Centre for Deep Sea Research
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New microbiology research shows inactive hydrothermal vents are not so ‘dead’ after all

A new microbiology study points to highly active microorganisms living on ‘dead’ chimneys long after fluid flow has ceased to supply them with traditional chemical fuels. The findings have important implications for understanding inactive hydrothermal vents of commercial interest for deep-sea mining.

Photo taken by Reeves from the Alvin submersible window of an inactive ‘black smoker’ vent at the East Pacific Rise. While venting, these fluids fuel extensive chemosynthetic microbial growth, but this study shows that microbial carbon cycling is just as active long after the smoker fluids have completely stopped venting, leaving only extinct chimneys.
E. Reeves / Woods Hole Oceanographic Institution / National Deep Submergence Facility / HOV Alvin team / National Science Foundation.

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An international team of researchers, including Eoghan P. Reeves - a geochemist at the Centre for Deep Sea Research, Department of Earth Science, University of Bergen, has just published a novel finding with significant implications for seafloor life around extinct hydrothermal vents on the East Pacific Rise. The researchers have found that extinct or ‘dead’ black smoker chimneys (inactive hydrothermal vents where hot fluids have completely ceased flowing) play host to surprisingly active microbial communities – as active even than their microbial counterparts on the spectacular black smokers that are more well-known.

The discovery on the floor of the Pacific Ocean at 2.5km depth could change scientists’ understanding of the impact that such ocean-floor extinct vent ecosystems have on carbon cycling in Earth’s oceans. The study was based on samples of extinct sulfide chimneys collected using the submersible ‘Alvin’ in 2019. These observations are especially important given that inactive hydrothermal deposits have become prime targets for a newly developing deep-sea mining industry.

The findings have been published this week in an article entitled: “Inactive Hydrothermal Vent Deposits are Important Sites for Primary Productivity in the Deep Ocean” in the journal Nature Microbiology (link to article).