertine deposits in Thermopylae hot springs (Greece) in association with cyanobacterial microflora

Abstract

The present paper deals with the investigation of abiotic and biotic influence on thermogenic travertine formation in Thermopylae hot springs, one of the largest active thermogenic travertine systems in Greece. Geological, mineralogical and microbiological data from three different types of travertines (cascades, terraces and fluvial crusts) revealed different cyanobacterial communities. Microscopic analysis of fresh and cultured material has shown that epilithic and endolithic cyanobacteria are almost the exclusive components of travertines' photosynthetic microflora. Thirty-one (31) taxa of cyanobacteria are presented here, among them the frequently found, in such environments, Phormidium incrustatum and Aphanocapsa thermalis, as well as the taxonomically interesting diazotrophic morphotype identified as Chlorogloeopsis sp. Sampling sites I and II have similar formation conditions characterized by laminated travertines with low porosity and shrub lithotypes, with the cyanobacterium Leptolyngbya ercegovicii occupying an endolithic zone, while the upper part is occupied by colonial chroococcalean species. On the contrary, sampling site III is characterized by laminated travertine with fenestrial type porosity and absence of shrub lithotypes resulting in a completely different community of cyanobacteria.

A new terrestrial active mineralizing hydrothermal system associated with ore-bearing travertines in Greece (northern Euboea Island and Sperchios area)

“…A salient feature of the geothermal activity in northern Euboea and neighbouring part of the mainland in eastern Central Greece (Sperchios area), is the dominance of thermogenic travertine deposition from the hot springs (Kanellopoulos, 2011(Kanellopoulos, , 2012(Kanellopoulos, , 2013Kanellopoulos et al 2015a). Kanellopoulos (2012) reported Fe-rich varieties among the studied travertines.…”

“…Although the formation of these thermogenic travertines is dominantly controlled by abiotic factors, also biotic factors are proposed to be contributing (Kanellopoulos, 2014b;Kanellopoulos et al, 2015a).…”

The effect of light intensity and shear stress on microbial biostabilization and the community composition of natural biofilms

“…Considering these structural aspects, the two detected dominant cyanobacteria might also be of high relevance, as they form long filaments up to 5 mm in length. 50 On one hand, these extended chains of single cells constitute an option to increase micro turbulence and availability of nutrients. On the other hand, these fibers can act as anchor points for settling cells and can be linked and tangled up, which can increase the stability of the biofilm network.…”

“…However, four species dominated in biofilms grown under high LI: Rubrivivax gelatinosus 47 and Rhodoferax saidenbachensis 48 in early development stages and Neosynechococcus sphagnicola 49 and Leptolyngbya spp. 50 in matured biofilms. In comparison to this, different levels of SS displayed no significant influence upon bacterial community composition, with Pseudomonas taiwanensis constituting the only exception, with a stronger appearance in biofilms cultivated under high flow velocity.…”

Time series metagenomic sampling of the Thermopyles, Greece, geothermal springs reveals stable microbial communities dominated by novel sulfur-oxidizing chemoautotrophs

“…Very few studies have been conducted in the Thermopyles and these were focused on geochemical features and measurements of physicochemical properties (Duriez et al, 2008; Lambrakis & Kallergis, 2005; Lambrakis et al, 2014; Verros et al, 2007; Zarikas et al, 2014) or the investigation of travertine deposits in association with Cyanobacteria (Kanellopoulos, Lamprinou, Mitropoulos, & Voudouris, 2016). Investigation of geochemical features has shown the increased concentration of hydrogen sulfide mainly produced by pyrite oxidation and reduced species of sulfates (Duriez et al, 2008; Lambrakis & Kallergis, 2005).…”