Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Diversity of habitats at natural oil seeps

22.08.2016

Research team investigates desolate sea-floor area in the southern Gulf of Mexico

Habitats surrounding natural oil seeps on the sea floor are multifaceted and diverse. During an expedition organized by MARUM, the Center for Marine Environmental Sciences, researchers discovered gas-bubble streams, massive gas hydrates, oil-soaked sediments, and deposits of heavy oil all closely spaced at a depth of around three kilometers.


Flow structures of heavy oil at Mictlan Knoll in about 3100 meter water depth.

Photo: MARUM - Center for Marine Environmental Sciences

Each of the different constituents: gas, light oil, and heavy oil congealed to asphalt, is home to its own characteristic group of organisms. The scientists have now published their initial results, along with photos from the remotely operated vehicle MARUM-QUEST, in the journal Biogeosciences.

“Recent years have seen a minor revolution in the field of marine research,” explains first author Dr. Heiko Sahling, a scientist at MARUM and the Geosciences Department of the University of Bremen. Many German research ships have been outfitted with state-of-the-art multibeam echosounders. These are of great help in the systematic search for natural seeps of oil and gas on the sea floor.

“In the past,” says Sahling, “this was more like the proverbial search for a needle in a haystack. Now we have found habitats on the sea floor that were unknown before.”

Scientists use the echosounders to detect gas bubbles in the water column. Where hydrocarbons are escaping, the acoustic signal is amplified in the water, and to some extent within the sea floor as well. The team of specialists from Bremen, Kiel, Vienna (Austria), Mexico City (Mexico) and Talahassee (Fla., USA) applied this modern technology during an expedition to the Bay of Campeche in the southern Gulf of Mexico.

Through a project financed by the German Research Foundation (Deutsche Forschungsgemeinschaft – DFG) scientists, under the leadership of Prof. Dr. Gerhard Bohrmann, have discovered hundreds of gas seeps and investigated a number of them in detail with the submersible vehicle MARUM-QUEST. Their goal was to reveal the processes of hydrocarbon movement at natural seeps. In what form are they released, how do they impact the biological assemblages on the sea floor, how rapidly does the oil break down, and what happens to the released gas?

“The gas, in part, is converted to gas hydrates, which form small mounds on the sea floor that are densely populated by meter-long tube worms,” continues Heiko Sahling. “Sometimes the mounds are broken open, allowing a view into several-meter-thick gas hydrates, a very rare observation until now. The gas hydrates are overlain by a reaction zone where microbial communities convert methane, carbonate is precipitated, and dense colonies of tube worms develop. These hold the mounds together and consume reduced sulfur compounds for nutrition. It is truly a remarkable habitat,” Sahling considers.

In addition to the gas, liquid oil also flows out of the sea floor. It ascends slowly through small white chimneys, the drops of oil attached by elongated threads or seeping through the sediments. “For organisms that are not adapted, the oil is harmful,” explains Heiko Sahling, “but the bountiful life at these sites shows that there are certain organisms that can even thrive on these hydrocarbons.”

On the other hand, some components of the so-called “heavy oil” dissipate. What remains forms flow structures of asphalt on the sea floor. “During the expedition we documented many of these unique structures,” says Heiko Sahling. “The asphalt covers hundreds of meters of the sea floor and thus also forms a habitat that is colonized by tube worms and bacterial mats."

Original publication:
Heiko Sahling, Christian Borowski, Elva Escobar-Briones, Adriana Gaytán-Caballero, Chieh-Wei Hsu, Markus Loher, Ian MacDonald, Yann Marcon, Thomas Pape, Miriam Römer, Maxim Rubin-Blum, Florence Schubotz, Daniel Smrzka, Gunter Wegener and Gerhard Bohrmann: Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico.
Published in: Biogeoscience, DOI: 10.5194/bg-13-4491-2016

Contact:
Dr. Heiko Sahling
Telephone: 0421 218 65054
E-Mail: hsahling@marum.de

Further information / Photo material:
Ulrike Prange
MARUM – Public Relations
Telephone: 0421 218 65540
E-Mail: medien@marum.de

Weitere Informationen:

http://www.marum.de/en/Diversity_of_habitats_at_natural_oil_seeps.html

Ulrike Prange | idw - Informationsdienst Wissenschaft

More articles from Earth Sciences:

nachricht NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center

nachricht Steep rise of the Bernese Alps
24.03.2017 | Universität Bern

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>