Scientists have been studying hydrothermal vents in the deep ocean for the past 46 years – but, beyond microbes in the sediment, they had never before looked for life beneath these volcanic hot springs.
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Now an international science team has peered into volcanic cavities beneath the “hot smokers” to discover a previously unsuspected ecosystem.
The breakthrough came during a month-long expedition led by Dr Monika Bright of the University of Vienna on the East Pacific Rise off Panama. They were using Schmidt Ocean Institute (SOI)’s research vessel Falkor and its deep ROV SuBastian, working to depths of around 2.5km.
The team, which included scientists from the USA, Germany, the Netherlands, France, Costa Rica and Slovenia, used the ROV to overturn chunks of volcanic crust at the site. Living in the 25°C water beneath the crust they found cave systems “teeming” with worms, snails and chemosynthetic bacteria.
When a new hydrothermal vent appears, it is known to become colonised within a few years – but scientists had always been baffled as to how animal larvae managed to find their new home.
Very few young specimens of vent-dwellers such as tubeworms had ever been found around the vents, and the team now believe they have found the evidence that the worms travel beneath the seabed through vent fluids to create their new communities.
“Our understanding of animal life at deep-sea hydrothermal vents has greatly expanded with this discovery,” said Dr Bright. “Two dynamic vent habitats exist. Vent animals above and below the surface thrive together in unison, depending on vent fluid from below and oxygen in the seawater from above.”
ROV SuBastian conducted experiments in which it glued mesh boxes over cracks in the Earth’s crust at the Tica Vent site to exclude the possibility of organisms gaining access from above the seabed. When the boxes were removed after several days, animals were found to have colonised the hydrothermal cavity – and they could have got there only through fluid-filled fissures below the seabed.
“This truly remarkable discovery of a new ecosystem, hidden beneath another ecosystem, provides fresh evidence that life exists in incredible places,” said SOI’s executive director Dr Jyotika Virmani. “Schmidt Ocean Institute is proud to have provided a platform for Dr Bright and her team to gather new insights into these systems that may be vulnerable to deep-sea mining.”
SOI was established in 2009 by Eric and Wendy Schmidt. “The discoveries made on each Schmidt Ocean Institute expedition reinforce the urgency of fully exploring our ocean so we know what exists in the deep sea,” said its president Wendy Schmidt.
“The discovery of new creatures, landscapes and, now, an entirely new ecosystem underscores just how much we have yet to discover about our ocean – and how important it is to protect what we don’t yet know or understand.”