Featured Research

from universities, journals, and other organizations

Organic chemical origins in hydrothermal systems

Date:
January 22, 2014
Source:
Tokyo Institute of Technology
Summary:
Researchers have revealed the mechanisms for the formation of methane, which may have been a crucial stage in the origin of life on Earth.

Geological map of the western Shiroumadake area. Circles and star indicate the studied hot springs. The star represents the location of the Hakuba Happo hot spring.
Credit: Image courtesy of Tokyo Institute of Technology

Serpentinite-hosted hydrothermal systems have been suggested as likely sites for the formation of organic compounds in the abiotic conditions of early Earth, that is, in the absence of living organisms.

"Such compounds were likely crucial for the chemical evolution of life," explain Konomi Suda and colleagues at Tokyo Institute of Technology, Japan Agency of Marine-Earth Science and Technology and the Open University of Japan. Their latest research identifies mechanisms in the abiotic formation of the organic compound methane in serpentinite-hosted hydrothermal systems, a process that so far has not been satisfactorily understood.

The researchers compared water samples from a series of hot springs in the Shiroumadake area in Japan. Here due to recent volcanic activity they could study ongoing serpentinisation processes.

They measured the pH and temperature as well as the gas and ion content of the water samples in terms of both concentration and the ratio of different isotopes of the chemical constituents. Different isotopes of the same chemical differ in the number of neutrons in the nucleus. Each reaction yield characteristic isotope ratio because reaction rate of each isotopes are slightly different depending on processes.

Suda and colleagues found unexpected values for the ratio of different isotopes in the methane (CH4) and molecular hydrogen (H2) dissolved in the water, and the water itself (H2O) at the hot spring Hakuba Happo. In serpentinite-hosted hydrothermal systems methane was thought to form from synthesis with molecular hydrogen.

However the researchers found that the ratio of different isotopes and chemicals could not be explained for this process in the temperature and pH conditions they had measured. They conclude,

"Based on a comparison of the hydrogen isotope systematics of our results with those of other serpentinite-hosted hydrothermal systems, we suggest that abiotic CH4 production directly from H2O (without mediation by H2) may be more common in serpentinite-hosted systems."

Background

Methane and organic compounds

Organic compounds are carbon based chemicals. The simplest organic compounds are strings of carbon atoms bonded to hydrogen. These hydrogen bonds can substitute with other atoms and molecules to provide the wide ranging organic chemicals that are found in living organisms.

Methane is the simplest organic compound comprising just one carbon atom bonded to four hydrogens. In the absence of living organisms methane synthesis can occur through abiotic mechanisms, which likely played a significant role in the early Earth environment. Possible abiotic mechanisms include the formation of methane directly from H2O or H2. The formation mechanism and conditions such as temperature and pH determine the relative levels of different isotopes.

The hot spring Hakuba Happo

The researchers compared water samples from five hot springs in the Shiroumadake area in Japan. One of these sites is Hakuba Happo, a newly discovered serpentinite-hosted system. Serpentinite is a rock that results from the geochemical processes of hydration and metamorphic transformation of ultramafic rock from Earth's mantle.

The water at Hakuba Happo is pumped up from two drilling wells Happo #1 and Happo #3. It is one of the most alkaline hot springs in Japan and the concentration of CH4 was 10-100 times that of the other hot springs.

Isotopic fractionation and fractionation equilibrium

Different chemical isotopes that differ by the number of neutrons in the atomic nuclei form the same chemical compounds. For example both hydrogen (no neutrons in the nucleus) and deuterium (one neutron in the nucleus) can form molecular hydrogen (H2), water (H2O) and methane (CH4).

Processes described as 'fractionation' affect the relative abundance of different isotopes in the chemical compounds in a given system. Fractionation equilibrium describes the system when the abundance of isotopes in the different chemicals no longer changes with time. Comparing known fractionation equilibrium values with the measured isotopic abundance provides clues of processes that have taken place in the system.


Story Source:

The above story is based on materials provided by Tokyo Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Tokyo Institute of Technology. "Organic chemical origins in hydrothermal systems." ScienceDaily. ScienceDaily, 22 January 2014. <www.sciencedaily.com/releases/2014/01/140122092449.htm>.
Tokyo Institute of Technology. (2014, January 22). Organic chemical origins in hydrothermal systems. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2014/01/140122092449.htm
Tokyo Institute of Technology. "Organic chemical origins in hydrothermal systems." ScienceDaily. www.sciencedaily.com/releases/2014/01/140122092449.htm (accessed October 21, 2014).

Share This



More Fossils & Ruins News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Fish Fossil Shows First-Ever Sex Was Done Side By Side

Fish Fossil Shows First-Ever Sex Was Done Side By Side

Newsy (Oct. 19, 2014) A 380-million-year-old fish may be the first creature to have copulative sex - and it was side by side with arms linked, like square dancers. Video provided by Newsy
Powered by NewsLook.com
As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

As Sweden Hunts For Sub, "Cold War" Comparisons Flourish

Newsy (Oct. 19, 2014) With Sweden on the look-out for a suspected Russian sub, a lot of people are talking about the Cold War, but is it an apt comparison? Video provided by Newsy
Powered by NewsLook.com
So, Kangaroos Didn't Always Hop

So, Kangaroos Didn't Always Hop

Newsy (Oct. 16, 2014) Researchers believe an extinct kangaroo species weighed 500 pounds or more and couldn't hop. Video provided by Newsy
Powered by NewsLook.com
1000-Year-Old Viking Treasure Hoard Found in Scotland

1000-Year-Old Viking Treasure Hoard Found in Scotland

Reuters - Light News Video Online (Oct. 14, 2014) A hoard of Viking artifacts dating back over 1,000 years is discovered by a treasure hunter with a metal detector in Scotland. Elly Park reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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