Is there oxygen in water?
Absolutely! Living organisms in
lakes, rivers, streams, and oceans require oxygen to survive! Dissolved
oxygen is one of the most important factors in an aquatic
can oxygen be in the water?
Water, like air, is a mixture of compounds.
Air consists of mostly nitrogen (about 78%) and some oxygen (about
21%). Water is also a mixture. While the overwhelming
majority of water is composed of water (H2O) molecules,
gases become trapped among these water molecules. Mammals
that live on land have lungs that are adapted to extract oxygen
molecules from the air. Fish and some aquatic insects need
a slightly different mechanism for extracting oxygen from the water,
and that is why they have gills. Oxygen is much less abundant
in the water. Air consists of 21% oxygen, but the oxygen content
in water is only 0.001%! Therefore, gills need to be much
more efficient than lungs in extracting oxygen.
Have you ever mixed sugar or salt in
a glass of water? If you have, you know that the sugar or
salt will disappear as it dissolves in the water; unless you mix
a very large amount of sugar or salt in the water and exceed the
ability of the water to dissolve these substances. In a similar
manner, oxygen dissolves in water. When oxygen molecules are
mixed with water molecules, attractive forces suspend the oxygen
molecules between water molecules. The attractive forces keep
the oxygen together with the water molecules and prevent its escape
from the water.
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