Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column

27.05.2020

For the first time, a research team from the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) has been able to determine the efficiency with which methane-oxidising bacteria from the seafloor can travel with gas bubbles from submarine methane seeps into the open water column and influence biogeochemical processes there. This transport process can be of importance for the reduction of the greenhouse gas methane in the marine environment and thus for global climate developments.

Methane is one of the most potent greenhouse gases. How and where it reaches the atmosphere and which processes can prevent this, are therefore important climate-relevant questions, also in marine research.


The "Bubble Catcher" - here in operation off the Californian coast - was specially developed at the IOW for the contamination-free capture of bubbles at natural seafloor methane seeps for the analysis of adhering bacteria.

S. Jordan

The focus here lies on various methane sources, mostly located at the sea floor, and on specialised microorganisms in the sediment and the water column that use methane as an energy source and thus remove it from the seawater.

These removal processes, which mainly involve methane-oxidising bacteria and methanotrophic archaeae, are so effective that usually almost no methane from the sea floor reaches the water surface and thus the atmosphere.

However, the situation is quite different at submarine gas seeps, where methane is released from the sediment into the water column as gas bubbles. If the seeps are located in relatively shallow shelf areas, the microbial methane filter only works to a very limited extent because the bubbles rise to the sea surface so quickly that the methane rushes past the areas with methane-consuming microbes too quickly for them to get to work.

“Methane oxidising bacteria are conspicuously abundant in the water column above methane seeps,” says Sebastian Jordan. “For a long time, it was unclear how these microorganisms can reach increased population densities there, because they only multiply very slowly and are constantly shifted by currents,” the IOW researcher adds, who is working intensively on microbial processes associated with methane seeps in his doctoral thesis.

“Since bubble-releasing gas seeps are important methane sources, we wanted to know more about how this phenomenon is caused and what influence these bacterial ‘methane eaters’ have on the methane flow from the sediment into the atmosphere,” adds Oliver Schmale.

The geologist has specialised in methane cycles in marine environments for many years and heads the DFG-funded Bubble Shuttle II project, which also includes the current study.

A pilot study at methane seeps off the Californian coast previously had explored the hypothesis that methane-oxidising sediment bacteria are swept up into the water column with rising methane bubbles. For this purpose, the scientists used the Bubble Catcher, a device specially developed at the IOW, which captures rising gas bubbles without contamination for the analysis of the bubble-attached bacteria.

“We know since then that this ‘methane bubble shuttle’ upwards into the water column exists. However, many questions remained unanswered, for example whether the bacteria that are released into the open water column survive despite the drastic habitat change and how much influence the bubble transport actually has on the composition of the bacterial community in the water column,” Schmale describes the approach for the new investigations.

Therefore, a team of IOW scientists, supported by US colleagues, carried out further bubble shuttle experiments in the Californian “Coal Oil Point” seep field at vents with different intensities of gas bubble release. They investigated the number of methanotrophic bacteria in the sediment, on the bubbles and in the water column, analysed their genetic composition and examined the influence of varying degrees of gas release intensity on the bubble transport process. In addition, on-site experiments were conducted to determine the methane reduction activity of the microorganisms adhering to the bubbles.

“That rising methane bubbles repeatedly inoculate the open water with methanotrophs from the sediment is supported by our genetic analyses. We have been able to detect the same methane-consuming microbes, for example from the family Methylomonaceae, as well as oil-degrading bacteria of the genus Cycloclasticus, in the sediment, on the bubbles, and in the water column,” Sebastian Jordan describes one of the results.

The efficiency of this transport is apparently determined by the intensity with which the gas comes out of the sea floor. Jordan: “If the gas slowly bubbles up, more than 20,000 methane oxidizers per millilitre gas can travel with it; if the gas flow is much stronger, it is only around 200.”

The experiments on methane reduction activity provided a clear indication that these passengers can survive and be active not only in the sediment but also in the open water. After three days, samples with trapped methane bubbles showed a methane oxidation rate 1000 times higher than those without.

“We also wanted to know whether bubble transport actually has sufficient potential to explain the increased population densities of methane oxidizers above seep fields. We used model calculations, which took into account factors such as transport distances, currents, different transport rates of bubble bacteria, etc., to successfully support this hypothesis,” concludes Sebastian Jordan, first author of the recently published study.

“The study is the first to show in a conclusive ‘all-round view’ how microbial sediment dwellers influence bacterial communities in the water column by bubble transport and are involved in important biogeochemical processes such as methane reduction, which is relevant for the climate. This comparatively fast vertical transport process for microorganisms can also play an important role in other aquatic habitats and matter cycles, for example in lakes,” concludes project leader Oliver Schmale.

Contact IOW press and public relations:
Dr. Kristin Beck: +49 381 5197 135| kristin.beck@io-warnemuende.de
Dr. Barbara Hentzsch: +49 381 5197 102 | barbara.hentzsch@io-warnemuende.de

The IOW is a member of the Leibniz Association with currently 95 research institutes and scientific infrastructure facilities. The focus of the Leibniz Institutes ranges from natural, engineering and environmental sciences to economic, social and space sciences as well as to the humanities. The institutes are jointly financed at the state and national levels. The Leibniz Institutes employ a total of 19,100 people, of whom 9,900 are scientists. The total budget of the institutes is 1.9 billion Euros. http://www.leibniz-association.eu

Wissenschaftliche Ansprechpartner:

Sebastian Jordan | Tel.: +49 (0)381 5197 3428 | sebastian.jordan@io-warnemuende.de
Dr. Oliver Schmale | Tel.: +49 (0)381 5197 305 | oliver.schmale@io-warnemuende.de

Originalpublikation:

"Scientific Reports", nature group (2020):
Sebastian F. A. Jordan, Tina Treude, Ira Leifer, René Janßen, Johannes Werner, Heide Schulz-Vogt & Oliver Schmale: Bubble-mediated transport of benthic microorganisms into the water column: Identification of methanotrophs and implication of seepage intensity on transport efficiency. https://doi.org/10.1038/s41598-020-61446-9

Weitere Informationen:

More information about the project "Bubble Shuttle II - Bentho-pelagic transport of methanotrophic microorganisms through gas bubbles" funded by the German Research Foundation: https://www.io-warnemuende.de/project/144/bubble_shuttle_ii_-_schmale.html

Dr. Kristin Beck | idw - Informationsdienst Wissenschaft

Further reports about: Atmosphere IOW bacteria bubble gas bubbles microbes microorganisms sea floor water column

More articles from Earth Sciences:

nachricht Satellite data show severity of drought summers in 2018 and 2019
13.07.2020 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

nachricht NASA analyzes Tropical Cyclone Cristina's water vapor concentration
09.07.2020 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron cryo-microscopy: Using inexpensive technology to produce high-resolution images

Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal "PLOS ONE".

Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new...

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Shedding light on the brown color of algae

14.07.2020 | Life Sciences

Color barcode becomes ISO standard

14.07.2020 | Information Technology

New substance library to accelerate the search for active compounds

14.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>