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Most versatile oceanic life

  1. Dec 4, 2006 #1
    Can certain microorganisms exist both on the ocean's surface and in its deepest trenches? How would they adjust between the physical extremes?
     
  2. jcsd
  3. Dec 31, 2006 #2

    Ouabache

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    According to this source, there are microbes that can grow under both conditions.

    With reference to microbes in the ocean, those at the bottom are under very high atmospheric pressure (700-800 atm) (atm = atmospheres). At sea level we are at 1 atm. In addition to pressure, many of these organisms will experience colder temperatures at depth compared to the surface.

    Evidently they are quite adaptable.
     
    Last edited: Dec 31, 2006
  4. Dec 31, 2006 #3

    Ouabache

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    The same source I referenced, also describes some of the properties (biochemical and cytological) of microorganisms that favor hyperbarometic (high pressure) conditions.



    I am not aware of specific mechanisms for these microbes to adapt to life near the ocean's surface. In may be simply that their structure and physiology are not impeded at lower pressure.

    Here's one physical analogy. Let's assume you change pressure conditions very slowly. If you made a balloon with a thick semipermeable membrane and fill it with water. Under high pressure it will not implode (membrane will not break), due to both the permeability and thickness of the membrane. At low pressure, the balloon will tend to inflate. However because the membrane is semipermeable, any pressure built up inside the membrane can dissipate, and again the balloon will not explode. It has the capability of maintaining its shape at both extreme conditions.
     
    Last edited: Dec 31, 2006
  5. Dec 31, 2006 #4
    Ouabache,

    Thanks for your excellent research.

    I wonder whether the osmotic (saline) balance is generally different for barophiles than surface cells.
     
  6. Jan 4, 2007 #5

    Ouabache

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    I am not a physical ocean scientist, so needed to read up on variation of salinity in the world oceans. In doing so, I learned of the thermohaline circulation system. Deep ocean waters are colder and have a higher salinity than warmer surface waters. See reference1
    Microbes living in the colder deep ocean would need a mechanism for coping with the higher salinity. Those capable of tolerating or thriving in this higher salt environment are called halophiles

    "Halophiles concentrate solutes inside their cells to maintain osmotic balance with the external environment." A good diagram and description of this is at reference2

    "Facultative" halophiles tolerate higher saline conditions but live quite comfortably under lower saline conditions too. It is likely that those microbes that can live at both the ocean depths and surface waters, are of this type. I don't know the specific mechanisms that allow them to cope under both conditions, perhaps some of our microbiologists can jump in here with their comments.
     
    Last edited: Jan 4, 2007
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