February 22, 2013
Deepest Hydrothermal Vent Discovered In Cayman Trough, Teeming With Life
Lawrence LeBlond for redOrbit.com - Your Universe Online
In 2010, scientists working for the National Oceanography Centre (NOC) and the University of Southampton made an astonishing discovery: the deepest and hottest known hydrothermal vents. These vents, which were found in an isolated trough in the Caribbean, have been named the Beebe Hydrothermal Vent Field (BHVF).With the discovery still fresh in their minds, a new team, led by the University of Southampton´s Dr. Jon Copley, returned to the BHVF to investigate it more closely. But upon their arrival to investigate the deepest known volcanic vents, the team made another remarkable discovery: a set of even deeper hydrothermal vents nearby, some 3 miles beneath the ocean´s surface.
Copley said these vents, some which are more than 30 feet tall, exist in the Cayman Trough, a deep trench formed by the boundary of two tectonic plates. This deep rise of hydrothermal vents has important implications for the physics and chemistry of the fluids that are emitted by the vents, and in turn, the organisms that rely on the vents for sustainable life in the deep waters.
The Vent Field is named after William Beebe, an early American ecologist who is known for his marine studies, which include the first ever observations of deep-sea animals in their natural habitat. Copley and his colleagues are set to follow in Beebe´s footsteps, using a remote operated vehicle (ROV) named Isis to study the marine communities hosted by the hydrothermal spires of the Cayman Trough. Isis is designed to operate at depths down to to 21,500 feet, giving the team plenty of room to spare.
Matt Hodgkinson, a member of the research team from University of Southampton Ocean and Earth Science, said in a blog post: “The extraordinarily high pressure (of 500 x atmospheres) at the Beebe site, situated at nearly double the normal depth of most known hydrothermal systems, is important due to the physical changes that seawater undergoes at extremely high pressures and temperatures. Instead of being a liquid or vapor, the vent fluid becomes supercritical. These supercritical fluids are very reactive, dissolve metals at depth in the Earth´s crust, and transport them to the seafloor where they form spectacular hydrothermal vents and mineral deposits.”
Copley said the discovery of the “astounding mineral spires [was a] complete surprise.”
“We initially thought it was a site we'd been to before but it looked so different we thought it had changed. But eventually we realized it looked different because it was different,” Copley told BBC News.
“The beauty of working in the deep oceans is that you're always stumbling over things that are completely new,” he added. “It's teaching us how little we know and for a few minutes it's not about the science, it's about the wonder of the planet, something that's been hidden for so long.”
These very unusual vents in the otherwise chilly depths (39F), heat the surrounding water to extreme temperatures (in excess of 750F at the vent site). It is because of these vents that bizarre creatures are allowed to come to life, and researchers believe it is vents like these that jumpstarted human existence.
The team hopes their work will eventually answer some of mankind´s most paramount questions. They feel their research will eventually help explain why and how life evolved in such a hostile environment.
Despite these extreme conditions, the vents were found to be teeming with thousands of new species, discovered with Isis, as the team gently steered it around the spires, taking pictures and gathering samples. One of the most astonishing finds was a whole host of pale shrimp that were found to have a light-sensing organ on their backs in place of eyes.
The team kept Isis on site for roughly 24 hours, investigating the site before bringing it back on board the British research ship the James Cook. The ROV brought back samples of water and wildlife, including the pale shrimp, for analysis.
Verity Nye, a researcher on board the vessel, took liberty to study these tiny blind organisms.
"We don't think they have functioning eyes but they have a really unusual organ on their backs which is like a warning system for them to tell them when they're getting too hot so they don't get too close to the hot water from the vents,” he told the British news agency.
He said it is very difficult to know exactly how life operates around those vents. “We´re still trying to understand it,”
Copley said several of the samples (including a white anemone and a starfish) returned by Isis could likely be those of new species, and should yield positive results when they can be analyzed in the lab once the team makes it back home.
But for now, the team remains busy collecting data and plan to make further dives in the coming days. Researchers from Japan and the US also plan to investigate the vent fields later this year.
The British research is funded by the Natural Environment Research Council (NERC).
The BHVF is among some 200 vent fields that have been discovered around the world´s oceans since the first hydrothermal vent was found in the 1970s.