Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cold seeps are hot spots for life

07.12.2007
New deep-sea images disprove doctrine

Thousands of white crabs grazing on an extensive mussel bed: Up to now such high biomasses in the deep sea were only known from hot vents. Now scientists from the MARUM at the University of Bremen have found such scenes at a cold vent off the coast of Pakistan.

Another first was achieved by the videos they took of the cold-vent fluids seeping from the sea floor. Furthermore, the scientists were astonished at the wide variety of seep types. The scientists returned from an expedition with the RV Meteor heavily laden with new data. The expedition investigated the continental margin south of Pakistan from 31 October to 27 November.

Widely accepted doctrine has suggested that life at hot vents, such as black smokers, is much more bountiful than on cold vents. But the images sent up by the deep diving vehicle, Quest, of the Marum_Research Center Ocean Margins in Bremen told a different story: Mussel beds of more than 30 meters in diameter literally crawling with white crabs. "This puts to rest the credo that cold vents generally are less lively than hot vents", says Gerhard Bohrmann, leader of the expedition. "The organisms seem to have a similar amount of chemical energy - in the form of methane or hydrogen sulfide - available to them as hot-vent organisms. This results in an equally high biomass."

... more about:
»Bohrmann »Expedition »Methane »Sediment »fluids

More surprises were in store for the scientists, like the variety of seep types: "We had a close look at nine separate seeps, and every one was different. The oxygen level in the water, which varies strongly with depth in the research area, is especially influential on the seep communities", explains Gerhard Bohrmann.

The great differences in seep types are also a product of the geological subsurface. "On satellite images the Pakistani coast north of the area we investigated looks wrinkled. The wrinkles continue under water off the coast. This is because the whole area is being compressed; at a speed of four centimetres a year the Arabian plate is being pushed beneath the Eurasian plate. While diving underneath Pakistan the muddy sea-floor sediments on the Arabian plate are literally being squeezed dry. The water, containing a heavy load of methane, hydrogen sulfide, and a host of other compounds, bubbles out of the sea floor at the so-called cold vents. "Normally such muddy sediments are about two to four kilometres thick, here they reach an astonishing seven kilometers". A good reason to look for vents in this area. "Where there is a lot of sediment to be squeezed, more fluids can seep out ", reasons Gerhard Bohrmann.

For the first time, the scientists from Bremen were able to observe fluids without associated bubbles seeping from a cold vent directly: "This is due to the extremely high-resolution video images of MARUM's diving vehicle, Quest. This has very likely never been seen before", enthuses Gerhard Bohrmann. Up to now such seepages have been postulated from measurements, but never directly observed because of technical limitations in the image quality. Cold seeps were either found through gas bubbles escaping with the fluids or because of the associated organisms growing at the seep sites.

"Seepages at the sea floor are of great importance to us, because they link the crust of the Earth and the ocean", reflects Gerhard Bohrmann about the relevance of the research. "Underwater vents transport enormous amounts of material like methane, sulfides and others as well as heat into the ocean, and therefore into the atmosphere. However, our understanding of these processes and how they shape the Earth are still sketchy." After all, methane is 30 times stronger as a greenhouse gas than carbon dioxide. "Every expedition teaches us more about how these systems work. On this one, we made a big step towards a better understanding of cold seeps at the ocean floor", resumes Professor Bohrmann.

Furhter Information / Images / Interviews:
Kirsten Achenbach
Tel: +49 421 218 - 65541
Fax: +49 421 218 - 65505
Mail: achenbach@marum.de
Bohrmann, Gerhard
Tel: +49 421 218 - 8639
Fax: +49 421 218 - 8664
Mail: gbohrmann@marum.de
Gerdes, Albert
Tel: +49 421 218 - 65540
Fax: +49 421 218 - 65505
Mail: agerdes@marum.de

Kirsten Achenbach | idw
Further information:
http://www.marum.de

Further reports about: Bohrmann Expedition Methane Sediment fluids

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>