Featured Research

from universities, journals, and other organizations

Hydrothermal Vent Systems Could Have Persisted Millions Of Years, Incubated Life

Date:
July 25, 2003
Source:
University Of Washington
Summary:
The staying power of seafloor hydrothermal vent systems like the bizarre Lost City vent field is one reason they also may have been incubators of Earth's earliest life, scientists report in a paper published in the July 25 issue of Science.

The staying power of seafloor hydrothermal vent systems like the bizarre Lost City vent field is one reason they also may have been incubators of Earth's earliest life, scientists report in a paper published in the July 25 issue of Science.

Discovered just 2½ years ago during a National Science Foundation-funded expedition in the mid-Atlantic Ocean, Lost City has the tallest vents ever seen – the 18-story behemoth at the site dwarfs most vents elsewhere by at least 100 feet. Water is circulated through the vent field by heat from serpentinization, a chemical reaction between seawater and the mantle rock on which Lost City sits, rather than by heat from volcanic activity or magma, responsible for driving hydrothermal venting at sites scientists have been studying since the early 1970s.

If hydrothermal venting can occur without volcanism, it greatly increases the places on the seafloor of early Earth where microbial life could have started. It also means explorers may have more places than previously thought to look for microbial life in the universe.

Although the Lost City vent field is a youthful 30,000 years old, Lost City-type systems might be able to persist hundreds of thousands, possibly millions, of years, says lead author Gretchen Früh-Green of the Swiss Federal Institute of Technology and co-authors from the University of Washington, Duke University and National Atmospheric and Oceanic Administration. One can imagine how such stable, long-lived systems pumping out heat, minerals and organic compounds for millennia might improve the chances for life to spark and to be sustained until it could take hold, say these scientists.

"It's difficult to know if life might have started as a result of one or both kinds of venting," says Deborah Kelley, University of Washington oceanographer, "but chances are good that these systems were involved in sustaining life on and within the seafloor very early in Earth's history."

As far as longevity and stability, it's possible that black-smoker systems might last as long as 100,000 years but it's unlikely, Kelley says. That's because black-smoker systems typically form where new seafloor is being created, a process that – even if a volcanic eruption doesn’t bury a hydrothermal vent field in lava – will eventually shove the seafloor bearing the vents away from the source of volcanic heat needed to power them.

Lost City is already nine miles from the nearest volcanically active spreading center and sits on 1.5 million-year-old crust. Seawater permeating deeply into the fractured surface of the mantle rocks transforms olivine into a new mineral, serpentine. The heat generated during this process is not as great as that found at volcanically active sites – where fluids can reach 700 F – but it is enough to power hydrothermal circulation and produce vent fluids of 105 to 170 F.

Tectonics, the movement of the Earth's great plates, contributes to the fracturing of the mantle rock. But a big reason this kind of system is so self-sustaining, the Science report says, is that fracturing also happens because rocks undergoing serpentinization increase in volume 20 percent to 40 percent. Kelley likens it to water seeping into tiny cracks in roads, then freezing and expanding to cause ruts and frost heaves in the pavement.

Scientists think many Lost City-type systems were possible on early Earth because so much of the mantle had yet to be skinned over with crust, putting it in contact with seawater and making serpentinization possible, Kelley says.

Lost City is the only vent field of its kind known today but scientists say more could exist. Within a 60-mile radius of Lost City are three similar mountains and there are other, potential sites along thousands of miles of ridges in the mid-Atlantic, Indian Ocean and Arctic.

Beyond Earth, peridotite – the mantle material that reacts with seawater during serpentinization – is abundant on all the terrestrial planets in our solar system, says Jeff Karson, Duke University professor. "Peridotite can be exposed by tectonic processes or by major cratering events. This means that Lost City-type venting could occur, or has occurred, in oceans on other planets, and such venting would have the potential to support microbial systems."

Lost City-type systems also may be conducive to life because their fluids are high pH and rich with organic compounds compared to black-smoker systems.

Black smokers get their name because it can appear as if smoke is billowing from the vents. What's actually being seen are dark minerals precipitating when scalding hot vent waters meet the icy-cold ocean depths. Water venting at Lost City, in comparison, is hot enough to shimmer but not "smoke." Because of the different chemistry, black-smoker vents are a darkly mottled mix of sulfide minerals whereas the Lost City vents are nearly 100 percent carbonate, the same material as limestone in caves, and range in colors from white to cream to gray.

The field, named Lost City in part because it sits on a seafloor mountain named the Atlantis Massif, was discovered Dec. 4, 2000, when scientists weren't even looking for hydrothermal vents.

"The discovery of the Lost City vent field is a wonderful example of serendipity in science – studying one problem and discovering something totally new and unexpected," says David Epp, program director in NSF's marine geology and geophysics program. "The detailed work is just beginning and should change the way people think about vent systems."

This spring, the NSF funded the first major scientific expedition to Lost City since its discovery. Led by Kelley and Karson, the expedition is documented at: http://www.lostcity.washington.edu/

Other Science co-authors are the Swiss Federal Institute of Technology 's Stefano Bernasconi, University of Washington's Kristin Ludwig and Giora Proskurowski, and National Atmospheric and Oceanic Administration 's David Butterfield.


Story Source:

The above story is based on materials provided by University Of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University Of Washington. "Hydrothermal Vent Systems Could Have Persisted Millions Of Years, Incubated Life." ScienceDaily. ScienceDaily, 25 July 2003. <www.sciencedaily.com/releases/2003/07/030725080845.htm>.
University Of Washington. (2003, July 25). Hydrothermal Vent Systems Could Have Persisted Millions Of Years, Incubated Life. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2003/07/030725080845.htm
University Of Washington. "Hydrothermal Vent Systems Could Have Persisted Millions Of Years, Incubated Life." ScienceDaily. www.sciencedaily.com/releases/2003/07/030725080845.htm (accessed September 22, 2014).

Share This



More Earth & Climate News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Will Climate Rallies Spur Change?

Will Climate Rallies Spur Change?

Newsy (Sep. 21, 2014) — Organizers of the People's Climate March and other rallies taking place in 166 countries hope to move U.N. officials to action ahead of their summit. Video provided by Newsy
Powered by NewsLook.com
Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) — Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
Climate Change Rally Held in India Ahead of UN Summit

Climate Change Rally Held in India Ahead of UN Summit

AFP (Sep. 20, 2014) — Some 125 world leaders are expected to commit to action on climate change at a UN summit Tuesday called to inject momentum in struggling efforts to tackle global warming. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins