Hydrogen and Methane Sustain Unusual Life at Sea Floor's 'Lost City'

March 3, 2005
Hydrogen and Methane Sustain Unusual Life at Sea Floor's 'Lost City'

The hydrothermal vents at the ocean bottom were miles from any location scientists could have imagined. One massive seafloor vent was 18 stories tall. All were creamy white and gray, suggesting a very different composition than the hydrothermal vent systems that have been studied since the 1970s.
Scientists who named the spot Lost City knew they were looking at something never seen before when the field was serendipitously discovered in Dec. 2000, during a National Science Foundation (NSF) expedition to the mid-Atlantic.
This week in the journal Science, researchers publish for the first time findings about the gases produced at Lost City and the organisms that live off of them.

Image: The top few feet of an actively venting carbonate chimney. Credit: University of Washington

Both are so different from so-called black-smoker hydrothermal vents they may provide a whole new avenue for studying the earliest life on Earth as well as looking for signs of life on other planets, according to Deborah Kelley, a University of Washington oceanographer and lead author of the report.

“This finding is an exciting example of NSF’s commitment to discovery through basic research,” said Bilal Haq, director of NSF’s marine geology and geophysics program, which funded the research. “Lost City shows us that geological, chemical and biological processes are intimately linked at a primal environment, and lends strong support to the need for interdisciplinary approaches to scientific research.”

The field was named Lost City in part because it sits on a seafloor mountain named the Atlantis Massif, and because researchers were using the Woods Hole Oceanographic Institution's vessel Atlantis when the area was discovered. The field is about 300 feet by 1,000 feet, has 30 large vents, some 30 to 200 feet tall, and contains hundreds of smaller structures. Steep cliffs behind the field are shingled with carbonate.

Microorganisms at Lost City live in highly alkaline fluids that are nearly as caustic as drain opener, Kelley says, whereas organisms inhabiting black-smoker vents are well adjusted to acidic fluids..

Further, she says, Lost City microbes appear to live off bountiful methane and hydrogen. But absent is carbon dioxide, the key energy source for life at black-smoker vents. And there is little hydrogen sulfide and only very low traces of metals, a common staple for many of the microbes at the other kind of vents.

According to researchers, a circulation pattern known as serpentinization creates a chemical reaction between seawater and the mantle rock on which Lost City sits and accounts for the differences in living environments in the two vent areas. The resulting fluids are 105 to 170 . At the other kind of field, first discovered in the early 1970s, volcanic activity or magma drives venting and heats fluids to 700 degrees Fahrenheit. The vents at such sites are often referred to as black smokers because some emit hot, mineral-laden fluid that looks like dark, billowing smoke when it hits the icy cold seawater.

Carbonate minerals from fluids at Lost City drape nearby cliffs in brilliant white and form vents ranging in shape from tiny toadstools to the 18-story column, named Poseidon, which dwarfs most known black smoker vents by at least 100 feet. Some places resemble the sort of deposits one might see in spectacular caves with spires and smoothly rippled surfaces in a complex 3-dimensional array, says Duke University’s Jeffrey Karson, co-author of the paper.

Although no one has yet found another field like Lost City, Kelley says she’s sure others exist, because there are so many other places mantle rock has been thrust up through the seafloor, exposing it to seawater and serpentinization.

Perhaps Lost City can provide additional chemical remnants of organisms to help identify ancient life in those rocks or on other planets. “We don’t, in most places, have access to early Earth conditions, so if we can understand the chemical reactions, sources of energy and how fluids circulate through Lost City, it may give us insight into how life started on this planet,” Kelley says.

Source: NSF

Explore further: Researchers discover deepest high-temperature hydrothermal vents in Pacific Ocean

Related Stories

Fossil find gives hope for animal life in 'lost cities'

June 7, 2011

(PhysOrg.com) -- The world's oceans could be littered with thousands of undiscovered 'lost cities' housing communities of creatures that thrive in some of the Earth's most extreme conditions, a new discovery suggests.

Hydrothermal vents could explain chemical precursors to life

June 16, 2014

Roy Price first heard about the hydrothermal vents in New Caledonia's Bay of Prony a decade ago. Being a scuba diver and a geologist, he was fascinated by the pictures of a 38-meter-high calcite "chimney" that had precipitated ...

The energetic origins of life

June 12, 2014

(Phys.org) —Imagination is perhaps the most powerful tool we have for creating the future. The same might be said when it comes to creating the past, especially as it pertains to origin of life. Under what conditions did ...

New study outlines 'water world' theory of life's origins

April 16, 2014

(Phys.org) —Life took root more than four billion years ago on our nascent Earth, a wetter and harsher place than now, bathed in sizzling ultraviolet rays. What started out as simple cells ultimately transformed into slime ...

Recommended for you

How bees naturally vaccinate their babies

July 31, 2015

When it comes to vaccinating their babies, bees don't have a choice—they naturally immunize their offspring against specific diseases found in their environments. And now for the first time, scientists have discovered how ...

A cataclysmic event of a certain age

July 27, 2015

At the end of the Pleistocene period, approximately 12,800 years ago—give or take a few centuries—a cosmic impact triggered an abrupt cooling episode that earth scientists refer to as the Younger Dryas.

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

Dense star clusters shown to be binary black hole factories

July 29, 2015

The coalescence of two black holes—a very violent and exotic event—is one of the most sought-after observations of modern astronomy. But, as these mergers emit no light of any kind, finding such elusive events has been ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.