Most of that methane, a greenhouse gas 23 times more potent than carbon dioxide at warming our atmosphere, is likely consumed by biological activity in the water, the scientists say.
Thus it will not make it into the atmosphere, where it could exacerbate global warming. However, the discovery does highlight scientists’ limited understanding of the global methane cycle – and specifically the biological interactions that create the stability of the ocean system.
Results of the study, which was funded primarily by the National Oceanic and Atmospheric Administration and the Federal Ministry of Education and Research in Germany, have just been published online in the journal Limnology and Oceanography.
“We didn’t discover any major ‘burps’ of methane escaping into the atmosphere,” said Andrew R. Thurber, a post-doctoral researcher at Oregon State University and lead author on the study. “However, some of the methane seeps are releasing hundreds of times the amounts of methane we typically see in other locations, so the structure and interactions of this unique habitat certainly got our attention.
“What made this discovery most exciting was that it is one of the first and best examples of a direct link between a food web and the dynamics that control greenhouse gas emissions from the ocean,” Thurber added.
The scientists first discovered this new series of methane seeps in 600 to 1,200 meters of water off North Island of New Zealand in 2006 and 2007. The amount of methane emitted from the seeps was surprisingly high, fueling a unique habitat dominated by polychaetes, or worms, from the family Ampharetidae.
"They were so abundant that the sediment was black from their dense tubes,” Thurber pointed out.
Those tubes, or tunnels in the sediment, are critical, the researchers say. By burrowing into the sediment, the worms essentially created tens of thousands of new conduits for methane trapped below the surface to escape from the sediments. Bacteria consumes much of the methane, converting it to carbon dioxide, and the worms feast on the enriched bacteria – bolstering their healthy population and leading to more tunnels and subsequently, greater methane release.
The researchers say that there is one more critical element necessary for the creation of this unique habitat – oxygen-rich waters near the seafloor that the bacteria harness to consume the methane efficiently. The oxygen also enables the worms to breathe better and in turn consume the bacteria at a faster rate.
“In essence, the worms are eating so much microbial biomass that they are shifting the dynamics of the sediment microbial community to an oxygen- and methane-fueled habitat – and the worms’ movements and grazing are likely causing the microbial populations to eat methane faster,” said Thurber, who works in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “That process, however, also leads to more worms that build more conduits in the sediments, and this can result in the release of additional methane.”
Methane seeps and worm communities are present in many other areas around the world, the researchers point out, including the Pacific Northwest. However, the deep water in many of these locations has low levels of oxygen, which the scientists think is a factor that constrains the growth of the worm populations. In contrast, the study sites off New Zealand are bathed in cold, oxygen-rich water from the Southern Ocean that fuels these unique habitats.
“The large amounts of methane consumed by bacteria have kept it from reaching the surface,” Thurber said. “Those bacteria essentially are putting the pin back in the methane grenade. But we don’t know if the worms ultimately may overgraze the bacteria and overtax the system. It’s something we haven’t really seen before.”
Also participating in the study were scientists from Scripps Institution of Oceanography, the National Institute of Water and Atmospheric Research in Wellington, New Zealand, and the Helmholtz Centre for Ocean Research in Germany.About the OSU College of Earth, Ocean, and Atmospheric Sciences: CEOAS is internationally recognized for its faculty, research and facilities, including state-of-the-art computing infrastructure to support real-time ocean/atmosphere observation and prediction. The college is a leader in the study of the Earth as an integrated system, providing scientific understanding to address complex environmental challenges
Andrew Thurber | EurekAlert!
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy