Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MBARI researchers discover deepest high-temperature hydrothermal vents in Pacific Ocean

03.06.2015

In spring 2015, MBARI researchers discovered a large, previously unknown field of hydrothermal vents in the Gulf of California, about 150 kilometers (100 miles) east of La Paz, Mexico.

Lying more than 3,800 meters (12,500 feet) below the surface, the Pescadero Basin vents are the deepest high-temperature hydrothermal vents ever observed in or around the Pacific Ocean.


These delicate carbonate spires formed at an active vent site in the newly discovered Pescadero Basin hydrothermal field.

Courtesy of MBARI

They are also the only vents in the Pacific known to emit superheated fluids rich in both carbonate minerals and hydrocarbons. The vents have been colonized by dense communities of tubeworms and other animals unlike any other known vent communities in the in the eastern Pacific.

Like another vent field in the Gulf that MBARI discovered in 2012, the Pescadero Basin vents were initially identified in high-resolution sonar data collected by an autonomous underwater vehicle (AUV). MBARI's yellow, torpedo-shaped seafloor-mapping AUV spent two days flying about 50 meters above the bottom of the Basin, using sound beams to map the depth and shape of the seafloor.

The AUV team, led by MBARI engineer David Caress, pored over the detailed bathymetric map they created from the AUV data and saw a number of mounds and spires rising up from the seafloor. Data from the AUV also showed slightly warmer water over some of the spires, which implied that they might be active hydrothermal-vent chimneys.

A team of geologists led by David Clague then used a tethered underwater robot, the remotely operated vehicle (ROV) Doc Ricketts, to dive down to the seafloor, fly around the vents, and collect video and samples of rocks and hot water spewing from the chimneys.

Reflecting on the discovery, Clague commented, 'Before the AUV survey of Pescadero Basin, all we knew was that this area was really deep and filled with sediment. I was hoping to find a few outcrops of lava on the seafloor. But we got lucky. The vent field was right on the edge of our survey area, along a fault at the western edge of the basin.'

The AUV and ROV dives showed that the new field extends for at least 400 meters (one quarter mile) along this fault. Within this area the researchers found at least three active hydrothermal chimneys up to 12 meters (40 feet) tall, as well as dozens of low mounds that are most likely collapsed chimneys.

After his ROV dive, Clague noted, 'This site was not at all what I was expecting.' For one thing, the fragments of chimneys that the ROV brought back to the surface were quite different from those collected at other vents in the area. The Pescadero chimneys consisted entirely of light-colored carbonate minerals instead of the dark sulfide minerals that are abundant in hydrothermal chimneys elsewhere in the Gulf.

The Pescadero Basin is only the second place in the world where carbonate chimneys (instead of ones made primarily of sulfides) have been found in the deep sea. The other known location is the 'Lost City' vent field in the middle of the Atlantic Ocean, at a spot on the Mid-Atlantic Ridge.

The geologists also noticed that their rock samples smelled like diesel. They hypothesize that hot hydrothermal fluids migrating upward through the thick sediments of the Pescadero Basin 'cook' organic matter in the sediment, converting it into petroleum-like hydrocarbons -- a process that has been observed at several other vents in the Pacific. Hydrocarbons may provide nutrition for the unusual microbes that thrive at these vents.

After Clague's initial ROV dive, MBARI biologist Robert Vrijenhoek made three follow-up dives in the Pescadero Basin. His goal was to determine how and why animal communities at the Pescadero vents differed from those at other vent fields in the Gulf. Clague's and Vrijenhoek's dives revealed at least three different types of hydrothermal vents in the southern Gulf of California -- black smokers, carbonate chimneys, and hydrothermal seeps. Each environment supports its own unique animal community.

Black smokers form in active volcanic areas. One such area is on the Alarcón Rise, about 160 kilometers (100 miles) south of the Pescadero Basin, where MBARI researchers discovered several hydrothermal fields in 2012. On the Alarcón Rise, massive, dark-colored sulfide chimneys rise more than 37 meters (120 feet) above the lava-covered seafloor.

These chimneys gush extremely hot fluids (over 350 degrees Celsius, 660 degrees Fahrenheit) rich in heavy metals and sulfides. When the superheated fluids come in contact with near-freezing seawater, these minerals precipitate, forming dark, smoke-like plumes of particles. The 'black smoker' chimneys are often colonized by giant tubeworms in the genus Riftia, which grow over two meters (six feet) long, as well as limpets, crabs, squat lobsters, and Alvinella palmworms.

In contrast, the carbonate chimneys in the Pescadero Basin emerge from a flat, muddy seafloor, and are smaller and more delicate than black smokers. They emit fluids that are slightly cooler (250-290 degrees Celsius) and do not form dark, smoke-like plumes. The Pescadero Basin fluids are, however, rich in oil-like hydrocarbons that form dark, oily crusts on the light colored carbonate chimneys. They also support a very different group of animals, including dense colonies of tubeworms in the genus Oasisia.

In the third type of vent environment, 'hydrothermal seeps,' much cooler (less than 30-60 degrees Celsius) water trickles out of lava flows interleaved with seafloor mud. These seeps support an entirely different community of animals, including anemones, tubeworms in the genera Lamellibrachia and Escarpia, and broad, white mats of bacteria. In contrast to the Pescadero and Alarcón vents, each of which hosted a single species of deep-sea clams, the seeps support at least four different types of clams.

One thing that all of these communities have in common is that the dominant tubeworms and clams host specialized intracellular bacteria (symbionts) that allow these animals to exploit potentially toxic chemicals in the vent fluids as sources of nutrition. Vrijenhoek and his collaborators are trying to figure out if the different vent communities in the Gulf are controlled by differences in water depth, geochemistry, symbiotic bacteria, or perhaps other unanticipated factors.

The discovery of the Pescadero Basin hydrothermal field is just the latest example of how MBARI's extensive use of underwater robotics has accelerated the pace of scientific discovery in the deep sea. As Vrijenhoek noted, 'In the 1990s, following the discovery of plumes of warm water over the Mid-Atlantic Ridge, researchers from four countries searched for seven years to find what eventually became known as the 'rainbow vent field.' They were limited by inaccurate and imprecise bathymetric maps. This spring it took us only two days to do the same thing in the Pescadero Basin, using MBARI's high-precision seafloor-mapping AUV.'

###

Online version of this release, including maps and photographs of the new vent field: http://www.mbari.org/news/news_releases/2015/pescadero/pescadero-release.html

MBARI's YouTube video about the newly discovered vent field: https://youtu.be/8RhOrKrNv2M

Media Contact

Kim Fulton-Bennett
kfb@mbari.org
831-775-1835

 @MBARI_news

http://www.mbari.org 

Kim Fulton-Bennett | EurekAlert!

More articles from Earth Sciences:

nachricht Stagnation in the South Pacific Explains Natural CO2 Fluctuations
23.02.2018 | Carl von Ossietzky-Universität Oldenburg

nachricht First evidence of surprising ocean warming around Galápagos corals
22.02.2018 | University of Arizona

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>