Dr Wilson Lennard on Fish, Food and O2

http://www.ecofilms.com.au Dr Wilson Lennard speaking at a Murray Hallam Aquaponics Workshop on the temperature requirements of fish, food and oxygen demand of fish.

Category:

Howto & Style

Tags:

• Dr
• Wilson
• Lennard
• Aquaponics
• Fish
• Plants
• Temperature
• Food
• Oxygen
• Demand

[dotalessons]

WOW, I can't believe he said that no oxygen exchanges when the bubbles are rising. I have been watching this guy's videos all day, and now I think he's a quack... but perhaps he just got this wrong. In my simple college BIOLOGY 1 CLASS we do an EXPERIMENT where we BLOW BUBBLES through distilled water. We TEST the water FIRST and see there is no carbon dioxide in the water. After we BLOW the bubbles that we exhale through the water we TEST again and BAM CO2. Surprised? Nope.

[flashtoons]

@dotalessons It is not actually the bubbles that provide the oxygen to the water (a common misconception), but it is their disturbance of the surface and ability to provide more water circulation that helps to raise the concentration of oxygen in the tank.

[Starrwulf7]

@flashtoons so which would be better? bubbles breaking the surface? or a spray over the top of the water?

[saeidmomtahan]

Not sure about a couple of things he said here. One is the Bubbles not giving water Oxygen, except when they break the surface, and the other about not feeding the fish for 2 weeks to a month and they;ll be OK.

Otherwise a very informative video

[1aquaponics]

The use of pure oxygen is used to saturate aquaculture water where high densities of fish are held in recirculation systems. Oxygen dissolves into the water as the rising bubbles are forced static and vibrate in the downward flow of oxygen saturator cones. Depending on the rate of contact time will depend on how much oxygen is a) released to the water and b) how far past saturation this level will rise.Carbon dioxide must be removed from incoming water by degassers after biofilter respiration.

[samoht1977]

yes indeed: little to none percentage of gas is diffused into water as the bubble raises to surface - as a matter of facts, if you want to dissolve CO2 in water and put an airstone connected with a carbon dioxide tank, the bubbles will escape the airstone and reach the surface as soon as possible, and most of the co2 escapes in the air. You'll have to go a different path to effectively dissolve gas into water, but "bubbling" gives poor results.

[dotalessons]

@flashtoons Yes, that's exactly what it says in the video, which is the whole reason I posted my comment. With all due respect, you are incorrect and so is Dr. Lennard. If you don't believe me, you can CONFIRM IT EXPERIMENTALLY. I am not sure how they teach science in AU, but here in the US we learn this scientific concept of diffusion in chemistry and biology, and it explains just how gasses diffuse as bubbles AS WELL AS the surface. To say it doesn't diffuse makes no sense in modern science.

[happygameshow]

You would think some of the oxygene would be transfered from the bubbles. Are there any studies on this?

[chickenbonewatt]

Wonderful stuff.