Biogeochemical insights into microbe–mineral–fluid interactions in hydrothermal chimneys using enrichment culture

Abstract

Active hydrothermal chimneys host diverse microbial communities exhibiting various metabolisms including those involved in various biogeochemical cycles. To investigate microbe-mineral-fluid interactions in hydrothermal chimney and the driver of microbial diversity, a cultural approach using a gas-lift bioreactor was chosen. An enrichment culture was performed using crushed active chimney sample as inoculum and diluted hydrothermal fluid from the same vent as culture medium. Daily sampling provided time-series access to active microbial diversity and medium composition. Active archaeal and bacterial communities consisted mainly of sulfur, sulfate and iron reducers and hydrogen oxidizers with the detection of Thermococcus, Archaeoglobus, Geoglobus, Sulfurimonas and Thermotoga sequences. The simultaneous presence of active Geoglobus sp. and Archaeoglobus sp. argues against competition for available carbon sources and electron donors between sulfate and iron reducers at high temperature. This approach allowed the cultivation of microbial populations that were under-represented in the initial environmental sample. The microbial communities are heterogeneously distributed within the gas-lift bioreactor; it is unlikely that bulk mineralogy or fluid chemistry is the drivers of microbial community structure. Instead, we propose that micro-environmental niche characteristics, created by the interaction between the mineral grains and the fluid chemistry, are the main drivers of microbial diversity in natural systems.

Enargite-luzonite hydrothermal vents in Manus Back-Arc Basin: submarine analogues of high-sulfidation epithermal mineralization

“…Biological observations showed that the external layers of hydrothermally active flanges were intensely populated by different communities (bacteria, worms, etc.) (Woods and Delaney, 1992;Sarrazin et al, 1997;Tokeshi, 2011;Callac et al, 2015). Our results indicate that fungi living at the seafloor hydrothermal sites (e.g., at the flanges of active chimneys) may not only be implicated in a mechanism of bio-sequestration of As and S (orpiment), but also in the biogenic precipitation of As, S and Cu (luzonite).…”

Comparative Study of Guaymas Basin Microbiomes: Cold Seeps vs. Hydrothermal Vents Sediments

“…The Guaymas Basin is a unique environment which harbors not only hydrothermal chimneys, mounds (Callac et al, 2015) and hydrothermally impacted sediments (i.e., sediments percolated by hydrothermal fluid) (Teske et al, 2002) but also cold seep sediments (Vigneron et al, 2013;Cruaud et al, 2015), within few kilometers. In this study, area of hydrothermally impacted sediments and cold seep sediments were investigated to compare the microbial community compositions and potential functions present in these contrasted ecosystems in absence of physical borders and in a similar geochemical context characterized by the accumulation of organic-rich sediments.…”

“…Despite these similarities, hydrothermally influenced sediments harbored numerous endemic lineages (seven bacterial and three archaeal phyla- Figure 3) with members of the ANME-1 Guaymas, Thermoprotei, Archaeoglobales, Thermotogales, GBG/HotSeep-1 and Thermodesulfobacteraceae, previously detected in hydrothermal chimneys (Callac et al, 2015) and sediments of the Guaymas Basin (Teske et al, 2002). Supporting the positive correlation between these lineages and the temperatures measured in the sediments (Figure 5 and Figure S1), cultivated representatives of these lineages are thermophiles, growing at temperatures from 50 to 90 • C (Amend and Shock, 2001).…”

Arsenic and high affinity phosphate uptake gene distribution in shallow submarine hydrothermal sediments

“…qPCR gene quantification was performed in triplicates in samples, standards, together with negative controls to check for laboratory contamination. The total gene copy numbers per gram of sediment or per litre of seawater was calculated from the triplicate sample averages as previously described (Callac et al 2015, 2017). Geobacteraceae 16S rRNA gene abundance was estimated according to the average of 4.1 for bacteria 16S rRNA genes per cell (Lee et al 2009; Callac et al 2015, 2017).…”