Breathe Deeply
Posted by Anonymous on April 10, 2005
Q: How do fish get oxygen from plants?
A: They get their oxygen in much the same way you do - by removing it from the medium (air or water) in which they live. Water plants produce oxygen during photosynthesis(they don't give off oxygen at night or when not photosynthesizing). Some of this oxygen gets dissolved in the water and is then available for organisms to remove for their own needs. Land plants do the same and we, of course, are able to breathe that oxygen from the air.
Much of the oxygen that is dissolved and available for aquatic and marine organisms has gotten there as water and air have mixed, not just from water plants. In other words, as streams tumble over rocks and waterfalls, and as the wind whips up waves on a lake or ocean, oxygen is being absorbed by the water. So, both water plants AND land plants are providing oxygen for organisms living in water. Thanks for your question.
John Wiessinger ( April 10, 2005)