Subject: naive q. re fish oxygen

From: [email-masked] (Anthony Kim)
Date: 15 Jun 1995 03:08:16 GMT

Please excuse this hopelessly naive query, but are fish able to capture 
the O's in H2O as their source of oxygen?  I have been told by somebody 
who raises fish that stagnant water loses its oxygen value for fish.  I 
recognize that this sounds correct, but how is this so?  Can one store 
water, say in a frozen state, thaw it and then use it as a source of 
oxygen for fish?
I apologize once again for these questions.  I realize that I could go 
out and spend hours looking this stuff up, but suspect that some one here 
has it on tip of fingers.

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From: [email-masked] (Jeff Burrows)
Date: 15 Jun 1995 06:52:45 GMT

Anthony Kim <[email-masked]> wrote:
>are fish able to capture 
>the O's in H2O as their source of oxygen?

No. Fish use oxygen that has dissolved in the water.
Aquatic plants provide some, but mainly it comes out of
air.

>I have been told by somebody who raises fish that stagnant water loses
>its oxygen value for fish.  I recognize that this sounds correct, but
>how is this so?

The bacteria that consume dead algae use up oxygen.
They can use up all the oxygen in fact, in a pond or lake.
Warm water holds less oxygen than cold water.
Depends what 'stagnant' means.

>Can one store water, say in a frozen state, thaw it and then use it as
>a source of oxygen for fish?

Can't see why not. 

If you want to know more, check out _Limnology_ by RG Wetzel,
chapter 9 "Oxygen."

	-Jeff.

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From: [email-masked] (Mari Ann Flott Hogas (KVS))
Date: 15 Jun 1995 07:31:52 GMT

Anthony Kim ([email-masked]) wrote:
: Please excuse this hopelessly naive query, but are fish able to capture 
: the O's in H2O as their source of oxygen?  I have been told by somebody 
: who raises fish that stagnant water loses its oxygen value for fish.  I 
: recognize that this sounds correct, but how is this so?  Can one store 
: water, say in a frozen state, thaw it and then use it as a source of 
: oxygen for fish?
: I apologize once again for these questions.  I realize that I could go 
: out and spend hours looking this stuff up, but suspect that some one here 
: has it on tip of fingers.

The oxygen in H2O is not available to any fish. The fish uses dissolved 
oxygen O2.

T.Pedersen

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From: "A.J.Cann" <[email-masked]>
Date: 16 Jun 1995 11:04:59 GMT

[email-masked] (Anthony Kim) wrote:
>Can one store water, say in a frozen state, thaw it and then use it as > a source of oxygen for fish?

Freezing water, like boiling it, tends to drive out most of the dissolved oxygen, or more accurately, AIR (look at those air bubbles in the ice cubes in your martini). It would probably be best to mechanically reoxygenate thawed water before using it for fish.

Dr Alan J. Cann  PhD,   Department of Microbiology & Immunology,
University of Leicester,  P.O. Box 138,  Medical Sciences Building,
University Road, Leicester LE1 9HN,  UK.
Email: [email-masked]     http://www.le.ac.uk/CWIS/AD/MI/ST/nna.html

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From: [email-masked] (Donald Jackson)
Date: Sun, 18 Jun 1995 14:32:47 GMT

In article <[email-masked]> "A.J.Cann" <[email-masked]> writes:
>Freezing water, like boiling it, tends to drive out most of the dissolved oxygen, or more accurately, AIR (look at those air bubbles=
> in the ice cubes in your martini). It would probably be best to mechanically reoxygenate thawed water before using it for fish.

Given the amount of energy required to freeze the water in the first
place, it would be far more efficient to simply aerate in a mechanical
fashion.  In fact, it would probably be less expensive venting pure
oxygen gas into the water than to use some kind of freezing approach.

-- 
-------------------------------------------------------------------------
Donald A. Jackson, Department of Zoology, University of Toronto,
		Toronto, ON, CANADA M5S 1A1   [email-masked]
                (416) 978-0976  Fax: (416) 978-8532

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From: [email-masked] (Lee Lewis)
Date: Mon, 19 Jun 1995 16:24:53 GMT

A worthy inquiry, but H2O is not an available souce of O2 for fish.
Oxygen is dissolved in water, and stagnant water will undergo many
conditions dependent on temperture, primary productivity,
decomposition, and nutrient imput.  I suggest you obtain a textbook on
limnology such as Wetzel and go from there.  Good luck!

>has it on tip of fingers.

Lee Lewis

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From: "Carey D. Cordell" <[email-masked]>
Date: 20 Jun 1995 02:11:15 GMT

I have been told by somebody 
>who raises fish that stagnant water loses its oxygen value for fish.  I 

Dissolved oxygen is measured on a scale of 0-12ppm.  During the 
day plants produce oxygen and use carbon dioxide 
(photosynthesis).  At night the opposite occurrs.  The level of 
dissolved oxygen can be influenced by these factors as well as 
many others ie. decomposing materials use oxygen, warmer 
temperatures hold less oxygen, a cloudy day.