Bacterial and archaeal populations at two shallow hydrothermal vents off Panarea Island (Eolian Islands, Italy)

Abstract

The aim of this study was to investigate the microbial community thriving at two shallow hydrothermal vents off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the vents on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two vents, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphur-oxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 10(5) cells ml(-1), expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77-3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR-DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest site (site 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest site (site 1). Sulphur-oxidising bacteria were detected by both culture-dependent and -independent methods. The primary production at the shallow hydrothermal system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs.

High Archaea diversity in Varvara hot spring, Bulgaria

“…Branching of the environmental sequences almost exclusively between unculturable Archaea has been already observed not only for hot springs [6,31] but also for other places where Archaea diversity was studied [32]. Most of the sequences retrieved in this study were related to Crenarchaeota, unlike the results from Panarea Iceland, where euryarchaeotic diversity in hydrothermal vents was significantly higher [33]. Almost quarter of the sequences belonged to the group of HSS.…”

“…Lack of specificity was observed in other investigations. Maugeri et al [33] reported the identification of 16S rRNA gene sequences affiliated to uncultured clones of Archaea from hot springs and hydrothermal vents of different geographical zones. Correspondingly newly described culturable Archaea were grouped together with already described culturable 16S rRNA genes [36].…”

Subsurface hydrothermal processes and the bioenergetics of chemolithoautotrophy at the shallow-sea vents off Panarea Island (Italy)

“…1b). In both areas, emissions are marked by white deposits of colloidal sulfur associated with microbial activity (Gugliandolo et al, 1999;Italiano and Nuccio, 1991;Maugeri et al, 2009). …”

“…Metagenome analysis supports the relevance of sulfur metabolism and of the rTCA cycle for autotropic life at Hot Lake (Huang, 2012). Maugeri et al (2009), suggested that sulfur-oxidizing bacteria were detected by both culture-dependent and -independent methods at two nearby sites within the Panarea submerged caldera.…”

Electrophoretic Techniques in Microbial Ecology

“…DGGE of PCR amplified 16S rDNA fragments have been used to profile community complexity of microbial mats and bacterial biofilms of a wide variety of ecosystems. DGGE analysis of PCR amplified rDNA fragments has been used to provide information on the microbial diversity of microbial communities associated to hydrothermal vents (Li et al, 2008;Maugeri et al, 2009), soil (Vaario et al, 2011) or extreme acidic environments (González-Toril et al, 2003) (Fig.1). PCR-DGGE has been applied to profile the distribution of microbial populations inhabiting regions with different temperatures in hot spring cyanobacterial communities (Aditiawati et al, 2009;Teske et al, 2009), to identify bacteria in a biodegraded wall painting (Rolleke et al, 1996) or historical limestone buildings (Ettenauer et al, 2011).…”