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    Jupiter Moon's Ocean May Be Too Acidic for Life

    The ocean underneath the icy shell of Jupiter's moon Europa might be too acidic to support life, due to compounds that may regularly migrate downward from its surface, researchers say.

    Scientists believe that Europa, which is roughly the size of Earth's moon, possesses an ocean perhaps 100 miles deep (160 kilometers). This ocean is overlain by an icy crust of unknown thickness, although some estimates are that it could be only a few miles thick.

    Since there is life virtually wherever there is liquid water on Earth, for many years scientists have entertained the notion that this Jovian moon could support extraterrestrials. Recent findings even suggest its ocean could be loaded with oxygen, enough to support millions of tons worth of marine life like the kinds that exist on Earth.

    Researchers have proposed missions to penetrate Europa's outer shellto look for life in its ocean, although others have suggested that Europa could harbor fossils of marine life right on the surface for prospectors to find, given how water apparently regularly gets pushed up from below.

    However, chemicals found on the surface of Europa might jeopardize any chances of life evolving there, scientists find. The resulting level of acidity in its ocean "is probably not friendly to life — it ends up messing with things like membrane development, and it could be hard building the large-scale organic polymers," said Matthew Pasek, an astrobiologist at the University of South Florida. [Photos of Jupiter's Moon Europa]

    Destructive chemicals

    The compounds in question are oxidants, which are capable of receiving electrons from other compounds. These are usually rare in the solar system because of the abundance of chemicals known as reductants such as hydrogen and carbon, which react quickly with oxidants to form oxides such as water and carbon dioxide.

    Europa happens to be rich in strong oxidants such as oxygen and hydrogen peroxide, which are created by the irradiation of its icy crust by high-energy particles from Jupiter.

    The oxidants on Europa's surface are likely carried downward in potentially substantial quantities by the same churning that causes water to rise from below. Oxidants could be of great use to any life in Europa's ocean — for example, oxygen was pivotal to how complex life evolved on Earth.

    However, oxidants from Europa's surface might react with sulfides and other compounds in its ocean before life could nab it, generating sulfuric and other acids, investigators said. If this has occurred for just about half of Europa's lifetime, not only would such a process rob the ocean of life-supporting oxidants, but it could become relatively corrosive, with a pH of about 2.6 — "about the same as your average soft drink," Pasek said.

    This level of acidity would be a significant challenge for life, unless organisms were to consume or sequester oxidants fast enough to ameliorate the acidification, researchers said. The ecosystem would need to evolve quickly to meet this crisis, with oxygen metabolisms and acid tolerance developing in only about 50 million years to handle the acidification.

    Extremophiles on Europa?

    Any surviving ecosystem in Europa's ocean might be analogous to the microbial community found in acid mine drainage on Earth, such as the bright red Río Tinto river in Spain. The dominant microbes found there are acid-loving "acidophiles" that depend on iron and sulfide as sources of metabolic energy.

    "The microbes there have figured out ways of fighting their acidic environment," Pasek said. "If life did that on Europa, [Jupiter's moon] Ganymede, and maybe even Mars, that might have been quite advantageous."

    Others have questioned whether or not rock in Europa's seabed might actually neutralize the effects of this acidity. Pasek does not think this is likely — even if such minerals were present, there is probably not enough of it exposed to reduce acidity by much, he said.

    The calcium-based materials that bones and shells on Earth are made from might dissolve pretty readily in such an acidic environment. However, "one of the interesting possibilities is that they might have used blue phosphates as their bone material instead to evolve large organisms," Pasek said. "If you have iron phosphates, you make a pretty blue mineral called vivianite."

    Pasek and co-author Richard Greenberg detailed their findings online Jan. 27 in the journal Astrobiology.

    This story was provided to by Astrobiology Magazine.

    • Arnold  •  1 day 10 hrs ago
      Scientists thought life would be impossible at the deep ocean steam vents, until they took a look to discover it's teaming with life adapted for the harsh environment.
    • truthsayer  •  Fargo, North Dakota  •  1 day 10 hrs ago
      Who knows what life forms can survive--and even thrive--on other planets in conditions in which earth life forms could not exist?
    • Randolph  •  1 day 9 hrs ago
      I say we go have a look.
    • Tiger  •  1 day 10 hrs ago
      I hope I live long enough for when they discover new life somewhere out there.
    • Mainelyretired  •  Manchester, New Hampshire  •  1 day 10 hrs ago
      And the folks on Jupiter are saying that the amount of salt in earth's oceans is too much to support life.......
    • Earl J  •  Reno, Nevada  •  1 day 10 hrs ago
      Jupiter's moons may be too acidic for life. Not if your an alien with acid for blood.
    • mm  •  1 day 9 hrs ago
      I think scientist center too much on the idea that extraterrestrial life must follow Earth like parameters. Life on other worlds may be based on physical properties that are totally unknown to us.
    • Chuck W  •  Philadelphia, Pennsylvania  •  1 day 9 hrs ago
      Microbes find a way the thrive in low pH environments. Biology doesn't have to fit within the same rules we have here on Earth. They've even proven that Arsenic can subsitute for Phosporus in the DNA of some microbes.
    • Mr.Jones  •  Carmel Valley, California  •  1 day 8 hrs ago
      To those who will say, 'why waste money on this?'..don't try and diminish humanities quest for knowledge because you're only quest in life in the sofa and mindless TV. The discoveries we will make in space, and the technologies we will develop to get to alien worlds will contribute greatly to human society. Its basic human nature to be curious, its who we are. The thought of 100's of billions of stars in the milky way, many with planets that may possibly have life, its so amazing. Then to think that there are billions and billions of other galaxies with trillions of more stars...all different, all unique...its so wonderous. I wonder how many other intelligent beings there are out there thinking similar thoughts, wondering about the infinite.
    • Benjamin  •  1 day 10 hrs ago
      why do scientists think that all possible life in the universe must conform to the parameters of life on earth? Who's to say that alien life doesn't thrive in acidic water?
    • Sebastian  •  Irvine, California  •  1 day 7 hrs ago
      If life were to begin in such an environment, it would adapt. Life is more tenacious than we usually imagine. There are organisms on earth that consume acids and live in extreme heat (the 'smoker vents' on the ocean floor). In my 40-odd year lifetime I remember how 'impossible' life was once thought to be within those tolerances as well.

      We owe it to posterity and human curiosity to look...
    • lawrence  •  1 day 10 hrs ago
      Life as WE know it,are we so egotistical to think that we can tell if there is life under a frozen ocean in a planet millions of miles from earth when we don't even know what's on the bottom of our oceans.These articles always crack me up.
    • Sergent Velcro  •  1 day 10 hrs ago
      Unless if its acid loving life.
    • JRM  •  Cleveland, Ohio  •  1 day 11 hrs ago
      jupiter moon....sounds like a future celebrity's childs name
    • rktompsett  •  1 day 10 hrs ago
      How do they know the lake is 100 miles deep, and yet they don't know how thick the ice on top is???????????????????
    • Mr W.D.40  •  1 day 10 hrs ago
      Scientists here used to think nothing could live near an ocean black or grey funnel too and look how wrong they were about that. They guess, just like everyone else.
    • tadsavage10  •  1 day 10 hrs ago
      purple haze no wonder aliens eyes are so big
    • thomas  •  Los Angeles, California  •  1 day 8 hrs ago
      "relatively corrosive, with a pH of about 2.6 — "about the same as your average soft drink," Pasek said.

      Do we need any other reason to cut way back on soda consumption?
    • MatthewU  •  Dallas, Texas  •  1 day 7 hrs ago
      Cool article. Nice to see something interesting for a change.
    • Scot  •  1 day 7 hrs ago
      deep water robots show life at water depths around volcanic vents to thrive. Life as we understand it? Truth is, there is much about life we do not yet understand
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