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 Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>