Your Ad Here Your Ad Here
Results 1 to 9 of 9

Thread: A question about Fish

  1. #1
    100%'s Avatar ╚════╩═╬════╝
    Join Date
    Jan 2003
    Posts
    13,671
    So you catch a fish in a net
    lets us call him/her - wasabi
    While wasabi is in the boat and you are untangling all the jellyfish, crabs, seaweed other fish etc,
    wasabi has been breathing pure oxygen for more than 15 minutes

    yet wasabi still lives.

    fish filter oxygen through their gills via the water

    Why can a fish not survive full time above water?



    (the above image does not represent Nemo unless you want it to)

  2. Lounge   -   #2
    thewizeard's Avatar re-member BT Rep: +1
    Join Date
    Jun 2003
    Location
    The Netherlands
    Posts
    7,607
    Lung fish can

    Good to see you back

  3. Lounge   -   #3
    Skiz's Avatar (_8(I)
    Join Date
    May 2003
    Location
    CO
    Age
    40
    Posts
    29,631
    Never thought about it, but probably something to do with how the oxygen is received when passing over the gill.

    Same reason we can "breathe" the oxygen while under water.



    ΜΟΛΩΝ ΛΑΒΕ
    The FST Last.fm group

  4. Lounge   -   #4
    100%'s Avatar ╚════╩═╬════╝
    Join Date
    Jan 2003
    Posts
    13,671
    pressure of oxygen maybe?

    @wzrd

  5. Lounge   -   #5
    Skiz's Avatar (_8(I)
    Join Date
    May 2003
    Location
    CO
    Age
    40
    Posts
    29,631
    You got me curious now.

    /me runs off to Google.




    ΜΟΛΩΝ ΛΑΒΕ
    The FST Last.fm group

  6. Lounge   -   #6
    Snee's Avatar Error xɐʇuʎs BT Rep: +1
    Join Date
    Sep 2003
    Location
    on something.
    Age
    38
    Posts
    22,677
    Quote Originally Posted by 100% View Post
    wasabi has been breathing pure oxygen for more than 15 minutes
    I normally don't bring a tank of that with me when I go fishing. Are you trying to save any fish that might have gill cancer or something?

  7. Lounge   -   #7
    mbucari1's Avatar Poster BT Rep: +35BT Rep +35BT Rep +35BT Rep +35BT Rep +35BT Rep +35BT Rep +35
    Join Date
    Jan 2007
    Age
    30
    Posts
    2,871
    Fish gills are remarkable things, but the conditions under which they function are pretty specific. For one thing, they are rather delicate, and their tremendous surface area (the main thing that makes them work so well) is dependent on being immersed in water to support their weight. Out of water, the gills collapse like wet tissue paper, and very little surface area is left exposed for gas exchange. Most fish, therefore, can only survive a short time out of water before oxygen deficiency catches up with them and they asphyxiate.
    If it were possible to keep the gills supported and moist without being submerged, a fish could survive quite a bit longer, but that isn't physically possible even in a humid air-filled chamber at zero gravity, the gill filaments will simply adhere to one another. Water needs to completely fill the gill chamber to keep all of the filaments in operation. For that matter, the water has to be flowing in the mouth and out the gills in order for oxygen extraction to work properly. If you force water to go in the opposite direction, in the gills and out the mouth, the system only works at about 50% efficiency, since the water flow needs to go counter to the flow of blood for maximum oxygen uptake.
    Many fish species have evolved mechanisms to work around this limitation (usually involving the development of lung-like structures in addition to the gills), and some can go for long periods out of water. But land-based critters haven't developed a comparable ability to breathe while submerged. The lungs of other vertebrates are simply not designed to extract enough oxygen for them to function underwater, where the oxygen concentrations are more than an order of magnitude lower. If water could hold about 20 times more oxygen than it does, things would be different there are apparently a few liquids (though not water) that can hold that much dissolved oxygen, and one can breathe a liquid of this sort, as in the movie The Abyss. But maintaining those high oxygen levels for long in a closed system might be a major practical stumbling block, so I don't think liquid breathing systems are going to be easy to design or use.


  8. Lounge   -   #8
    Sextent's Avatar Version Five
    Join Date
    Apr 2006
    Posts
    4,106
    What does disabled privs mean.

  9. Lounge   -   #9
    Alien5's Avatar μετά BT Rep: +6BT Rep +6
    Join Date
    Jun 2005
    Location
    Posts
    13,107
    not allowed into the invite secton

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •