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 Making fuel out of thick air
08.12.2017 | DOE/Argonne National Laboratory

nachricht ‘Spying’ on the hidden geometry of complex networks through machine intelligence
08.12.2017 | Technische Universität Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>