Ice covers an Iowa pond. Wind blows snow in drifts around
the edge - a barren landscape devoid of life. Or is it?
Beneath the ice is a world still teeming with life. Fish, aquatic
insect larva, frogs and turtles hibernate beneath the mud and leaf litter.
How do they survive in this cold aquatic land deep beneath the icy winds of an
Iowa winter?
Amazingly enough cold is
not the biggest threat to Iowa fish in the winter - it's lack of oxygen. Fish can
survive very cold temperatures as long as there is enough dissolved oxygen in
the water. Colder water holds more
dissolved oxygen than warm water; this means that there is more oxygen
available in the water in the winter. Fish metabolism and respiration
slow down in cold water so they require less oxygen to survive.
Fish are
“cold-blooded”, meaning their body temperature is dependent on the temperature
surrounding them. Therefore when the water is cold, they are cold. They eat
very little and require less oxygen and so they survive the winter in a
semi-dormant state.
Why Don’t Fish Freeze in the Winter?
Why Don’t Fish Freeze in the Winter?
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