Metaproteogenomic Profiling of Microbial Communities Colonizing Actively Venting Hydrothermal Chimneys.

Petra Pjevac,Dimitri V Meier,Wolfgang Bach,Dörte Becher,Harald R Gruber-Vodicka,Christian Hentschker,Thomas Schweder,Michael Richter,Rudolf Amann,Anke Meyerdierks,Stephanie Markert

doi:10.3389/fmicb.2018.00680

Abstract

At hydrothermal vent sites, chimneys consisting of sulfides, sulfates, and oxides are formed upon contact of reduced hydrothermal fluids with oxygenated seawater. The walls and surfaces of these chimneys are an important habitat for vent-associated microorganisms. We used community proteogenomics to investigate and compare the composition, metabolic potential and relative in situ protein abundance of microbial communities colonizing two actively venting hydrothermal chimneys from the Manus Basin back-arc spreading center (Papua New Guinea). We identified overlaps in the in situ functional profiles of both chimneys, despite differences in microbial community composition and venting regime. Carbon fixation on both chimneys seems to have been primarily mediated through the reverse tricarboxylic acid cycle and fueled by sulfur-oxidation, while the abundant metabolic potential for hydrogen oxidation and carbon fixation via the Calvin–Benson–Bassham cycle was hardly utilized. Notably, the highly diverse microbial community colonizing the analyzed black smoker chimney had a highly redundant metabolic potential. In contrast, the considerably less diverse community colonizing the diffusely venting chimney displayed a higher metabolic versatility. An increased diversity on the phylogenetic level is thus not directly linked to an increased metabolic diversity in microbial communities that colonize hydrothermal chimneys.

Highlights

At sites of marine hydrothermal discharge, mixing of reduced venting fluids with oxygenated seawater leads to the formation of metal sulfides, sulfates, and oxides, which form hydrothermal chimneys and flanges (Schrenk et al, 2008)
Thermophiles related to the epsilonproteobacterial order Nautiliales, and the phyla Aquificae and Deinococcus–Thermus, as well as gammaproteobacterial and alphaproteobacterial sequences accounted for the majority of the remaining reconstructed Small subunit (SSU) rRNA gene diversity in the RMR5 dataset (Figure 1A)
Zetaproteobacteria were almost exclusively found on the diffuser RMR-D, while Bacteroidetesrelated sequences were reconstructed from both chimney metagenomes (Figure 1A)

Summary

Introduction

At sites of marine hydrothermal discharge, mixing of reduced venting fluids with oxygenated seawater leads to the formation of metal sulfides, sulfates, and oxides, which form hydrothermal chimneys and flanges (Schrenk et al, 2008). Characteristic of high-temperature venting (>300◦C), fluids flow through crystalline conduits, resulting in the formation of sharp. Metaproteomic Analysis of Hydrothermal Chimney Colonization temperature and substrate gradients throughout the chimney walls (Tivey, 2004, 2007). Such structures provide a variety of microenvironments, facilitating the co-existence of phylogenetically and physiologically diverse microorganisms (e.g., McCollom and Shock, 1997; Xia et al, 2011; Brazelton et al, 2012; Cao et al, 2014). Thermal and geochemical gradients are less pronounced, and the geochemical environment is more homogenous than in black smoker chimneys (Koski et al, 1994; Tivey, 2004, 2007)

Methods

Results

Conclusion