A new aluminum deep sea probe, the prototype of one designed to withstand crushing pressures and extreme temperatures, is set to be lowered to depths of 9 meters (30 feet) in Monterey Bay Aquarium's giant kelp forest July 28 as part of NASA's hunt for clues to life's origins.
Scientists from NASA's Jet Propulsion Laboratory, Pasadena, CA, will sink the new package of underwater cameras, temperature sensors, optics and a spectrometer into the emerald waters of a controlled aquatic environment to test the capabilities of more advanced instruments to explore the interior of volcanic vents. These cracks in the sea floor, occurring at depths of between 500 meters and 4,000 meters (1,650 feet and 13,200 feet), are known to nurture a pageantry of macabre bottom-dwellers such as salps, siphonophores, crustaceans and gelatinous animals only recently discovered at such depths.
"These instruments will be able to record water temperatures in the throat of a vent, capture video and low- and- high- resolution still images of the walls of the vent, and record spectral or fluorescent signatures of minerals and bioluminescent life dwelling in these crevices," said Dr. Arthur Lane, manager of the Underwater Volcanic Vent Mission probe at JPL. "The experiment will demonstrate a more sophisticated set of instruments that will be used in late August and September to probe the Pitcairn, McDonald and Teahitia seamounts near Tahiti, where hydrothermal vents range from 900 meters to 3,600 meters (2,970 feet to 11,880 feet) in depth."
The mission will gather preliminary data and serve as a stepping stone in the development of technology and instrument housing required in the search for evidence of life in extreme, high-pressure liquid environments. This information will aid in NASA's proposed efforts to develop technologies capable of exploring more extreme liquid and ice environments, such as Lake Vostok in Antarctica, and eventually, to send instrumented probes to the Martian polar caps and frozen oceans on Jupiter's moon, Europa, and Saturn's moon, Titan.
The discovery of gelatinous material in underwater volcanic vents has opened a new chapter in the search for life and organisms that can survive in extreme environments. Hydrothermal vents and the biological communities thriving in these remote pockets of the sea floor are found primarily at tectonic plate junctions at temperatures ranging from nearly 80 to almost 400 degrees Celsius (170 to 750 degrees Fahrenheit) and at pressures as high as 6,000 pounds per square inch. Typical water temperatures inside the vents range from 200 to more than 350 degrees C (392 to 662 degrees F) and drop quickly to ambient temperatures of about 4 degrees C (39 degrees F) outside of the vents.
To date, organisms living near the vents are known to inhabit only the waters outside of the vents. Layers of gelatinous material attached to the vents are presumed to be organic and the product of living organisms. Researchers have reported that on at least one occasion the gel appeared to emanate directly from a vent throat.
"If there are indeed life forms present inside these vents, their presence may challenge accepted notions of the temperature ranges at which life can function," Lane said.
Last year, Lane and colleague Lloyd French of JPL, in collaboration with Dr. Gary McMurtry of the University of Hawaii, developed and deployed an instrumented probe into the Forbidden Vent Fields near the summit of the Loihi seamount, an underwater Hawaiian volcano. That probe was tested last year in Monterey aquarium's kelp tank before its deployment in Hawaii.
"The probe was capable only of limited visual imaging and temperature determination at depths of approximately 1,500 meters (4,950 feet)," French said. "Since that time, we've been able to increase the depths at which these instruments can operate to more than 4,000 meters (13,200 feet). The free-standing package of instruments will be able to acquire temperature data, video imaging and high-resolution digital stills. This year we're also testing a new light source and spectrographic instrument to see if we can gather more information about the bacterial growth -- what looked like thin veils of jellyfish-like material -- we observed last year around the Loihi vent."
During the mission this August and September, scientists will use the French research vessel L'Atalante to test their instrument probe in several deep ocean volcanic vents in the South Pacific. Using a deep submersible called Nautile, equipped with a robotic arm, they will place the 142-centimeter (56-inch) titanium tube housing the instruments inside several vents in the area to investigate the presence and nature of organic matter.
Once the technology has been developed and demonstrated to work at depths of 4,000 meters (13,200 feet), the probe's external shell will be modified for use in sub-glacial lakes like Lake Vostok, an ancient freshwater lake that appears to extend about that deep beneath Antarctic's surface. The design may also become a prototype for a probe that could penetrate Mars' icy polar caps and search for microbial life, or explore a liquid ocean thought to lie 7 kilometers to 8 kilometers (about 4 miles to 5 miles) below the icy surface of Europa.
The Tahiti underwater volcanic vent mission is a collaboration of the international POLYNAUT campaign in the South Pacific, conducted by the French Institute of Research and Exploitation of the Sea, with involvement from the University of Hawaii and NASA/JPL. JPL's work on the project is conducted for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA.
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