Underwater
pond plants are generally very good oxygenators. In fact,
if you take a look at an underwater pond plant on a sunny day that
shines right through the water, you are likely going to see little
bubbles of oxygen attached to the plant’s leaves.
Of course, do not try to take the underwater pond plants out of the
water to see these bubbles – totally submerged, underwater pond
plants cannot exist outside of the water. It does not matter whether
they float rootless beneath the surface of the water or are planted
in the ground at the bottom of the water, they need to be underwater
to survive.
There is actually quite a variety of pond plants. Pond plants range
from those that must remain totally submersed in the water (like the
underwater pond plants mentioned above) to floating plants to ones
that need only a wet mud (like bog plants).