Such "methane seeps" are fascinating environments because of their extraordinary chemical features and often bizarre marine life. The area of interest, roughly 20 miles west of Del Mar, is centered on a fault zone known as the San Diego Trough Fault zone. Methane, a clear, highly combustible gas, exists in the earth's crust under the seafloor along many of the world's continental margins. Faults can provide a pathway for methane to "seep" upward toward the seafloor.
The Scripps graduate students made the discovery during the recent San Diego Coastal Expedition (bit.ly/sdcoastex), a multidisciplinary voyage conceived and executed by Scripps graduate students. The cruise was funded by the University of California Ship Funds Program, which supports student research at sea and provides seagoing leadership opportunities.
While conducting surveys in search of methane seeps aboard Scripps' research vessel Melville, the graduate students mapped a distinct mound on the seafloor at 1,036 meters depth (3,400 feet), spanning the size of a city block and rising to the height of a two-story building. The area had been recommended by Jamie Conrad, Holly Ryan (U.S. Geological Survey) and Charles Paull (Monterey Bay Aquarium Research Institute), who surveyed the faults in 2010.
"Below the mound," described Scripps geosciences graduate student Jillian Maloney, "we observed a disruption in subsurface sediment layers indicative of fluid seepage."
The Scripps researchers then deployed instruments to collect sediment cores, gathering further evidence such as seep-dwelling animals, sulfidic-smelling black mud and carbonate nodules. These samples are currently being analyzed in Scripps laboratories for chemical clues and other telling elements of the environment.
Organisms collected from the site include thread-like tubeworms called siboglinids and several clams. Siboglinids lack a mouth and digestive system and gain nutrition via a symbiotic relationship with bacteria living inside them, while many clams at seeps get some of their food from sulfide-loving bacteria living on their gills.
While food is scarce in much of the cold, dark ocean depths, it is abundant at seeps due to the bacteria that proliferate around the methane source. Microbes there are eaten by worms, snails, crabs and clams, leading to a rich and productive community that helps sustain the surrounding deep-sea ecosystem.
"These chemosynthetic ecosystems are considered 'hot spots' of life on the seafloor in an otherwise desert-like landscape," said San Diego Coastal Expedition team member Alexis Pasulka, a Scripps biological oceanography graduate student. "New forms of life are continuously being discovered in these environments. Therefore, it is important to study these ecosystems not only to further appreciate the diversity of life in our oceans, but also so that we can better understand how these ecosystems contribute to overall ocean productivity and the carbon cycle."
Methane is a potent greenhouse gas, and researchers don't yet fully understand the magnitude to which seeping methane in the ocean contributes additional carbon to the atmosphere. Moreover, on many continental margins, frozen methane hydrates could represent a future energy source. Along the West Coast, methane seeps are known to exist off Oregon, California (near Eureka, Monterey Bay, Point Conception and Santa Monica), in the Gulf of California and off Costa Rica.
"This is a significant and exciting discovery in part because of the possibilities for future research at Scripps," said biological oceanography graduate student Benjamin Grupe, a member of the seep contingent on the San Diego Coastal Expedition. "The existence of a methane seep just a few hours from San Diego should allow Scripps scientists to visit frequently, studying how this dynamic ecosystem changes over days, months and years. Such regular data collection is difficult at most cold seeps, which rarely occur so close to ports or research institutions."
Grupe will lead a follow-up cruise in December that will revisit the newly discovered seep to collect additional samples and learn more about this ecosystem. The team of graduate students hopes to raise funds to employ technologies such as video-driven coring instruments and towed video cameras that will give them an up-close look at the methane seep.
The search for local seeps was one focus area of the multidisciplinary San Diego Coastal Expedition, which included teams of students investigating the oceanography and marine ecosystems off San Diego and led by chief scientist Christina Frieder. In addition to Grupe, Pasulka and Maloney, other members of the seep team included geophysics graduate students Valerie Sahakian and Rachel Marcuson.
R/V Melville, the oldest ship in the U.S. academic fleet, is owned by the U.S. Navy and has been operated by Scripps Oceanography for all of its 41 years.
"The students should be congratulated on their hard work and perseverance leading to this exciting find," said Lisa Levin, a Scripps professor who has studied methane seep ecosystems in most of the world's oceans. "Other scientists have suspected that methane seeps were present in the San Diego region, but these new data and samples provide the first convincing evidence. We know very little about what lives in deep waters-the planet's largest ecosystem-so it is not unexpected to find surprises on the deep-sea floor right in our own backyard. Having a 'local' seep should be a great boon to deep-sea research, education and public outreach at Scripps."
UC San Diego News on the web at: http://ucsdnews.ucsd.edu
Mario Aguilera | Newswise Science News
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences