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 Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America

nachricht Ice stream draining Greenland Ice Sheet sensitive to changes over past 45,000 years
14.05.2018 | Oregon State University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>